Oil pressure

[mwizard]

Fired up my Van Diemen after an engine rebuild and got about 45 lb oil pressure. It stayed above 15 on idle when it got warm. After several breakin runs I noticed the oil pressure regulator screw had backed out about 1/4 in(appears that the factory did not lock down the set nut), so I turned the screw in to the nut and tightened it. New oil pressure now topping out at 85lb. I backed it down to 78 lb, but is that still too high?
Mark

[Purple Frog]

I'm guessing you are the engine builder...

Otherwise, I would say to call the engine builder.

Me thinks 60 cold is high enough.
Maybe 40 after its warmed up and you blip the throttle on grid.

Hot I'd see close to 40 at 7000 rpm.

On warm days rolling into pit lane after a hard 30 minute race I'd see the warning light flash if I didn't rev it. My engine builder thought that normal.

As always... YMMV

[Hawke]

What the frog said.

[mwizard]

I'm guessing you are the engine builder...

Otherwise, I would say to call the engine builder.

Me thinks 60 cold is high enough.
Maybe 40 after its warmed up and you blip the throttle on grid.

Hot I'd see close to 40 at 7000 rpm.

On warm days rolling into pit lane after a hard 30 minute race I'd see the warning light flash if I didn't rev it. My engine builder thought that normal.

As always... YMMV

Thanks for the info. I had a hand in the rebuild and the Brains on the project was doing his first Kent rebuild. I will back it down more.
Mark

[DaveW]

Back in the day when I ran Kent FF's, I would want to see at least 30 psi hot at speed. Putting around the paddock after a session, we would often see as low as 5 psi at 1000 RPM or so.

So, IMO, anything over 40-50 psi cold is not necessary, since you will usually see lower than that while running once warmed up.

We ran 10W30 or 10W40 synthetic - Redline or Valvoline VR1 (or equivalent).

[Ralph Z.]

My Farley motor runs at 60 psi when cold.

[troyt]

I talked to Arnie at Loyning after my last rebuild by him, similar remarks. 10-15psi at idle, post race with hot oil is normal.

[tim voth]

OK, I want in on this one. I had my 1.6 L kent engine rebuilt, after that, the oil pump has not been able to hold pressure. I have the pressure screw adjusted all the way out, it's still in between 70 and 80 pounds cold. And, will not hold pressure. I keep taking apart,and putting it back together, same thing. I get the feeling after reading the posts, something is up with the way the engine was rebuilt?

[Offcamber1]

what does the pressure drop to once the motor warms up?

[DaveW]

OK, I want in on this one. I had my 1.6 L kent engine rebuilt, after that, the oil pump has not been able to hold pressure. I have the pressure screw adjusted all the way out, it's still in between 70 and 80 pounds cold. And, will not hold pressure. I keep taking apart,and putting it back together, same thing. I get the feeling after reading the posts, something is up with the way the engine was rebuilt?

what does the pressure drop to once the motor warms up?

Good question.

What oil viscosity are you running? A heavy oil such as straight 40 or 50 will result in very high cold pressures, and adjusting the screw all the way out may not be able to compensate. And then warm, with the screw all the way out, pressure may drop to the relief setting, which, with the screw all the way out, may be as low as 5 or 10 psi.

A good oil viscosity is 10W30 or 10W40, preferably synthetic. If you are running that weight, there may be an issue with the relief plunger being worn or sticking shut causing the high cold pressure.

[tim voth]

I guess it never fully warms up, because the oil is always spewing then I shut it down.
I took it to the track this way( not on purpose), and it would turn on the oil light every session, when I was off the throttle.
is it possible to buy different pressure springs for your oil pump?

[DaveW]

I guess it never fully warms up, because the oil is always spewing then I shut it down.
I took it to the track this way( not on purpose), and it would turn on the oil light every session, when I was off the throttle.
is it possible to buy different pressure springs for your oil pump?

What do you mean by "spewing"?

What pressure is your oil light set to go on at? If it's at 30 psi, hot idle pressure, normally below 20 psi, will light it up.

What do you mean by "off the throttle"? Decelerating in gear but still over 3000 RPM, or at idle?

We need to clarify the issue before suggesting solutions.

[DaveW]

All of this assumes everything is operating as it should.

1. When engine is cold and the oil is still thick:
Spring-loaded regulator (relief valve) attempts to bring pressure down to regulator's set point. If oil is very heavy, regulator cannot divert enough oil back to the pan, and oil pressure may be very high.

2. When oil is somewhat warmed up, and its viscosity is in the "normal" range:
Over ~3000 RPM, regulator should control oil pressure close to regulator set point.

3. When oil is hot, and pressure is below regulator set point (normal operating condition for a racecar):
Pressure is controlled by oil pump capacity, engine clearances, and oil viscosity. At speed (4000 RPM and up), oil pressure should be over 30 psi. At idle, oil pressure may be below 10 psi, depending on oil viscosity, oil-pump capacity, and clearances. That is also normal.

[rickb99]

What Frog said in post number 2 is the FACT's. 70 and 80 pounds of oil pressure is just plain too high (no need). And low pressure with the warning light flashing at idle when you pull off the track is perfectly normal with a properly built Kent and Pinto racing engine.

[tim voth]

I guess it would be seeping, not spewing. But seeping with some intensity.

I never thought much of viscosity playing a part in all of this.

I swear the engine builder got me to put 20/50 regular oil in it. I do know this, it's pretty thick.

it is a new Tilton sidemounted pump on a 1.6 driven off the crankshaft.

any suggestions for viscosity?

[DaveW]

I guess it would be seeping, not spewing. But seeping with some intensity.

I never thought much of viscosity playing a part in all of this.

I swear the engine builder got me to put 20/50 regular oil in it. I do know this, it's pretty thick.

it is a new Tilton sidemounted pump on a 1.6 driven off the crankshaft.

any suggestions for viscosity?

Where is it seeping from? There should be no oil seeping out from anywhere. If it is seeping out from the adjuster screw, my solution was to use a "Nyloc" nut so the Nylon would seal it. If it is seeping from oil hose joints, something is wrong with them. What type of hose/fittings are you using?

As I mentioned above, a 10W30 or 10W40 full synthetic racing oil (Valvoline VR1, Redline, etc.) would be my choice.

[tim voth]

somehow the pump to block connection is now sealed. The other two layers of the pump are seeping now, I think it's just from high pressure.

something is causing this high pressure. In your opinion, is it the viscosity, the spring, the engine rebuild?

[DaveW]

somehow the pump to block connection is now sealed. The other two layers of the pump are seeping now, I think it's just from high pressure.

something is causing this high pressure. In your opinion, is it the viscosity, the spring, the engine rebuild?

It is unlikely to be the rebuild causing the issue UNLESS AN OIL PASSAGE IS TOTALLY BLOCKED causing vastly excessive pressure at the pump, and NO OIL SUPPLY to the engine.

Another thought - if you are using a remote filter, is it plumbed correctly (inflow to the outside, outflow in the center)? That is very important for correct filtering and so that if you have a filter with an anti-flow back internal flap, it does not stop the oil flow.

Pressure under 100 psi should not cause a leak. The spring may not be ideal, but that has, in my experience, never been an issue. The relief plunger may be sticking, but in a new pump, that is unlikely, but not impossible. My 1st guess would be too high viscosity is causing the difficulty setting the relief pressure.

There are O-rings between the sections. If they are seeping, either the O-rings are incorrect or damaged, or the pump bolts that hold the sections together are too loose, OR THE PRESSURE IS REALLY OVER 100 PSI.

Sometimes the fittings on the top of the pump leak (the AN-to pump adapters have o-rings between themselves and the pump), or the fittings may be mismatched making it look like the pump section joints are leaking when they are not.

IMO, the oil viscosity is likely too high. So, to properly diagnose this, you need to first try setting the pump oil pressure relief screw to ~50 psi at 1000-1500 RPM or so with a lower-viscosity oil.

Whatever you do, use racing oil so that you have enough anti-wear stuff to not scuff the camshaft, etc.

[tim voth]

thanks Dave, much appreciated. I'm going to try these ideas and I will get back to you.
have a great day!

[DaveW]

thanks Dave, much appreciated. I'm going to try these ideas and I will get back to you.
have a great day!

I added some more comments to my previous post while you were reading it, so please read it again.

Good luck!

[tim voth]

thanks again Dave, I'm on it. I will report back

[tim voth]

Thanks To Dave W and a little perseverance, a positive outcome has been achieved.

So for this particular problem, I will lay out the solution.

After several attempts with hylomar,shellac,even a thin layer of rvt didn't do the trick at sealing the pump.

A combination of oil viscosity(to bring pressure down) 5w30,and back to the rvt,this pump seems to be sealed.

To seal against the block,I used a gasket and rvt. Which the pump to block was never really the problem. The problem was in between the layers of the pump.
To remedy this(after several attempts) I put a thin little bead on the outside of both mating surfaces. When I torqued the bolts(8-10lbs) it squeezed out a tiny bead all the way around the outside of the entire pump. Let dry for 24hrs,which is not helpful if you are in a pinch.

The real test of driving it has not been done. Once I do that, I will report back

[xmazdatracy]

Thanks To Dave W and a little perseverance, a positive outcome has been achieved.

So for this particular problem, I will lay out the solution.

After several attempts with hylomar,shellac,even a thin layer of rvt didn't do the trick at sealing the pump.

A combination of oil viscosity(to bring pressure down) 5w30,and back to the rvt,this pump seems to be sealed.

To seal against the block,I used a gasket and rvt. Which the pump to block was never really the problem. The problem was in between the layers of the pump.
To remedy this(after several attempts) I put a thin little bead on the outside of both mating surfaces. When I torqued the bolts(8-10lbs) it squeezed out a tiny bead all the way around the outside of the entire pump. Let dry for 24hrs,which is not helpful if you are in a pinch.

The real test of driving it has not been done. Once I do that, I will report back

I'm assuming no news is good news.

[Ecclestone]

Changed your brand of oil filter during the rebuild. ???
Make sure your filter has the by-pass valve inside. Many of the cheaper brands don't.