Big(ish) Hybrids and dropping oil pressure

[DZL JIM]

How about some details on what oil pressure is cold, warm running, ipr duty cycle? Condition of the lpop and cam and rod bearings? Type of oil used?

Oil psi cold is around 70 psi, warm 25-30 psi. I run 15W40 Schaeffers Racing oil.
Fresh engine build last winter so everything is in great shape, including the lpop. I have no idea what IPR duty cycle is, I have no way to record that during a run.

 

[pwrstrk01]

I have similar problem not as extreme as yours but 300/200 with bts dual hpop and 65-70 psi cold 45-50 hot at the oil cooler. but on a hard pull (3300 psi 39% Ipr) it will drop the oil pressure at the oil cooler to 40 and the reservoir will drop to about 5, until you get out of the throttle it will drop to zero on the reservoir but the oil cooler will pick back up to 45. I run Delo 400 15/40 rebuilt the engine less than 6k miles ago. I have changed the lpop thinking maybe I had a bad one but no change. I have this problem with all my hot tunes from different venders. My 96 will also do this but only if it is on the rev limiter, need to have the rev limiter bumped up just haven't gotten them adj yet.

 

[DZL JIM]

That's a big concern of mine, going with dual pumps. I am hoping a more 'proper' sized pump like the one I have will work out, I just don't think I need the oil of 2 pumps.

Unless someone has come up with a way to dump the IPR back to the reservoir, with access going back to the oil pan. Some kind of pressure sensitive dump valve or ??

 

[pwrstrk01]

I wanted to try a diesel site lpop. I do agree with being able to dump at least one of the pumps back into the reservoir. Something else I have wondered about is if the oil passages in the front cover is a restriction causing some of the problem.

 

[DZL JIM]

If you don't have the Diesel Site LPOP, get one. 15% m re flow is quite significant.
I don't think the front cover passages are an issue, they are pretty big.

 

[psduser1]

I wanted to try a diesel site lpop. I do agree with being able to dump at least one of the pumps back into the reservoir. Something else I have wondered about is if the oil passages in the front cover is a restriction causing some of the problem.

Didn't a couple guys try dumping back to the rez a few years ago?
I think it caused more problems than it fixed.:shrug:

 

[pwrstrk01]

Just waiting for them to be back in stock hopefully soon. We can't be the only two people that ever had this problem.

 

[Jennifer@Dieselsite]

Just a heads up - found out this morning we're still like a month out. Bob makes these personally and there were some small delays (probably hurricane related). Thought we'd have em back by this or next week but it's more like first of November now.

Sucks because I'm getting a weird wave of calls about them and I kept telling people ETA was 4 weeks... 4 weeks ago.

 

[DZL JIM]

Didn't a couple guys try dumping back to the rez a few years ago?
I think it caused more problems than it fixed. :shrug:

You can't just dump the IPR to the reservoir. It needs to be some sort of pressure compensating valve that will dump excess oil to the pan. Dump enough to fill the res back up and pressurize it to whatever (pick a number, 40 psi?), then the rest needs to go elsewhere, like into the front cover and back to the pan. I don't see why this won't work, I just haven't figured out exactly how to do it yet.

I've made a remote IPR block before, pretty straight forward there, and once there's a hose off the end of the IPR you can do what you want. But selecting how to only dump so much oil has me still scratching my head.
Is there a valve with an adjustable crack pressure?

 

[DZL JIM]

I took a minute to think...
What about:
Use the Riff Raff HPOP spacer, run a line from the pressure port of the spacer to a check valve set at 40 psi (or something better?), run that to a line to a port in the spacer that dumps to the front cover. Then run the IPR dump to the top of the reservoir.

Thoughts?

 

[psduser1]

I don't know of any check valve that will open on low pressure, and close on high pressure. Not without an actuator of some sort, and a limit switch to run it.

In my earlier post, I was referring to hot aerated oil being returned to the resivoir. An inline cooler could fix the heat issue though, possibly.

 

[DZL JIM]

The discharge of the IPR is not high pressure, it goes to atmosphere, but does come out at a decent pressure due to how it's evacuated from the IPR. The issue with dumping the IPR into the reservoir is that it's moving a LOT of oil and can't go anywhere in the reservoir other than being pumped back through the injectors. There is more oil being dumped than used so it builds up in the res and backs up into the IPR. All that oil has to go somewhere and it can't if you dead-head it to the res. Hence why I am thinking put a discharge on the reservoir with a check valve of "X" psi holding power so that the res will fill with oil and always hold "X" pressure. Now dump the IPR back to the reservoir and any excess oil it can't hold will be discharged through the check valve to the front cover and back to the oil pan. But the reservoir will always hold "X" psi full of oil due to the check valve.

I found several check valves like this one: Adjustable check valve
Can be purchased to crack open at whatever pressure you want.

 

[mikeeg02]

Ive never measured pressure at the reservoir. (not saying there cant or isnt any, Ive just never tried to measured it there ) Is there actually pressure there? Or is it the same as the crank case pressure? Since it is vented (the over fill drain tube that goes back into the pan right?) Seems to me you could just make sure the return passage is large enough to allow the additional flow of the IPR (including the lpop) in the event of a full load let off, when so much oil is flowing. Maybe you dont need a check valve, as much as you need a fitting in the hpop above the point were it leaks back down into the pan?

If there is actually pressure there, out of the IPR put the check valve, and plum it into the hpop anywhere. Again, being certain the return port for the overflow is large enough to dissipate the extra oil.

 

[Bluke]

You could also just tee off the line from the ipr to the res and use a regulator to meter it to the front cover. If you want you could put a check valve at the res.

 

[psduser1]

Going back and re-reading your original post. You said you are dropping to about 35 psi midrun- roughly 4400 psi?
If so, based on 60ish psi at idle, I'm wondering if you shouldn't start with a little higher vis oil? How many passes on The bearings?
60 psi down to 35 psi is a big drop. Assuming of course that those values are based on stable oil temps, and tuning is where you want it.
You are assuming that you're not running out of oil in the sump? As I read it, anyway.
Just want to clarify details.

 

[pwrstrk01]

Ive never measured pressure at the reservoir. (not saying there cant or isnt any, Ive just never tried to measured it there ) Is there actually pressure there? Or is it the same as the crank case pressure? Since it is vented (the over fill drain tube that goes back into the pan right?) Seems to me you could just make sure the return passage is large enough to allow the additional flow of the IPR (including the lpop) in the event of a full load let off, when so much oil is flowing. Maybe you dont need a check valve, as much as you need a fitting in the hpop above the point were it leaks back down into the pan?

If there is actually pressure there, out of the IPR put the check valve, and plum it into the hpop anywhere. Again, being certain the return port for the overflow is large enough to dissipate the extra oil.

Yes there is pressure in the reservoir I have measured it, that's how I now I have an issue, you do know that the oil pressure switch for the gauge in the dash is on top of the reservoir right?

 

[pwrstrk01]

You can't just dump the IPR to the reservoir. It needs to be some sort of pressure compensating valve that will dump excess oil to the pan. Dump enough to fill the res back up and pressurize it to whatever (pick a number, 40 psi?), then the rest needs to go elsewhere, like into the front cover and back to the pan. I don't see why this won't work, I just haven't figured out exactly how to do it yet.

I've made a remote IPR block before, pretty straight forward there, and once there's a hose off the end of the IPR you can do what you want. But selecting how to only dump so much oil has me still scratching my head.
Is there a valve with an adjustable crack pressure?

I think this could be done with a hydraulic sequence valve I will look at the hydra-force book tomorrow at work and see if I can find something

 

[DZL JIM]

Going back and re-reading your original post. You said you are dropping to about 35 psi midrun- roughly 4400 psi?
If so, based on 60ish psi at idle, I'm wondering if you shouldn't start with a little higher vis oil? How many passes on The bearings?
60 psi down to 35 psi is a big drop. Assuming of course that those values are based on stable oil temps, and tuning is where you want it.
You are assuming that you're not running out of oil in the sump? As I read it, anyway.
Just want to clarify details.

I probably have 15 passes this summer on the motor with it acting that way. Fingers crossed that running schaffer's racing oil is helping to keep things protected.

I believe that my main issue is that I have the external regulator set too low and it's dumping too much oil when it's really flowing at the end of the track. Track closes in a couple weeks and I have plans every weekend, so I am scrambling to figure out if I can get there somehow before it gets parked for the winter to know for sure.

Yes, I am assuming that I am not running out of oil in the sump. I added 2 more quarts to see if that does anything, too.

 

[DZL JIM]

Ive never measured pressure at the reservoir. (not saying there cant or isnt any, Ive just never tried to measured it there ) Is there actually pressure there? Or is it the same as the crank case pressure? Since it is vented (the over fill drain tube that goes back into the pan right?) Seems to me you could just make sure the return passage is large enough to allow the additional flow of the IPR (including the lpop) in the event of a full load let off, when so much oil is flowing. Maybe you dont need a check valve, as much as you need a fitting in the hpop above the point were it leaks back down into the pan?

If there is actually pressure there, out of the IPR put the check valve, and plum it into the hpop anywhere. Again, being certain the return port for the overflow is large enough to dissipate the extra oil.

There is pressure in the HPOP reservoir. It sees engine lube pressure, there is no return passage, no vent.

 

[psduser1]

If your holding 35 psi, while not ideal, you're not running out of oil.
At the end of the run, hpo spikes, and lpo drops?
I really think you should consider adding a second ipr. No reason to dump oil to the resivoir, there is plenty of pressure (adequate oil) available for the hpo system to work as you want it to. In fact the problem occurs when you ask it to stop turning 4400ish rpms.
Dump the second ipr into the sump, or down the hole in the valley-whatever-and i bet this smooths out.
On a side note, at the level you are running this machine, Imo, a straight racing oil 50-80 at might be worth looking at. Won't fix your current problem, though.