My reference says normally fitted to 850 Mini, A35,A40,Minor, Sprite MkI also can be fitted to 998 and 1100 - inlet 1 1/16" as opposed to a 202 that has 1 5/32" inlets - combustion chamber is 1.5cc smaller therefore compression should increase but flow inside the chamber is worse.

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

A change in compression ratio or valve size can make a difference to performance or make an engine ping but shouldn't make it idle or run roughly. I'd be sorting this problem then see how it performs.

Also, I wouldn't assume whet valves it has based on the numbers on it. After all this time it could have had numerous rebuilds and who knows what valves. It comes down to whether it performs to your expectations when you get it going right.

Hope you get it sorted soon.

Cheers
Pete

Well its running alrite now well yeh it is idleing abit to high but i spose i just have to adjust the timing etc. but yeh well if it is a smaller head it should be rite shuldnt it i dont want it to wreck the engine. Im not all that worried about performance at the moment i just want a car that runs.

Blake...998 and 1100 have the same bores so not a "small" head...you can get different sized valves and yours may be smaller with unleaded inserts... what people are saying is that your compression ratio may be different from normal...would be nice to know.....but it will still run fine

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"Show me the Mini!"

Wombat,
Your reference is wrong, 12A1456 head used on 850 and 998 and Morris Minor 1000 etc had 1.090" inlets not 1-1/16". RTFM
On a 1098, I'd be wanting a 202 head, minimum. Small 850/998 inlet valves and ports strangle the top end performance. I know this `coz I have one (was in Barney when bought).

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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.

Bleeding dutch website - http://drcwww.uvt.nl/~bogaard/heads.htm should have known not to quote it Any way as the Doc says unless it has been modified it will strangle the performance .

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David L


My greatest fear in life is that when I die my wife will sell my Mini and tools for the price I told her I paid for them!

Doc...this engine just has to tootle around on the weekends....are you saying that it will be absolutely asthmatic and require premature down-changes on hills etc just like a very tired engine or are you saying it is not your cup of tea as someone interested in the performance end of the scale (if ya get my drift ).....cripes, theres even people zipping around in 850s having fun

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"Show me the Mini!"

No it'll go OK and pull well up hills, will just be down a bit on top end compared to what it should be.
We drove Barney to Can-Bra the 1st time like this, hey he went OK really...

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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.