Thread: chevy 400 what could cause this?

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How big was the threaded screw thing? Did it look anything like an oil journal plug? (since one was missing before it seems reasonable to ask) How did the combustion chambers and valves look? Have you figured out where the coolant came from?

Definitely check the rods for straightness and length, I would replace the ones from the damaged holes for sure. Check the valves in 3 and 5 also in case they got slapped by a piston. Have the block checked for cracks and the crank checked for straighness and cracks.

And go back to the engine builder to get some money back.

Pat

Thanks 1stgencamaro! I am having my block prepped right now and I think it will be money well spent to have the block decked and then use a regular gasket. If the gasket is compressed to about 0.039"-0.040" I will talk over a deck height of 9.005" with my machinest/builder to get the quench with still a slight safery factor. As it shapes up now I will end up with about 9.9:1 with flat top eybrow pistons, but it looks like I will still have to use 91-92 octane. For streets, our power was out for a day here due to some wind storms in this area, but I did want to compliment you on the earlier documentation you submitted on adjusting hydraulic valves, thats the kind of info I need and hoped for on the head sequence. I still have no answer on reliability of thin head gaskets and I wonder what thickness was used in the 400 engine discussed above. Until I learn more I am going to assume that ultrathin head gaskets may be more likely to leak than the usual one which compresses to about 0.040"?

P.S. in edit thanks for several comments on gaskets used.

Don Shillady
Retired Scientist/teen rooder