I watched mine last time I ran it and the pressure varied very little from cold too hot. [read that way too much].... I dearly hope I can squeeze enough feeling good time and spare time together and get the rear cover sealed up to I can at least get it out and run it to lubricate everything good! -- Mark Price Morgantown, WV 1969 AMC Rambler, 4.0L, EFI, T-5 2004 Grand Cherokee Laredo, 4.7L, Quadratrc II " Chronic Pain Hurts" -------------- Original message ---------------------- From: Tom Jennings <tomj@xxxxxxx> > On Fri, 2 May 2008, Greg Taylor wrote: > > Thanks Greg! > > This is the important part: > > > > Davis Martin <martin-davis@xxxxxxxxxxxxx> wrote: > > > OK, on to poor oil pressure. > > The problem with the stock setup is there is a Powdered Iron > > gear living in an aluminum housing. The 2 have very different > > expansion coefficient's. So when you set your nice tight pump > > clearances on the bench they do not hold up. When the engine > > heats to operating temp, the gear does not expand as much as the > > housing, and you have a looser pump then optimum. This is why > > most see warm engine pressures in 18 PSI or lower. > > > The fix. > > > Bill figured this out 20 years ago when we were loosing > > bearings. He found an alloy with the same expansion coefficient > > as the timing cover. We have gears made from this alloy which is > > harder on the RC scale then the factory gears. Once we swapped > > to this set up our amc oil problems were no longer. > > Very clever! > > So warm-engine-oil-pressure-drop is not dominated by the oil > thinning as it gets warm? I always assumed it was that! I don't > own an AMC V8, and all my sixes have cast iron pumps --but no oil > pressure guages. I assume there's some temp-related-oil-thinning > pressure drop? > > It does seem to be the weak part of the AMC 8, that aluminum > timing cover. > > _______________________________________________ > Amc-list mailing list > Amc-list@xxxxxxxxxxxx > http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list _______________________________________________ Amc-list mailing list Amc-list@xxxxxxxxxxxx http://splatter.wps.com/cgi-bin/mailman/listinfo/amc-list