Who knows this? "Mystery oil loss"

[75Carrera]

I have an 86' SC 3.2 motor in my '75. The car runs and sounds great. The motor came with Ross forged pistons (that rattle like forged pistons will). Around the city at moderate speeds my oil level holds. However when run at high RPM and spirited speeds my oil consumption goes off the chart. On a recent 850 mile (spirited) road trip the car consumed 8-10 quarts of oil. Sounds impossible but it's true!

There is no smoke visible from my two out exhaust either (No cat). The smell of oil on my heat exchangers is strong. Parked the car drops a silver dollar sized puddle daily but no where near the volume that escapes from (SOMEWHERE???) My wrench thinks it might be an "O" ring on a case through bolt but the volume of the loss is baffling. The bottom gets a little damp with oil but not dripping wet. We're pulling the motor out Monday morning. Any experienced tips would be very helpful.

Do any of you know of cases, examples, where this much oil can be pumped out of a motor under pressure? I've been told the pressure can reach 90 PSI at high RPM. Could oil leave a motor at this kind of rate without heavy smoke or an oil track on the ground? At high speed (90-130) the car literally pumps the oil through the motor and out somehow. If it were my P&C's the car should be smoking like a crop duster...

Anybody had a problem like this before???

[75Carrera]

BUMP-drip-BUMP??

[75Carrera]

Bump,
Doesn't somebody must have an idea what causes high oil losses like this?

[mb911]

its being consumed and coming out the exhaust you just are not seeing as it is diluted.. Don't fool your self. if it is not leaking its burning it

[tonythetarga]

If you are dropping the engine today, this might be too late. I had a mystery leak that was not that bad (compared to you) but it smoked a lot at high speed but did not drip more than a few drops between runs at the track. We dynoed the car and discovered the leak came from the O ring between the cam housing and the cam chain tensioner box. Not suggesting that is your problem but you might consider putting the car on the dyno and looking for leaks while the car is running at or near redline.

ps. 3.2 engines are Carrera not SC

[75Carrera]

Thanks Ben and Tony,
I tend to agree with you both, it's most likely burning it and leaking too. Either way it's time to fix it! My motor comes out tomorrow morning after we see what happens while running it up on the lift (no dyno here in the mountains). I'm prepared for anything from an "O" ring to replacing my P&C's. We'll be checking the case through bolts for sure.
I realize oil questions are among the most common on Pelican and are the most difficult to pinpoint.
Wish us luck...

[Steve@Rennsport]

Donny,

Assuming for the moment that you have no oil leaks, I'd be going a leakdown test right away. Thats a LOT of oil consumption,.............

A leakdown test will help you locate any source of compression loss and if its coming from the crankcase, that can explain where its going. I would do this before the engine is disassembled.

Oil leaves the engine via either some leaks (gotta be big ones to use that much), worn guides, or past the rings. I'm no fan of Ross pistons so thats one place to check. If the engine is coming apart, I'd be measuring ring gaps, piston-to-cylinder wall clearances and cylinder finish as well as checking if those are Yankee or Goetze rings.

If you really have 10.5:1 pistons in there with single ignition, don't be surprised to find a bunch of broken rings. AZ 91 octane fuel cannot support such configurations,...

[75Carrera]

Steve,

Good advice Steve. The Ross pistons are about to come out anyway I think but I'll wait for the leak down and run-up tests tomorrow. Everything seems to point to the need for nikasil liners and stock injection pistons with new rings. I posted this in hopes some guru out there would say he knew how oil could pump out at that rate and the P&C's I have would be just fine. But not so far!

I was told the motor had 10.5x1's but I've always thought that would require a twin plug set up. So I'm thinking we'll be finding 9.5x1

Stay tuned...

[ischmitz]

Oh ha, I don't think I can add anything at this point but I am sure curious as to what you'll find.

Just one question: Is there anything odd with your breather or outside oil circuit configuration that would allow excessive amounts of oil mist being ingested into the intake at elevated RPM?

Ingo

[craigyirush]

Just curious - is it possible to burn that much oil and NOT have blue smoke pouring out the tail pipe?

[75Carrera]

Originally Posted by craigyirush

Just curious - is it possible to burn that much oil and NOT have blue smoke pouring out the tail pipe?

That was my question. I would have thought that much oil loss would smoke like the "last wood burning 911" in Arizona!

The comment about ingesting it back into the intake is interesting. If there were a way for it to make it's way into the air injection I would think it would clog wouldn't it? I'm here to learn.

Tomorrow should be an interesting day.

[the]

Well, like said above, the oil is either leaking out onto the ground, or coming out of the exhaust pipe. Nowhere else for it to go.

I had a friend with an 80s BMW with a very high mileage, worn out engine. It went through a ton of oil (a quart every couple hundred miles), but didn't smoke! The mechanic said that the cat converter gets hot enough to burn off the oil so that you can't see the smoke.

But since your car doesn't have a cat, it is a bit of a mystery. Burning that much oil, with basically a straight through exhaust, hard to see how it could not be smoking at least somewhat!

[75Carrera]

Well the motor is out on the ground. There is a significant leak at the base of #3 and it's evident oil is being pushed out there.

Now the interesting news: My car has nikasil cylinder liners. BUT... thy have been honed down by someone who left some scratches in the walls. The Ross pistons are caked up along with my fairly fresh iridium plugs. My wrench believes nilasil's should never be honed but rather scuffed up with a scotch brite or 2000 wd paper with WD40...
The choice is made to replace the entire P&C set with (unmolested) nikasil and mahle, injection 9.5x1 pistons. I've posted a question about the wisdom or the ability to hone nikasils and arrive at a dependable tolerance for long term dependability.
The motor history shows the Ross Pistons were originally sold to" Motor-Meister'. That being the case, it's a pretty sure those lame *********s slapped this together by honing barrels that shouldn't be honed and then dropped in Ross Forged pistons to absorb the slop. Easy to see why they are no longer in business. If I had been told this was a Motor-Meister engine I would never have bought it. Shame on the guy who sold it to me... But... on to the fix.
So... the new P&C's are on the way. We'll slip in new rings (probable with an extra compression keeper ring) and put it back together. While it's out of the car I'm looking into getting my headers and painted and the heat exchangers cleaned. My muffler is S/S and cleaning my engine compartment.

[Rot 911]

Your mechanic is correct that you should only scuff up nikasil cylinders and not hone them. Smart move (but expensive) on getting new pistons and cylinders. One other thing to check, look in your heat exchangers and see if they are caked with oil. My 3.2, before rebuild, had worn exhaust guides and was sucking oil through the guides right into the exhaust at the rate of a quart every 300 miles. No smoke out the exhaust, but plenty of caked oil in the heat exchangers!

[75Carrera]

Originally Posted by Kurt V

Your mechanic is correct that you should only scuff up nikasil cylinders and not hone them. Smart move (but expensive) on getting new pistons and cylinders. One other thing to check, look in your heat exchangers and see if they are caked with oil. My 3.2, before rebuild, had worn exhaust guides and was sucking oil through the guides right into the exhaust at the rate of a quart every 300 miles. No smoke out the exhaust, but plenty of caked oil in the heat exchangers!

Yea, Kurt, I'll be looking at them this morning. I actually found a set of nikasil P&C's here on Pelican (used but cleaned and mic'd). We'll be sure they are perfect and add the new ring set and carefully put her back together. Cleaning the oil and grime off the heat exchangers and cleaning up the compartment and underside will be a good feeling for sure.

[scottb]

Originally Posted by 75Carrera

The motor history shows the Ross Pistons were originally sold to" Motor-Meister'. That being the case, it's a pretty sure those lame *********s slapped this together by honing barrels that shouldn't be honed and then dropped in Ross Forged pistons to absorb the slop. Easy to see why they are no longer in business.

Unfortunately, they are still in business, unless something happened recently. Do a search here on the board and you'll find a bunch of threads on them.

[75Carrera]

Getting the motor on the ground made quite a difference. The big leak was coming from what we originally suspected (through case bolt at #1) Pretty obvious once you get it out and can see the flow.


But that's only half the problem. I do have nikasil liners but they've been honed (again as we suspected) making for a poor seal. The Ross pistons are "coked" and the iridium plugs are all but obliterated.



The valves don't appear to be damaged but are coked up as well. THE P&C set I bought here on Pelican should be here by Monday. We'll check the bearings just to be safe.

I decided to vat the heat exchangers and then I'll either paint or try to polish and treat them with something. Might as well make it look pretty while I have the chance.

Hopes are that this will be the last time I will have to take the motor out of this car. I'm looking for a motor that will be both strong and dependable.... aren't we all?

Thanks guys

And should Motor Sheister still be in business out there somewhere. I'd love to toss a few of their "accomplishments" through their front window with the preverbal "strong letter to follow"... I've never heard anything that would lead anyone with any brains to do business with that company. It is well documented here on Pelican.

[mb911]

well the good news is you could send the cylinders out to be recoated along with the pistons and be able recoupe some cost of the project your core set as they sit are worth good money so don't forget that

[Rot 911]

Donny, can you take a picture of the liners on the cylinders. Here is what mine looked like at 133,000 miles, needing only a scuff up with a grape hone to be reused:

[kodioneill]

look at the tops of those pistons, man it was burning it.