How close do the weights of each conrod have to be on a 2wd cosworth engine? Iv had everything else balanced but am doin the rods myself.One is 0.713 kg,the other 3 are 0.728kg.how close do they have to be?

 

on normal old road engines, usually within about 5 grams, ut i'd hope they'd be within 1g on a cossie. you probably have 'H' etched into the end of the three rods and possibly 'S' on the other one? probably had one replaced at some point in its life by someone who dosen't know what they're doing.

 

I thought they had to be balanced end to end?

 

Yep. definately sounds like a stray S or L one in a set of H's

 

Ah right, so either balance the odd one to match the rest or get a matching set? it looks the same,has the same part numbers just machined slightly different.Im building the engine to around 400hp so i want it right.