Hello all, having a problem that is about to drive me to drink. Car is a 62 Buick special wagon with 198 v6. Motor has less than 100 miles on it after rebuild. I rebuilt motor for my brother in law since it was so old. Car has been in his family since new. Problem is this- when cold, oil pressure is 55-60 psi, warmed up at idle it is 25-30 psi, when warm if I raise idle, pressure drops down to 5-10 psi. Motor has new pistons, lifters, push rods, oil pump, bearings(crank and cam) originally installed high volume pump and removed cause I thought that was problem. Now has normal volume pump and steel plate on end of pump between oil filter adapter and pump gears. Pulled motor back out and went back thru crank bearings and rod bearings checking oil clearance and all were within tolerance. Getting oil to lifters and oil to rockers ( I think rockers should be getting more ) any ideas? Never had a situation like this
Try a mechanical (not elec.) oil pressure gauge.......just to be sure what you have. Remember....do the EZ and cheapest stuff first!(Wish I could remember that!) 6sally6
Filled with 5 qts oil, book says 4.5 qts. I also put a mechanical gauge in it besides the idiot light
Mmmm, if "the book"...says 4.5 quarts...then exactly why do you feel the need to raise the oil level by going to 5 qts..?? What weight oil ? Heavy weight (thick) oil, not a good thing. Did you check the impeller clearance in the pump ? Those aluminum housings get messed up pretty easy. Any scars up inside or around the impeller teeth of the pump cavity ? Who installed the high volume kit (that you removed)...and why ? Does the engine have a windage tray ? Is the running oil level "below" the tray ? Mike
I always disliked the oil pumps on those engines. As stated above you have to be careful of your clearances when you put them together. A wrong gasket can mess things up. It sounds like too much clearance. The shaft is walking in and out according to rpm. Is there a spring and a check ball on it? (been 20 years since I worked on one.) There could be a problem in that area as well.
Okay, I put high volume pump in when I rebuilt, I removed it because I was thinking maybe it was pulling all the oil out of the pan and cavitating the oil pump . There is no windage tray, I am running Castrol 10w30 oil and an ac filter (pf61c). Other than eye balling the gap between the gears and housing, they were not measured with a feeler gauge. The gears were pretty close to the walls of timing chain cover but not hitting it. The gears spun freely without any rough spots. Oil pump was packed with Vaseline also prior to starting engine. Inside on pump body where gears sit was pretty clean with out any scarring also. The oil filter adapter had some minor grooves worn in it which is why I installed the steel plate between the adapter housing and pump body. I also used the black gasket between the steel plate and gears.
you really don't need the extra pump plate for it, your not racing it. stock setup, use the same thkness gasket it came with. early engines didn't have a windage tray. only thing you might/should change is the pressure spring as the oem is probably tired. building a buick is way different than a chevy. if a chevy shop builds it like a chevy, expect to replace the engine. the other issue is a lot of companies say the chevy and buick lifters are the same. not! looking at the oil pressure issue, something is not assemble correctly or wrong parts, to drop off like that. I race a s/c 350(6500-7500rpm) and run about 100psi(no oil filter). but that develops wear/drag issues. I am going to change the oil system a little hoping to alleviate the wear/drag issues.
Only reason I asked about the filter was because sometimes you'll get a bad one. I run Delco filters and haven't ever had an issue, but some people did with Fram. I believe they collapsed internally. Just thought it might be something easy to check/replace before you take the whole thing apart again to mess around with clearances in the pump.
Those pressures are right on for a 198 V6. We had a service bulletin where we had to change the oil pressure switch to a lower pressure one because of all the complaints for the light on at idle. Use the paper gasket inside the pump will slightly raise the pressure. We ran the oil pump gears from a 350 and a spacer plate for more volume. Drilled the main oil gallery to 9/16 (still have the drill). You did not include the bearing clearances that are very critical for good oil pressure. I built the odd-fire V6's for the street and a dirt modified. 2X^ Delco filters have the check valve to keep oil in the filter. 10 PSI per 1,000 rpm.....
Have built many Chevy small blocks, this is my first Buick. Is there any material I can reference on building this motor correctly? I got oil clearances from web site that had Buick factory oil specs for year of car and motor. Checked all clearances with plastigauge. Machine shop that did work said crank and cam were okay, only needed a little polishing. Motor was all original when taken out and ran pretty good. Found a few things but nothing major . Going to pull timing cover off and go over it with a micrometer to check gear clearance and any play up and down. Will do that when I get back to shop on Friday. Thanks for all the help
I don't know. I just vaguely remembered seeing this article a while back and thought it might point you in a direction where you could research it on line.
Did you check the oil pump end clearance? I'll include a link from V8Buick.com. I rebuilt the pump on my Buick 300 because it took a while to build pressure from a cold start, and I used shims from TA Performance to end up (ha ha) with an end play of .002. http://v8buick.com/index.php?threads/oil-pump-clearances-and-oil-pressure.326597/ http://www.taperformance.com/products.asp?cat=72
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