oil pressure for 427 aluminum block

[flipscobra]

I have a Shelby block it holds about 75 lbs at start an runs about 60 lbs when hot an idles at about 45 to 50 lbs been holding this for 7 years. I run 20W50 racing oil. Great motor Flip

[Al G]

Coach Mike - Since Keith built your engine have you asked him what your oil pressure should be?

[COACH MIKE]

Thanks for info. I will contact builder. Mike

[Gaz64]

We had the same problem, bad hot oil pressure in one engine years ago.

Any large clearance within the motor will give low hot oil pressure.

In our case, rods and mains were in the middle of spec, BUT cam bearings were too loose.

[patrickt]

It wouldn't be as much of a nuisance if the engine wasn't already delivered, installed, and running in his car. It's not like a case of "my horn won't blow." Considering how much dough we drop on these POS FE engines, you would think they would all be burned in on the dyno, run in nice and hot, and pressures and leaks checked and double checked. But NOOOOO.... But wtf, I'm not even sure were it came from.

[Bernica]

Patrick,
Take a breath and don't stroke out on us. We need you!
It is what it is, and he needs any help and/or advice we can provide. Yes, it may suck in the end, or maybe not. I think we all owe it to a fellow member to chase every corner. That's why we are here, right?

[olddog]

It may have a thin break in oil, in the engine, and we still do not know if the gauge is accurate. To early to tell if there is a real problem.

Warm idle oil pressure will drop off the most if there is a lot of clearance someplace, but it is not necessarily a good indicator of the likely hood of an engine failure. I have had people claim that the oil pressure at higher rpm is more indicative of will the engine fail.

I had an old junk truck I used to haul firewood. It idled at 5 psi and only carried 30 psi at high rpm. I ran the crap out of it for 7 years. It was drove to the junk yard under its own power. I realize this does not compare to a $12+K FE. Just saying people may put more focus on oil pressure than it deserves.

[patrickt]

Originally Posted by olddog

It idled at 5 psi and only carried 30 psi at high rpm...

FEs were absolutely notorious for low hot idle pressures. For the most part, it meant nothing. Just like the "commercially acceptable" amount of oil that would leak from them.

[Bernica]

Originally Posted by patrickt

FEs were absolutely notorious for low hot idle pressures. For the most part, it meant nothing. Just like the "commercially acceptable" amount of oil that would leak from them.

Yep, I've had 390's, 406's, and 427's back then. That's when we all ran plain old 30-weight and the tolerances were pretty loose, compared to these days. Oil pressures were 30 psi at best, and sometimes much less. Oh, and they all leaked oil from somewhere. That's why we all had those sheet metal drip-pans under our cars.

[Cobra #3170]

FE's and old Harleys have a lot in common.

[Eljaro]

A few months ago I received my new KC482 Pons Sideoiler block with the new forged crankshaft.
After assembling the engine and installing it in the car I was surprised at the low oil pressure I was getting.
I drove the car for about 30 minutes do do the break in and when hot at idle oil pressure would come down to less than 20 PSI with 20-50 Oil. This being a new engine I knew something was wrong.

I drained the oil , removed the oil pan and found one bolt from the oil pump cover laying in the oil pan and the other 3 bolts of the Melling HV oilpump could be undone just with the fingers.
Luckily the oil pump is submerged in oil, so it did not take in air, but some pressure was seeping out of the cover.
I took the oil pump cover to have it shaved flat and installed it with the bolts tightened at 19 ft/lb torque using red locktite .
Pressure is now 40 PSI at idle and very stable across the rpm band, between 40 and 60 psi hot.
The bolts on the Melling pumps as they come from the factory may not be tightened as should so I would check that.I also removed the aluminum tag with the model code.

[ERA Chas]

Originally Posted by patrickt

FEs were absolutely notorious for low hot idle pressures. For the most part, it meant nothing. Just like the "commercially acceptable" amount of oil that would leak from them.

Pal-Please stop dragging out the ancient history lessons. That stuff doesn't apply to the 1.2 to 1.5HP engines we (well most of us ) have today.
We use small journals, bearings, better rings and much tighter clearances. Plus oil is 1000 times better.
Only the newbs are impressed with you archival skills...
that's not helpful info anymore.

[ERA Chas]

Originally Posted by Eljaro

The bolts on the Melling pumps as they come from the factory may not be tightened as should so I would check that.I also removed the aluminum tag with the model code.

That's surprising to hear from a KC motor. Checking a new pump or blueprinting it is SOP with good builders.

[Eljaro]

KC didn´t supply the oilpump since this was a short block. Pump came out of the box and I installed it myself. Should have checked the bolts beforehand.
Anyway, one place oil pressure can leak out is the oil pump and if you have an oil filter take off and did not seal it right or with too much RTV sealant, pressure can push its way out somewhere it should not.
Just one place Mike should have a look.

[Bernica]

Originally Posted by Eljaro

KC didn´t supply the oilpump since this was a short block. Pump came out of the box and I installed it myself. Should have checked the bolts beforehand.
Anyway, one place oil pressure can leak out is the oil pump and if you have an oil filter take off and did not seal it right or with too much RTV sealant, pressure can push its way out somewhere it should not.
Just one place Mike should have a look.

NOW we're back on topic. Good info for you to check Mike. See msg #8 from Keith C as well. Not sure of your setup, but there are threads here about removing your oil pan if it comes to that. As stated above, pull a pressure check straight from the engine with a reliable gauge, from cold to hot.

[patrickt]

Originally Posted by ERA Chas

Pal-Please stop dragging out the ancient history lessons.

But one must have an appreciation for whence forth one has been in order to appreciate the journey. Much less what lies over the horizon.... And besides, Bernica likes it.

[ERA Chas]

Originally Posted by patrickt

But one must have an appreciation for whence forth one has been in order to appreciate the journey. Much less what lies over the horizon.... And besides, Bernica likes it.

[Bernica]

Originally Posted by ERA Chas

"Each generation imagines itself to be more intelligent than the one that went before it, and wiser than the one that comes after it."

- George Orwell

One scoop chocolate, one scoop vanilla.....Don't waste my time!

[patrickt]

Originally Posted by Bernica

- George Orwell

Little known fact around here, but "Some Thoughts on the Common Toad" is one of Chas' all time favorite books.

[ERA Chas]

Originally Posted by Bernica

"Each generation imagines itself to be more intelligent than the one that went before it, and wiser than the one that comes after it."

Mike has had his motor down to the crank-and this is the replacement short block.
He needs no advice about pan removal or reliable gauges-he's well beyond the 101 stuff.
Dispensing advice is only valuable if you've been around frequently enough to know who you're talking to. Apparently, 70 posts a year is not that frequency.