oil pressure LOST, and then 24 hours later BACK

[Pete Munroe]

All,

Seems there is a lot of this oil pressure stuff going on...!

Track day at Willowsprings this week. In turn 2, long sweeping right hander, looked down and the oil pressure had dropped from ~65 to 20.

Backed off and opened the turn expecting it to pop back up, but it stayed at 20. Took is very easy the rest of the way around. As I pulled into the pits it was at 0. No noises, ie: rapping, thumping and clatter as if to suggest internally all was ok (maybe-sort of-fingers crossed).

Sat about 5 minutes oil temp was around 200. Started it and the pressure was still 0. Pushed it on the trailer and then (up-hill! ) into the garage.

24 hours later started the engine and at idle instantly its normal 40 psi cold. Blipped the throttle a little and it rose right up where I would expect.

Can the pressure relief valve in a SB Ford pump stick open...? I had bounced it up on the rev limiter on the front straight, 6300. was thinking the pressure may have been higher than normal and pushed the valve pintle (?) far enough to jam it open...? Can that happen..?

Engine is a 65-289" with AVIAD pan, roller cam and rockers.
Crank scraper was removed to clear a lower end support. Checked oil before I went out it showed ~ 7 1/2 to 8 qts in the pan (that does not include the cooler and thermostat).

In the PAST have seen very brief oil psi fluctuations in turn 2 but it always jumped back up as soon as you unloaded the car.

Am not familiar with the valve internals on the SB Ford pump, but assume the pressure valve is a spring loaded piston in the side like on my old Corvette.

Was going to cut open the filter and take a look, and may drop the pan to inspect the relief valve and pump/pump screen.

Ideas on why the pressure would drop to 20, then 0 and then, 24 hours later, system seems normal. I can only assume the valve was stuck open. Cooling off and the drive home loosened it up.

Thanks, Pete

[Tom Wells]

Pete,

Since I wasn't there this is a guess: could the oil have foamed? Oil pressure goes to zero instantly if that happens.

Also, oil level can contribute to no oil pressure. Early on I was told it is better to add an extra quart to be safe on the track. The result was the opposite! An extra quart can cause some real problems. It turns out that running 1/2 quart low is much much better.

Also, are the drainback areas from the heads clear? At those engine speeds for sustained runs, an amazing amount of oil goes into the valve covers, which can stay a while if it can't drain easily back to the pan. Remember, it's being pumped up there under pressure, while gravity is all that's getting it back down.

Another suspect could be the gauge. Worth checking.

Might be extra cautious and cut the filter just to be sure nothing else is in there but oil...

At the very least I'd change the oil & filter.

Just guessing,

Tom

[DAVID GAGNARD]

Like Tom said, cut open the filter and inspect,then oil change and double check the oil pressure gauge....sounds very odd.......
what kind of oil pump do you have???

I'm running a road race Canton 8 quart pan on a small block Ford in my 65 coupe road race car, I've tried to watch the oil pressure is some long sweeping turns and have never seen my oil pressure fluctuate at speed, normal oil pressure at speed is from 50 to 55 psi, with the oil temp from 220 to 250......The canton pan has the 4 spring loaded trap doors and evidently does a good job at keeping the oil in there for the pickup...I'm running a Melling HP Series standard volume/standard pressure pump......

David

[Rick Parker]

Yes Tom that is a LOOOONGG uphill RH sweeper that will do crazy stuff. I think you are on to something with the relief valve staying open. Any small bit of grit could prevent the plunger from closing. Did you have any abnormal amount of oil coming from LH Valve cover fill tube?

[RICK LAKE]

Pete Munroe Pete I have had the same problem. ended up with adding 1 extra quart of oil to the system and 3 quarts for the accusump. I have the accusump with 40psi to help save the motor on long sweeping turns or high bank oval parts of tracks. It sound like something did get into the pump. You banged the motor off the limiter, I have done this too but not lost oil pressure. For my 2 cents, I am pulling the oil panand replacing the oil pump with a blue printed one. I would also look in the bottom of the pan for any debrie or metal flakes. If found, pull motor. Not an easy choice but could save you alot of money now and not break the motor. It's no fun to oil down a track and some tracks give you a bill for time and materials up to $500.00. The other possiblitity is that the gear in the oil pump jammed or is loose on the shaft. When the oil is hot enough the gear may just start slipping and it just happened at this time of the race. Also check gasket or "o" ring on pickup tube and replace. I think motor is not damaged at this time. Good luck Rick L.

[Pete Munroe]

All,

Guessing not enough oil vs. too much here caused pressure drop. Overfilling can create problems...AVIAD is quite wide. Think it takes a relatively more oil to get the level high enough to where you are in the crank windage compared to a overfilled narrow stock type pan...? But, my pan DOES have the fence/scraper removed to accommodate a main bearing support...maybe that created more problems than I thought.

Had pressure gone back normal I was going to add 1 qt...AVIAD has always surprised me as to how much oil it NEEDS to be stable...thought it offered more margin of error. I have to have 8 qts "in the pan" to be stable...thinking I misread the dip stick, actually closer to ~7. Will re-check marks on dip-stick when refilling to make sure which mark 8qt is...drilled 3 holes in dip stick last time, but now second guessing myself which one is 8qts...dumb. Can not find my notes...!

Foaming...last minute on the track drove slow due to the 20 PSI. after parking it sat for 5-10 minutes. Restarted psi still 0. If foaming, how long would to go back to essentially liquid? Oil is Castrol 10-30, fwiw.

On assembly (16,000 miles and 10 years ago) while on the test stand the guys pulled the pan to shim pump to lower pressure. Too high at 100+.

After shimming runs 80 cold, 60-70 hot. At idle 40 cold, 25 hot.

Guessing its a high volume pump (do not think they have gone with high pressure unit). Looked in the Ford engine book by Pat Ganahl and no info on oil pumps other than # M68HV for the high volume pump. Will check that.

A diagram of the relief valve setup would help. Push out a roll pin and remove a spring/piston? Looking for flashing, grooving, to cause it to stick. Especially after unusually high psi pushes it deep it to the passage.

Best guess, relief valve stuck open, bleeding off pressure. After cooling and the trailer ride home for 2 hours, it freed itself.

SO, 24 hours later, all seems normal...cold idle is at 40, psi responds instantly to throttle. Assuming then gauge OK (a SW mechanical).

Have intended to run a ACCUSUMP. The ERA 289 it is hard to put under the hood. Take 5 ft hose to get to the pass footbox. Better sooner than after scoring a crank.

For today...

cut open the filter (should be a flippin' mess), look for debris, check the pan for debris and trap doors free, and pull the pump/screen.

Guys...thanks for the input, any other ideas on oil pressure relief valves, etc welcome. Will get back on what I find asap.

Pete

[DAVID GAGNARD]

I think I'd pull the pan and change the oil pump,if nothing more than for future peace of mind.......

David

[Bill E]

loose wire or loose nut. lol

[Pete Munroe]

All,

Good news/bad news...good news first...lots of GOLD in the filter...( a cynic would say it looks like copper) but I am SURE its gold...oh, joy. At $1600/oz...maybe enough to pay for the new bearings...I'd post a picture, but it would make everyone jealous.

Real good news, there does NOT seem to be anything FERROUS in the debris...ran a large magnet under the aluminum pan and just a very few tiny pieces of ferrous type junk move around.

Total volume is about a full, large thimble full of flakes and particles...I assume that is too much...random flakes, ok...this much, no.

About 1500 miles on this filter, so all the debris is recent, and probably from Thursday's track day.

Will pull a rod cap and main cap later, but judging from the swarf looks like a bearing(s) are/is toast...no ferrous so maybe the crank is good with a polish.

As this unfolds I will see how much can be reused on an otherwise tight engine...ie: oil cooler and lines...if the mess is soft copper, and not iron, flushing should be OK...? I HATE making new hoses...etc,

This thread should provide lots of material for opinions on how far to go in a clean up/rebuild...I will post a few follow ups as I tear down the engine.

Thanks,

Pete

[Pete Munroe]

All,

This photo may be too small to see, but it is the copper flakes I found in the oil filter.

Checking with a magnetic, there are almost no ferrous particles...tear down will tell.

Plan to pull the pan and caps, or just pull the engine and get it on a stand. Engine has to come out anyway.



Of course hoping no crank damage, etc. How to clean roller lifters, oil cooler and thermostat, lines, etc ? Not sure you can ever clean a oil cooler, but if its copper swarf and not steel, I may take a chance...

The engine was at 16,000 miles and quite tight...total cleaning and new rings and valve job seem in order. Just hate to throw away roller lifters, rockers, etc. Will take it one step at a time, and do it right with out throwing money at it.

Was talking to a friend with years of vintage racing in a GT-350, Cobra, Lola-Ford and he said a huge mistake to use 10-30 on the track as no margin for error with a starved bearing. I am not so sure, if you have good oil pressure and quality oil, seems it should be ok. That is open for discussion.

Now, I still do NOT know why the oil pressue goes away one day, and the next day its normal again. It DOES appear there is very significant bearing wear.

Pete

[289miller]

Just a thought-----are the flakes copper or bronze distributor gear material? I would recommend oils that have more anti wear additives like Joe Gibbs racing oil or Brad Penn racing oil from summit racing. Joe Gibbs has a great web site and has done a lot of research in high performance lubrication.

[Pete Munroe]

Miller,

Good thinking, I have not pulled the distributor yet, may do that before I drop the pan.

Still, a lot of stuff in the filter. Mainly flakes rather than granules. The flakes appear to be copper colored on one side and babbit grey on the other, inclined to think mainly bearings.

The distributor drive gear did look new about 2500 miles ago when I installed the oil thermostat. Had to pull the distributor to prime the empty thermostat lines and checked out the gear.

With a rollerized cam/lifter/rocker engine, never thought of the wear on the distributor gear...hoped to dodge the bullet of going to the pricey Gibbs type oil for the ZDDP...

Wonder if bronze is porous and soft enough to not have a problem with lack of protection against scuffing due to high contact pressure.

If the cam is replaced, the gear will go to.

Will try to photograph as many wearing surfaces as I can for a post-mortem.

At this point, it seems I got off easy compared to some of the current mechanical disaster that have befallen some guys with VERY pricey blocks...

Thanks, Pete

[Bill E]

the oil thermostat could be the start of your problems.

[Tom Wells]

Pete,

Agree with Bill -> lose the thermostat.

Also agree about the Accusump. I wouldn't do a track day without it!

Tom

[Pete Munroe]

Guys,

Well, you got me thinking about the pro/cons of adding any complications to the oil system, point well taken.

Certainly do want to add the ACCU-SUMP, and look into replacing the AVIAD oil dam/scrapper I removed to allow the pan to fit over the lower main support. Not sure how to do that.

Thermostat was added 3 years/~2500 miles ago. (16,000 on engine) Nothing has changed in terms of pressure problems in Willow's turn 2.

Since the first time the car was on the track in 2003? I have had the intermittent oil pressure problem in LONG SWEEPING turns. Have tried to avoid overfilling the pan but it seemed a fine line between too little and what I "imagined would be too much" and create aeration problems.

Mainly, my concerns have been with oil FLOW, not pressure.

Thermostat is the CANTON, not the MOCAL. Very large volume inside, few angles, compared to the MOCAL.

On my install hoses/fittings in/out are #10. Installed it with as many straight in, or 30-60 degree hose ends as I could. (see my gallery)

Many of the installations I see are about as BAD as they could be in terms hydraulic resistance. Acute angles, 90's, 120's, etc or complete reversal type fittings are what I tried to avoid. My hose runs are not much longer than when only the oil cooler was in use.

IMHO, if temps are too low, a GOOD thermostat installation that doesn't impede oil flow and gets oil into a better operating range is more of an asset than liability.

Thanks, Pete

[Bill E]

Out of five oil thermostats we have installed had 3 failures. Call Dave or John at AVIAD they will talk you through it. Accusump is the way to go if you cant find out what the problem really is. I have run them in the past. Call to Aviad. If you are runing hard eought to need a Accusump then a dry sump is a better choice.

[DAVID GAGNARD]

Originally Posted by Tom Wells

Pete,
Agree with Bill -> lose the thermostat.
Also agree about the Accusump. I wouldn't do a track day without it!
Tom

FWIW: I'd pull the engine and do a complete tear down and see what's damaged and what's salvagable.....
I'd also lose the oil thermostat,add the accusump...depending on the type of oil cooler,you may not be able to clean it out.....if it is the "stacked plate type" kinda like a trans oil cooler, I'd say throw it away and get another,if it the round tube type,you should be able to flush it out and re-use it..flush all your oil lines throughly and they should be good to go.....I'm betting your crank will be good with just polishing the journals.
If it were mine, I'd wash the roller lifters in a parts washer and then inspect them, chances are most all the debris was caught in the oil filter.
I use 15/50 Mobil 1 synthetic oil in my race car,rev limiter is 7000rpms, and I've run oil temps as high as 270 degrees on extreme days, normal is in the 220 to 230 range......on cool/cold days, I block off part of the oil cooler with clear packing tape or duct tape to keep the oil temp in the 200 to 220 range......
I'd defintely change the oil pump, I like the Melling HP Series in standard volume/standard pressure, what's in my race and street motor.....
Looks like your oil filter did it's job,probably should not have much other engine damage.........
Good luck with it.........

David

[Jerry Clayton]

check crankshaft end play---it could be that your thrust bearing has suffered excessive wear from riding the clutch, bottoming out of the clutch or no free play in the linkage--any of these will kill the thrust side of the bearing ( and sometimes not the crank, other times, crank also)

Its possible that a partical of the copper/brass stuck the relief valve open, causing your low pressure reading---
How is your oil system plumbed and where is the oil pressure taken from???

[Pete Munroe]

All,

The oil pressure line is off the block in the lower front left, just behind the boss for the fuel pump...it is a stainless line screwed directly into the back of the Stewart Warner gauge.

In my gallery are some photos of the thermostat install, I have lots of others for the entire install.

The clutch is activated with a McLeod hyd throw-out bearing. I do not think it leaves a residual pressure when not disengaged ? Do not know.

I could try to move the crank back and forth at the bolt that holds on the dampener and see how much end play. Awkward to get a dial gauge down there.

In a week or so hope to pull the engine. Need to clean up the garage clutter and decide how to organize the disassembly. Do not want confusion of parts. What ever is salvageable going back in the bore it came from.

Goal is to be able to keep bearings in order, etc and see if there was a method to the madness as the pressure dropped.

I have more pics of the oil line setups I could repost on my gallery if need be.

Pete

[Jerry Clayton]

Sooooo------why are you taking the engine out????Why don't you drop the pan and check the bearings????/at least then you would know what caused the trash and low oil pressure