oil presure good bad evil

[pickemup]

hey ive got one of those high vol oil pumps and the psi is about 100 or so
cold and 80 90 hot. some say its bad to have that much on pretty much stock engine others say wont hurt . im concered about blowing seals.
i have not ran this engine except to ajust valve train . reminds me still need to retork head bolts. what do you all think. any engine guys there.
ive got a new stock pump and was thinking about changing the spring to lower psi. allso the psi gauge is on the rear of engine if that matters.

[wolfthing2000]

I am running a high volume pump ( Milodan) on a V-6 in my Jeep with 60,000 miles on the engine ( thats about 120,000 on a highway rig due to off road high RPM usage) . The pump ( gage at lifters and one at pump, about 10psi drop from pump to lifters) usualy reads cold 80 psi and more depending on RPM, and levels out about 70 and 60 after warm up on a day say 80 degrees temperature and stop and go traffic ( may drop to 40 and 30 at idle).
My seals never leak and the engine seems to be holding up real well since the Buick V-6 with external pump has been noted for oiling issues.
There is no real pressure applied to the seals since your crankcase is vented anyway and the oil is pumped only into the main bearings . That 80 psi is certainly not your crankcase pressure as you would probably blow the oil pan right off the engine!

[rage'nrat638]

i have a high vol.will say this adjusting the rockers sucks......oil goes over the fenders and hits the work bench......
plus my rear main seal leaks.......new engine......just bought a 80 lbs oil pressure guage.....out of fear that the stock one might blow......

i would have been happy with a good stock oil pump my self......

you asked thats imo.....your pal mark

[Green Machine]

I would double check pressure with a known good gauge, But I would say thats too much. Many come with 2 relief springs, I would change back to stock spring. Keep the high vol pump if you must. Maybe not a problem in California, but around here(Iowa), you run the risk or rupturing the oil filter can or blowing out the rubber gasket on cold starts.

[fastwillie 696969]

Originally Posted by rage'nrat638

i have a high vol.will say this adjusting the rockers sucks......oil goes over the fenders and hits the work bench......
plus my rear main seal leaks.......new engine......just bought a 80 lbs oil pressure guage.....out of fear that the stock one might blow......

i would have been happy with a good stock oil pump my self......

you asked thats imo.....your pal mark

hey rat get a old pair of valve covers and cut the tops of the valve cover off to expose the rockers and oil will stay inside the cover than flying all over the place

[wolfthing2000]

I think if you check around and wait for input on this, you will find that high volume pumps and all of the related components are for a good reason and not an inconvinience. I can't imagine why a higher oil pressure at a bearing can cause a seal to leak, unless of course the seal was on it's way out anyway. Bearing clearances that are excessive will cause seals to go out.
I believe also , unlesss you have solid lifters, that rocker adjustment should not be an issue.

[69 longhorn]

I run a Melling 10555 pump on my 383. It runs 72 psi (hot) @ 3000rpms, & tween 30 -40 psi idle in gear (hot). The old truck has a 6 quart pan from a 1 ton truck,& causes no problems......just let it warm up good before you "jazz" the throttle! you need 10 psi per 1000 rpms that you run.....any more than that is a problem tho L

[arkracing]

Originally Posted by wolfthing2000

I think if you check around and wait for input on this, you will find that high volume pumps and all of the related components are for a good reason and not an inconvinience. I can't imagine why a higher oil pressure at a bearing can cause a seal to leak, unless of course the seal was on it's way out anyway. Bearing clearances that are excessive will cause seals to go out.
I believe also , unlesss you have solid lifters, that rocker adjustment should not be an issue.

You are contradicting yourself in the same statement.

A larger bearing clearance will actually result in lower oil pressure - so why would that cause a seal to blow out and not a motor with normal bearing clearnaces with a HV pump????

if you can't imagine why a seal would leak because of a higher pressure @ a bearing surface than why would you be concerned with exessive clearances blowing out a seal - the clearance is @ the bearing surface.


anyway. a 100 psi is a little much for a street bound motor. I'm assuming that this is a small block chevy (if it was a BBC I wouldn't be too concerned. they usually have more oil pressure anyway). as was mentioned before you run the risk of blowing out the oil filter. I think most stock replacement Filters are good to about 200 psi burst pressure and some of the racing ones are good to about 500psi burst.
plenty of stock motors run fine with 30-40 psi and 20psi @ idle. you only need about 10psi per 1k RPM as was stated above. The HV might cause starvation issues @ higher RPMs, Takes a little more HP to turn, etc, etc.

[wolfthing2000]

very simply put, if clearances are excessive, the eccentric movement of the journals will prematuraly wear out the seal.

[pickemup]

i did some reserch on filters and the mobil one is supposed to be the best
as pressure goes. any who this is a newly rebuilt 350 4bolt and its
pretty tight. pressure is high and when i gas it the gauge is burried.(it only reads 80) well maby ill change the pump i got to pull the engine anywho.
thanx