Pontiac renovations, part 14.

When I removed the engine from the car, I had undone some of the cylinder head bolts in order to attach the lifting chains. As such, the whole lot needed to be slackened off and re-torqued down in the correct order.

Collection of head bolts.

The bolts were all very randomly tightened, mostly due to dirt and rust in the threads, by the feel of it. I decided to remove them all, take the head off, give it an inspection and clean, chase the cylinder head bolt threads through in preparation for refitting.

Block side of cylinder head.

The cylinder head came off without any trouble. It doesn’t appear to have been leaking badly and the deposits were a little dark but still within acceptable range.

Head gasket.

The head gasket is in moderately good shape, although it appears to have been reused a few times already. I think I shall be purchasing a replacement. The head and deck facing surfaces were a bit dirty. One valve was stuck open (far right in the image below, no. 8 exhaust), as the coolant gallery had weeped past the gasket, drawn in and made the valve stem rusty enough to stick. I coated it with penetrating oil, freed it up and now it operates correctly again. I had noticed one cylinder was down on compression the last time the engine was run- this will be why.

Cylinder block.

The deck itself appears to be in good order. The top is straight and level, though it required a clean. With no compression the engine turns over moderately smoothly. I think the bearings have been replaced without the crank having been ground. It feels a little tight between power strokes, indicating mild ovality of the crank journals. I can turn it over with my 8″ ratchet, so I’m going to leave it as-is because the oil pressure was very good and there are no other issues.

Hone marks on cylinder walls.

Two of the bores show fairly heavy hone marks still.

Worn shiny bore; 0.040 mark on piston crown.

The rest are quite mirrored but are not scored. All of the pistons are stamped 40 thou’ overbore.

Clean piston crowns- pots 4 and 5.

A rag with some carburetor cleaner on was all the pistons needed to come up clean. I do not think this engine has seen many miles since it was last apart.

Gasket scraper.

I started to clean the cylinder head up and came to a rapid halt- the blade in my scraper was no more good.

New tools.

I went to the store and bought some more tools- a box of 100 #9 razor blades for my scraper, a big wire brush to take the black paint off the engine and a tap set to chase out rusty and dirty bolt holes.

Making a start on cleaning the cylinder head faces.

With a new blade, I was able to start cleaning the cylinder head. In the image above, the baked-on dirt in the corner between the bolt hole and coolant passage is visible still. Although very fine, this is enough to cause a new gasket to weep.

I also made a start on de-coking the combustion chambers with a brass brush. It would appear that somebody had made a half-hearted attempt at it, but had missed a lot around the periphery, where the gas flow needs to be smooth and uninterrupted for good power and economy.

Clean cylinder head.

The cylinder head started to come up nicely. I ran out of time to do any more but initial impressions are good. There’s no pitting, marking, cracks or any other problems to be seen. It just needs meticulously cleaning and then it will be ready to refit.

Spray protectant.

I bought a can of heavyweight oil, designed to sit and prevent rusting up of the internals of an engine that’s to be lain up for winter. It also works well to protect engine surfaces that are left uncovered (bores and mating faces) while they are disassembled.

Coating the metal to protect it.

Everything was given a liberal coating of oil before being left to sit up overnight. More cleaning is due. The engine is going to receive a coat of paint also. It should be a deep green, the closest I can see it should be is Brunswick green. I may have to buy John Deere green and Ford blue engine paints and mix the color myself.

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