Gaz 88

Im new to the cosworth scene and looking at getting some parts together for my engine, When looking at 200 blocks just wondering whats an acceptable bore seen some on standard bore and some at .5 ect
Also 4x4 heads some say 138mm but dont know whats acceptable and safe

cheers

BRAMMER

iTrader: (23)

I wouldn't worry too much regarding the block bore but the head is a dodgy subject - when you say 138 it's whats after the . that you need to worry about, FMC recommend a min of 138.68 i think it is but some will say they can go as low as 138. but if you buying try to find one thats 139

Gaz 88

cheers brammer

With the block can you just put bigger pistons in or do you need to put liners in?

cheers

LHD220Turbo

iTrader: (4)

acceptable bore depends on what power you are aiming for.

heads - many say 138.62mm is minimum, its the valve seat area which becomes thin beyond that. However i have seen many heads used beyond this measurement running big power, so its a lottery

COCHYN

You have a 205 and 200 block. 205 came from a 2WD and the 200 from the 4x4 Sierra and Escos. The 200 being discussed greatly as being stronger with thicker casting around the bores.

The boring sizes would be standard, .25, .5 and 1mm over. For up to 350bhp any of those sizes would be fine, but to push over towards the 400bhp and more, then I wouldn't want to go further than a .5 bore.

Once your block has been machined to one of those measurements, then you will need .25, .5 or 1mm oversize pistons to match.

Job done

Gaz 88

Cheers Alan that explains it all clearly! Dosent look like I'm gonna get a decent 200 standard block for less than £800!!