Hello
I've got hold of a e36 2.8 crank. It fits the block fine, but the later pistons fowl the webs even with the 135mm rods, so when I fit my 130mm rods for the conversion it's going to be worse obviously.
From what I've read, the standard thought of using a non TU crank (think that's the correct terminology) is the way to go but I'm really struggling to find one and this was nice and cheap at £40.
The question then is instead of using custom pistons, can I instead machine the webs/counter balance weights down on the crank itself. If it's possible then this would be a much cheaper option. I'm waiting to speak to the main man at my local engine builders so I thought I'd get some input, perhaps someone has tried this and knows whether it will work or whether the engine will simply fall apart.
Kind regards
Nick Hine
Machining the webs on a 2.8 TU crank?
Moderator: martauto
Machine the skirt of the pistons to suit not the crank.
Yep, I've read that is required often when using the early and some of the later pistons, but with this being a TU crank the webs are larger than the earlier crank and the machining of the pistons looks like it will be excessive.
I've spoken to the local engine builders now and he says that in theory it's possible. They machine the webs down on 1400cc Peugeot rally cranks often for example, then obvisouly re-balance them. He's happy to give it a go and we'll see, but he's also on the look out for an earlier crank too. For the price of it, it seems worth a try, if it balances OK after the machining then in theory that should work. It's not been mentioned on the zone as far as I can tell, so maybe no one has tried it yet?
I found a thread on here earlier, where someone has had the same problem with a later crank. The concensus was, get an early crank the later ones won't work, but perhaps this is a route for many more cranks to find their ways into M20, which can only be a good thing....
I've spoken to the local engine builders now and he says that in theory it's possible. They machine the webs down on 1400cc Peugeot rally cranks often for example, then obvisouly re-balance them. He's happy to give it a go and we'll see, but he's also on the look out for an earlier crank too. For the price of it, it seems worth a try, if it balances OK after the machining then in theory that should work. It's not been mentioned on the zone as far as I can tell, so maybe no one has tried it yet?
I found a thread on here earlier, where someone has had the same problem with a later crank. The concensus was, get an early crank the later ones won't work, but perhaps this is a route for many more cranks to find their ways into M20, which can only be a good thing....
After a quit chat with malcolm at lancaster engines he produced the correct crank, easy peasy job now, but my mahle low comp pistons still need machining a little to clear. 320 rods turned up today too. After finally managing to get in touch with ant atech, have gleaned better info. Block off for skimming and flywheel off for lightening on monday, got four weeks to have the engine in and running and many parts to buy yet, skates on....
Yep, block skimmed 0.5 mm down to Ant's recommended height, pistons are having their skirts shortened to clear too. Whilst I'm about it I'm having the flywheel and the front crank pulley lightened and balanced to the crank. Oh and the bores honed too.
Getting it back this week, so then it'll be a case of getting hold of the other bits and bobs I need to finish off, went mad and bought a full btb system as they're on special at the moment. Dented the rest of budget somewhat!
Still, it'll all be worth it in the end, and I've got Magpie coming to pickup all my M42 stuff today so I'll be able to get back in the garage at least.
Getting it back this week, so then it'll be a case of getting hold of the other bits and bobs I need to finish off, went mad and bought a full btb system as they're on special at the moment. Dented the rest of budget somewhat!
Still, it'll all be worth it in the end, and I've got Magpie coming to pickup all my M42 stuff today so I'll be able to get back in the garage at least.