Small Block 350

[Gooseneck]

I have a mid 90's 5.7 engine 144,000 miles, that was running low on oil pressure so I pulled the pan to take a look at the main bearings. What I found was two main cap bearing bolts broken off in the block (one on #1 and one on #2) There were no tale-tale sighs that the engine has ever been into before. The engine is clean and the crank and bearings (normal ware on both) look fine. Just curious has anybody seen this before?

[JusGene]

If no one ever went into the pan, this is a screwy situation. I had a customer who imported screws/bolts that were hard-case treated when made in Japan and they had many failures. Shearstrength, etc., on fasteners could account for such a failure - but still only if someone tried to 'crank' then beyond their limit, or if the crank took a 'hit' from a powerful source (backfire, trans.lock??).

If you are already suffering from low oil pressure, it would behoove you to have it fixed.
Good Luck

[Gooseneck]

Ya JusGene, screwy to me too, I've never seen this before. I did fix the engine, scared me when I saw the broke bolts in the block although I didn't figure they would be very tight. They backed out fairly easy with a left handed drill bit. I replaced all the main and rod bearings and all new main cap bolts. Engine is running strong with good oil pressure. By the way I know that this engine had been running that way for over a year. Small Block 350 is one tough engine!

[JusGene]

Yeah Gooseneck,
Seems they must have made millions and millions of those 350s, and got'em perfected by now. Things could have been worse....?

Gene

P.S.
I posted 97-3500. Could you give it a look?