By the time there are "signs that the flexplate needing releasing", the damage is already done. About the only "sign" I've seen is that the engine is slow to crank over. This means that the thrust bearing is gone and the crank is machining the block.

If you have 2mm-3mm of endplay, you don't need to waste time measuring it more accurately.. Since the block and the crank are going to be junk, there is little to loose by driving it...except for those "euro" pistons. If you are going to build a hybrid, anyway, nothing to loose.

 

Yeah, i'll try to measure it properly tomorrow. Its really quite a visible movement, and I don't think i'm far off with my 2-3mm estimation. I can easily pry the crank one way or the other... I'm pretty sure its done But as Sean says, since the engine still has plenty of go, there isn't a reason for it to not carry on like this for a while yet. Well, at least until I get something else to put in there.

I can't check the oil anymore though, its gone into my big drum of waste oil already.

As far as the mileage, thats anybodies guess. I've had the car about 2 1/2 years, and the records that I have with the car show that for at least 4 years before that, the odo's been on 163k miles. Looking back also, I can see that the car had a new transmission due to stalling problems at idle! It says 'Disconnected torque tube, and engine runs fine' If only i'd known what this meant before I bought the car!

I think that even if the block is salvageable, i'll probably just end up going with a different block that's a known runner. Pulling heads is one thing for me, but messing about with the bottom end of my existing block is going to eat heavily into my wallet i'm sure. And like I said, i'll probably go with a 5.0 block and make a hybrid.

 

Malcolm, great rhetorical question and better insurance for us Roger-box guys...and, as you know, mine was a ROW model. The clamp is very well made...Once clamped...it's clamped!

Thanks Constantine!

 

I try Mike..........there's obvious deficiencies with the design that IMHO require change.

The car is +30YO from a design perspective.............I personally want to drive my 928 for as long as possible with modern engineering/design improvements where applicable so when I hand it on to my son its as good as, if not better than, what the factory produced.

The basic concept is awesome.

 

Thanks Mike and you are very welcome!

We designed and made the clamp to stop the whole drive shaft creep issue elegantly, like Porsche should have done in the first place, to keep auto 928s on the road where they belong.

Very sad to hear about the TBF'd cars recently.

Hopefully with the new TT rebuild parts it will give another reason for owners to get into their drivelines and update the whole system. IMHO, there is currently too much concentration and thousands spent on SC/Turbo systems to get the engines to produce more HP/TQ without first getting the driveline up to snuff.

Regards,
Constantine

 

Well, maybe my estimation skills are a little out! It measures at 1.4mm movement. Still a hell of a lot.

See here for some pics. Sorry they aren't the best.

 

1.4mm is still so little that its possible replacing bearings is all it takes to fix the block.

 

looking at your pictures, I am seeing normal markings on the block and that there is thrust bearing still there.

I agree with Erkka, pull the block, spit and replace the main bearings. Good to go!

 

You guys reckon this is still fixable?

The counterweight has definately been in contact with the block. But like I said before... there has never been any shortage of power, or overheating etc.
Maybe i'll have to put in an order with Roger.

 

Is the discoloration on the counterweight in pic #4 an indication of contact? Or is that normal?

 

Can you take a pic like pic #1, but on the other side?

You might also think that the crank has contacted it, it has happened alot before. But there is alot of markings there that would give that apperance.

As to the pic #4, I cannot say if that is heat colouration or not. It doesnt look like any heat colouration I have seen on other cranks, which do have some heat colouration normally.

 

Colin, do you mean normally as in normal heat colouration for a TBF crank or normally for your average good crank? I am soon to be doing an oil pan gasket and trying to get an idea of what is good. My endplay is .007 so not expecting anything ugly

 

Sorry Brian should have clarified that.

Normal as in for your average good crank.

 

what did you find by doing the oil test????
If you find metallic particles then it answers you question of if it was hitting.
Youy should still pull the engine and separate the girdle, you might get lucky and just have to install new mains, and do a thorough cleaning of all the other contaminated parts, that is if they are contaminated

 

Agreed. Blueish color is from electric hardening process. Its perfectly normal.

There is also machining marks in block from the factory which look somewhat similar to early stages of TBF. Thickness of #3 bearing sides is good indicator whats going on. If there is material left on rear side permanent block killing damage is unlikely.