Need some help - loosing oil pressure at high rpm's

[madmaxx]

Progress Update.

I removed the pan (14 minutes) to install the new spring. Prior to removing the existing spring I screwed it in to see how far off bottom it was. It was 1/2 turn off bottom sooooo the Mellon rep was right max pressure stock spring 70 psig. As you may recall my last engine had 79 psig before bypassing. I surmise the builder on that one installed the stiffer spring during the build. The new spring is much stiffer than the old. I installed about 2.75 turns in which is 1 turn off bottom.

Since the car had the wrong thermostat 180F the engine would never get above 65C after the thermostat openened. I changed to 195 and wow as I suspect now I am at 80C right where I want it. I have said it before a thermostat opens at it set point but does not close until 15F below it!!!!! The spf cooling system is soooo efficient. Please don't ask if my gauge was accurate. That took 45 minutes, longer than the spring change LOL!!




Ok, fire it up, wtf, 70 psig oil pressure at idle and I had put the oil cooler back in the circuit!!! This means the pump is probably 90 psig. I still have the stock oil filter fl-1A on the engine. I blip the throttle and oil pressure spike to 80 psig. I let it idle forever to get the oil temp up to 60C, what are the odds coldest day in Houston in a fking year.
Engine coolant at 80C but fuking thermostat housing dripping like a sieve since I didn't let the sealant dry ( I have no patience).

Any way I take it for a drive and I am nervous the fl-1a is going to blow apart lol. Oil pressure up to 4k rpm is now 58 psig! an 8 psig gain or put another way the oil pump is not dumping 8 psig of oil back into the pan since the rv is not lifting!!!!!!!!!! Remember the most on the last one was 50 psig with an engine running at 60C not 80C!


Sooo that was great news, I run it to 6K rpm and same scenario at 4.3K oil pressure drops from 58 psig to 52 psig. This is acceptable as it was dropping to 43 psig. Last thing in the test is put the Royal Purple Filter on as I will not start it again with the fl-1a. If the pressure swing goes away I will drop the pan and back out on the oil pressure spring to 1/2 turn from all the way out.

I reinstalled the thermostat housing last night but the sealant is not dry it 35F out so I guess I will get the ride height corrected today. Hopefully tomorrow I can try it.

On a side note my buddy from work calls me. He said we all got 15K raises, yea right I am trying to install this spring don't bother me. Lucky I checked my work since I put the plug in backwards the first time, the spring sits in the cup side. Turned out we did get the raises!! Houston is hot for engineers!!! that's good I have about $85.00 into this fiasco so far!!

[blykins]

I've never understood the need of an oil cooler in a street driven Cobra. I despise them, as well as remote filter adapters. I understand that in some Cobras, such as the SPF cars, the filter adapter is almost necessary due to room constraints. However, on others, the excuse that it makes it easier to change the oil isn't worth the extra expense and trouble.

I would not tolerate any pressure drop, especially at just 4000 rpm.

I would also not tolerate a Royal Purple oil filter. Keep the Motorcraft, or better yet, a Wix Racing filter.

[madmaxx]

I agree with the oil cooler they are useless but look cool and sell cars!! Surprised by the rp statement. My shade tree mechanic analysis indicates different, lol. The analyses rp performed showing flowrates vs pressure drops at 30cst were pretty thorough. To boot not that it matters in our world they filter to 20 micron at 99% efficency. I have cut them all apart and I know the rp uses synthetic media, not sure about the fl1 hp. I also know on same set up the rp worked perfect and I had 2 psig more pressure at 5500 rpm going down the freeway over the fl1 hp.

As far as the pressure drop lets see what happens with the filter change. The previous owner been driving like this for 4 years and 4 k miles with zero ill effects. I am 100% confident this spring been in their from beginning as builder dyno showed 58 psig now we install in car take with oil cooler and he has been running 50 or less since new.

[madmaxx]

Before the rp did their own analysis flames. Wtf is the ford analysis on their products??. I challenge anyone to supply them.

[olddog]

It takes a certain amount of energy to pump a given quantity of oil, in a given time period.

The more pressure you build the more energy it takes to build it.

So if you increase either oil flow volume or the pressure, you increase the load put on the gears that are turning the pump.

Cranking the pump pressure up to keep the oil pressure at the engine where you want it, because you have a turd plugging up your plumbing, may exact a price. Ford SB engines are noted for having cam/distributor gear issues, along with twisting off pump drive shafts.

I would not go down this road. I would get rid of the restrictions.

[blykins]

Yeah, not a fan of Royal Purple anything. Their oil is expensive, doesn't rate too high, and IMO there are other filters that are higher quality, for less money.

[madmaxx]

I do not use rp oil to expensive!! One of my plants make the base stock for them. They as most just use an additive package. What an incredible story. Started in a tiny little building. As far the filter I just poured 3/4 quart into it, I never stopped pouring. On the fl1a I fiddled and farted for 5 minutes to get a half quart in, shaking the filter and I still overflowed it. So bench test the rp flows better lol.

I use mobil1 for 25 from walmart. In today lubes for what my street use is they all exceed my demands. Doing a quick blast onto the freeway is not tracking. I have no interest in tracking for one simple reason u can't drink while doing it!

[Jerry Clayton]

You had no comment about my suggestion that you may have a venture effect where you are mounting your guage????????????????

Have you checked crankcase pressure/vacume for the possible effects of pressure differential causing the lower reading at the 4k?

And about your comments about the water temp thermostat--------if you (and others) weren't removing so much engine temp from the unnecessary oil cooler, the H2O wouldn't be so wacko--------

We have been running some engines with dry sumps and crankcase vaccume pumps pulling so much crankcase pressure out that the oil feed pressure goes to less than 5 psi because of the differential ---------

Why haven't you changed the bearings while you had the pan off----------proper bearing clearances is number ONE item in any list chasing oil pressure problems----------

[madmaxx]

Slow down. I am no expert. How do I check crankcase vacuum??? It has a PVC valve, I will check if it rattles. What else do I do. I am open to everything!


As far as bearings I wanted to replace and orderd them and after many many people they all said it waste to change not my problem. I pulled a main and rod and like everything else they looked perfect. The new bearings are sitting on my dining room table.

No doubt the Rv was set to low to begin with, set to high now but progress was made.

Last mystery is the flutter at 4.2krpm. I agree there is a restriction but where??????????

This engine and car is identicle set up as my last one, except single plain intake. Same gauge location. I used stand alone gauges to verify.

Originally Posted by Jerry Clayton

You had no comment about my suggestion that you may have a venture effect where you are mounting your guage????????????????

Have you checked crankcase pressure/vacume for the possible effects of pressure differential causing the lower reading at the 4k?

And about your comments about the water temp thermostat--------if you (and others) weren't removing so much engine temp from the unnecessary oil cooler, the H2O wouldn't be so wacko--------

We have been running some engines with dry sumps and crankcase vaccume pumps pulling so much crankcase pressure out that the oil feed pressure goes to less than 5 psi because of the differential ---------

Why haven't you changed the bearings while you had the pan off----------proper bearing clearances is number ONE item in any list chasing oil pressure problems----------

[PLDRIVE]

Max Glad to hear the spring worked for u. Nice follow up.

Mark

[madmaxx]

Thanks, as I roll into my 5 th beer watching Auburn I am skeptical about the filter causing the dip. My pressure gauge last test was after the filter and never saw a dip. Sooooo I will try for grins but rod and mains are probably going in. Easy work. If that doesn't get it who Kobe's I will hae exhausted all avenues and will be forced to install a dummy light in place of gauge.

[blykins]

I honestly don't think it's bearing issues. If you had loose clearances, the oil pressure wouldn't just dip at 4300 rpm. You did check a couple right? If they looked new, chances are that you don't have a problem with the others.

I think you have a problem with the pickup, or the oil is not returning as it should.

If I would have been checking this, I would have bypassed all the remote filter junk and the cooler altogether. Slap a filter directly to the block, even if it is a shorty, and then see if the pressure dips.

[Rick Parker]

The more you describe your concerns the more it sounds like you are getting a vortex at the pump screen and sucking the pan empty.

[madmaxx]

I found a shorty filter which will be tight but shoild screw to block once I remove the adapter. It will be a pain you guys are the experts. As far as the pickup it is a square box about a .75 deep. A tube exits the top. Sooooo the bottom of the box is .5" off the bottom the tube inlet inside the box is 1.5inches off bottom. The builder has produced in excess of 700? of these engines with the same the pickp it is not a homage job. I think the shorty filter directly to lock is next.

Thanks for all the input!!!! A high of 40 today and rain, this is nuts

[madmaxx]

I will say this on my last one if I was driving it wide open from 3rd to 4th to 5th I would notice the oil pressure drop. And when it did it was quick. But If I went down the feeder at 60 mph in 2 nd gear at 6k rpm the pressure was solid At 58 psig. That was pump starvation as the pressure would just keep dropping until i let off the gas, this one doesn't keeps falling it stops. That said I haven't taken it to 140mph rowing through the gears yet and don't care to anymore. I have used up the majority of my 9 lives.

[PLDRIVE]

Max follow Brents instructions (put the filter on the block). I will bet you 5 more beers pressure returns to normal.

Mark

[CHANMADD]

Thats the problem..... get a stock round design pickup and definately with a screen.... what about some baffles to keep the pickup covered ........when I changed to a K&N filter I got a few pounds gain...

Originally Posted by madmaxx

I found a shorty filter which will be tight but shoild screw to block once I remove the adapter. It will be a pain you guys are the experts. As far as the pickup it is a square box about a .75 deep. A tube exits the top. Sooooo the bottom of the box is .5" off the bottom the tube inlet inside the box is 1.5inches off bottom. The builder has produced in excess of 700? of these engines with the same the pickp it is not a homage job. I think the shorty filter directly to lock is next.

Thanks for all the input!!!! A high of 40 today and rain, this is nuts

[Rick Parker]

Make the bottom of the pickup max 3/8" off floor of pan. Install H/P spring in pump and adjust the screw to be flush with the machined face where the pickup attaches. Be sure to use gasket at this junction and where pump attaches to the block. If the pan does not have the square or diamond shape containment area with trap doors to control oil flow, this could add to the problem of the oil getting away from the pickup under acceleration or braking.

[madmaxx]

I put a high pressure spring in but will readjust as you state. The pan is fully baffled with door where the pick up sits in a diamond shape area, windage tray and all. Once I get the filter on the block I will have new data.

Originally Posted by Rick Parker

Make the bottom of the pickup max 3/8" off floor of pan. Install H/P spring in pump and adjust the screw to be flush with the machined face where the pickup attaches. Be sure to use gasket at this junction and where pump attaches to the block. If the pan does not have the square or diamond shape containment area with trap doors to control oil flow, this could add to the problem of the oil getting away from the pickup under acceleration or braking.

[olddog]

Since the measured pressure at the cooler inlet is constant, when all this happens, it proves three things (at least in my mind).

1) Since the pressure is not changing, the PRV has opened and it is regulating the pressure.

2) The problem is after the cooler.

3) There is no problem before the cooler. The oil pump, pan pickup, baffling is not causing the problem or the pressure before the cooler would drop at the same time it does at the engine.

Since the PRV is open some of the oil (that the pump is pumping) is dumping back to the pan and some of the oil is flowing to the cooler, and thus into the engine. The point at which the PRV lifts whatever amount of oil is flowing through the engine, will not increase no matter how much the rpm increases. So the oil flow through the bearings is not increasing with rpm (after the PRV lifts).

Oil is heated in the bearing from the shear action created by the speed differential between inner and outer surfaces. The longer the time the oil spends in the bearing, the hotter it gets. The higher the rpm the quicker the oil heats. If the oil flow through the bearing is not adequate, it overheats and the viscosity drops rapidly (inside the bearing).

I am suspecting that the cooler and plumbing after the cooler is causing the oil flow to the engine to drop so low that there is not enough oil flow through the bearings to prevent viscosity breakdown, above 4K rpm. The pressure drop you are seeing is the oil viscosity dropping in the bearings. If I am correct, going to a thinner oil should improve the situation, because you will get more flow through the cooler an plumbing after it, and thus more oil flow to the engine.