can any one tell me wot the smallest size you can grind a 2wd cosworth crank down to i dont mean .25/.50/.75 i need to no the size like 50.00 mm /55.00 mm

 

i was told std is good for any power .25 for 550 bhp and .50 was only good for 400bhp i may be wrong

 

no mate thats not wot i need to no im thinking about getting a crank to build a spair motor out of and i no the crank has got to have a grind as it spun a shell the lad has told me the size it is now i just need to now if it has got a grind left on it .its 51.40mm at the mo

 

STD Mains are : 56.959-56.975mm
Big Engs are : 51.977-51.993

Think 0.5 undersize is the smallest.

 

Depends how good the machinist is as to how low you can go and still retain strength.

 

Amen to that my friend

 

Unless they lose it of cause

 

im a bit worried about one of mine thats been there for a couple of years tbh, i keep asking about it, as ive never paid for the grind, yet it never appears hmmmmmm gonna give some pressure tomorrow i think.

 

Well if he digs one out and it doesnt look like yours let me know

 

i have a freshly ground crank at 0.25 that was done by harvey SCS for sale if you're interested mate.

chop

 

Some info for you Coley :


Main bearing journal diameter:

STD: 56.975 to 56.969

Undersize
0.25: 56.725 to 56.709
0.50: 56.475 to 56.459
0.75 56.225 to 56.209

Big end bearing journal:

STD: 51.993 to 51.977

Undersize
0.25: 51.743 to 51.727
0.50: 51.493 to 51.477
0.75: 51.243 to 51.227

 

Oh and I have a couple of cranks for sale if anyone needs them