JT's Turbo Clubman
Turbo Mini Forums

wooof thats broken . you could maybe use that ring again , and as joe says get hte case welded , is that a gearbox short stud that was in there ?

Medusa + injection = too much torque for the dyno ..https://youtu.be/qg5o0_tJxYM

My best initial guess from the thread size and where it ended up would be one of the 3rd motion shaft bearing retainer plate bolts.
Four bolts on early cases and three on later ones where the casting was strengthened and the bolt in the weak point omitted.
If the trapped bolt has put enough shock on the diff housing to fracture it I'd look very closely at the area around the 3rd motion shaft bearing to make sure it hasn't cracked the casting around the bearing before considering welding up the broken housing.

Schrödinger's cat - so which one am I ???

I've got 2 spare gearboxes I can strip and rebuild this box into. If need be.

How hard would it be for a pro to Tig this up without distorting it?

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

should be ok from the look of it, all the damage is at the back away from any gasket faces as far as I can see.

the real problem is getting it clean, will need a damn good degreasing and get the paint off. and also check theres no other cracks.

If you have other casings, it might just be best to swap to one of those, its nto that much work to swap the cogs really.

found where the bolt came from yet??

I can tig it up but it will probably distort somewhat. It's not worth it when cases are easily avalible imo.

Not had a chance to look at it yet. Thus weekend hopefully.
Here's another pic of the casing...




If I decide to put it all in another case should I get new bearings etc? The gearset has only done about 1000miles tops since new.

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

I'd run the same ones, but I would check over the double roller carefully, and give it a rinse in thinners to see if any debris comes out
.

Right I took the center main cap off just to see if I've messed the crank or bearings up as I enjoy out of oil after the diff casing broke...



Now I can't feel the marks with my nail.. should I replace them? Or leave them in? The crank is spotless. I'll check the other two but just thought I'd check the center one first. I ideally don't want to disturb to much.



Could this be the bolt that has caused the problem? Should there be a bolt in that hole?

Regards,
Josh

Edited by JT on 25th Mar, 2019.

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

Hi if the casing part number is DAM5626 there shouldn't be a bolt.

Thanks I'll check.
What about the bearing? Re fit it or replace them?

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

DAM2886 is the earlier box which used all four bolts and, as above, DAM5626 should only use three (even though they kept the same retaining plate with four holes).

From the raised rib on the casting in that area it certainly looks like a 5626 but, more to the point, is there a threaded hole there ???

It is always possible someone in the past may have mistakenly drilled and tapped it.

Schrödinger's cat - so which one am I ???

Personally for what they cost, and that its a major strip down to get to them in future, I'd replace those shells while you are there.

yeah, likewise.

if it was a std lump then yeah id run them again, but for this.

Better replace them, for the price they cost its not worth the time you wast to dismantle a hole engine and risking to do more damage if something goes wrong with the old bearings. Check also the oil pump because if it sucked some of the broken metal parts it could also damaged it self.

Cheers guys. Just ACL bearings or is it worth the extra for the race bearings?
Also should I replace the big ends? While it's in bits?

The hike looks like it's solid as in no thread there.

I'm unsure where it has come from.

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

got pics of the rougue bolt? might be recognizable,

yeahI'd do the ends too if they look similar

I'll have a look tomorrow evening when I'm next with the mini.

Just normal ACL bearings or there race ones that are double the price worth it?

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

Also what else to check while it's in bits?

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

I’d ensure oil the oil galleries (block and crank) are flushed through and are clean the last thing you want to do is pop a new set of bearings in and them be ruined by some debris that’s still floating around/been picked up. A few more hours now is far better then many wasted later.

Ok I've got the crank out. Looks fine. Going to replace the besrings though.
And the big ends.

I've now noticed that piston 4 does not move up and down the bore very freely. I kind of makes a sucking noise. All the others move up and down freely. What could this be? Looks like I'm going to have to pull the head off and check it I guess?

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

If both valve are closed on piston no 4 it will be harder to move because you are trying to compress the air in the combustion chamber. Remove the spark plug and see if it will make any difference.

Good point turbominik! That's what happens when you are looking for problems when your tired!! 😂

I'd rather not take the head off adding to more work lol.

Still can't find where the bolt/stud has come from!

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

Have you got a good photo of the mystery bolt? Personally i’d Probably swop the casing.

It's still wedged in the casing 😂

Here's a pic of the big end bearings...



Going to replace them and the mains as I've come this far already!

My build thread..

http://www.turbominis.co.uk/forums/index.php?p=vt&tid=542985

Once almost happened the same thing to me, when I was assembling my engine, a valve cotter flew off my hand and I couldn't find it. The first time I changed the oil I found the cotter on the drain plug magnet. Luckily it didn't do any damage to the gearbox. Who knows maybe you where working around the gearbox and accidentally you dropped a bolt. These are things that happen.