Will High oil pressure ( 75psi) contribute to oil burning ?
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Will High oil pressure ( 75psi) contribute to oil burning ?
No it won't make the engine to burn oil. But it will rob you gas mileage if the pressure too high for street. It take about 40 HP to pull the oil pump at 70 PSI.
Hydraulic horsepower is;
HP=P*Q/1714 where P is in psi and Q is in gpm (gallons per minute).
Therefore I seriously doubt the 40 hp number which leads to 970 gpm oil flow rate. :eek:
I believe the issue is more related to stress on the distributor drive leading to timing issues etc. 70 psi is getting up there though for the street IMO .............
Kitz
My 392 runs a constant 60 at highway speeds.
Jack
I have a 302/347 stroker and it runs 70 to 75 of pressure. I was also concerned about mine .
Rocky
My old motor was running 80 psi at idle cold and dropped to around 60 warm (at idle)... I also was worried about it but never had a problem.
My current motor sits about 35psi hot idle and 60 cruising, except sustained cruising near highway speeds (~55mph at 3200rpm) the pressure gets erratic and drops around 40... I was told I'm probably sucking the pan (7qt) dry so I drive like a grandma on the highway :HMMM:
Did you use a high pressure pump or put a different spring in the oil pump? That would account for the high pressure. Normally, you could expect a higher oil pressure at start up (like 60-70 lbs.), but I have never run more than 55 lbs. cruising down the road.
Clearance also effects psi right? My 283 stays at 80 psi, 80 psi while driving and drops to 60 or more at idle.
Old L6 dodge should be worn out as oil psi drops to nothing with reg oil, we have some 90# in it now but only drive it less than 1500rpm and only about 1 or two miles per year, until I drop the rebuilt one in.
I'm impressed.... my 1/2 drill motor will spin the oil pump to 70psi......do I really have a 40 hp drill? Wow, I could run a Model A Ford with it.....oops, the battery would run out quickly.
That's funny Robot.....my cordless 3/8 spins my engines I set for "kill" hard enough to smell smoke and the gauge is pegged......me thinks there is a drill on your X-mas wish list coming up :LOL::LOL:
Thanks for the replies. Sometime this winter I will be looking into the burning Its only on one side. It does have a HV pump and I was thinking of changing it to a stocker. I know the pressure is not the cause but was wondering if it was contributing.
Ummmm........an SAE 90 gear lube is about the same viscosity as an SAE 40 motor oil, and the sulphur/phosphorous e.p. additive in gear oil is enjoying your rod and main bearings for lunch.Quote:
Originally Posted by chevydrivin
Some last thoughts,
1) The old rule of thumb is 10 psi for every 1000 rpm
2) I'm guessing a high volume pump puts out a total of ~6 gpm at 70 psi. This data is not easily found btw. Anyhow that would be about 1/4 hp which is why you can prime an engine readily with a hand drill.
Regards, Kitz
People have to keep reminding me about the old rule of thumb being 10 psi per 1,000 rpm.Quote:
Originally Posted by kitz
That was true for a long time.
Like what was said in an earlier post to much pressure will cost you hp,break your pump drive and make you oil pump work that much harder.
To be honest if the engine has 50 lbs. at 7,500 rpm's I am fine with that has long as you have the right oil clearence for that application.
Screw the motor lets put 20 of those drills under the hood:whacked:Quote:
Originally Posted by nitrowarrior
i wanna 40 hp drill, is that with a 39.5 hp shot of nos? :LOL:
FWIW - I've primed a couple of builds with a 3/8" drive speed wrench spun by hand.
Reaching 40# was not a problem.
Both engines exceeded 70# on startup and carried 45#+ running at highway speeds on a hot summer day.
Are you seeing high pressure on cold start-up?
And does it go down 20# or a little more after the engine is fully warm?
Key thing is to keep the RPM's at a reasonable level on startup.
Some oil pumps will fail due to excess pressure and some spin-on oil filter cans will blow out if the engine is revved to high at high pressures.
My moderately built 462" Buick running street clearances will show 75# - 80# on cold morning startup and run 47# on the highway after it's warm summer or winter.
You have to watch the electric chokes as well.
Many times the fast idle cam is set too fast for a particular engine and it's easy to hit 100#+ on cold start-up.
If the engine roars to life when the choke is on, tap the throttle to get the carb off the high spot of the fast idle cam.
Almost always the engine will keep running.
Adjust fast idle cam RPM's so the start-up RPM is reasonable
ive got 85 lbs at start and 70 lbs at running temp. i did this summer break the roll pin out of my distributor shaft holding the distributor gear. that was probably caused from high oil pressure. i guess ive been wasting my time with this motor, all i needed was about 15 drills instead!
20 and you would really fly, imagine the torque