Re: V8 Rebuilding

Posted by BH On 2013/7/7 17:36:07

The article in that PDF appears to be something of a follow-up to Dick's previous article, "Click 'n' Clack, The Tappet Druthers", which was published in The Packard Cormorant (Issue #69) back in 1993. It seems to reiterate some key points, but brings up a few good new ones.

I experienced the same problem with plugged oil drains in the heads of one of the much-revered SBCs back in the 1980s. With less than 60K on the clock, the 305-V8 was burning oil at the rate of about a quart every 400 miles. Everyone thought it was rings, but my dad wanted to pull the valve covers. As we did, oil spilled out and onto the garage floor - well over a quart in total.

Clearly, the trapped oil had been sipped into the combustion chambers, as the oil level in the heads rose above the intake valve seals. Also, there was baked on crud (looked like wrinkle finish paint) all over. We replaced the intake stem seals, one-at-a-time, cleaning up the crud as best we could, and rodded out the drains. I put another 30K on the clock and never had to add a quart of oil between changes (and at 5K intervals).

Moral of That Story: Never underestimate the potential for neglect by some P/O, no matter who made the engine.

I fully respect the insights of anyone who has rebuilt as many engines as Dick has, but don't fully agree with his view of the different types of V8 oil pumps. Originally, there were three types of pumps: 1st) the Packard application, with the integral vacuum pump; 2nd) the American Motors application, with a heavy cast bottom plate (but no vacuum pump); and 3rd) the Studebaker (Golden Hawk) application, with a flat steel bottom plate (also no vacuum pump).

IMHO, the presence of the sump/dip tube does not constitute a "type, as that part was intended for field service by dealers and was recommended for BOTH Packard (per STB 56T-20) and Studebaker (per SSL No. 936) applications. However, a second design of the Packard pump, with the relief valve plugged, was introduced in production for both Packard and Studebaker applications (but not AM), which would constitute a 4th and 5th type.

Meanwhile, except for normal wear of internal pump clearances, I never really believed that the separator plate used with the vacuum pump was the culprit. Surely, 56J Golden Hawk owners must have reported similar problems, else they would not have recommended the sump tube. Yet, the Studebaker application had no vacuum pump and even used thicker material for its bottom plate. I do, however, suspect that Packard might have been onto something WRT to the relief valve sticking; installation of the sump tube in that regard might be cheap insurance.

I suspect there might be other little running changes that even the Zones weren't briefed on (WRT block as well as pump), but those might only be discovered, now (in lieu of bona fide engineering notes), by a careful audit of available factory engineering drawings.

Still, I'm glad to see that Dick touched on the matter of wear at the driving shaft, which has been addressed by other rebuilders.

Also, I can imagine how any grit left in the crank journals could have, in lieu of modern, full-flow filtration, gotten by the pickup screen and would accelerate wear of the pump - and anything else, downstream. Yup, that might just explain a lot.

I'm no master motor rebuilder, but there's no substitute for careful forensic analysis, on a case-by-case basis, to see why the the lifters are making noise - could be more than the pump is involved. Increasing pump volume might only be a temporary fix.