RS 5tu

iTrader: (2)

My mate is building a 2.1 zvh using a blacktop but had been told by the time the conrods have been machined they will probably brake as there is not a lot on them, So can he use silver top conrods and a blacktop crank? in a blacktop engine?

RS 5tu

iTrader: (2)

bttt

bad boy

not sure on this one mate as most people use silver tops. shouldn`t imagine thier would be that much difference. u will just have to get a set and marry them up to the black top ones and see if they fit round the crank.

clarke5700

from what i can rember the black top rods are shorter i would use a silver top rods and crank in the black top block

RS 5tu

iTrader: (2)

So u can use a silver top crank and rods no problem in a blacktop.

SiZT

Its the black top rods that are longer, so silvertop rods with black top pistons would give a lower than advertised comp ratio. I take it your using LET Pistons seeing as you said that the rods are being machined. the rods should be fine for 220bhp as long as you got them de-stressed and shot-peened

pa_sjo

Yes

RS 5tu

iTrader: (2)

But the problem is once the rods have been machined out to 21mm there is not alot left on the top side, So what options do we have??
Silvertop crank and rods?? Will this be ok in a blacktop?
Before any one says just use a silvertop the blacktop has already been rebored hence the problem

pa_sjo

Use the silver top rods on the black top crank and be done with it...

RS 5tu

iTrader: (2)

Ok we will give it a go and do a dry test make sure there is no problems