RB30E block + RB20DET head

[grimr33per]

hi guys,

I saw a thread earlier on about building an RB30DET engine using an RB25DE head and RB30 block, t04 turbo etc.....

i'm getting an R32 and i wanna know if it's feasible to build a 3-litre engine using an RB30E block (non-turbo internals for higher compression, correct?) and RB20DET head.

what sorta compression ratio will that leave me with, and what would I have to replace on the block to make it handle the power? my first thought was oil pump and water pump..... but after reading JNR24's post it looks like i could be up for some big-end bearings too.

anyways, any input would be greatly appreciated. I'm gonna try and tackle this one myself (with the help of one of my friends who's done rebuilds before) so i wanna do thorough research first. i'd love to know how much power to expect (ballpark) from an RB30DET (keeping in mind that i'll at least be rebuilding & hi-flowing the stock turbo, if not replacing it with something a little more pricey)

thoughts/opinions/advice?

[browny]

So you have already read all of this thread? -> R33 RB30 Converstion

From all reports the RB20 head is a lot of work because it has a much different bore size.

[Sumo]

If you can find out the Cubic Centimetre of the clearance volume on the rb20, go and find the stroke are bore of a rb30 NA and voila.

R = Bore / 2 (work in centimetres)

~ = Pie (cant find pie on the character map)

H = Stroke (in centimetres)

~R^2 = A

A x H = Volume (in CC's of the swept volume of the piston)

V + Clearance Volume (of RB20 head) = Capacity (of one cyl)

Capacity / Clearance Volume (of RB20 Head) = Compression Ratio

Its pretty easy if you can get it explained face to face.... But to work it out you have to know all your volumes.

Sumo

[MonstaS4]

Like browny said, different bore size + smaller valves (i think) = not worth the effort.