BB oil problems

[John M.]

This is a 67 427-390, professionally rebulit and assembled. Before starting we used the tool and drill to get oil pumping through the engine and the pressure pegged on the gage at 80 psi.

Started the car up, clattered like mad, felt like the rockers were hitting the valve covers. Took the valve cover off, no oil on the rockers. Put the cover back on and ran the engine for about a minute and there was no change.

Is there any chance that the rear cam bearing is in wrong? Can it be put in wrong like the 66? I don't think so. Any ideas welcomed, we don't want to pull this thing out if we don't have to.
Thanks,
John McRae

[Duke W.]

Re: BB oil problems

There have been a couple of extensive discussions on this subject in the last year or so, including photos.

I'll summarize it as follows:

'67-up big blocks were originally built with a single hole rear cam bearing and the rear camshaft journal did not have a groove. The Chevrolet Power Manuals from the seventies recommend that if a grooved rear journal camshaft is used in these blocks, the rear cam bearing oil hole should be soldered up and redrilled to .060", however, this advise was later rescinded.

For decades the only BB camshafts available through GMPD had rear grooves, but some non-grooved camshafts were apparently found relatively recently and added to service parts, but I am not sure if they are still available (Joe Lucia contributed this part of the discussion.)

'65-'66 big blocks require a three hole bearing AND a grooved rear journal camshaft.

Please correct me if I erred in this summary.

John - if you can audit whatever receipts/documentation you have for part numbers to determine what bearing and camshaft configuration you have, that should help isolate the problem.

Duke

[John M.]

Re: BB oil problems

Thanks Duke,
The engine work was done by the same guy who did my 327-300. I saw something from John Hinkley that said the rear cam bearing location in the block had a groove under it in 67 which would indicate that the oil should get into the gallery no matter what bearing was used. Tonight we plan to run the oiling tool, distributor with no gear, for as long as we can to see if any oil will show up upstairs. We have all the part numbers from Leo and I will get them tonight. We also have a bare 68 block which I will check for this groove. Thanks for the advice.
John