rb20/26

[r31 Koop]

I was wondering if anyone knows if the br 20 head fit's straight on to the 26 bottom end???

And if it does do all of the oil galleries and water jackets line up???

Any help would be much appresiated.

Thanks

Blair

[Roy]

It doesnt even go close, bores are massively different...and the Rb20 head may struggle on a 2.6L...anything can be done, but not worth the agro and dubious results:(

[r31 Koop]

It doesnt even go close, bores are massively different...and the Rb20 head may struggle on a 2.6L...anything can be done, but not worth the agro and dubious results:(

i WAS UNDER THE IMPRESSION THAT THE BORES WERE VERY SIMILAR. IT IS THE STROKE OF THE RB26 THAT GIVES IT MOST OF IT'S LARGER CAPACITY.

And i am sure the 20 head would handle the capacity as long as the power is kept under 300rwkw.

Thanks for your input.

Does anyone know if this head will definatly physically fit on or not as the RB25DE one does.

Any one attempted this???

[r31 Koop]

What about vise versa does the 26 head line up and sit on a 20 block???

[mr_rbman]

I don't see y u would bother, seems pointless to me!

[mr_rbman]

I don't see y u would bother, seems pointless to me!

[blind_elk]

The RB25 / 26 are 86mm bore, the RB20 is only 78mm bore.

If you try and fit a RB20 head on a RB25 / 26 block, you will risk having the piston smash into the head. The other thing is that the RB20 head will have relatively small combustion chambers, which will cause a big rise in compression ratio, which is dangerous for running high boost levels.

The converse (RB25 / 26 head on RB20 block) gives too much protrusion of the block deck into the combustion chamber, and a big drop in C/R, making it a bigger dog off-boost.

[N I B]

Water passages dont line up etc etc ,really not a good idea sorry.

[r31 Koop]

Thanks for the info