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In an effort to prevent my 351W from burning rod bearings I installed shims under the spring in the oil pump. Now, when the engine is warm it idles on 80psi. When you rev it up to about 2000rpm its on 100psi. Any higher than 2000rpm it pegs the needle all the way back to zero!
Is this too much? I'm not worried about it busting the oil filter because I have one with a thicker shell. I have no leaks either. I have a bronze distributor gear and the stock 3/8 oil pump drive. Am I in any danger of breaking the oil pump drive? How long do you think the gear might last?
 

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Heres what Ive read; You need at least 7 psi per 1000 rpm to properly oil your bearings. This came from a mag. I read years ago and I havent read anything that made better sense since. Real high oil pressure Looses hp,due to oil pump working so hard,may cause oil starvation,due to oil being all in the top of your engine,can erode bearings,just like running water errodes rock and hoses,does cause high stress on cam gear ,pump shaft and timing set. Your best off with good quality synthetic oil, not too thick,10/30 or 5/30, and stock or so oil pressure. If youve got 7 at idleand 42 at 6grand that should be plenty.You also need to know your bearing clearances. If your pressure is dropping your clearances are probably going up.You could go up a little on the oil viscosity. Full racing engines used to run large clearances with thick oil. If you run thick oil in modern engines you may break someting or starve the bottom end. The oil must be able to run through the little return holes fast enough to keep the sump full. I ran 20w50 racing oil in my 76 Cobra II and the crank started rattling at 30k after a complete rebuild. I also noticed a lot of lifter noise and a delay in oil pessure on cold startups. Theres good reasons why they do things the way they do nowadays. :D
 

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wow

wherever you read that send them an email and tell them there nuts

yo 100 psi is way to much 80s is good when its cold you would want about 70 when under a load


relative to thumb
heres a way of knowing
at 2000 rpm if you have 40psi oil pressure your motor has good oil pressure and isnt hurting anything prematurely

thats a good starting point all the oil pressure your running witht he shims in the pump will not hurt anyting but gaskets you will start to get a bunch of leaks the pressure will cause gaskets to blow out


mike
 

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I will search for this info and get back, but this was from engineers who test engine bearings with sophisticated equipment that rodders cant afford. Im quite sure thats close but Ill search some myself. I been a well trained auto parts salesman and parts manager in the past and have driven cars with 2 an 3 hundred thousand miles and never needed high pressure. I had a 390 that had about 2psi at idle and 25 when running hard and it never had any problems with 10w30 oil. The only engines I ever had trouble with were the ones that had the high pressure pumps. Well I forgot the Ranchero that broke the pump shaft(high volume pump 20w50 racing oil and a chrome moly pump shaft) with 30k on a complete rebuild. It had about 20psi at idle and 80 running hard. I Had the filter on my cobra blow off one morning on startup. turns out the relief was stuck. Probably from being open all the time.The best advice is going to come from experience with several engines with lots of miles and machine shops and others who actually rebuild thier own stuff.
 

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I just found it! The book is called How to build Horsepower Volume 1. It says that 55psi is the max for 6grand with a stock engine with good bearings. Anything above increases pump drag(Horsepower loss),increases chances of oil entering cumbustion chambers(cooked oil and detonation)and does not provide improved bearing lubrication or extend component life. Also more oil on the crank is called windage and thats weight that your engine is trying to spin. Read some books. Its way safer to read what the pros say. The book says leave high volume pumps to the engines that see 6500 plus regularly (like Nascar). Ive had trouble with every engine thats been upgraded from stock, and my 92 gt is running perfect with what it came with. Ive got over135k and still idle about half way on the stock guage(whatever that is). Books are cheap, time and engines are not.:)
 

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cool

im an engine builder and havent had problems with any of them that i have built in the past i have a relatively stock 306 with 70 psi oil pressure and has 139000 miles on it and runs great has cam heads intake still running mid 12s n.a

now my race car 347 stroker motor, ys trim vortec and 80 psi oil pressure going mid 9.60s all day long at 7200 rpm shifts motor priobably if i had to guess has about over a 100 passes on it no sign of any concerns


just my o2
high oil pressure does lack horsepower but it also does supply the motor with confort
 

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Good luck with the Bronze distributor gear! They usually dont like 100+ pounds of oil pressure.
 
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