After reading a recent thread on here re. Blacktop Zetec heads (HERE) I was wondering if the silvertop zetec heads were interchangeable?

I only ask as my 1800 head had seen better days, so I've now got a 2L head and internals (inc. cams etc.) on my block. I've had it cough and splutter just to ensure it's turning over correctly, but it won't idle (did originally when I 1st tried the complete 1800 head).

I hasten to add the engine isn't complete in terms on key-turn start yet, just jumped from an external battery on the starter.

My understanding is that the 2.0l silvertop cams are the same as the 130bhp 1800 cams, and shouldn't make a difference, but is it the valve size/fuellin or similar that needs adjusting?

I really don't fancy stripping the whole thing down again, got bigger and better things to do on the build at the moment!

Im sure they are interchangeable if anything the bore or the stroke will be different, are you sure you have the timing correctly set ???

the only difference between 1.8 e2.0 heads are the camshaft, and if you use genuine ford throttle body there is a difference in diameter between 1.8 and 2.0

I'm using ZX9R carbs with it, not the OE throttle body.

I'm not overly worried, as they looked the same when I changed them over. Jusat seems odd that it turned over before but not now.

Still, if I know they're the same then my major worries are quashed for the tme being!

The combustion chamber volume is different between the 1.8 and 2.0l silvertop heads. 1.8 has a smaller combustion chamber.

It's a cheap way of raising the compression on a 2l if you fit a 1.8 head - it raises the CR from 10:1 to about 10.5:1

The way you've done it will have lowered the ratio, although at what is probably 9.5:1 it shouldn't be stopping it idling. Check your cam timing - this is the thing that is most likely to be wrong.

Tom