CBR600F4

Here's my question: I have a 90 si motor and a 90 dx motor. How hard would it be to put the si head on the dx motor; and what would be the bennies if any?

EvolutionBoostin

How hard? Easy swap. I don't see any reason to do it unless the si bottom end is bad. I don't know any exact specs, but I've done both and they seem the same. Just my .02

GreySquirrel

a dx bottom and a si bottom are practically the same thing, you won't get any gains at all really. you'd be better off finding a nice z6 or y8 head and do that swap if you want some cheap easy power gains. the real question is, are you doing this in a dx or a si? if it's a dx then you'll need to do the whole mpfi swap and what not. a little more info on what you're looking to do would be real helpful.

Cpt. Non-Spell

no the dx bottom end has differnet coolant passages than the si... and the cam in the si is mor loppy(sp). to be honest i would just put the whole si motor in the dx and do the harness conversion..... whats up on those springs by the way?

CBR600F4

I know the dx bottom end has different coolant line positions and stuff. And the EFI is different as well.

I'm asking cause I wrecked my si. Bought a dx of the same year (1990). My si motor is fine, except for one of the main seals.......leaks some oil. The dx motor doesn't leak at all.

So if I can swap heads right now for nothing, I'd be good to go.different compression should give me some gains as far as I know.

I could put the si motor in; but I'd have to replace the main seal and re-wire the whole damn system. If I do a mini-me I'll have to re-wire as well.

So just changing the head seems like the simplist, cheapest way to go right now.................................


Springs are on the dx right now. If you want them I can still swap them out (again). Just let me know.

xk84f9ds

just put the si cam in it....and take mad weight out and boost it

EvolutionBoostin

Ah ok I understand. You should just put the si head on the dx. It's easy to do and it'll be basically the same as the si. G/L.

CBR600F4

Thanx man...................