Oil Pressure
We recently started my 70 454 after having a complete rebuild. The engine was broken in for 20 mins at 1500 RPMs. We used 30 weight oil for the break in as the temperature in our area was not too cold. The cold oil pressure using a Snap On gauge was approx. 55 PSI and the motor ran fine. After the 20 mins. we idled down and the pressure dropped to approx. 12 PSI. This seems low. What should the pressure be for a 454 at idle and operating temp? Also, can one oil filter brand over another affect oil pressure?
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Re: Oil Pressure
Depending on Idle rpm, 10# would be "normal" at slow idle. When Corvettes went to digital readouts in '84, my new Corvette scared the H--L out of me showing about 5# at a stoplight in drive, perfectly normal.Bill Clupper #618 -
Re: Oil Pressure
My 63 only carries about 15# at 500RPM idle. I think the important thing is the oil pressure at 2000RPM which should meet the spec. for the engine and of course it's important that the engine has oil pressure at idle.
If you tighten the oil pump gear end clearance to .002 I think idle pressure may be better. I have a new GM oil pump that I did this too and I could not get over how the mounting surface was not flat where it bolts to the main cap. There's a leak for sure, I have always wondered about those shim copper gaskets at this location to seal the connection..
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Re: Oil Pressure
Joe, the scenario you describe is exactly what happens to my '72 LS-5. 55 psi. cold, 10-15 hot. The engine was rebuilt by the previous owner and I have no idea what type of pump was installed. I'm guessing that it was a stock type pump, was yours? If so I think the oil pressure in both of our engines is OK. Have fun!!Comment
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Re: Oil Pressure
Lynn, the pump is a stock unit. It's reassuring to know your pressure is similar, but it just seems low.
Any other 454 owners have a comment?Comment
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Re: Oil Pressure
Joe I also did a rebuild on my 70 454 in early 2009 my cold oil psi was also 55, when at operating temp at idle it was 18 psi i used a couple of gauges to check accuracyComment
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Re: Oil Pressure
Tom, what weight oil are you using?Comment
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Re: Oil Pressure
Here's an update on my low oil pressure concern. Today we changed the oil and added 10-30 wt. along with a HP 4 filter. The engine on start up had 55 psi. The motor was allowed to reach operating temp and at idle had 14 psi. When reved the oil pressure went up immediately. All of these readings were measured using a known mechanical gauge.
It still seems low, but maybe it's just me. Any thoughts are welcomed.Comment
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Re: Oil Pressure
Functionally its fine as long as you have enough pressure to keep the lifters pumped up that all it needs. The only function that pressure serves is to insure that the VOLUME of required oil is delivered to the different components in the engine. The lifter galley in a big block is the last to be feed so if the pressure is adequate to keep the lifters pumped up your fine. Presuming the pump is working properly and it internal regulator is okay, and it sounds as if they are okay then some pressure loss could occur from engine component wear. When your engine was rebuilt were the cam bearing replaced? If not there can be pressure drop due to increased leakage at the cam to bearing due to increased clearance. Also some high millage blocks especially ones that may not have been receiving proper oil changes can also have loose lifter bores which cause the same symptom as the cam bearings. All this means is that you have slightly less top end pressure but as everyone said 10 lbs is totally acceptable.Comment
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Re: Oil Pressure
Kenny, tx for the response. Yes, the cam bearings were replaced along with all other internal components. I'm reassured now from all the feedback. I guess it was just my own paranoia.Comment
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Re: Oil Pressure
With 15W-40 (Diesel grade) at operating temperature I have 25 psi @idle and 55 psi @rpm's over 2500.
My engine was rebuilt. I purchased a NOS GM stock pump. I did check all the clearances and had a machine shop make sure the plate and mounting surface were flat. I also made very sure there was no leaks where the pickup tube enters the pump (had it welded in place).
I also have very tight clearances on my rod and main bearings.Comment
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Re: Oil Pressure
Just a note on Bills comments. He is using a thicker oil and thay probably contributes to higher oil pressures at idle. After having the same concerns as Joe M. I tried using 20W-50 oil and pressure increased at idle as well as at higher rpm's with the oil both cold and hot, but I don't remember exactly what the numbers were.
I mentioned this to the engine builder I use and he said that using the thinner oil would be Ok unless the pressure did not jump up as engine speed increases, which it does. I'm now using 10W-30 and just watching for any indication of trouble, none so far.Comment
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Re: Oil Pressure
I don't think that there is enough difference between 15w-40 and 10w30 at hot engine temperatures to make a near 10# + difference in pressure at idle.
I would be willing to bet on "engine tolerances".......Comment
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Re: Oil Pressure
Sounds like the general consensus is that a lower oil pressure at idle is not a cause for concern as long as it rises rapidly as RPMs increase. I appreciate all the comments to date and welcome any further discussion.Comment
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Re: Oil Pressure
Joe I use 15w40 oilComment
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