I am rebuilding my 977 Cooper motor and would like to get a bit more power , but still keep it original looking . I was thinking to use an 1100 crank & pistons in the 997 block .
Can the 997 block be bored to take 1100 pistons , and will any have to be taken off the top of the block ?

don't!! 997 motors are too rare to modify

just use an 1100 and be creative after the top of the block has been machined

+1 on this...

IMHO, like Simon said, getting very rare and scarce these days, if its still a runner, fill it up with oil and wrap it in something and leave it in a corner, get a second hand 1100, bore it 100' do all the head and cam combo stuff and you fly away with your 1188 powa!

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I will give you a free 1100 motor as part of a deal for your 997 stuff

I believe that to fit 1100 crank etc means you have to machine a huge chunk off the top of the block, from then on it is effectively scrap as a 997 restoration motor

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Sir Alec! we are not worthy!

as all the others have said put it aside in dry storage

It will lose all value $$$$ after you do those mods!

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1966 Morris Mini Deluxe
.... 4 bicycles and 3 screaming kids.

You could source a 998 cooper block which had the fuEl pump hole similarly filled and has the handy 9f engine number to boot. Then an 1100 crank will slip right in with nil mods, or make yourself a great little 998 with a 12g295 head.

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SooperDooperMiniCooperExpertEngineering

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

Unlike some people, I have actually built a 997 with an 1100 crank (many years ago). I used +.030" 997 pistons and faced the tops off them to make them flush with the block. It was 1058cc, went like the wind with twin Amal Monobloc carbs, a Waggott 18/58 cam and big valves in the head.

A 997 block is basically just a 1098 block with a smaller bore. I eventually bored mine out to 68mm and fitted Imp pistons, 1098 rods and a new 1098 crank..

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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.

Thanks for alll the info , think i'll keep the 997 engine intact and try an 1100 ....cheers

AND they reckon a Cooper "S" engine is rare!!! Just try finding a 997 Cooper engine.
Well OK maybe a 970 "S" is. But I've seen more ads for 970's than 997's on Ebay over the past 10 years (including Ebay UK).

I want to know who's got all the 997 engines stockpiled. Be nice to have an original engine to go with the surviving and original COOPER MINI's.

I am lucky to have found one about 15 years ago along with a NOS crank and 2 sets of Hepolite pistons.. It has been rebuilt and is going in the '62 Cooper very soon. My '63 Cooper runs a 1275 (spare race engine with different cam and head) but would replace it with an original 997 if anyone would be so kind etc etc. I would give it a nice home etc etc.

AJ please don't muck with an engine that rare. They go quite nicely with the common garden variety 1100 engine.

Apart from the obvious engine number differences, are the details of the block itself identical to 998/1100 blocks? Casting details, welsh plug placement etc? Would you know it wasn't a 997 externally? (excusing the fuel pump hole)

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SooperDooperMiniCooperExpertEngineering

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

A 997 looks the same as a 998/1098 block, except the bores are even smaller than an 850's!
And there's no fuel pump hole, as you said.

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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.

The 997 came from the 948 in line engine block, as Kev says, the stroke was lengthened (from 3.0") to 3.2" and the bore reduced slightly from 2.477" to 2.457, thus being just below the 1000cc class break for racing at the time, remember, they thought they might only make a thousand of these things!

The 1100 crank has a 3.3" stroke, but a shorter piston to allow the long stroke in the same block as the 998 (3.0" stroke) and comon bore 2.543".

So Kev did it right using the 1100 crank with taller 997 pistons, but an all 1100 (pistons etc.) set up is too low, hence the block machining.

Oh and I have no idea where all the 997's went

Mick you are correct, 99% of folk would not tell a 997 block from a 998 or 1100, esp the early 1100 (ADO16) that also had no fuel pump hole!

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Sir Alec! we are not worthy!

I have seen A lot Of 997 Blocks with a con Rod sticking out the back of the block

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I sold a NOS 997 cooper crank on ebay a while ago. There were 3 different 997 cranks available. I have a couple of blocks still but no one ever rebuilds them cos you could never get the pistons, these days you can use JP pistons or Honda motorbike pistons or just bore it out and use 850 or 998 pistons. They had 12G202 or 206 heads on them too, 206 heads are just as rare as the blocks these days.

You can use a early M1100 block if you want an 1100cc engine, make it look like a 997, early 1100 blocks didnt have the fuel pump hole.

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