I am currently on a trip to Lincoln, NE. with the wagon. On the highway running about 80. I am running a little above 25lbs on the pressure gauge. When I got into town and local driving it is about 25lbs. stopped idling in gear she drops to a little above 10lbs. I am running Valvoline VR10-30 How concerned do I need to be? Tim
What RPM at 80? If you are under 3,ooo RPM, you are OK. Idle, hot, in gear is fine at 10PSI. What filter are you running and when was the last change (miles)? Factory or aftermarket gauge? Electrical or mechanical? Temp at 80 after 15 minutes?
With only 10 psi at a hot idle I am surprised your oil idiot light is not flashing! in fact does it come on when the motor is not running, but the key is in the run position ? above 3000 rpm you really want to start seeing 10 additional psi of hot oil pressure for every 1000 rpm, and the only way to keep your motor out of danger to me at this point is to put a mechanical gauge on it at least until you confirm what may or may not be going on. 90 percent of the time if your oil pressure goes low enough to get the lifters clacking at idle then your Rod Bearing are getting harmed also.
Normal oil pressure for all Buick 350s is 37 psi @ 2400 RPM. If you are topping out at 25 psi, that is low. I would watch your RPM until you can remedy it. What is the pressure when you first start the engine cold? It should be 40 psi +. Engine oil will get as hot as it ever will after about 20 minutes of highway driving. The 10 psi @ hot idle is not concerning at all, but the 25 psi maximum is. I would try pulling and inspecting the oil pressure relief valve and spring. Make sure the valve moves freely in it's bore, and the the spring is not broken. If everything looks good, I would try shimming the spring with a small allen bolt, or get one of TA's adjustable oil pressure regulators. http://taperformance.com/proddetail.asp?prod=TA_1502 If that does not increase your oil pressure, I would take the pump apart and check the clearances. https://v8buick.com/index.php?threads/oil-pump-clearances-and-oil-pressure.326597/
Running a K&N filter. Been about 1000 miles since oil change. Aftermarket electric gauges. 0-25-50-75. So at 80 I am turning about 3000. Temp at 80 after 10 is about 190. Tim
Yes, only 25 psi at cruise (80 mph, 3000 rpm) is a bit low. IF you still have the stock spring in the oil pump it should still be higher than 25 lbs at 3000 rpm hot. What gets me is your seeing 25 lbs @ 3000 rpm and near the same @ say 1500 to 2000 rpm around town hot……. SO, that’s telling me that’s all the pressure the pump is ALLOWED to produce….. the relief valve is opening for some reason, the pump sounds like it’s capable of making more pressure, but it’s not allowed too because of the relief valve. What kind of oil filter adapter ( pump cover) you have on there??? Is it still the stock one or a later version? Reason I ask is the old originals (up to 1976 or so) had a flat phenolic disc for a valve for the OIL FILTER BYPASS, these would get cocked sideways, and your pressure would drop to around 20/25 psi max under any circumstance. Spin the filter off and you can see if it’s sideways. Buick changed that valve to a conical self centering valve because of problems
Filter, temp, oil time are good. For the cost and confirmation, I would put on a cheap mechanical gauge, and see if it matches your electrical readings.
Well she ran good the whole trip. I am looking to rebuild her in the winter. Provided I am able to find a new place with my own garage.
Well the rebuilding is going to hopefully get done over the winter. I finally have a garage. So I will need some guidance on everything. Tim
Congratulations on the house and garage! It’s fun to set up shop, and just walk out and start wrenching
The better idea is to get an entire new cover assembly and have them do the oil mods on it to open it up and they will put the adjustable regulator on it and use the booster and the larger gears. They do not wear out the distributor gear like on the 455 I have had mine in there for 28 years now and no wear on the gear. Then you do the oil mods on the galleys and you will never have oil troubles. On my old motor the oil pressure gauge would go down to 5 lbs at idle in gear so if you get this much it will be ok for now and I ran the piss out of it at that. It took 10 years of that before it blew up I had 35-40 lbs max...maybe lol
