chilibluepepper

Thanks for the concern and support! I'm through being upset, and now I'm on a mission to get past this setback ASAP. As soon as I get back home, I'm going to attack this thing with some wrenches, and figure out what happened. In the immortal words of Monty Python, "its only a fleshwound!"

Ski

Alex, check your S&R sensors - just an easy thought and I doubt the car would have run as long as it did but...if the reference sensor was hitting the set screw, maybe this was your knock and when it went the car died. I would hope it's that easy, best of luck.

Abby Normal

Sorry to hear, Alex. Constantine has told me of your project and I can for sure relate to your frustration and efforts. I've encountered numerous set backs from time to time over the past 5 years of my turbo 928 project. And even now as I am getting really close to finishing, either something or at this point someone keeps me from getting it finished. It sounds like you have the right attitude to keep going, and I commend you for that. Projects like your's and mine are not for the faint of heart (or wallet) and when you are breaking new ground (so to speak) there are bound to be things that do not go as planned.

I know it's a tough setback however as you pointed out, it is "only a flesh wound"

And we are the Knight's who say.....NI

All the best as you forge ahead!

chilibluepepper

Thanks for the kind words Abby.

Well, my friend Constantine and I spent all day tearing into the engine, and this is what we found, starting with the good:

Reference sensors intact, valve timing good, timing belt was good condition, valvetrain and lifters appeared fine, cylinder head also appeared fine, but we found scuffing on cylinders 3 and 4. We found a little coolant pooled in the cylinders and exhaust, but couldn't really tell if it got there as we were taking things apart, or if it was there before. Makes me wonder if coolant leaked through the MLS headgasket into the cylinders, causing the knocking and promoting the scuffing, but that is speculation at this time. In any event, after our finding, we focused on preparing the engine for removal. Other than the necessary engine removal, I'm not sure what my next plan of action will be, but the goal is to come up with a plan in the next few days.

Ski

Alex, do you remember if you (machine shop) used .020mm clearance on the machining of the bores and IIRC, you used 104.5 pistons?

chilibluepepper

Bret, I used the Mahle 1st oversize pistons for use in a 104.500 bore (pistons are actually 104.480). Instructions to the machine shop were to use .020 clearance as per factory specs. I believe I did a rough check of the bore size after the work was done.

Ski

Best of luck to you. Did you find any shavings or metal in the oil or have you drained it yet?

chilibluepepper

No, I haven't drained it yet, but I will probably do it later today. Any thoughts on what might have been the problem?

special tool

What was the installed axial crank play?

chilibluepepper

Special Tool - I did not take that measurement. But, for whatever its worth, the crank to block clearances were within spec, and axial play seemed tight (as in minimal, not binding).

Ski

How does the engine turn over by hand, with the top end off?

chilibluepepper

It turns fine most of the way, but seems to tighten up a little bit at a given spot.

Jeremy Himsel

Bret and I are watching this thread closely because we're doing the same project. Piston to cylinder wall clearance is a cause for debate these days because Mahle NA is recommending clearances of .040, Milledge is recommending .038 ( I believe), and Andial says keep it at .020 when using the Mahle pistons from germany. Who's right? The factory matched pistons to the blocks using a .020 with a +/- factor on the TG1 pistons and TG1 cylinders(most common) and spec'd .008 to .032 clearance when new with a wear limit of .080.

I hope your issue is minor and look forward to hearing the cause.

Duke

For what it's worth, my experience with leaking MLS gaskets are that the car will not run on all cylinders. No other noise were present.

Oh, I almost forget, when a leaking gasket affect the spark plug the injected fuel will ignite at the tail pipe even when cold.

chilibluepepper

Jeremy - You bring up an interesting point about the piston to cylinder wall clearances. I went with Andial's recommendation of .020, and did not question it because it coincided with the factory specifications. I guess the good news is that if there is a trend for looser clearances, then I have a better chance of being able to repair the cylinder walls, while staying within an acceptable tolerance.

Duke - Thanks, all input is valuable, as I am treading unknown territory. The car was running roughly, but I don't know what to attribute that to. It was the initial start-up for this engine, and I expected the idle might be rough until the valve train settled in, and until I adjusted the idle settings on the piggy back computer. For the purpose of background, I am using a Vitesse S5 kit on this project.