pjg

I 've seen the docs on how to check for crankshaft endplay, my question is, can the end play check be done from the front of the engine instead of the back.

Landseer

Of course, just the other end of the thing you are measuring.

I've done it there but it seemed harder to find a flat surface for measurement.

You have to release flexplate either way.

I've mounted / clamped steel near the flexplate for a firm base for the magnetic gage base.

pjg

Thought it would be a lot simpler to take this measurement from the front, no need to remove exhaust or headers if you have them to get at the flexplate. I suppose it must be done from the back because an accurate measurement could not be taken with tension on the flexplate. Just looked at the feeler gauge .2mm is about as thick as 2 sheets of paper, .4mm is about the same thickness as a business card, not much room for error.

Ed Scherer

I don't know if it'll help, but here's the setup I use... magnetic base stuck to starter motor housing, dial indicator gauge tip on back of flywheel:

Mrmerlin

I would say NO part of the check is to inspect the flexplate for bowing then loosen it.

Then move the crank all the way back then tighten the pinch bolt.

Dont forget if you have never inspected the rear pinch bolt at the transaxle then this needs to be done before you retighten the front clamp bolt

gearz

You can remove the lower bell housing cover to access the flexplate without dropping the exhaust. Four of the six cover bolts will remove easily, the two bolts at the rear of the cover will unscrew most of the way till they contact the exhaust pipe. At that point cut the heads off the bolts with a hacksaw or the like.

Shark Attack

Im going to say no. Unless you can get the pressure off it at the shaft anyway. I think you will get a much better read at the other end

pjg

Ok then the consensus is crankshaft end play must be measured from the rear of the engine after releasing the flexplate tension.

Thanks for the responses.

I was just looking for a shortcut method to determine if a 928 has TBF or the start of TBF.

Landseer

No shortcut, I thought you just wanted to work up front so you had a more solid base for the endplay gauge.

Once bell housing is down and bolt is removed, it doesn't make a bit of difference. BTDT.

pjg

What I really wanted to be able to do is walk up to any S4 Auto for sale, slap a dial indicator on the front of the crank and check the end play without ever putting it on a lift or releasing the flexplate, this does not seem possible based on the feedback. If this was possible you could weed out cars with TBF and move on until you find one in spec.

pjg

This answers my question.


http://jenniskens.livedsl.nl/Technic...1/MyTip100.htm

A crude crank end play test is easily done with a flashlight and a large screwdriver. It is just axial shuck of the rotating assembly. It should be near undetectable for the mere human. If it's a millimeter it is baaaaaaaaaad. That can be felt by even gently prying behind and in front of the large crank pulley cluster even with the belts on in a motor that has run and is oiled.

Thrust bearing failure should make millimeters not thousandths of an inch of end play. I have seen motors with 1/8" still running and not leaking any fluids and not really making any noise (not just talking about 928 motors here. Heck, I saw an old beetle motor with the case halves so loose you could see them separate on idle strokes and it was still running

Landseer

You got your answer from a diatribe that isn't right?

Not checkable without removing bell housing cover and releasing tension.

Actually, its pretty ridiculous to think somebody would walk up to any seller's car, whip-out a pry bar, and go to work on the front pulley.

Great destruction photo's, though, thanks.

Black Sea RD

I understand what you are trying to do but it really isn't that simplistic when it comes to 928 engines.

Understand that once the thrust bearing wear surface is ground away, further running of it can cause heat build up by the crankshaft, with eventual grabbing of the thrust bearing by the crankshaft spinning the thrust bearing within the block, which then leads to cracking the block, which then leads to a very expensive ruined engine.

All this mayhem is started by a few thousandths of play from specs, with the outer limits of the spec already seeing some wearing of the thrust bearing surface.

I too witnessed a 928 engine running with the thrust bearing ground away so badly that the rotating surfaces were making audible "knock-knock" noises until the front flex plate clamp was released from it's tension. That engine was reported to run but with heating issues and weird oil pressure readings. Not a 928 I would want to drive around or own.

Cheers,

martyp

Probably a stupid question, but I'll ask anyway:

Why does the TT need to be clamped/pinched at the flywheel end?

Would it be possible to let the splines slide axially in a non-stock flywheel attachment fixture, i.e. let the TT "float" at that end? Lack of lubrication maybe? Spline/TT metal too weak?

Always curious. Thanks.

Black Sea RD

Hi Marty,

The OE drive shaft material will not work well in a sliding system since the material is not treated correctly.

We made a sliding coupler but the drive line vibrations caused a severe vibration in that coupler system. The drive shaft needs to be pinned into the rear of the crankshaft like the 5 speed drive lines with their sliding coupler system, the clutch.

We finally came up with the Super Clamp design to positively and mechanically stop the drive shaft creep at the front flex plate that causes all these problems with TBF. It was also much cheaper than our sliding coupler design.

There has been much already discussed about this topic on this Forum and a search will give you plenty of reading material if your interested about this subject matter.

Cheers,