24 replies to this topic

[mini13]

well, the fiat option has never really been proven, robert on turbominis gut somthing together and got it bench running based on a 16v  but didnt get furthur than that,

 

http://www.turbomini...p=vt&tid=222255

 

of all the 7 ports available the SC is best, as mentioned Will Hamer is running about 180 hp on approx 19psi, thats on somthing running to about 7-7.5k with am mg metro cam, on a 970 bassed bottom end you shpould be able to crack 200hp at 9k probably more.

 

there are 1242cc puntos making 200+ hp on the 16v head at 7000ish rpm,

 

there are 8v 1242 cccinqs making 130ish hp at about 8-9k, and i think 11k has been seen,

 

the kiwi land speed car is impressive, but I think a lot of development has been done in terms of cams, i think its in terms of 250 hp at 9000rpm.

[Caddy]

I like the sound of 200bhp!
That will need a straight cut dog box as well to handle the power! I can hear pound notes disappearing now! Haha

I think the 7 port or a bmw head will be the way I go.

The other thing I'm worried about is that the crank is on a 60 60 regrind, I've found the bearings from one company but I don't know wether they will sustain these amount of revs and abuse!
Any suggestions? Should I approach a company and get a set made up?

[Cooperman]

At 60/60 the grinding will have gone through the nitriding, which is what gives the EN40B steel crank its hardness and ability to rev well.

For what you intend it might be wise to find a better 970 crank. The one I sold for £450 last year was at 10/10 and just newly re-ground.

[Caddy]

Ahh right so basically I've bought a paper weight then!?

[Cooperman]

The beauty of the original 'S' cranks, 970, 1071 & 1275 is that they are made from drop-forged EN40B steel and were nitrided by Rolls-Royce The nominal depth of the nitriding was up to 0.020", or 40 thou on the diameter. I have, however, heard of cranks ground to -0.030" where the grinding has gone through the nitriding.

For what you will be spending on a 970 turbo engine everything considered, even if you do the entire build yourself, you would be best advised to get a crank no more than -0.020".

The one I sold last year for £450 was -0.010" and I had had it freshly ground to that size. Mini Spares provided the new competition bearings to match it.

You can fit an 'S' crank into a non-'S' 1275 block, but that needs some fiddling with the centre main bearing as the 'S' centre main is narrower than the non-'S' blocks, although the main bearing diameters are the same. Of course, the 'S' cranks have 1.625" dia big-end journals instead of the 1.75" of the non-'S' cranks/rods.

But if you do find a good 970 crank & rods you will have a really good class-winning car for racing, hill-climbs & sprints.

[Caddy]

Ahh I see, can you not get the crank nitrided again? Or is it a one time treatment?
Thanks for all the information as well guys, much appreciated!

[Cooperman]

Nitriding is very expensive and for a 60/60 crank would not be worth doing really.
I don't know that I would want to use a 60/60 crank in a very high powered application using mega-revs.
There are better 970 cranks out there for sensible prices. You should be able to find one for around £500 to £600 and that, compared to the likely build cost of the rest of a 970 turbo engine is low.

[Caddy]

Yeah fair enough.
Il be keeping an eye out for another crank or possibly look into a billet crankshaft, however they are mega money!

[Cooperman]

The billet crank is still not as good as a genuine 'S' EN40b crank. The 'S' crank is drop forged.

Try to find a genuine one no more than 20/20.

[Caddy]

Oh is it not? Ok thanks il get searching for one!