59 replies to this topic

[Matt Zane]

Well, I got the wok off, and I've found the issue.

Everything was loose, I was able to undo everything by hand. The flywheel came off, in my hand.

The keyway is all chewed up. The taper on the crank is ruined.

Question is, is the crank salvageable?

I am totally gutted. I'm going home to drink beer.

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[nicklouse]

Unfortunately it is as I thought.

it may well lap in ok if there are no high points.

 

you either forgot to tighten it up. Or the offset washers was not correctly orentated.

 

enjoy the drink and have a fresh look in the morning.

[Matt Zane]

It's even worse than that Nicklouse, I didn't even check it.

I saw the videos of the engine running on a stand prior to me buying it, and didn't check the clutch at all. Really bloody stupid of me.

Sorry a bit of a noob question, how would I go about lapping back in? Emmery paper?

[nicklouse]

It's even worse than that Nicklouse, I didn't even check it.

I saw the videos of the engine running on a stand prior to me buying it, and didn't check the clutch at all. Really bloody stupid of me.

Sorry a bit of a noob question, how would I go about lapping back in? Emmery paper?

Same as a valve. Grinding paste (fine) on crank well spread. Then rotate flywheel so as to grind them together. Then big clean up on both. Then fit and tighten.

[Matt Zane]

It's even worse than that Nicklouse, I didn't even check it.

I saw the videos of the engine running on a stand prior to me buying it, and didn't check the clutch at all. Really bloody stupid of me.

Sorry a bit of a noob question, how would I go about lapping back in? Emmery paper?

Same as a valve. Grinding paste (fine) on crank well spread. Then rotate flywheel so as to grind them together. Then big clean up on both. Then fit and tighten.

Thank you Nicklouse. I really appreciate the solid advice.

If I could buy you a beer, I would!


If I'm not able to lap out the damage, do you think the crank is repairable?

Could it be welded and the taper refinished on a lathe?

[nicklouse]

Get it lapped and then photos. From what I can see, hard to really see in that photo. Better to host full size on imgur and link. It will be fine for road use.

[GraemeC]

If there are any high spots carefully file them down first. Then lap as Nick describes - you'll be surprised just how well it might clean up.

If it is well lapped together then even with a few craters it will be useable 

[Matt Zane]

If there are any high spots carefully file them down first. Then lap as Nick describes - you'll be surprised just how well it might clean up.
If it is well lapped together then even with a few craters it will be useable

Thank you GraemeC! I owe you a beer too!

[KTS]

One other thing to bear in mind after lapping the flywheel onto the crank is that you'll need to make sure the flywheel has not moved so far up the taper that it contacts the primary gear c washer when torqued up - if it does, the primary gear won't spin on the crank and you'll effectively have no clutch.

A little bit of machining of the flywheel should fix the issue if it arises

[Earwax]

Ah that is no good Matt.  The excitement of buying or the last hurried efforts to give the thing a try often leads to an omission  ( I can own up to driving off without wheelnuts on one wheel - yes ended up on 3 wheels - luckily all low speed). So don't get too down on yourself.  As KTS suggested , when cleaned up make sure you check that the flywheel hasn't been drawn so far inboard on the taper that part of the flywheel jams - or otherwise no rotation of crank

[Matt Zane]

Hi All,

 

Just a small follow up on my last post. I managed to get down to the garage on Sunday, and used the suggested technique of lapping the flywheel onto the crank. 

 

Luckily there were no high spots on the crank taper, and the lapping process did seem to polish the taper quite nicely, and it feels much smoother to the touch, so I feel much better now. 

 

I ordered a new clutch kit from Mini Spares, as I thought that it would be an ideal time to replace it, bearing in mind that the clutch is out of the car at present.

 

Mini Spares suggest that the clutch and flywheel assembly is dynamically balanced prior to install, so I contacted my local machinist to ask whether this is something he was able to do. He said that this was possible as he has a spare 1275 crank in the shop at present, but stated that this probably wasn't necessary for a road car.

 

I did some further research on here yesterday afternoon, and some people agree with him and state that unless the car is going to be regularly used at 6500+ Rpm then a balance is not necessary, but others state that the verto clutch assembly always needs balancing. 

 

For the sake of clarity, I've ordered the kit that contains the 180mm wide clutch plate, pressure plate and release bearing, and my intention was to mate this to my existing flywheel, then get this into the car.

 

Bearing in mind my previous oversight, I am thinking of airing on the side of caution, and just getting the whole assembly balanced for peace of mind. However, if the general consensus is that I'm being overly cautious, and the balancing is going to be massively overkill for a relatively stock (stage 1) 1275 engine, I will bow to superior knowledge.

 

Thank you all once again for your invaluable input, my offer of pints definitely stands, and if I ever (hopefully) see you guys at a show or meet, I would be happy to furnish you with one, and shake your collective hands!

 

Kind Regards,

 

Matt

[GraemeC]

Get it balanced - AC Dodd has done many videos on Facebook showing just how far out of balance the Verto flywheel can be.

[nicklouse]

Get it balanced.

[Matt Zane]

Thanks guys! I'll check out the AC Dodd Videos

[Matt Zane]

Just watched the video on youtube! Bloody hell, I'm definitely going to get it balanced!