Rb25det heads

[Dr chops]

Hi all bare with me on this one.  I have a project I want to have a nudge at but I don’t want to go into to much detail as I’m 99% it hasn’t been done yet. My question is as silly as it sounds is can you change what side the exhaust and intake port are on? eg. change it from exhaust on the right side of the head to left hand side and the same for the intake. 
 

one would assume a custom cam would be needed to get the exhaust and intake lobes in the right place 
 

im asking on here as I don’t have a head or the experience to work it out and collective knowledge always seems to work

 

 Cheers

lucas

[GTSBoy]

I would say that that is a hard no. The shapes and sizes of the intake and exhaust ports are quite different, and you don't necessarily have the room to hog out the (small) exhaust ports to approach the size of the intake ports because the water jackets are quite close to the exhaust port walls.

Then you would have to look at whether it would be possible to fit intake sized valves where the little exhaust valves come from (which would require removing a lot of metal and you'd probably face a similar problem with water jacketing there) and then you'd have to close up the inlet valve holes to take smaller valves.

Just use a 1JZ.

[Dr chops]

Very true thanks. when you say just use a jz are you talking the head or the whole motor?

 

cheers

lucas

[r32-25t]

The whole engine 

[Dr chops]

Sweet

 

cheers

lucas

Edited August 9, 2021 by Dr chops

[Ben C34]

You wouldn't  need new cams, you would just set them in the correct positions.

it is a completely mental plan!

[Dr chops]

Oh of course hahaha yeah mental is as mental does haha thanks Ben that solved a problem 

 

cheers

[Dasmbo]

You can do what i did send your head to Lewis engines and get it machined to suit your purpose it cost me about $4500.00 and it makes one hell of a difference

[Ben C34]

On 8/9/2021 at 6:14 PM, Dasmbo said:

You can do what i did send your head to Lewis engines and get it machined to suit your purpose it cost me about $4500.00 and it makes one hell of a difference

You swapped the sides of the inlet and exhaust manifolds?

[GTSBoy]

On 8/9/2021 at 6:14 PM, Dasmbo said:

You can do what i did send your head to Lewis engines and get it machined to suit your purpose it cost me about $4500.00 and it makes one hell of a difference

Yeah, nah sweetheart. We'd be talking about $20+k of work here and it still probably wouldn't work.

[DaymoR32]

On 8/9/2021 at 8:33 PM, GTSBoy said:

Yeah, nah sweetheart. We'd be talking about $20+k of work here and it still probably wouldn't work.

I'll do it for $19,999 and bore it out to a 4L at the same time. 

Heres one i did earlier this week

[Dasmbo]

You could try and find a cnc machine shop to make a new head from a new alloy billet but i wouldnt like to recieve that quote

 

[Dr chops]

Thanks daymo speaking of stroking I’ve seen 3.4l kits but is there anything bigger or is it a case of water jackets becoming too close to the boRe 

 

cheers

lucas

[GTSBoy]

I think the largest RB30 is either 3.6 or 3.8, but it really doesn't matter because you are talking pure drug money at that point and would be better off with a Barra.