Engine Sizes. Bore v's Stroke

[Nevsmini]

Here is a very helpful chart for anyone thinking modifying an engine with different pistons etc. I wonder what is the best combo???

[mk1]

A useful table.

But, what crank has a 66mm stroke?

Also some of the colour coding is a bit misleading.

No one has used Imp pistons in a mini for years.

M

[Nevsmini]

Answers

1. Stroked crank
2. Change the colours if you want
3. So what!!!

[rich@minispares.com]

it doesn't have the SA1100 crank stroke(s) on it either, so you need to add 68.26 & 70.00 to take into account both variations

[mk1]

3. So what!!!

That's my favourite answer

Well done.

M

[Nevsmini]

Your just lucky I did use the word Imp in one of my answers

Anyway my point to this was to kick off a discussion on what combo's people have used in the past etc etc failures and successes!

[Rusty old S]

Back in the 70s yes imp pistons were used along with triumph PI and what they called Devon pistons ( BMC ) but as special piston sizes were produced ie 73.5 etc they melted away into the distant past , possibly literately .

[swifty]

Having owned and built a couple of 1480 cc race engines , this would be my choice . You can't beat the tourque of the extra cc . They may not rev as high a a short stroke but a lot less chance of a blow up ...... Ken

[smithyrc30]

it doesn't have the SA1100 crank stroke(s) on it either, so you need to add 68.26 & 70.00 to take into account both variations

Isn't the third column from the left 68.26????

[Pete]

Went the 1149 route on a Mk1 Cooper many years ago, wasn't really worth the effort and a gudgeon pin came loose trashing the block. Did a 1341 which revved nicely and produced 108bhp but just didn't have the b*ll*cks that my 1426 had in my Vita-ish Cooper S. Had so much torque that it didn't really recognise the steepest gradients!

[mk1]

I have always been a fan of the short stroke revers. I have built a 970 crank / 73.5mm screamer for my brother which went like the clappers & easily revved to 9,500+, it did however get through head gaskets like I get through underpants.

I have built many, many 1070 /SA1100 cranks with various standard overbores, usually plus 40 or 60, these always go very well & give a smooth & beautifully behaved road engine.

I have never liked the lumpy bumpy nature of the 1275 engine, but the short stroke 1299 in the Hornet was a bit of an eye opener, no where near as smooth as a true short stroker, but it gave excellent power, well until Rich blew it up it did anyway

I am currently building an all steel appendix K 1293 for it, so we will see what that is like won't we.

I have over the years built many other engines both small & latrge bore, but the above ones are my favourites.

M

[mk1]

Weren't "Devon" Pistons from one of these?


Austin A40 Devon

[rich@minispares.com]

, but it gave excellent power, well until Rich blew it up it did anyway

these car breaking works drivers eh............

[mk1]

[Oldskoolbaby]

Last A series I built was a 16v 73.5x86mm 1460. Now I'm building the other end off the spectrum with an 8 port 970 at +40. Not sure what I'll prefer but I suspect the high rever is likely to tick more boxes for me.