41 replies to this topic

[coopertaz]

Those are my concerns Lplus, I'm sure it could work with a new flywheel, but how well and for how long is a mystery...

 

The best I could do at home considering taking out the crankshaft as a last resort could be to mount the new flywheel/clutch system and use a dial to measure the wobble in both planes.

 

What a nightmare...

may be true but still not fully down the taper. i have fitted flywheels to less fretted shafts than this and had them weld on. i learn't from my MANY mistakes pre. forum days so just throwing my opinion in here.

[68+86auto]

You are going to want to replace the crank.

[Ethel]

Agreed,

 

You'd just be throwing good money after bad if you tried to use that crank. I don't think a lock washer would have prevented that, but the lack of one might have stopped the bolt being tightened properly.

 

 

 

I note your location, but in the UK the seller's liability would be different depending on if it was a trader or somebody selling their own car. The same would go for the "mechanic" and their liability to the seller. If either have some legal liability, it might be an idea to get a quote off a mechanic for recovery & a full repair, just to have a starting point.

 

If you end up sorting out yourself, if you have anywhere off road to put it, lifting out the engine & gearbox should be manageable. It'd be far easier to transport that lump than the whole car if you do need to outsource the job.

[Spider]

Nothing to loose by spending about an hour lapping the flywheel on the crank and then see how they look.

I've always found they look way worse 'as found' but usually, after some basic work, they can come up OK.

[sonscar]

I am with spider,clean it up,lap it in,see where it engages and check runout with a dial.Cost nothing except time and will remove doubts as to the next step.Steve..

[Icey]

The crankshaft nose seems to have melted due to friction. Reusing as is has significant risk.

Will the new clutch centre accurately on the nose so as to run true and not wobble?

Will the taper contact area on the melted metal be adequate to transfer load without coming loose and stressing the keyway ?

It’s not melted, it’s fretting which is a specific type of wear.

While my instinct is also that the crank may well be scrap, fretting, generally, doesn’t cause deep fissures in the material so lapping/polishing is worth trying. (Warning: I’m not a material scientist or metallurgist).

[aguiloco]

I think I could try the lapping process, as you said is worth an extra hour or two of work to check the condition. This must be done with a new and fresh flywheel or could I use the actual one? I don't have it in hand but judging by the photos I have seems like the inner taper is also a bit rough.

 

Researching this topic I found some mention of elongated rods at the clutch slave cylinder to be able to push the clutch further to work. Now I remember that the push rod on my car has some weld added, so seems like something happened there, maybe the flywheel could be already a bit recessed into the crankshaft from previous rebuilds, hard to know for sure right now.

 

Before the fault the gearbox was working mostly fine, I'm not experienced in this car, it was hard to change from 3rd to 2nd, but with a double clutch, it was fine. I don't think it was rubbing the C clip, but can't be sure it won't with a new flywheel. I have seen that some mechanics increase the recess at the flywheel from new just to avoid any possible contact with the C clip.

 

This is a mess, but I'm learning a lot.

[Cooperman]

That crankshaft is beyond economic repair and as it is will not 'clean up'.
The lowest-cost way to proceed is to find a good replacement crankshaft. Then pull out the engine and rebuild it.

[rww]

  Hi  Aguiloco.

 

          Have sent you a private message.

 

                Cheers, Richard.

[aguiloco]

  Hi  Aguiloco.

 

          Have sent you a private message.

 

                Cheers, Richard.

I'm sorry Richard but I don't have any messages, maybe there is a limitation as a new user? 

[aguiloco]

Just a bold idea here as a desperate solution in case I want to keep the car and the crankshaft:

 

I do the lapping, check that the flywheel is not touching de C clip or the case, and use a dial to detect any wobble.

 

If all of that goes well, how about a hardened keyed washer, hardened retaining bolt, and torque it up more than usual?

 

I know is not the greatest solution, but maybe it could last as long as the clutch disc, then when the time comes for a replacement suffer the nightmare of a stuck flywheel.

 

Just thinking about my options here, lots of factors to consider.

[Ethel]

What would concern me is having to take so much off the crank, the flywheel  moves so far down the taper it hits other stuff. You have nothing to lose in trying though.

 

A hardened bolt & washer would put more load on the taper anyway, what you won't do is make the thread in the crank nose any stronger.

[stuart bowes]

Surely also hardened is more brittle which is undesirable

[Spider]

What would concern me is having to take so much off the crank, the flywheel  moves so far down the taper it hits other stuff. You have nothing to lose in trying though.

 

A hardened bolt & washer would put more load on the taper anyway, what you won't do is make the thread in the crank nose any stronger.

 

That's true that it would move further up the taper, but having saved many like this I haven't had one move more than 0.004". I don't think their manufacturing tolerance was that close.

The Key Plate is (or should be !) already on the hard side, but if the flywheel is fitted correctly to the crank, the Key Plate does nothing after the initial alignment.

The Stock Flywheel Bolt is already Grade 8, with it's size, it already has a huge tensile rating. With it's long length, engagement in to the end of the crank and the crank material (either EN16T or EN40B) the thread here is well suited for tensile applications. I routine do these up to at least 150 lb / ft and I can't say I've had an issue. Likewise, for what ever it's worth, the Bolt at the other end I also found needs to be tight, while a much shorter bolt, I do these up to at least 120 lb / ft. I found using the factory figure of 70 lb / ft not nearly enough. The Torsional vibration that the crank normally sees in everyday use acts like a Rattle Gun in particular on this end of it, loosening this Bolt fairly easily.

[Earwax]

If  you try and clean it up and re tighten etc - please get the correct (borrow) tap to clean out the internal thread for the crank retaining bolt. As above for the flywheel end 150 ft lbs is plenty but i do use loctite  - 

 

FOR emphasis - the correct thread !!!! -