Oil pressure-How much is too much?

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Doosterfy

Doosterfy

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I finally got my 440 running. It's a street strip motor with about 11 to 1 comp. solid roller, 440 Source Stealth heads and a single plane intake. It seems to run well but I was only able to drive it very little because the transmission has an issue. My concern is the oil pressure. IDK what the bearing clearances are, I did not build the short block. It has a Sealed Power high volume pump. The pressure is about 80 psi at start up and has not gone below 75. I have not reved it over 4000 rpm. The oil is Valvoline 10w40 conventional. My questions are, 1) How much is too much? 2)Should I do something to reduce it? My biggest concern is having an oil filter burst at high speed. I'm planning on going to about 6500 rpm so I imagine the pressure will be very high at that rpm. I did install an MRL top end oiling kit and it looks like the rockers are getting plenty of oil.
 
You might want to opt for a thinner oil and have a lot of volume with a lower pressure.
I read an article that changed my mind about using thicker oil and having a high oil pressure.
The basics of it were that having a higher flow of thinner oil is better for the motor than a lower flow of thicker oil.
Also that the thinner oils would travel through the block with less restriction, so the combination of those two would be a lot better for the bearings because it cools them better because of the flow volume.
Of course it was a lot more involved than that in the article, but that was the basic idea of it.
 
I believe you can take a coil out of the spring to bring the pressure down some. Or 440 source has an adjustable spring setup. Never used it but may be worth a shot. I'd guess nice, tight clearances which means you really don't need that pump.
 
Has it reached full operating temp yet?

Try switching to a 5w or 0w oil in the meantime.
 
80 psi on start up is not bad, in fact most pressure regulators set at 80 to default. Where does it go once warmed up and with rpms? If your regulator keeps it capped at 80 regardless of rpm that's not bad. Are you running any type of oil flow restrictors?
 
I would ditch the 10/40 conventional and try 10/30 VR1 valvoline. I have a hi psi spring in my 383 cold it goes to 80, warm it idles at 32 when you rev it past about 2,200 it tops out at 72
 
Are you running a 180 or 195 thermostat? Are those readings basaed on a hot motor?

Is the engine broke in completely?

If so:

Redline 5w30 synthetic. Plenty of zinc ( I realize you have rollers). Or run 10w30 conventional Rotella T. Napa has store brand 5w30 syn on sale quite frequently.

No need to spend horse power pushing thick oil past the relief valve and also thru passage ways.

Thinner oil returns to pan quicker for more available oil at high rpm, flows better thru oil passages, arrives at upper engine more quickly during start up.
 
Rice Nuker said:
No need to spend horse power pushing thick oil past the relief valve and also thru passage ways.

Thinner oil returns to pan quicker for more available oil at high rpm, flows better thru oil passages, arrives at upper engine more quickly during start up.
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These were also some of the other things the article I read mentioned that convinced me to go to a thinner oil since I had good pressure.
 
Once certain of adequate Engine Temperature, and the Oil.... IMO, your concerns should then focus on ascertaining actual Oil Temperature @ Load... more specifically is the Engine Oil getting too Hot(200+) too quickly ?
Without any knowledge of the clearances used in the Shortblock.... one of the biggest cautions to Bearing fatigue.... is the free Flow of Oil to the Bearings to maintain Bearing COOLING !
Vertical Bearing Clearance, and Side Clearance in Rod pairs.... are responsible NOT just for lubricating the Bearing.... but for allowing Oil in... and OUT to cool the Bearings.
just saying.... if this Engine continues to have extremely High Oil Pressure even if after warm, with lighter oils, potentially the clearances may be too tight... Pressure = HEAT !

Question;
What "kind" of Solid Roller Cam are you running on the "Street" to 6500 rpm ? What was the Head Flow ?
"Race", or a "Street" Roller profile ?
What Spring Rate & installed Seat Pressure ?
 
I willing to bet the clearances are just fine. The high volume pump is designed to help out higher mileage motors that are loose. Toss in a HV pump, cam & headers & you've got yourself a hotrod. We just don't need these pumps on a fresh shortblock. I've been contemplating switching my hv pump out on my 451 build as my bearings are tight as well.
 
80fbody said:
I willing to bet the clearances are just fine. The high volume pump is designed to help out higher mileage motors that are loose. Toss in a HV pump, cam & headers & you've got yourself a hotrod. We just don't need these pumps on a fresh shortblock. I've been contemplating switching my hv pump out on my 451 build as my bearings are tight as well.
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Just us I guess..... but for street stuff running anywhere around 500-550hp and up to 6,000 rpm we target .003" vertical on the Mains and .0025" for the Rods on 10W-40 weight with "P" Eccentricity Bearings(up to 500).... moving the Rods closer to .0026" to .0028" on "H" Eccentricities past 500.
We then "set" Rod Side Clearances in pairs for oil leakage/bearing cooling.
With an HV Melling....typical Cold is 75-80 psi....moving to 40-45 psi Idle Hot with back to 70-75psi @ rpm... 170-180* F Oil Temp.

We get VERY SCARED of tight clearances for Bearing cooling reasons on these older generation Engines when making power.
IMO, .0015" Bearing Clearance is NOT satisfactory for ANYTHING !
 
Had same problem with 340 stroker engine.Had high volume melling pump.
Put stock melling pump in pressure is around 75 cold and 35 40 heated up.
 
Wow, that's alot of responce. Lets see, the motor has run for a total of about one hour. It has gone over 200 degrees, because the fans are not adequet. When its hot the pressure was still 75-80 @ idle. I doubt the clearances are too tight, the short block was built by a long time reputable race engine builder and he knew what the application was. I did wiggle the rods and saw that there was side clearance. Just by eye I would say plenty more than .0015. The cam is a COMP Extreme energy XR292 and the COMP specs say the power range is 3500 to 6600. OK with that said, the consensus is that I should take measures to bring the pressure down. Once I get the trans and cooling system sorted out, I'll start by going to a thinner oil. If its still too high, I'll probably trim the pressure spring in the pump. If that fails, I'll ditch the HV pump and go with a regular volume one. If it still too high after that, I'll tear the engine down and invest in a good micrometer set and start checking the clearances. I'm not even going to think about putting my foot in it and reving it up until it's resolved. Thanks to everyone for the input. I'll keep you posted on how I make out.
 
Why not just try taking out the Oil Pump Pressure Relief Valve(Big Nut on the side of the Pump), accessed externally on the outside of the pump, see if there is anything you can do to lower the relief spring pressure itself... let it dump back at lower pressure ?

Sometimes they have a small washer behind the spring ? Remove it, as long as the Nut Housing Bore still has a seat for the Spring, or add washers on the large external Nut Housing that you remove to access the Spring ?

If still gunga pressure, even with thin Oil....clearances are too tight.
 
Challenger340 said:
Why not just try taking out the Oil Pump Pressure Relief Valve(Big Nut on the side of the Pump), accessed externally on the outside of the pump, see if there is anything you can do to lower the relief spring pressure itself... let it dump back at lower pressure ?

Sometimes they have a small washer behind the spring ? Remove it, as long as the Nut Housing Bore still has a seat for the Spring, or add washers on the large external Nut Housing that you remove to access the Spring ?

If still gunga pressure, even with thin Oil....clearances are too tight.
Click to expand...

I would feel a lot more comfortable with thinner oil, especially If I had tight clearances and high pressure.
 
Simple economical thing to do would be to get rotella T 10w30 (not 15w40) and a new, quality filter. Run it and get your radiator and whole system stableized. Then reassess. Just like you said above. Let us know how it's going !
 
Was the pump disassembled and cleaned prior to install? A couple things pop up for me - even with an HV pump the pressure should drop when hot.
So to me it might be either the clearances are too tight for the HV pump, or it could be a function of a sticky relief valve. I would pull the pump and take it apart. Clean it well and verify the relief valve bore is clear and it moves smoothly. Note if it has a washer in there (leave it if it does), then reinstall and run it. If it still is high and doesn;t drop, pull out the washer through the plug. If that doesn;t work, replace the pump with an HP or a standard pump with the HP relief spring from the HV pump. Pressure is always a function of both the pump used and the clearances ran.
 
I just ordered a Sealed Power regular volume/regular pressure pump. I'm getting the trans back next week and have to get it in and test drive it to verify the trans problem is solved. It a cold winter here in New England and I'm not comfortable at all running it with the high pressure in these conditions. I'm going to simply swap in the new pump as is and if the road is clear of ice and snow just get the testing of the trans done and if the trans is OK, go on to dealing with getting the cooling system up to speed by upgrading to much higher CFM fans. After that I'm waiting till springtime to do any additional sorting of the oiling system.
 
Have you tried a different gauge?

Summit Mopar Performance relief spring is rated to 70 psi.
 
440outlawdart said:
80 psi is about the norm,ive had that since I had big blocks 30 years ago,at start and will come down once warm
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That's the problem. When I first started it I was not concerned. I did get it up over 200 degrees on the coolant gauge and the pressure stayed high. The oil pressure gauge is a Stewart Warner mechanical gauge I had been using for many years in a truck and it always worked fine so I don't think there's an issue with the gauge.
 
A HV pump is a great idea... until you pump your sump dry.. People treat oil pumps like they do Camshafts... the bigger the better.
 
Bakerlite said:
A HV pump is a great idea... until you pump your sump dry.. People treat oil pumps like they do Camshafts... the bigger the better.
Click to expand...

You're right. I have used HV pumps in most engines I've built or replaced the oil pump in. Some engines such as Buick V-8s really benefit from them. I did think about it when I ordered the HV pump and even posted about it. Considering how easy it is to change the pump on big block Mopars, I don't regret my choice either. I now will have two pumps to work with and fine tune the relief spring pressure to get the results I'd like to see which to me would be about 60-70 at cold idle and 30-40 warm idle with 50-70 at high RPM, (input welcome on this). Also, you're right about sucking the pan dry. I spun a bearing on a big Chevy by doing just that, loose clearances with high volume/pressure pump and stock pan and one bonanzi top speed highway run.
 
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