help regarding RB20 concept!

[Walkingpig]

Hello

i've been considering the RB swap for sometime...

i was told by a decently reliable source that the 200zr (z31 300zx) rb20det actually bolts straight onto the 260z....

as opposed to the R32 skyline models which need modified mounts

can someone confirm or othewise this!? as i have the oportunity to buy one in hte next few days!

Thanks, Charles

[Mr Camouflage]

Ok Hows this.

An RB20 turbo head will bolt onto a RB30 (skyline or commodore VL) giving you a RB30 turbo.

None of this single cam L series 3.1 stroker stuff. RB30DET!!

That would haul arse!!

Commodore VL engines are common and cheap.

Something to consider.

[Walkingpig]

Thats a nice and talked about idea. and something i wouldn't mind doing at some point!

BUT, my question was in regard to mounting, and i have since had confirmed that the 200zr engine mounts will mount an RB series engine perfectly.(thankyou stony's website:))

Thanks for your time!

[Bruce Woolmore]

does anyone know what CR this would give? more suited to a non-turbo perhaps?

[Mr Camouflage]

Dont know, but there is a member here that had put a rb20 turboe head and turbo on a rb30 bottom end. I cant remember his name, but i think he was an engineering lecturerer at tafe or uni or something similar.

[nixcars]

The RB20 head won't go on without major work to the water galleries. These need to be welded up re-drilled otherwise you will have water entering the cylinders. The other problem is that the combustion chambers are too small & the compression would be too high. The head to use on the RB30 block is the RB25/RB26.

If anyone is interested, I have brand new RB30 turbo blocks @ $450ea & also have a RB25 head with most other bits to make a RB30DET.

Nick.

[Zpeed]

Ive talked to a person at JMS as i tryed to source 200zr mounts, and they told me that on the 200zr the mounts are the same as the R31 mounts, as the differance on the 200zr compared to the 300zx is the crossmember, and they use the normal R31 mounts.

might not be confrimed, but can try something, mounts for a R31 Rb from a wreckers would be less than $40,

but the 200zr Rb20det sump and pickup is the one that will bolt straight up to any Rb engine, and fit staright into the Z, not like the R31,R32, R33 sumps etc which need modifying, but a 200zr sump with pickup from nissan, cost around $550

[81na ZX]

The bigger problem is the Bores. the RB30 uses ~87mm bore, the RB20 is a 79mm bore... Thats 8mm to make up either way. And the 20 has tiny valves.

A 25 head on a 30 block would be much much better.

Anyway - any RB engine will mount into a S30/S130/z31 chassis with the 200zr mounts. HOWEVER, custom mounts would place the engine lower and farther to the rear. AND either way, you almost certnally need a custom plenum, as the stock one that crosses the valve cover is high. If you put the engine REALLY low and cut hood structure, you can leave the stock plenum on. The RB26 has a front opening Plenum so that doesn't apply.

Any RB engine will need a new oil pan and sump unless its a RB20 out of the z31, but you don't want that engine, less than 200hp stock But the 200zr sump and pan will bolt onto any other RB block (as stated above)