Pops' 1997 S6 - 07k BLK WDW

[EDIGREG]

uh oh...damn that sucks. What exactly do you mean by "steel bits"...?

[chaloux]

sorry. coulnd't find the right word when typing. "Steel bits" = shavings. but he said not many, so at least that's good that we caught it early.

[Hank]

Can you be more specific about the noise?

Hank

[chaloux]

I just wrote the longest dang response and hit refresh by accident. AGH

Dad said he found four very small shavings. And the end of the oil stream when draining almost looked like flaked paint, a very fine metal dust in it.

Basically we think it's rings. The car smokes under load changes now, whereas before it would smoke when cold and then go away. Rings would also cause excessive pressure in the crank case and thus an overflowing catch can whereas valve seals would not.

We originally thought the smoke was bad turbo seals since we changed the whole unit when we got the .82 housing and it started smoking soon afterwards. We never pulled intake tract to check if there was oil or not, it coulda been a coincidence that rings started to go at the same time as installing a new turbo, but were able to expand when hot enough to seal well.

The noise is like a tick. Almost sounds inejctor like but is definitely deeper in the motor than that. With the stethoscope dad was able to pinpoint cylinder 4-5 and loudest right where the head meets the block. It is audible in the car, especially on load changes like a slight application of throttle. It's also very easy to hear when turning the car off. Compression is 130-140 across the board, not great.

I think step number one is to check the turbo coldside for oil, at least that will clear up whether it needs to go back to comp or not. Then step number two is just to determine whether or not to pull the subframe and oil pan or just pull the whole motor.

[fasterthenrs2]

il say do a leak down before taiking whole thing a part, that will def tell the storry

[EDIGREG]

il say do a leak down before taiking whole thing a part, that will def tell the storry

Big 2nd. Pulling the turbo to check if it's leaking is easy, but do a leak down before going any further.

130-140psi is normal compression for an 8.5:1 AAN, no?

What was your break in procedure for the motor?

[UrSobsessed]

Bummer! Sorry to hear this, and after all of the hard work you guys have put into it!

[fasterthenrs2]

il say do a leak down before taiking whole thing a part, that will def tell the storry

Big 2nd. Pulling the turbo to check if it's leaking is easy, but do a leak down before going any further.

130-140psi is normal compression for an 8.5:1 AAN, no?

What was your break in procedure for the motor?

Compression is relative,(with my guge i get 150psi with 8.1:1, and around 168 with 8.5:1) two similar gauges will never show the same nr, that said if it is 130-140 all across the board that be looking ok to me, leak down is easy to do, and if motor has troubles’ it will tell the story, if say you pushing 80 psi in a cylinder and gauge on a another side reads 65 70psi, find where it is going, normal leak down should not exceed 10%, bad rings you will hear air rushing out of crank case, valves not sealing, crack tb and will hear that by turbo air inlet, ex valves exhaust will push air.

[ralleyquattro]

Sorry to hear that guys, but yes, I would do every test imaginable before taking it apart.

Cheers

[chaloux]

As we suspected, leakdown points to rings. Valves are good. % is as follows:

cyl 1 - 25%
cyl 2 - 34%
cyl 3 - 40%
cyl 4 - 52%
cyl 5 - 40%

Pretty bad. Dad is removing the head now, so we'll have a report on the condition of the cylinder walls soon. Worth noting is that cylinder 3 and 5 are bad enough that it leaks back up into cylinder 4. Cylinder 4 must be pretty dang weak (clearly what the numbers show).

The race engine builder shop neighbour took the car out for a ride before dad started pulling the head and after the leakdown. This is a guy who has said he's had enough of turbo junk, that he's done with piddly little motors. He works mostly on big NA stuff. Anyway, his report back was, "how could this car be having such huge problems, it's a rocketship after 3krpm" - gotta take the bad with the good!

Also, turbo is absolutely clean and dry. Shoulda checked that looooooong ago. Obviously the rings have been a problem for a while. I'm wondering if they didn't seat because when we were breaking the engine in it was on very little boost with problems all over the place. We broke it in using this procedure: http://www.mototuneusa.com/break_in_secrets.htm - but I wonder if the low boost/boost issues kind of screwed it up. I dunno. Anywaaaaaaaaay. Looking forward to Carlisle!

[loxxrider]

So you WILL be at Carlisle huh? Looking forward to meeting you!

[chaloux]

Haha that came out wrong. I won't be but the car will if everything goes well. I meant looking forward (in time) as a goal. Gotta get motivated, right?

[Katman]

Way back when.. I had rings break up on my TR6 motor.

Big clues were HUGE blowby, forcing oil out of the crankcase everywhere inaginable. Other big clue was that one plug would foul almost instantly.
What had happened was the top ring had broken up, and had been flopping around in it's groove.
Eventually, it got so bad that the ring groove wore wide from the ring bits flopping around that the broken ring bits got loose above the piston.. :frustrated:

[UrSobsessed]

Eventually, it got so bad that the ring groove wore wide from the ring bits flopping around that the broken ring bits got loose above the piston..

Had this happen also, many years back, in the engine of a Saab. The engine in that Saab was made by none other than Standard Triumph! The pistons were made by a company called Hepworth. But I digress...

The ring bits danced around in the cylinder, had their fun, and exited through the exhaust valve bending it on the way out.

And that was the second time that happened...

[chaloux]

Oh boy, not what we were expecting. Haven't seen it myself but dad says the pistons flop around in the cylinder. Over the phone I could hear the click click of the top and bottom of each piston hitting the cylinder wall as he moved it around.

Yikes!

Might be time to go back to a 2.2L. He said the cylinder walls look okay to the eye but he's going to check it for round/taper etc. We have 83mm JE pistons (not coated) and a stock crank that we can put in if need be. But jeepers. Perhaps the bore was too big? What would cause this... it seemed so tight during assembly.

[roortube]

How many miles did it take to do this?

[Hank]

Hello 220mm deck stroker. So nice of the high thrust loads on the cylinder walls to show up. :(. I would give the crank a try in a tall deck config. Poor rod ratios plus high rpms will play hell on an engines life span. Sorry to hear

[crappyoldaudis]

Hank, man I thought it was well-ironed-out that a 92.8 with 144mm rods in a short block would work fine????

This motor has like, 2000 miles on it. WTF?

[chaloux]

Yeah it is the 92.8 with 144mm rods and shorter pistons. RPMs weren't that high, usually under 7500. When we did rip on it it was always to ~7000 though. There are others with more miles with this config. I dunno. This motor has approximately 5000-10000km on it.

Anyway, I think even if we go to a 86.4 crank the QSV is the main factor in the great spool. I think it'd be a great comparison - same build but with 2.2L vs 2.5L. Then we could go to 8000 - 500rpm here 500rpm there

The nice thing about going to an 86.4 is that we have everything here including JE pistons (not coated this time). If we want to keep the 92.8 I assume we'll need new pistons which would take a bit. The other thing is we could put the Pauter rods in in place of the Scat rods, not that it would make a difference really but it's a nice touch.

[bradyzq]

Oh boy, not what we were expecting. Haven't seen it myself but dad says the pistons flop around in the cylinder. Over the phone I could hear the click click of the top and bottom of each piston hitting the cylinder wall as he moved it around.

Yikes!

Might be time to go back to a 2.2L. He said the cylinder walls look okay to the eye but he's going to check it for round/taper etc. We have 83mm JE pistons (not coated) and a stock crank that we can put in if need be. But jeepers. Perhaps the bore was too big? What would cause this... it seemed so tight during assembly.

Zoiks! That sucks!

Did the skirts really take that much of a beating? How unevenly worn are they? Can they be built up and saved using ceramic coating?

[chaloux]

Zoiks! That sucks!

Did the skirts really take that much of a beating? How unevenly worn are they? Can they be built up and saved using ceramic coating?

Haven't got the thing totally apart yet, we'll see tomorrow. It seems that the pistons have taken a beating but we'll have to see when it comes apart. The pistons are definitely worn, just not sure on the block yet.

[chaloux]

Just talked to dad. If the block is good I have a feeling this will turn into a high(er) revving 2.3L.

I'm just very cuirious to see the difference in spool that .2l makes. Any guesses?

[Wheeljack]

~10% or 300rpm

[EDIGREG]

Damn - sucks bad. Something had to be wrong tho for it to go south this quickly. I mean the motor barely had any miles on it and there are plenty of people running around with 92.8 strokers and no issues. Honestly it sounds like the bore may have been too big, or the pistons were the wrong diameter? ...doesn't take much.

[Hank]

I tend to agree with Ed. While a 144/92.8 is a poor rod ratio, it should not be going through motors in 10,000km intervals. Although Hap and other 92.8 builds are not daily driven, there are tons of vw 92.8(including all the new audi's, from the FSI 2.5L, FSI 2.0L, ect) that get away with it day in and day out. Sounds like the piston to wall clearance was not set up perfect. Usually being tight eats motors like this. If they are overbored, you just get the nasty piston slap/knock noise at warmup, and the deep scratches in the thrust side of the cylinders where the ring comes unseated at the top of the stroke. Post up some pictures of the pistons and cylinder walls when you get a chance.