Disturbing loss of oil pressure

[tsunari]

I'll try and make this quick and concise . . .

- New 6-bolt swap with ~ 1k miles
- '90 Oil filter housing
- Setrab Air-cooled oil cooler
- Castrol GTX 10W30

Was out this past weekend @ an autoX even in Memphis and it was HOT as hell out there! Anywho, right before my last run of the day, I'm pulling out of the grid to go stage @ the line and when I pushed in the clutch, I noticed the RPMs dropped just a tad and the oil idiot light faintly started to flicker. I immediately revved the engine up a bit to build more pressure and pulled back into the grid . . . killed the engine, popped the hood and let 'er cool for a minute or two then checked the oil. Oil was clean on the dipstick and at the full mark.

To add to the story, from the time this motor was built/installed, cruising around the stock gauge would read up @ the 'H' mark and now after this weekend, the needle is horizontal when cruising (never really goes to the 'L' mark, not even when turned off).

Haven't had the light come on again and all sensors look fine & are hooked up. I was thinking maybe everything got real hot and thinned the oil out, but shouldn't the external cooler take care of that (or perhaps not since I wasn't actually moving . . .)? Either way, why would I be reading lower pressure now that everything has had ample time to cool off?

Any ideas or insite?

 

[sweet97]

Replace the sending unit or at least get a gauge and check the ctuapressure. Remove the sending unit and screw in an adapter that would cone with a tester if youcan borrow one and find out ewhat the pressure is. We have 2 idiot pressure units, the light and the needle. I bet a bad sending unit. Let us know. Mark

 

[tsunari]

Just got a *CHEAP* mechanical oil pressure gauge from a local auto parts store and hooked it up. Seems to read roughly 10PSI per 1000 RPMs except it doesn't read anything @ idle! From what I've read, I should have at least 15-20 PSI @ idle . . . I popped open my oil cap while everything was running and the cams are still getting oiled, so maybe I should go out and get a GOOD gauge?

ideas?

Replace the sending unit or at least get a gauge and check the ctuapressure. Remove the sending unit and screw in an adapter that would cone with a tester if youcan borrow one and find out ewhat the pressure is. We have 2 idiot pressure units, the light and the needle. I bet a bad sending unit. Let us know. Mark

 

[sLoGSX]

Similar situation happened to me and it turned out my thrust bearing went. This was w/ 500 miles on a brand new 6 bolt, running 20w50. Oil pressure was running nice and "high" as you had stated, and then all of a sudden dropped to "normal" while driving and "low" at idle. The highest I could get the gauge was halfway up at cruise compared to over 3/4 of the way up at cruise before.
This is worse case scenario, and I would do as everyone else has said and check guage, sending unit, etc. Then if you can't figure it out, check for crank endplay and/or drop oil pan and check it out... Try changing the oil and see if you see anything "unusual".

BTW, my rpm's also started to drop noticably w/ clutch pressed in when all of this started.

 

[2-0turbo]

Similar situation happened to me and it turned out my thrust bearing went. This was w/ 500 miles on a brand new 6 bolt, running 20w50. Oil pressure was running nice and "high" as you had stated, and then all of a sudden dropped to "normal" while driving and "low" at idle. The highest I could get the gauge was halfway up at cruise compared to over 3/4 of the way up at cruise before.
This is worse case scenario, and I would do as everyone else has said and check guage, sending unit, etc. Then if you can't figure it out, check for crank endplay and/or drop oil pan and check it out... Try changing the oil and see if you see anything "unusual".

BTW, my rpm's also started to drop noticably w/ clutch pressed in when all of this started.

What oil clearances and thrust clearance did you run on that new motor?

 

[tsunari]

What oil clearances and thrust clearance did you run on that new motor?

Talked to Polk Performance and they're running like .001 clearances everywhere on the motors they build . . .

On the flip-side of things, I tore off my Oil filter housing and discovered the source of my problems *picture attached* For those who aren't really sure what they are looking for, there's a hole with a 'line' in an almost vertical position inside of it on the right-hand side of the filter housing. This is the oil-bypass valve and it is stuck about half-way open !! WTF

So I ended up taking the cap off, pulled everything out and there was a gritty substance that had lodged the plunger in place. Upon closer inspection, the gritty stuff looked to be tiny metal flakes. Not sure where they came from, but I'm hoping it was junk that wasn't completely cleaned out of the housing when it was built/assembled @ the factory (it was purchased new/rebuilt).

Now my oil pressures are pretty much twice what they were before (roughly 20psi per 1k rpm) and I have between 5-10 psi @ idle. Sound good/normal?

(Running 10w40 oil w/ external Setrab cooler -8AN lines)

So guess my next concern is . . . did I mess anything up driving around between Sunday and Today with the pressures being so low @ idle?

 

[2-0turbo]

Talked to Polk Performance and they're running like .001 clearances everywhere on the motors they build . . .

On the flip-side of things, I tore off my Oil filter housing and discovered the source of my problems *picture attached* For those who aren't really sure what they are looking for, there's a hole with a 'line' in an almost vertical position inside of it on the right-hand side of the filter housing. This is the oil-bypass valve and it is stuck about half-way open !! WTF

So I ended up taking the cap off, pulled everything out and there was a gritty substance that had lodged the plunger in place. Upon closer inspection, the gritty stuff looked to be tiny metal flakes. Not sure where they came from, but I'm hoping it was junk that wasn't completely cleaned out of the housing when it was built/assembled @ the factory (it was purchased new/rebuilt).

Now my oil pressures are pretty much twice what they were before (roughly 20psi per 1k rpm) and I have between 5-10 psi @ idle. Sound good/normal?

(Running 10w40 oil w/ external Setrab cooler -8AN lines)

So guess my next concern is . . . did I mess anything up driving around between Sunday and Today with the pressures being so low @ idle?

Wow, that is interesting. 0.001" is tight. I built my motor with 0.002 on all oil clearances and 0.004 on thrust. My philosophy was a higher HP motor needed FLOW through the bearings to keep them cool. I make great oil pressure even with thin 10W-30 oil, so time will tell if it works out. I have 1000 miles on the engine now and I've flogged the hell out of it.

There is really no way to tell right now if you have damaged your engine. You might have wiped a bearing or two (or more), but the fact that you can now make good pressure tell me you haven't totally wiped a bearing out. I would change it out a couple of times to make sure you get all the crap out. If you were making the 10psi per 1000 RPM's during cruise, you'll probably be okay. My pressure at idle with hot oil (175F) will drop down to the mid-teens. My gauge has an oil pressure alarm that I have set at 15psi and it rarely comes on. Only if the oil gets over 200F.

Drive it and see what happens. Good luck!

 

[ddavisaf]

Concerning your oil pressure at idle. 20psi at idle is usually with BS removed. I run around 10-13psi at idle depending whether or not my car likes on that particular day.

*edit* Now that I actually read your profile I see you removed your BS disregard

 

[tsunari]

Concerning your oil pressure at idle. 20psi at idle is usually with BS removed. I run around 10-13psi at idle depending whether or not my car likes on that particular day.

But I DON'T have 10-20 psi @ idle . . . that's what I'm concerned about

***UPDATE***

Decided to check and see if my oil bypass valve had stuck open again (it hadn't) so I went ahead and dropped my pan. Found metal shavings in the bottom of the pan! Also took a look at my cylinder walls and there are what seems to be verticle scratch marks. . .

Something tells me this isn't normal- Still have the low oil pressure @ idle (750 rpms) . . . compression seems normal (all 170+).

ideas?

 

[tsunari]

Alright guys (and gals) . . . I've been battling with low oil pressure on a built 6-bolt for a few months now - I'll spare the details and cut to the chase.

The oil pump seal was leaking so I pulled it off to replace it and low-and-behold . . .I think I MAY have found the culprit for my low oil pressure (mechanical oil pressure gague reads ZERO @ warm idle and 'decent' pressure while cruising . . . 60-70 psi @ 4k RPMs) !!!

It seems as though somehow the hole in the front case where the oil pump shaft comes through got damaged @ some point (I have NO idea how this happened). There seems to be a decent amount of slop when I grab the shaft and shake it side-to-side . . . since it's on a radius, I cant exactly measure the clearance with feeler gauges and I don't have my calipers with me at the moment

Just kind of eye-balling it, I would guess that the clearance where the damage is . . . is about 0.016". Anyone know if there should be this much movement of the oil pump shaft? Seems to me that there should be very little (if any).

If this is indeed damaged, then it would make sense that @ idle, the oil getting pumped is gushing through the crack and returning straight to the oil pan. But I guess there's just enough oil still circulating to not trip the oil idiot light.

I'll try and post some pictures if they turn out- but please . . . any ideas?

*EDIT*
If you look in the upper left portion of where the shaft comes through the hole . . . see the irregularity in the metal? That's the damage I was mentioning

 

[Nt-Eclipse-Dail]

You were smart to use a mechanical gauge to check your oil pressure as our stock gauges can be off. Are you sure that the slop is not in the oil pump? Have you checked any of the clearances yet? I have not read anything about 'front cases' going out yet, This is why I ask...

I hope you get your ride fixed up soon. That is one awesome looking DSM you have and it would be a shame to see it get oil starved...

I see DSM's like yours and it makes me want a second job so I can have one...

 

[tsunari]

You were smart to use a mechanical gauge to check your oil pressure as our stock gauges can be off. Are you sure that the slop is not in the oil pump? Have you checked any of the clearances yet? I have not read anything about 'front cases' going out yet, This is why I ask...

I hope you get your ride fixed up soon. That is one awesome looking DSM you have and it would be a shame to see it get oil starved...

I see DSM's like yours and it makes me want a second job so I can have one...

I've never read/heard about the front cover going out either, but the whole motor was torn down about 2 months ago (another long story) and all clearances were checked by the builder. Apparently everything inside looked brand new (as it should!) . . . bearings still had the protective coating on em . . . oil pump gears didn't have any wear. . . etc . . . I guess this part just got overlooked, which is fine because you dont even notice it until you pull off that oil seal. That's when you can actually see the damage and feel the slop in the shaft.

I sure hope I get it fixed soon as well- I've been fighting this oil pressure issue for a few months now and I have just about had it. I don't know how many times I've had the Oil Bypass Valve apart looking @ it and checking to make sure it hadn't stuck open. I've even replaced the oil pressure switch to make sure the idiot light will come on when it's supposed to, but so far . . . nadda. I'm hoping as long as that doesn't come on, I'll be OK until I can get this fixed.

ThanX

 

[renovatio]

The best way to measure the play would be with a dial indicator. .016" seems like a lot of play to me. Its hard to eyeball something like that. Without looking in the book I would say that you shouldn't have more than .003". Oil pumps are a vary persis thing. The half shaft that also is driven by the timing belt though your oil pump can wreak havoc on your oil pump. If you end up replacing your front cover/oil pump you may want to consider a balance shaft elim. kit.

 

[tsunari]

The best way to measure the play would be with a dial indicator. .016" seems like a lot of play to me. Its hard to eyeball something like that. Without looking in the book I would say that you shouldn't have more than .003". Oil pumps are a vary persis thing. The half shaft that also is driven by the timing belt though your oil pump can wreak havoc on your oil pump. If you end up replacing your front cover/oil pump you may want to consider a balance shaft elim. kit.

Yeah, I wish I had my calipers here with me so I could get a more accurate reading on the slop- it's definitely more than it should be though . . . Also have already had the BSs taken out . . . thanks for the suggestion though

 

[WatchItExplode]

It's normal to have some metal shavings in your oil pan, I know that for sure. As far as how much or how big, I couldn't tell you. Once you get your problem figured out, you should maybe try putting a few of those oil pan magnets in there to keep the shavings from getting clogged in places like your filter housing.

 

[Spoolin4Ever]

Why are you running 10W40? That's not a great choice from what I hear. The tighter the tolerance, the thinner the oil you should use.

Also the more numbers in between the first number and second, means it has more additives to achieve that wide vicosity range.

Seems like 10W30 would be better. It probably won't effect/raise the pressure, but you will get better flow, especially when it's HOT.

And let's face it alot of these cars have low oil pressure. I think flow is more important. Not saying low OP is good, but if it's gonna be low no matter what you use, use something that flows well, and holds up to heat better.

Yes I think you should try another gauge. At least try an autometer.

 

[tsunari]

Why are you running 10W40? That's not a great choice from what I hear. Ihe tighter the tolerance, the thinner the oil you should use.

Seems like 10W30 would be better.

Well 10W40 is what the builder recommended (Polk Performance) for break-in . . . after that I switched to 10W30 synthetic and now I'm up to 15W40. Still have next to no oil pressure @ idle . . . apparently there's still enough to keep the idiot light from coming on. Here's what my FSM says about how to troubleshoot Oil pressure drop:

1)Engine Oil level too low -- Check engine oil level
2)Oil pressure switch faulty -- replace oil pressure siwtch
3)Oil filter clogged -- install new filter
4)oil pump gears or cover worn -- replace gears and/or cover
5)thin/diluted engine oil -- change oil to correct viscosity
6)oil relief valve stuck open -- repair relief valve
7)excessive bearing clearance -- replace bearings

So looking @ the list . . . 1 is out . . . 2 is out (brand new switch) . . . 3 is out . . .4 - maybe?! . . .5 is definitely out . . . 6 . . . every time i check it, the valve seems fine- so it's 90% out . . . 7 ? It's a BRAND NEW MOTOR . . .so I'm Hoping #7 is out

I actually found some damage to the front case so am putting a new one on this weekend and hope that fixes the problem (just hope nothing else has been damaged . . .

 

[Turbo Talon DL]

Vertical scratch marks are normal. My cylinder walls looked identical to yours. My compression isnt quite as high tho, that probably is because of the thicker MLS head gasket and the fact that my motor only has 447 miles.(i hope )

 

[tsunari]

Vertical scratch marks are normal. My cylinder walls looked identical to yours. My compression isnt quite as high tho, that probably is because of the thicker MLS head gasket and the fact that my motor only has 447 miles.(i hope )

well hopefully you broke it in properly

 

[tsunari]

Well here's another update . . .lately while the motor is under a light load (not while free-revving), I would hear a 'clacking' sound coming from the belt side of the motor. Long story short- turned out the oil pump was TOAST WTF -- I have no idea what the hell happened to get to this stage . . . maybe the builder did not pack it with grease for the initial startup? I dunno . . . It's all speculation.

So new pump is in and all seems to be fine now- much better pressure while cruising:
16psi @ 1200
50psi @ 2k
70psi @ 3k (10w30 synthetic)

Will continue to keep an eye on things and keep this thread updated.

Here's some more info on this problem:

http://www.dsmtuners.com/forums/showthread.php?p=1643101

 

[tsunari]

. . . turned out the oil pump was TOAST WTF -- I have no idea what the hell happened to get to this stage . . . maybe the builder did not pack it with grease for the initial startup? I dunno . . . It's all speculation.

So new pump is in and all seems to be fine now- much better pressure while cruising:
16psi @ 1200
50psi @ 2k
70psi @ 3k (10w30 synthetic)

The pix do not do justification to how bad this oil pump has been treated. Both the stubby shaft & the drive gear shaft are essentially welded into the pump & front cover respectively. They still spin . . . but man- this is ugly. Wish I knew what caused this so it could be prevented in the future.

On a side-note . . . anything I should check to see if there is damage lurking elsewhere? Rod bearings . . .etc?

Oh! and one more thing . . . notice the bolt that is holding the driven gear onto the stubby shaft (with the #4 on it) Does that mean that it is a grade 4 bolt? B/C the one that is SUPPOSED to be on there has a #10 on it. The one in the picture has a split lock-washer on it and I could not even get the 29 ft/lbs of torque on it (just kept spinning . . .) So I had to make a quick trip to the JYard Sat morning 2 pick one up.

 

[Maglin]

Well the scratchs on the cylinder walls isn't normal. And those metal shavings in your pan are not good as well. When you break in a motor metal shavings are more like microscopic metal flacks when people refer to them. Those are actuall large metal shavings. Looking at your pic of the cylinder wall it would lead me to think your piston to cylinder wall clearance was to tight and you scored your walls and posibly wore the hell out of the piston skirts. The metal shavings are probably from the pistons. I would have it replaced if you have a warenty from Polk Performance. It the old days of hot rodding people used to go crazy tight on piston to cylinder wall clearance and let the pistons wear down to have the tighest possible motor. They would even almost sieze or even sieze at times during break-in. This of course isn't good practice and people now know that the damage caused to the piston and cylinder walls will shorten the lifespan of the motor greatly. Your cylinder walls should just have the cross hatch and not scratches. If you plan on putting down a good amount of power I would again take it back to polk and have it replaced. Of course they might tell you it's normal in which case I would get a Lawyer and a few dealer mechanics involved and you could get a free motor cause they are tring to lie to you about a faulty build.

That is just my .02, and what I would do. I hate lawyers and people that sue for no reason as it rises the prices for everyone on products, but you can't let people get away with shaddy practices either. It's a double edged sword it is.

 

[Spoolin4Ever]

They probably didn't lube the oil pump as you said.

 

[1LE]

Ugh, this sounds very similar to my 6-bolt (except it suddenly happened after working for several years and 30k miles). You should see a MINIMUM of 11psi at idle... Higher with BSE. Haven't torn mine apart yet, but we suspect catastrophic oil pump failure. Started getting 5 psi at idle on occasion, then all of a sudden it just dropped to 0, went "clackity clack" and that was all she wrote.