Ok, I cant figure this one out without stripping the thing back down to block. I did a complete rebuild on my 350 along with a custom grind cam, new lifters and Hyperutectic Flat Tops. Crank turned .020 Mains .030 Rods by a reputable shop. Clearances were all in very good shape when assembled. I installed the High Volume Pump with the adjustable regulator and the thrust plate, along with installing a brand new Timing Cover. I know the high volume pumps are death to these motors, so before you go into it, understand that the pump was added after breakin. I have the 60lb spring on this thing with the regulator turned in pretty far. Upon start up it gets like 90 PSI at 1,200 RPMS. but once warm sits at 10 PSI. THis is such a radical difference and a whole lot of crap to get 10 psi at idle. It runs like a scalded pig, and has not failed me yet, but where could that pressure be going?? The only thing I can attribute some of it to is the lifters. I bought them through Scheider racing cams when I had the custom cam built. I have a fear I got the dreaded Chevy Lifters that everyone tries to pass off as Buick. As you know they are not the same. Any ideas here? All components in the engine have oil on them, so nothing is dry? Goin gout of my gourd figuring it out. It was like this before the rebuild too, hence all the new oil stuff and cover. Thanks, -Jon
Jon, With a new timing cover, you definitely don't need a HV pump on a 350. I would put the stock gears back in and pay alot of attention to the gear end clearance. With the pump disassembled and the gears installed, put a straight edge across the face of both gears and measure the distance between the straight edge and the gasket surface( without the gasket) with a set of feeler gauges. TA performance sells a kit with various thickness gaskets to dial in the end clearance. Your aiming for .002. The gears in a new cover should be higher than the gasket surface. Say they are .004 above the surface. If you use a .006 gasket, you'll get the optimal .002 end clearance. Turn the regulator down, 90 psi cold is way too high for a street motor. All your doing is backloading your cam gear and wasting power making all that pressure. When you have everything together, check you WOT shift point oil pressure and adjust the regulator in a turn at a time till you get it. 60 psi at 5500 RPM is plenty for a 350. Hope that helps.
Hmm good point Thanks Larry, You know, sometimes it takes a 3rd part to asses the situation. Through all this I never thought about the end clearances on the pump. I will have to check that. I guess the reason I am suspicious is the fact that the same thing happened on the pre-rebuild motor on which I did set the oil gears clearance on. I also thoguht about the lifters too, and I replaced them with the T/A lifters, thinking it was the problem. no change. I agree totally, 90 PSI is insane upon start up, but it is the only way I could get 10 psi at an idle, and 50 psi at 6000. Oh, I know 350's arent supposed to be winder motors, but this thing is real happy running up to 7500 RPMs. That T/A intake is awesome! Some headers to match the cam, and this thing will really move! Anyone have any other ideas where all this oil is going? Thanks, -Jon
Also, check to make sure that the oil bypass that is in the pump cover behind the oil filter isn't stuck open...
Dont believe the hype about Chevy lifters bleeding off oil pressure in a Buick, there the same Diameter as Buicks (.842) the only difference is the depth of the pushrod seat, which requires longer pushrods, or adjustable roller rockers. I have tried every lifter for the Buick, and am currently running Crane lifters for the Chevy motor in mine, they solved the lifter clatter on start-up. Take Larrys advise and check your gear end clearance for the oil pump. Also if the valve train is quiet, and the oil pressure is stable at 10lbs at hot idle with 10W-30 oil I wouldnt worry to much. The Buick V-8 and V-6 are great motors, but the aluminum timing cover with the oil pump in it kinda sucks, 'cause the pump housing expands twice that of iron, making gear side clearance even greater resulting in a drop in pumping capacity, but you cant control the side clearance. Too bad Buick didnt use and iron liner in the pump housinguzzled: Mark
