Standard SR-H105L transistor radio

My father received this radio from his father in 1961 shortly before being shipped to Africa in the RAF. It had seen a lot of use and over the years had fell silent. It was brought along the last time my parents came to visit, and I started work on it recently.

It had seen a lot of travel. It was filthy and full of dents. First task was to disassemble, remove dents and clean the front grille.

Being aluminum, the dents were fairly easy to massage out. A quick soak in the ultrasonic bath saw all the nooks and crannies clean.

Inside, it received a good clean. Looking at the witness paint nobody had been inside it ever to perform any kind of work- that tallied with what I remembered, it was just boxed up when it stopped working.

I cleaned the dirt out of the tuning circuit, repaired one of the capacitor fins that had a twist, causing it to touch its’ neighbor when tuned more than halfway up the scale which made the circuit go completely silent at that point.

A small bit of alignment adjustment made a very faint radio station come in- a good sign, indicating the set itself was almost operational.

A lot of the resistors had “gone high”, that is their resistance was significantly more than it should have been. This is common to components that have been exposed to heat and humidity for extended periods. This set had certainly experienced that. The replacements are high stability 1% metal film, resin cased which should last a long time. The capacitors were replaced with like-for-like components which brought the set back to life.

After alignment, the set works again as it should. There, picking up Cuba and Mexico on shortwave.

Delco Model 984592 Car Radio – Part Four

I finished wrapping up the last of the items I had on the to-do list for this radio.

I bought a Sprague “Orange Drop” 0.0068uF 1600V capacitor, and upgraded the 15kOhm resistor to one capable of 2 Watts power dissipation.

I decided to paint the front up in the same silver as the rest of the chassis, so a visit to the hardware store saw a can of “cap denotes color” spray paint- a dull military silver. Spraying it resulted in a bright aluminum finish! Not common. So, I drew an outline around the loudspeaker on card, cut that out and painted the area the speaker occupies black, as per original.

I then used some foam rubber I had to make a funnel like it would have originally had. On top of that, I fitted the Front/Front+Rear/Rear loudspeaker selector switch that came with the other radio once I discovered where it attached to the radio. That has now given the option to install another loudspeaker in the car (potentially in the back, or another one with higher fidelity characteristics).

Delco Model 984592 Car Radio – Part Three

Bluetooth board

I finished wrapping up the internals of the radio. I had needed to build a standoff for the Bluetooth board and went looking for something suitable to make some legs from. I ended up going to the hardware store, where a bit of innovation led to the purchase of 4 nylon pipe joiners and some screws that fit into them well, with a coarse thread.

Rear of radio

I drilled some holes in the case and mounted the board in place (bottom right). I wired it in and tested it, successful connection from across the room even with the case fully assembled. I’m guessing the high frequency Bluetooth radio can traverse the cooling holes. If not, I was going to get an external antenna for it.

Radio installed

I went and test-fitted the radio to the car (not an easy task, a few things need to be undone and moved aside for it to fit) which works nicely. I peaked the input cap to the antenna (which goes up and down when the radio is switched on and off) and tested the Bluetooth.

Small blip in the editing was just me cutting 6 seconds of awkward silence as my old phone decided to be slow to pair to the Bluetooth in the radio. I’m still tempted to add a little something else to it. We’ll see. I need to change the buffer capacitor on the rectifier before it sees any serious use but overall, that’s done and ready to go.

Delco Model 984592 Car Radio – Part Two

Old chassis parts

I turned my attention to the remainder of the chassis once the power supply and volume control were built. I took a permanent marker and wrote the part identifier from the schematic plus its capacitance value where it was illegible or facing the wrong way.

Rebuilt chassis

I decided to replace every component. I’m glad I did, because easily half of the resistors were wildly incorrect in value and I’m sure all the old paper/wax capacitors were equally bad. I pushed the tubes in and powered up gingerly. After wiggling one tube a bit to clean the contacts I was greeted with AM static.

Rear of chassis

It was nice to see the thing fully populated with tubes again, and assembled. I cleaned it up a bit (it was rather dusty) and put the face back together.

Front of chassis

It’s far from perfect, but I think it looks okay. I might paint it in the original silver to match the back of the case.

Bluetooth board

I had done a bit of research into Bluetooth modules, and found a nice one that has an audio pass-through using a mechanical relay. When nothing is connected, the relay is connected in such a way that the audio in passes through to the output connector. With a Bluetooth device paired, it engages and disconnects the input audio and sends its’ own generated audio out. Ideal, as the radio can function as original until a Bluetooth device is connected, then it’ll feed through from that. I had started work on this as you can see; the connectors de-soldered from the board and a rather large ferrite core inductance choke connected to the power input. There was quite a lot of hash being picked up and send back into the radio and out the loudspeaker through the heater circuit. I added that choke and a couple of high value capacitors to the heater chain which silenced the noise. I replaced the audio wire that goes to and from the volume control because the original had a short circuit break somewhere inside, and had the out and back signals twisted together, inside a shield. When it was just an AM radio this was perfectly acceptable but when the Bluetooth module engages, the amount of cross-talk from the radio circuit made the end result unintelligible. I separated the radio output and volume control mix return wires in their own shielded, individual wires. That resolved 99% of the interference issues and made the audio output very clean.


I set the radio on the side and streamed music to it for several hours. The quality of the audio is impressively good; the design of the power amplifier circuit is good and while not quite a full 12 Watts due to a lower plate voltage than usual (at a guess it’s about 8 Watts) it is a good, hi-fi design, and with a full-range loudspeaker the sound it produces far surpasses any expectations of the device. Last to-smile-at feature will be in the car, installed. With my phone connected, it represents a hands-free calling system… not a bad option for 1951!

1951 Delco Model 984592 Car Radio – Part One

When I bought my Chieftain, the original radio was long-since gone, replaced with a more modern stereo cassette-player. The new one was designed to look a little “retro”, but really was better suited to a mid 1970’s vehicle than one from the 1950’s. At a guess, when the vehicle was converted to 12 Volt the converter either realized that the radio was incompatible, and required a converter to operate at 12V or they powered it up and it let all the magic smoke out very, very rapidly…

What happened is mere speculation- I’m guessing the former because there are no marks up inside the dash to indicate there was any electrical fire. More likely an upgrade was decided upon.

So, that was pulled out pretty quickly because it was horrible. I had a bit of a thought and went took a look at the radio sets used in these cars and similar cars of the era. I put a bid in on a radio with the correct knobs to match the rest of the dash and won it. It had been stored damp, and the tuner assembly had suffered zinc pest, a crystalline breakdown of the zinc due to lead impurities and moisture. Undeterred, I did my due diligence and determined that the 1956 Buick “Sonomatic” radio held enough in common with the 1951 Pontiac set that it could be used to supply parts to repair the broken tuner assembly and also liberate the all-important high-voltage transformer to convert the set natively to 12V operation.

Way back last year I made a start on the set then shelved it following a trip out of state, where I got distracted by the Zenith radio in the previous post. Having completed the Zenith, I was able to clear my bench…

Delco radio on the bench

…which was promptly filled up with Delco radio. I took a look at it and tried to figure out exactly what I had done some 14 months earlier. Having pulled the Riders schematic up for both the Pontiac and Buick radios, I set about re-familiarizing myself with both the schematic, the chassis and the work I had done and then stopped.

Power supply work

I took a look at the socket for the vibrator that I had made a repair to previously. I saw that the center lug needs to be connected to chassis, so I bent the tang down and… snap. The thing broke off where the brass had work-hardened. So, I split the two pieces of phenolic apart and began work on a solution.

Socket repair

I hammered a fork connector flat, bent it up in profile to meet up with the socket. I then took my propane torch and soldered it to the chassis- at this point I could use high heat because there was no phenolic in place. After it had cooled and made a very strong connection, I slid the phenolic in under it, with the lug in place, which was then soldered with a less intense heat from my iron so as not to char the insulator.

Reassembled connector

The rest of it then screwed in place. While not as strong as it was originally (and missing two brass rivets), supporting the back while inserting the vibrator is adequate to prevent it from breaking further. On the other side there is a heavy 6-fingered spring holding the vibrator secure so there is very little mechanical load on the pins.

New capacitors

I then went on a spending spree and bought the 12V equivalents of the original tubes (sadly the Buick set used 12V6 output tubes and had no others in common- but the Pontiac set used 7C4 output tubes, which are 6V6 with a Loctal base), along with a full compliment of new capacitors.

The Analog Gang

While I was waiting for the parts to arrive, I got bored with the old ones and utilizing a bag of googly eyes I have in the drawer of my desk created The Analog Gang, the meanest bunch this side of the B+ rail…

Filter cap

The first thing I decided to tackle was the power supply. I wired the vibrator and the power transformer up, connected an old 9V battery to it and the output pegged my meter set on 1500VAC range. Safe to say, unregulated, the power transformer was still good. Once the capacitors arrived I decided to tackle the 3-in-1 HT rail capacitor. Originally the can was stuffed full of a big wad of foil and paper, comprising 3 independent, common cathode capacitors. One 10uF, one 15uF both at 400V and a 20uF 25V one. This had all gone bad with age, so the can was sawn open, gutted, cleaned up and the base drilled out to give access for new wires to be threaded through.

New multi-cap

I bought short but fat capacitors, high temperature, 450V. Because there is the possibility of a solid-state vibrator in this set’s future, I needed to add more filtering to the B+ high voltage lines as the SS devices create more hum than the original mechanical ones. So, I used 2x 40uF B+ capacitors with a 20uF cathode filter.

Multi-cap all together

The can was all polished up. Being aluminum it came up looking pretty. The values stamped into it are wrong but the connectors do lead to the correct part. With the back off the inside of the radio looks a little more original.

Rebuilt HT supply

I finished up the HT supply. I will need to change the resistor and the cap marked TOPMAY because the value of them are too low- the resistor is meant to be a 2 Watt item (that’s a 1/2 Watt) and the buffer capacitor should be 0.007uF, not the 0.005uF that’s in there. As the value is quite critical I have been advised that 0.0068uF is closer and should be substituted.

Cleaning tool

In the picture above this one you can see that there is quite a lot of wax on one of the socket pins on the right-hand side. This is from the old buffer capacitor, which had failed quite spectacularly and sent liquid wax all over the inside of the HT supply case. I shredded the top of a Q-Tip onto a small jeweler’s screwdriver, dosed it with isopropyl alcohol and used that to clean the wax out of the connector.

Wax on, wax off

With that thoroughly cleaned and the socket bent back into shape, I was able to give a test of the HT supply properly, with the rectifier in place.

90 Volts

Using a half-dead 9V square battery, I was able to bring up 90VDC on the high voltage side of the power supply. This was immediately considered a success.

Rectifier tube, with lid off

Out of curiosity, I removed the metal lid off one of the 0Z4 rectifier tubes I have and powered it up. It glows quite spectacularly! It is a cold-cathode device, rather like a neon sign tube, except there is an anode connection and two cathodes. As the voltage rises on one, it reaches a critical threshold where the argon gas inside ionizes and begins to conduct- releasing the bright mauve glow. This is encapsulated in a metal shield to try and reduce RF emission.

Volume and tone control

With the power supply operational, I started on the next loose piece. I had removed the volume and tone control previously, so figured it would be a good place to continue. It’s a triple stacked item, with a power switch operated by the volume control, the volume potentiometer and a 4-position switch for tone control.

Rebuilt volume and tone control

I cleaned it up, removed the old components and replaced them with new. I’m glad I did because the resistors had all drifted well out of spec (2 were more than 50+ more resistance than they were marked for). In working out how it was all assembled and operated, I determined one thing that made me smile- the set has rudimentary loudness compensation. At low volume, the bass and treble are boosted, with the mid tones reduced. As the volume is dialed up it reaches a transition point on the track where it is tapped (25/75% of the sweep) where a different capacitance takes over the tone control and allows full treble. Simple, but effective. With that complete, I moved on to rebuilding the main chassis.

Zenith/Ford Glovebox radio

A while back now I took on a project for a friend. A 1933/34 Zenith “Glove-box” automotive radio.

Vacuum cleaning radio

This is the first picture I took of it- not a very good one but you can see that it was rusty, missing the knobs and generally full of old dead spiders and dust.

Upper chassis, removed from case

I stripped the radio down. The lower half of the chassis is at a 45-degree angle and houses the speaker and power socket. That was removed so it would sit flat. I pulled the dial bezel and glass aside to safety as the glass was unbroken and in good condition. The dial face was equally in good shape so was removed and stored safely after a gentle cleaning.

Repainted bucket and cleaned dial

I repainted the bucket the dial sits in and finished the face.

Original wiring and components

I tested all the wound components and they were good. That was good because they’re the hardest parts to source and replace if they are bad.


I cleaned up the screws. In the image, the one on the right looked like the one on the left to begin. The set has some nice panel-headed screws that hold the chassis in the frame that are prominent on the front and sides. So, I spun them against a file and de-burred the surfaces, polished and nickel-plated them.

Dielectric, wax and a dead spider

I started to clean the power supply chassis up. The capacitors were past their prime when the set was in operation and the mess there is a mixture of wax, capacitor dielectric paste and dirt- the set was also home to quite a few spiders, all of which were petrified and crispy. The failure there where the main smoothing capacitor had vented was also likely the reason for the set being removed. that would have caused the fuse to blow every time it was switched on.

Cleaned power chassis

The power chassis cleaned up well enough to continue. There are a lot of high voltage parts in this section, all of which tested bad. It also runs quite warm, being encased in a metal box with no ventilation- to prevent RF noise.

Inside volume potentiometer

The volume control also tested bad. the schematic showed it to be 1 MegOhm from end to end but it had dropped in value (odd behavior, usually they go up) which meant that the set would never be adjustable to quiet, it would start at loud and get louder. I had never seen a potentiometer like this before- a good design in theory. Normally in a carbon track device there is a phenolic wafer with a carbon trace printed on it, and a metal finger that touches the carbon as the center tap. As you dial it round, the finger slides across the carbon. Eventually the track wears out and the potentiometer becomes noisy and unreliable. This one had a carbon track and a spring-steel ribbon that was slightly smaller than the inner track. A finger pressed the ribbon against the track, making the contact and the only friction was of the finger against the spring steel, which would last a very very long time. As the ribbon was only pressed against the carbon and not dragged, it would also last. I think the carbon track, printed on cardboard, had become damp and deteriorated that way. so, I replaced the volume control and power switch with a new one, modified to suit.

Main chassis

I replaced all the old paper and wax capacitors and after more than half of the old resistors tested bad (most had either gone open circuit or had drifted very high resistance) I replaced them all with high stability metal film 1% devices.

First test

I managed to get the old mechanical vibrator apart, clean the contacts and get the high voltage to come up operational. First test was positive, nothing smoked up and I was able to just about get a local radio station to come out of the speaker, proving all stages of the radio were at least operational. The vibrator, which interrupts the input to the power transformer providing a rudimentary AC, was very loud, almost intolerably so. So, I purchased a solid state one which is very efficient and mostly quiet, changed the socket for a new porcelain one (the old one had 6 pins, this one a more standard 4) .


With the electrical portion of the radio working as expected, I set about tidying up the cosmetic parts of the case. The face was rusty, so I took to it with my DA sander and removed the pitting and rust.

Bare metal

I left the smaller dents because they are part of the original character- there were a couple bigger dinks that I knocked out. All down to bare metal, it was time to prime and paint.

Craqueleure black

The original paint finish was wrinkle-black. I bought some of this horrible finnicky paint and redid the front in it. First revision above, part of it bubbled (it has to be heated) and the rest went psycho-insane and wrinkled up like craters on the Moon. Second revision went much better and has the correct finish.

Paint revision two, front panel.

I then redid the rest of the case (three attempts for the main case, another three for the lid).

Beauty ring

I cleaned all the rust off the dial beauty ring, polished it and clear-coated it.

Grille cloth

I was able to carefully remove a very fragile remnant of grille cloth from where it was attached to the metal behind the grille aperture. I washed it and the pattern became visible- most of the cloth had rotted and was just threads. I found a company in Shreveport, LA who was re-manufacturing original Zenith grille cloths, so bought a length. A very rich color, in shiny thread as per the original.

New grille cloth

The grille cloth, glued to the freshly painted case. Looks most excellent.


I got the Dremel out again, removed the rust from the clip, polished and nickel plated the clips that hold the lid on.

Reinstalled chassis

I bought some nice yellow cotton covered cloth to fit and replace the very dry, crispy original wires that led to the tube top caps. This keeps the nice period look but gives new wire. All re-aligned for its’ home in the case, picking up a bunch of local stations during the day.

Finished radio

A couple of new original-style knobs finished the radio off, and an auxiliary-in socket for when the AM radio has nothing to offer.

Pontiac Renovations, Part 29.

New workshop lighting

I finished up the workshop by replacing the original light fixture with a newer one. I still want to fit more lights but a couple of 40W tubes work for now. Better than having to fight flipping the light switch repeatedly to get the room to illuminate.


I bought a new set of points to fit in the distributor. The old set was a bit pitted (which did clean up) but the fulcrum was worn and the points would not align very well by themselves. I’d been seeing some misfire at higher engine RPM so figured it was worth a shot at replacing the points. It didn’t help much but it did at least eliminate that as being the cause.

Vacuum motor

Having been parked up int he garage for a while, the wipers stopped working. I took the motor apart and tried soaking the rubber seals in mineral oil to try make them swell up a little, but this was to no avail. It really just needs to be rebuilt. There is a firm in NY state that’s doing Trico wiper motor rebuilds so they’re on the to-call list.

Driver’s side brake drum

After the wipers, the car went on a little hiatus. I decided to finally do a little work on the car and adjust up the driver’s side brake because it would snatch and lock the wheel if the brakes were pressed moderately hard, instead of braking progressively. This is a sign of badly adjusted or contaminated brake shoes in drum brakes. I jacked the car up, pulled the wheel off and took the bearing race to pieces.

Front outer wheel bearing

With the outer bearings removed and cleaned I took a look at the brake shoes. They were greasy from where the bearings had been over-packed, which is never a good thing. The shoes also showed signs of having over-heated and the lining on the leading shoe is beginning to fall apart.

Bad shoe lining

Given that, I turned my attention to the drum, which was in good shape, albeit very greasy.

Crab pan

I traded a six-pack of beer for an old, beaten up aluminum pot from my neighbor, which I beat back into shape with a lump hammer.

Brake soup

I put the brake drum into the pot, filled it with dish soapy water and boiled it a few times to remove the grease. This proved most effective.

Fresh brake drum

I beat the bearing dust cap back into shape and painted the lot to stop it from flash rusting.

Brake fluid

I had tried the brakes with the drum removed and saw that only the rear shoe was being operated. I held the rear shoe and prevented it from moving and applied force to the pedal, which freed up the front piston. The wheel cylinder then began to leak badly from the newly moving piston. No good! Time for new hydraulics.

Warning lights

I made a little warning light panel to fit under the dash. The alternator has provision for a no-charge light (an accompaniment to the ammeter) and someone had fitted an oil pressure switch to the main oil gallery (in accompaniment to the oil pressure gauge).

Letter punches

I borrowed a set of letter punches and used them to press an impression of letters into the plastic of the light lenses.

Warning light panel installed

I decided on era-appropriate descriptions- GEN (for GENerator) and OIL. I dabbed a bit of black paint into the recessed letters.

After purchasing some correct Wattage bulbs, both lights function as expected. The OIL I decided to be orange because it is bright and that one I am much more concerned about. the oil pressure gauge is heavily damped, so doesn’t give a quick reading, the light comes on immediately below 5 PSI. The GEN light flickers and comes on at low RPM which is normal for this engine. I would need a smaller pulley to prevent that from happening, but it charges well over 800RPM.

Dual points conversion kit

Turning back to other issues with the car, I went on the look for a replacement distributor or vacuum advance plate. Someone turned up a new-old-stock dual points conversion kit, which I bought. This solved a few problems, primarily the lateral wobble in the old plate because it was bent and worn. Second, it extends the life of the points and decreases the need for routine inspection, cleaning and gapping. Third, it has an added benefit of extended dwell which allows the coil to saturate fully at high RPM (admittedly much higher RPM than my engine can achieve but the principle is sound).

Single points distributor

I took the distributor out and dismantled it.

Painted distributor

Being as it was out, I cleaned the rust off and painted the body.

Dual points distributor

I fitted a new condenser to the set and reassembled it with the dual points plate in, which moves very smoothly compared to the old one and also keeps the points in the correct plane with respect to the cam.

Spark wire manifold

Continuing with the ignition system, I removed the spark wire manifold, which was missing a part and also was all dented and dirty.

Straightened sheet metal

I hammered the sheet metal back into shape. I turned my attention to the lead-out tube which was missing the lower half (the curved section).

Lead-out tube lower panel

I bent, hammered and shrunk the metal into shape.

New spark plug wires

I painted it all up and fitted a new set of spark plug leads.

Wires fitted to engine

I gave a test-fit and that showed a significant improvement over the old set of leads; 4 new spark plugs of the 8 that I had ordered arrived, so I fitted them, switched out a couple of the older plugs and managed to get the engine running on 8 cylinders again. I need to tidy up a little bit but that’s progress, at least.

Back to cosmetics, the horn push had always been a sore point for me- the center of the emblem should be bright red, but with sun and time it had faded to a pale brown. I managed to take the thing apart by carefully bending the lip of the chrome surround ring up.

Lacquered emblem

I cleaned the old lacquer off, masked up and painted new red lacquer with the remnants of the red in the can I used for the rest of the badges on the car.

Reassembled horn push

I polished the clear cover as best as I could and reassembled it. A significant improvement, especially considering it’s right in front of you when you sit in the driver’s seat. Shortly after that, a mysterious benefactor sent another one that was in very good condition, with almost no crazing to the lens, which was very kind.

Slam panel

finally, I took the time to rebuild the cable and latch for the slam panel. All reassembled, the hood finally closes correctly and can be pulled open from inside the car.

Pontiac Renovations, part 28.

So, a new year and new things to do on the car. After having done a little work to clean some of the paint I decided to try mix up a color match for the 1957 Ford blue that is on the car.

The first attempt was not too far off but didn’t look right- the blue dried a lot darker than it mixed up. I tried again.

The second attempt came out a much closer match. Acceptably good, I touched up a few more of the spots where the paint had been knocked off, to try and protect it a little.

I touched up the back of the car to tidy it up a little. It all needs cutting out and new metal letting in but that’s a little ways off happening yet. It makes the car look better from ten feet away, at least.

I also made an attempt to flatten out the faces of the intake/inlet manifold, as it was not sitting well enough in all places to seal. Apparently common with long manifolds like this, it has warped with age and heat/cool cycles. I managed to get all but the center two exhaust ports flat enough to sit into the gasket; really it needs to be put on a milling machine and be milled down like the deck of an engine block. For now it is good enough that I can double-gasket the center two ports to get them to seal.

A little bit of pleasant weather allowed me to bring the car outside and start smartening the paint up. The roof has lost a lot of the clear lacquer, and I was trying to figure if I had wanted to polish the paint or not. If I were to polish it, re-applying clear lacquer would be difficult without almost completely stripping the paint back. In the end I decided to polish it up to seal it and protect what color is left. The mid-blue on the rest of the body responded well to wet-flatting and polish.

The roof has a nice gloss to it when finished well. I just need to carefully blend in the edges of the remaining clear coat.

The rear light lenses on this car are unique to the year- they are very bulbous compared to the preceding and following years, and are slightly smaller so the more common 1952 lenses, popular with hot-rodders are available easily and cheaply but these are not. The sun had done a number on these so I decided to try sanding one down and giving it a few coats of red lacquer to try and get a little more life out of it. the result is not perfect but looks much better than it did. I am also considering finding some reflectors to put inside because they are quite dim, even with LED’s inside.

I soldered in the brass overflow tube to the radiator and polished the radiator cap up. I do need to replace the cap as it is the wrong pressure (4lb instead of 7lb) but in the interim it looks better.

I took the front right brake to pieces because it was not really providing much int he way of braking effort and was quite snatchy. The lower adjuster was fairly easy to free up but the top one which has a large nut to hold it in place was stuck fast. I ended up having to borrow a larger socket from a neighbor and with most of my weight on a 5 foot extension bar finally managed to get it to free off.

Only a small portion of the threads had gone rusty but that, coupled with it having been done up by a gorilla, had meant it took upward of 2500lb/ft to undo. I cleaned it up and refitted it.

Armed with a copy of the manual pages pertaining to the brakes, I checked the shoes were free to move, both brake pistons were free to operate and then set the clearances and adjusted the shoes.

A few things arrived in the mail. first, someone sent me a gift of a replacement dome light cover as mine was long gone. This is a Chevrolet item but is not dissimilar to the Pontiac one and fits the same light assembly.

More goodies, in the form of a new “diode trio” for the alternator- the purpose of which is to feed half-wave rectified DC into the voltage regulator circuit to allow it to boost or drop the armature winding on the rotor and thus increase or decrease the output of the alternator.

Apart came the alternator again. Buried down in the depths is the offending article.

The diode trio was replaced (orange and black pieces, black being the new one) and the alternator reassembled. This provided a good output- I wired it temporarily to the ignition switch to get it to make the ammeter move. What I didn’t think about was how it was actually wired in; when I switched off the ignition the alternator was disconnected from the battery and no longer had a regulated reference so went into a free-running wobble which fried the 12-to-6 volt converter unit for the fuel gauge.

The car had also developed a bad misfire once it warmed up a little, resulting in clicking valve followers. I decided to pull the head off and soak the valve stems in Marvel Mystery Oil (which is essentially just mineral oil) to see if they would free up.

The oil was unsuccessful in freeing the valves up adequately- with the engine cold they would work perfectly for about 15 seconds before getting stuck open. In the interim I had ordered a replacement DC-DC converter for the fuel gauge which thankfully got it working again. I prefer it to have taken that out rather than burn the gauge coils or sender unit up.

My parents came to visit just before Christmas break, so the car took the sideline for a little while whilst much needed repairs were done to the house and workshop. The decking was replaced, and the roof repaired to the workshop and the walls replaced where they had rotted out as a result of the leaky roof.

The workshop was made significantly more airtight than it was, the little window unit air conditioner was taken apart and the mud dauber nests all removed meaning it had a chance of dehumidifying and cooling the area.

I painted the walls and doors white to cheer them up a little. After having done that I decided that it was too plain and needed something to make it a bit more interesting.

I bought some oil paint and painted a mural of the car, which was a nice distraction from the fact the car wasn’t running well.

I stripped the top end off the engine again and removed the valves (with thanks to Lloyd from the H.A.M.B. for the tool), a couple of which were very very difficult to remove from their guides.

I cleaned all the valves up, and let the collets and springs soak for a while to clean them up also.

I made a tool from an old toothbrush and a length of wooden dowel.

This allowed me to soak cleaning fluid down through the guide and scrub away any dirt.

I then made a second tool from another piece of dowel and a worn-out piece of 220-grit emory paper. That was spun down each guide to gently hone it, then the brush used to sweep up any debris.

I then started lapping the valves into the seats- they had been replaced by the previous owner but not matched (nor cleaned, from what I can tell) so this helped until I reached the third exhaust valve which didn’t want to lap in evenly. It turned out to be bent, from having hit a spark plug- guessing someone put the wrong length plug in and started the engine.

I ordered a replacement valve and once that came in the engine was reassembled.

The valves are awkward to get at even with the correct tools, but eventually I put them all in and set the clearances by eye.

I bought some tube and fittings and reconnected the oil pressure gauge. Now all my gauges work (though at 14.4V on the alternator the temperature gauge over-reads significantly. In that picture it should have been pointing just below 180) which is a nice thing to have.

I connected up the vacuum system from the manifold through to the pump and up to the windshield wipers. The vacuum motor is tired and really needs a rebuild. The washer pump is also similarly tired so work needs to be done there to make better.

It is nice to see the parts going back on the car though. Each makes it one step closer to working well.

Onward and upward. With the air filter removed the Carter makes a nice noise with the throttle opened up. It does run smoothly now.

Pontiac renovations, part 27.

With the engine and transmission back together, I decided to finish up doing the things that are difficult to do with the engine installed.

Looming tape

I wrapped the wires that are now in place (lights and such) and tidied up under the hood.

Delco 10si alternator ident

I undid the clamp bolt and cleaned up the body of the alternator. 1100542 shows it’s a Delco 10SI, 63 Amp remanufactured unit.

Alternator in pieces

I stripped the alternator down, thankfully Delco have the manuals online for their older models. There are 4 individual parts inside the end case; the rectifier bridge (silver finned heat sink), a capacitor, the voltage regulator (white plastic) and diode trio (orange).

The principle of the alternator is moderately simple. A magnetic field in the armature, created by passing an electrical current through a couple wound around it, rs rotated by the engine next to a series of wound coils (stator). As it moves past each coil winding, the change in magnetic flux generates an electrical current in the coil winding. As the magnetic field moves towards the coil, a positive field is created, as it moves away, a negative one is created. There are usually 3 windings (either in a Y or Delta configuration) so an alternator creates 3-phase alternating current. This is no good for a car battery which is direct current, so it is rectified through a bridge rectifier set of diodes before it’s connected to the battery.

This output is connected through the diode trio to the voltage regulator. The voltage regulator changes how much current passes through the winding in the armature, making the magnetic field stronger or weaker depending on how much voltage the stator coil windings produce.

The diode trio tested bad- two of the diodes are open circuit (do not conduct at all) and one doesn’t diode any more so that should be the root cause of the alternator not charging. The voltage regulator isn’t getting the voltage it needs from the output so isn’t applying voltage to the armature winding and the alternator is producing very little charge.

Valve lash adjustment.

I readjusted all the valves. The manual states to make sure they are all set correctly.

Installing engine

I bought some new bolts for the rear engine cradle, rated 8 (strong for shear force) with the correct fine pitch thread. That was cleaned and reinstalled and the engine wired in temporarily.

Securely mounted

It was good to see it back in. I set about reinstalling the ancillary parts and started to look at the manifold, which has never sealed well. It is made in two parts, with a “hotspot” flap in the exhaust that directs the exhaust around the outside of the intake by the carburetor before letting it escape though the downpipe.

Heating bolts

It was suggested that I split the two parts and re-settle them to allow them to seat square against the engine. Easier said than done, as all four bolts were seized and all four broke upon attempting to undo them, despite heat and releasing oil.

Drilling out old bolt

I carefully center punched the remains of the bolts and started to drill them out.

Cleaning threads

I then used a thread tap to clean the last of the bolt from the threads.

Original threads

The two most accessible bolt holes were straightforward, but the two at the back are obscured by the casting of the manifold and proved impossible to drill out straight. I ended up drilling them oversize and tapping the holes with a new thread.

Reassembled manifold

I made a temporary gasket and reassembled the manifold, which allowed me to put it back on the engine. It leaks but the correct gaskets are many times thicker and take up a lot of the gap.

Radiator hose

The original lower radiator hose was so badly rusted to the spigots I had to cut it to remove it. I took the old hose to the auto parts store and a replacement with the correct bend in was sourced. I cut it down to length and put the anti-kink spring inside.

Engine plumbing

I finished putting everything into the engine compartment that was required to make the engine run. I filled the radiator up with water and connected the fuel.


The three gauges that are currently connected all worked. Fuel gauge reads a quantity of fuel in the tank, engine temperature reads as it warms up and the ammeter reads a discharge.

First time outside in a while

I connected up the propeller shaft and took it for an experimental drive. The gears changed, it went forwards and backwards and overall worked.

Throttle linkage and spring

The throttle linkage was very sloppy and had a lot of free play. This was causing the gas pedal to move the gearbox modulator lever quite a distance before the throttle began to open, with the net result the gears were holding until high speed before changing and under light throttle were quite harsh.

Tight connection

I added some springs to the connections to hold them all in line, peened the bar of the throttle down to remove the slack and readjusted eveything as per spec. The result was as hoped for; gears that change gently under light throttle and more positively and at higher speed with heavier application of the gas pedal.

Testing wires

I started to track down a misfire under light load, I checked the spark wires for continuity. They are all good, but the insulation is poor so I think new ignition parts are required (cap, arm, coil, wires, plugs).

Water, soap and 2000 grit paper

I turned my attention to the cosmetics of the car because the weather had turned fine. I started to wet-flat the paint with dish soap, plenty of water and 2000 grit paper.


After finishing with the paper, I started to polish the paint with scratch remover cutting compound, then a finer grade polish, and finally wax.

Regaining a shine

The day became too hot to continue, as the polish was just flashing off, so I stopped. The improvement is noticeable.


I also masked up and painted the driver’s side hubcap with red lacquer. That made an improvement also.

Shiny paint

I loaded the car back up into the garage, and looking across the hood, I was able to smile. It is beginning to look nice. Much more yet needed, but this is a good start.

Pontiac renovations, part 26.

Work continued on the gearbox with the arrival of a box of parts.


A brand new oil delivery tube (for the clutches), a pair of clutch lids for the drums, new clutch friction material and steel packs, a set of new bearings and some other odds and ends.

Front servo

I started with the front servo, which was due new oil rings and a new main spring (the original fractured).

Front servo piston assembly

The front servo has a couple of independent pistons inside, separated by a couple of springs. It is all held in place by simple geometry and during assembly everything liked to get out of line. After a few failed attempts where springs launched themselves or the piston fell out past the rings I magnet to get it all reassembled.

Front servo rebuilt

I fitted new bearings (more on that later…) and started rebuilding the reverse gear mechanism.

Reverse piston return spring

The reverse piston is pushed back from being activated by a wavy spring steel washer. The original had broken in half. This appears to have been the reason the gearbox was taken apart originally. The broken part appears to have come free and become mangled up in the rear epicyclic gear set.

Brake light switch

I took a bit of a break from mechanical parts of the gearbox to work on the wiring. I fitted the replacement new brake light switch, as the old one had failed.

Headlight loom

I bought some new wire and rebuilt the headlight loom.

Turn and park light wiring

I redid the turn and park light wiring, as there were a bunch of Scotch-Lok connectors and excess wiring in the harness. I added a good ground and connected it all up.

Light wiring block

The wiring was then terminated at the rebuilt terminal block.

Bulb wiring terminal

I ordered some rivets, which are soldered to the end of a wire to form a terminal in bulb holders.

Rebuilt bulb holder

With the bulb holders rebuilt, I started to run new wiring under the dash.

Wiring spaghetti

This began to turn into a complex task, despite the wiring in the car not being too many circuits. The brake lights and front indicators all wire through the turn signal switch.

Turn signal flasher and switch connector

The original connector was loose to the switch and the wiring was a little crispy. I took the connector apart and started to de-solder the wiring.


This demonstrated just how flammable the old wiring is- it caught fire very easily and did not put itself out.

Flasher circuit harness

The harness was loomed up neatly, with wires for the brake lights, front indicator bulbs, wiring to the brake light switch and wires for the dashboard telltale lights.

Dash harness

I built the loom up for the dashboard and connectorized it for easy connect/disconnect.

Dashboard lights and gauges

I connected the dash up to test. All the lights work, the dash dimmer operates, the ammeter registers current and even the fuel gauge registers not-empty.

Clutch pack debris

With wiring completed, I turned my attention back to the gearbox. I pulled the clutch packs apart and discovered a lot of metal debris inside, a lot of melted alloy.

Annular piston

I fitted new bearings to the clutch pack after cleaning it all up. The new parts fitted together nicely.

Clutch pack reassembly

The clutches are made up of a number of rings, friction material rings with centered teeth that grab the sun gear and steel plates that locate on pins to lock the gearset solid and stop the thing being in reduction.

Clutch pack rings

With all the clutch rings in place, the piston assembly then sits in the top and is held is place with a large snap ring.

Front and rear drums

The drums then locate onto the fluid delivery sleeve, which in the book calls for a special tool to compress the oil rings down for easy assembly.

Improvised tool

I improvised and wrapped wire around the rings to hold them compressed.

Front drum on

The front drum went on easily because access is good.

Both drums on

The rear drum… not so much. However, both fired on successfully after a long fight.


I then started to refit it all into the case. I then started to run into trouble with it all not fitting. I decided I needed to order some more parts to adjust lash.

Dirty chrome

While I was waiting for parts I went back to working on the wires. Part of that included wiring for the heater fan. The fascia panel was particularly dirty so that was cleaned up.

Dirty panel

The switch for the fan was rewired at the same time, the switch itself being in good condition.

Clean panel with switch

I rebuilt the dome light because the switch did not work. It had corroded and the contacts had become poor and had caused the plastic to become distorted.

Dome light switch

A little work with a craft knife and sandpaper saw the plastic in the correct shape again with the slider being spring loaded against the terminals.

Dome light switch operational

I then had to rebuild the driver’s door switch as it has seen some water ingress and was also corroded.

Door plunger switch

Now the dome light and trunk light both operate (though the trunk light mercury switch is unreliable).

Antenna installed

I fitted the electric antenna I had bought and tested operation, successful. No radio yet installed but it’s ready to go.

Bent steel

I had wanted to purchase an alternator that is fitted into a case that looks like the original dynamo generator, for two reasons. Firstly, the look of it and second, it utilizes the original mounting points. However, those are very expensive so instead I decided to build a bracket that mounts to the original points but correctly holds the alternator in line. Previously the alternator was mounted upside-down, with the main mounting point providing no reaction torque and the adjustment bolt hole holding it all up. As a result the alternator was sitting at an angle and the belt was slipping.

Alternator bracket

The new bracket holds the alternator in line with the pulleys and allows now for correct adjustment.

The alternator warning light won’t go out and I get just over 13 volts from it, so further investigation is required.

Timing marks

While I was working in the area, I cleaned up and painted the timing marks. There was a blob of white paint that covered all 3 marks (at 3 degree intervals). I found the timing was set very far off, close to 45 degrees. I re-indexed the spark plug wires and discovered the engine was very happy to idle smoothly when the timing was correct.

Clamped vacuum advance

I saw with my timing light that the ignition wasn’t moving with manifold vacuum. Discovered someone had clamped the vacuum advance arm with the condenser bracket. I freed that up and found the screw holding the condenser was far too long, had fouled the mechanism underneath and the plate was bent. I corrected that so now it advances but it does move a little far. There is a bendable tab that limits how much advance is applied, which will need modification to prevent light throttle from being lumpy without impacting idle.

Headlight beauty ring clip

Between times I had a thought and decided to make a new clip for the driver’s side headlight beauty ring. I had some baling wire, which is nicely flexible but has all the strength of putty. So, I bent the wire to shape then heat-treated it with my propane torch.

Heat treatment

The wire is heated to incandescent orange then quenched rapidly in cold water. This hardens the metal. A couple of repeats, then heating the metal up to a dull cherry red and letting it cool slowly brings back capability to be springy.

Headlight trim

The headlight trim is now securely held in place, which is an improvement over the previous implementation courtesy of the previous owner of gooey sealant. Which, incidentally didn’t work.

Gearbox reassembly

A bit of a saga occurred with the gearbox. I couldn’t get the main shaft endfloat correct. Everything was too tight and would bind up solid. I figured perhaps a bearing hadn’t seated well so gently tapped the mainshaft against the rear drum. This translated the force to the oil pump, which was the root cause of the problem. The bearing hadn’t seated correctly when I put it in and was sitting proud. As a result the retaining flange on the oil pump shattered (I think it had been weakened in the past). I ordered a new oil pump and the correct thickness shim which allowed me to reassemble the gearbox.

Rear servo measurement

The brake bands need to be carefully preadjusted for correct operation. The manual shows the use of a special tool- with care vernier calipers can be used. The setting is to dial the band in against the spring until the distance from the back of the servo to the actuator pin is 5 7/16″.

Rear band adjustment

With tension set, the locknut is tightened down and the rear band is done.

Front servo adjustment tool

The front servo needs to be pushed in 300 thou’ and the band set snug at that position. The servo case has a plug in the end which is tapped blind so it seals. The brass insert is a hydraulic fitting that I tapped a thread through to allow a bolt to be screwed down and push against the piston.

Domed end

I filed and rounded end onto the bolt and polished it so it could turn and push against the alloy piston without damaging it.

Front servo preload

A little bit of mathematics showed with the thread pitch of the bolt 5¾ turns were required for 0.3″ of travel. I set the front band against this and reinstalled the servo plug.

Painted gearbox

I reassembled and painted the gearbox.

Engine and transmission

I then cleaned up the flywheel and bolted the gearbox to the engine. I gave the engine an oil change and filled the gearbox with ATF. I started the engine up and engaged Drive and was greeted by the gearbox changing through all gears as the revs were brought up.