Thank you for that info, Jim i been siting quiet reading all these "not to use the high flow" pump.... eating my fingernails, i am using a high volume pump but i did a lot of presure messuring before i dicided what spring to use not to get to high pressiure( i changed to the high volume pump ten years ago, still working) Lars
It measures 40 psi when first started. I don't want to let it run very long because it has a knock. I am taking it out this weekend and putting in another buick 350 until I fix this one. I will find out whats wrong soon. Thanks
Larry, you don't have a pressure / RPM requirement "list" laying around sam were?? It would be of great interest ! Lars
Lars, The 350 needs 10 psi/1000 RPM, the 455 needs 12 psi/1000 RPM. This chart is in the Guide to Buick GS book. It's part of Buick's "Service Recommendations for Heavy Applications, 1967 and later 400,430, and 455 Engines"
Larry, What book is that? Where did you get it? I've seen you reference it many times on this board. Is it still in print?
Larry, Im starting to think you got a book or a work shop manual on everything! (I only whish I had them to!) :laugh: Is it OK to use the 5000 and 5500rpm / oil pressure numbers on a 350 as well? (-2 -3 psi or so) o No: Lars :Comp:
Aubrey, Yes it is still in print. GS facts and figures book. I.S.B.N. 0-9621059-4-5, Library of Congress No. 92-081745. I believe Poston still sells them, and Steven Dove is at the Nats selling them most of the time. Lars, For the 350, 10 psi/1000 RPM is all you need. There is no advantage to running more oil pressure than you need to. It takes more horsepower to pump the oil, and it heats the oil more also. That's not to mention more pressure on the cam bearings/timing chain and cam gear.
gray poop does a 69 and 70 buick 350 have these aluminum parts that cause this? Aren't they steel? SHould they be replaced by something not aluminum?
I have a newly rebuilt 300 that runs about 60-70psi at initial startup. After warm-up, it runs about 30 PSI at idle & up to 60 - 65psi at 4500rpm... I do have the booster plate installed & a new cover. I used the middle-range spring with the pump kit (can't remember the color). I've not put too many miles on the engine yet, actually probably only about 4 hours of driving so far. I wish I would have researched this more before purchasing the high-volume kit, anyone have recommendations? Replace the pump with Stock or leave as-is?
Some one said that if you use a stiffer sprig in the pump then you will have a lower volume of oil flow. I think this is what you want.
Aaaa ! now i see.....It's a matter of reading and understanding ! This means 20psi at 2000rpm 30psi at 3000 and so on! Lars
A stiffer spring means higher pressure before the relief plunge/ piston moves and the relief valve opens.... Oil passing the relief valve goes back to the oil pan trough a "back door" passage.... This means that a part of the oil flow will go straight back to the oil pan. A stiffer spring will NOT reduce the oil flow volume! But it will raise the pressure! (to) High pressure puts an extra (unwanted) load to the distr.gear....and all the other negative tings mentioned earlier in this tread! worried thers to much flow and the engine cant handle it, pressure will raise as a result and let it out trout the release valve = no harm done . What you need is a softer spring! After what i just learned from Larry, on the 350, 4500rpm = 45psi AT OPERATING TEMPERATURE is where your aiming. . High "pre operating temperature" pressure is due to the fact the relief valve and oil return passage is to small/narrow, and can't handle the cold thick oil flow... and the engine internal distribution and leak flow is not as high/fast when oil is cold and thick. Think like this: cold oil flows like syrup and hot like water (this is one of the reasons not to put the pedal to the floor until engine is at operating temp. it's possible the oil isn't reaching "the lubrication point fast enough, or there's to little of it...=disaster) Oil pressure and the viscosity number do have a relation... A straight 40 gives higher pressure (to high?) before reaching operating temp than a 10W/40. But the same pressure when hot. Same thing with a 20w/50 (to high?) compared to a 0w/50 Try another spring if operating temp. pressure is "off" in any direction And another oil "xx W/ yy" combination if cold pressure is way to high Word of warning! Do not tamper with the size of the relief valve, or the "return" passage!!!! Sorry for the length on this "input", i got carried away...... And, feel free to slap me on my fingers if i got something backwards! Lars
