Have rebuilt the engines and put them back in the Twini. Runs sweet, great gear change, etc. but:
Put your foot on the clutch and the rear engine drops revs, to the extent that it will stall at the lights. This is from idle at around 1200 RPM. Other engine has no issue.
Clutch assembles are MED with orange diaphragms. Changed the thrust bearing over to another one that also feels like new and no difference.
Any ideas on what I can check next? Just because it is the rear engine, it is no different to a normal configuration.
Do I recall a similar post to this in recent times?

I remember a post with similar clutch / engine idle issues.

When you push the clutch in, it forces the crank towards the front of the engine. Was it something to do with crank thrust washers? or primary gear clearance / issue? I think Matt Read posted something of that nature.

Sorry, not alot of help.

Cheers Shane

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If it's not a Cooper S, the mini was designed to be modified!

If you have turned the thrust washers around the wrong way on installation, this will prevent oil from getting into the moving face , and cause the engine to slow down.

The steel face contacting the crank will also cause a lot of damage!

http://www.ausmini.com/forums/viewtopic ... 6b2a1e67f4

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SooperDooperMiniCooperExpertEngineering

All garage work involves equal measures of enthusiasm, ingenuity and a fair degree of irresponsibility.

Mick, thanks for the link.
My symptoms are the same.
Revs start to drop as soon as the clutch arm starts to take the pressure. Clutch doesn’t have to be all the way in.
So sounds like I should check it out before too much damage is done.
So far there is no excessive build up on the sump plug. Just some really fine paste (from the rebuild).
Also noticed it gets worse as the engine warms up.

My bet is the thrust washers too. If they are fitted arse about and you leave it like this, they will destroy the crank face.

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DrMini- 1970 wasaMatic 1360, Mk1S crank, 86.6HP (ATW) =~125 @ crank, 45 Dellorto (38 chokes), RE282 sprint cam, 1.5 rockers, 11.0:1 C/R.

bugger! pull it out

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did I tell you that I won a trophy?