yep,,, we can have one made for you no problems

we can even have the rods "Straight" as in --> the center of the piston centered to the center of the big end if you like... no off-set

it`s only money

How many would you like?????

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Sure can, people like Sainty Engines make cranks (V8 ones) all the time. They CNC mill theirs instead of turning, it's much quicker metal removal.
I got a quote many years ago for a nice billet of EN40B, but it was worth a small fortune even then. Even before I could start turning.
And you would want a serious bigass lathe for this, or it'd take a million years. Not yer average 6 or 9" centre lathe.

On the other hand GR can fix you up with a nice 4140 nitrided 8 counterweight S race crank, made in Melbourne, for around $4K. Hey it's only money...

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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.

I was thinking more of an "ultimate" 850 crank though , I know there are options for 1275 but a nice strong crank and set of rods setup to use bike pistons of appropriate size so it all works out close to original bore and stroke ....

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How about cutting and shutting two blocks together to make an inline six? (seeing how we are now fast approaching fantasy land)

why make a straight six where you wouldn't be able to fit the radiator when for the same amount of work you could make a V8 ...

More a hypothetical than anything but a seriously strong 850 crank that would fit in a standard block (cheap and plentiful) would be great .

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A V8 is actually a lot harder to make. There is the big problem of trying to fit two con-rods on one crank journal and keeping that within the length of the existing block.
An inline six would fit quite nicely in a Morris 1100.

Righty Oh, back on topic , lets start crunching some numbers to give us a true picture of what we are trying to do ,

my first attempt at calculating a possible result using the the parts I could find was interesting, Melling cylinder sleeves , using their stock 2.7950 inch bore Sleeve would require a 0.381 bore ( 15 thou ) and with the sleeve thickness 3/32 inch 2.3813mm would give you a 68.6117 mm 2.7012 inch bore, so 1202 cc

Now using a forged flatop 69mm piston, we now move to a bore of 69mm and stroke 81.29mm - 2.7165 inch and 3.20 inch , so 1215 cc 74.185 cubic inch . Now obviously with flat top pistons like these , some careful thought is needed for the final compression ratio in regards to head modifications.

[img][img]http://img185.imageshack.us/img185/9484/gre104buggati.jpg[/img]


So now its just matching it with longer and stronger conrods and a suitable crank and we are getting close to the longer lifespan 1275 block according to my theory , true it is with reduced capacity , but still with good torque.




.[/img]

( Thank,s Mr Green , I couldn't find a good photo of a 69mm 4 stroke motorbike piston and the Lambretta Scooter piston being 2 stroke doesn,t have oil rings but it was a good photo, this a Bugatti piston )

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Dean, nice pistons there, but you'd better find some with oil rings, or there'll be tears before bedtime...

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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.

quite a number of 6cyl bike engines out there Morry,,, Benelli & kawasaki & triumph to name a few,,, the kwaka 6 would be the most avaliable & cheaper than the others tho

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

I did finally get a better photo of 69mm motorbike pistons, yes , with oil rings , it is quite a common overbore size in motorbikes so there are choices available.

It is certainly an interesting exercise so far, a sleeved 1275 with a 69mm bore / 2.7165 inch and stroke 81.28 mm / 3.20 inch , 1215 cc 74.185 cubic inch

[img][img]http://img508.imageshack.us/img508/1874/juegopistonessanglas400.jpg[/img][/img]





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Psst - Mr Asparagus - 1215 Cubic Centimetres (cc), not Cubic Inches (ci). Of all the people on this forum Mad Mr Read's the closest I know about to getting to 1215ci in a Mini, but his Rover V8 is only something like 215ci (3.5L), 241ci (3.9L).

I know, I know I wrote it arse about , 74.185 cubic inches, 3.715 cubic inches LESS than standard !

And thats the whole idea !

Less is more for longer !


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with the bike pistons honda cbr 600 f3 had 67 std with 68,69 o/s. the f4 was 69 std and has 70, 71, 72 o/s then the 900 continued from that size in bore ,but heights gudeon pin dia are different.
When I went thru the exersise before it meant that the rods had to be quite a bit longer.
Now here is a interesting one for the crankshaft. Search for a sectional constructed crank shaft and where they are used. One application is in aircraft engines.
As for billet ones I made 4 up for john mc cormacks formula 5000 in 1974. He was the first bloke to use the p76 engine in one. It is one hell of a job doing them on a mill and lathe.

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Research is the difference between speculation and investment. Anyone who copys some one else will always be second
www.minisprintgt.com

Ahhem,,, it`s actually ---> 4.7litres thank you
But Shhhhh,,, don`t tell anyone,,, it`s our secret ok?

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No offence intended here but--> anyone writing a book about minis 30 years ago may not have experienced such worn or stuffed-with components as we are finding these days.

You should put your heart & soul into everything you do.

Thanks David , I could,nt find anything on those cranks , Google was not my friend this time, the only cranks that came up in searches was VW billet nitrided 84mm stroke crankshafts, ( of course they wouldn,t fit )

I was doing research on 69mm pistons and rang Wiseco and they were very rude to me when I asked about details on 69mm pistons and told them it was for a 1275 Mini engine, the conversation was cut short and they hung up on me . The main problem with ringing parts places and asking about 69mm size is that they have no idea about sizes , only Bike/Model/Part No !


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