Bought a Buick 300 with what I was told had less than 50,000 on the stock motor. I pulled the oil pan and checked the main and rod bearing clearance. Had about .0017 checking with plastigage The bearings had very little if no wear. Today I primed the motor with a drill and it pegs my oil pressure gauge. Looks like well over 100 lbs. Gauge goes to 80 and drill driving the pump pins it in the corner. I did put a booster plate and new stock gears in the pump. Set clearance to around .002 and used the white spring. Is this normal? I am getting oil up to the rockers on both sides. Again this is a stock motor. Thanks for any help
What oil are you using? I'm pretty sure Buicks of that era ran 20wt oil in the summertime so if you put 10w40 in it that's why your pressure is a bit on the high side. Also drive it a bit and see what it drops to once it is thoroughly warmed up. Overall though that's an excellent result. Jim
Ok Jim thanks for the reply. I messaged you about this motor and the swap into a 1978 MGB. Just trying to get things sorted out before I get things swapped.
I don't know what RPM your drill runs but the distributor runs half of engine RPM so if you have a 1,000 on the drill, that is 2,000 RPM when the engine is running. If the pressure is too high, you can swap to the non-Stage 1 spring to lower it a bit. The warm idle pressure is what you are looking for. The spring only regulates the maximum pressure. Overall, I'd say your pressure will be more than sufficient.
The only thing you confirmed was the oil pump is primed, and the pressure is excessive. You’ll have to adjust your max hot oil pressure after a long freeway drive and see where it ends up. CAUTION here, if you saw 100 plus with your drill, you MAY end up blowing your filter apart on a cold start! Similar situation I had over 100 lbs with the drill, I could SEE the oil filter extending length wise from excessive pressure. Reduce the pressure ( lighter spring) before you fire it up.
One issue you may have is seepage from the front and rear main seals as well as past the threads of one of the oil pump bolts. Sometimes the seals will absorb enough oil to stop seeping enough that it is objectionable, sometimes they won't. The only real remedy is to use modern lip seals but that requires removal of the hash marks on the damper and the rear of the crankshaft which requires a teardown to do the rear main seal. The bolt can be sealed with thread sealant and a plastic washer. The front seal requires removal of the damper and front cover. OTOH if you've owned British cars you are already used to oil leaks. Jim
With those motors and .017” of clearance you do not need anywhere near even 60 psi of hot pressure. Those distributor gears where not made to take that level of loading ! 10 to 12 psi per every 1K rpm the motor will be called upon to spin up to is all you need.
Thanks for all the info. At least now I know what to watch out for. I did install a new lip seal in the timing cover since I replaced the timing gears and chain but did not do anything with the rear main. It looked like it had not been leaking.
10w 30 I was priming it with a makita 1/2 ac electric drill. Today I tried again with my dewalt 18v battery operated drill and the best I could get was 70lbs of pressure. Apparently the makita drill has more power. It didn't even slow down any while priming. With the dewalt drill it would drag down to about 3/4 speed.
The main problem you have is the white spring it’s for a stock stage one 455 oil pump and combine with a booster plate, Use the lightest spring you have in the kit check the oil pressure again and see what the pressure is if you need a little more go to the medium spring.
With clearances and pressure like that, you could run 5W30 to bleed a little cold pressure and not hurt your hot pressure. That's what I run in both of my Buicks, a 455 and a 350 with no issues.
I'm running 5w20 and have over 60psi heat soaked at cruising speed. Try a thinner oil and see what it is hot once you have the car finished. For now I wouldn't worry about it. Sounds like good luck on the rear main seal, so I agree. Leave it alone as long as it isn't a big problem. Your relief spring should be stiff enough that it doesn't affect hot cruise. It's there mainly for cold starts. Jim
