Quote:
Originally Posted by Big Bear
When I dug out my bolts there were a couple of washers still on them. Measured .060 thick. Dont know why they used them but was talked about on this site some time ago. There was GM part number for them. Sourced .100 thick hardened washers and used them on the reassembly.
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Those washers were under the heads of all 20 bolts on my engine. I had no idea they were factory installed. But since found out they were supplied on early SD engines for some reason not clear to me. The washers were not hardened or parallel ground. They were also deeply embedded by the bolt heads. IMO, a bad idea to use them as they would certainly would lose clamp load as they relax from being embedded. I replaced them with hardened washers, .120" thick. They are parallel ground and the little extra thickness makes up for square decking the block and making the heads flat again. The OE washers were also a poor fit on the OD and the ID. The ID was too large and let the washers move around over 1/8'. The OD was so large it overlapped the poor factory spot facing on the top of the bolt holes, bending the edges of some washers. Overall, not one of Pontiac's best designs. I thought someone just threw some hardware store washers under the bolts until I learned they were factory installed.