Jump to content
SAU Community

Recommended Posts

I have a RB25det block that I got for next to nothing and I would like to know if it is possible to fit the RB20det head to this block?

Reason being I have a damaged RB20det block from my R32 but the rest of the motor is in tact. $$$ are a big issue and I have not yet torn down the RB20 to see what will fit an what won't.

I would like to be able to fit my RB20 head with no variable cam timing if possible and use a RB25 crank to get the extra cubes.

Hoping someone can shed some light on this before I spend money onthe RB25 block.

Rgds

Grippy

Link to comment
https://www.sau.com.au/forums/topic/178717-rb20det-head-on-a-rb25det-block/
Share on other sites

If its a silvertop ECCS head then water/oil and head studs will line up. The bore however is different so you will need to modify the combustion chamber to suit. I actually ran a 20 head on a 30 bottom end for a little while and modded the combustion chamber myself to suit.

One thing you will have to do with the 25 block but is you will need to drill and tap the VVT gallery in the block and block it off. What you can do is rip off the old rb20 HG and use that as a template on the 25 block like I did. Pretty much shows you straight away what will go and what wont.

But like I said, rb20 silvertop head from a r32, its basically mod the combustion chambers slightly and then block the VVT feed off.

Cost vs gain - simply not worth it.

Too much stuffing around as its not bolt-up

Thanks, As I thought too many problems. I will continue to source a RB20det block and transfer everything over. I'm not after any power gains anyway, just thought if I could do it for no extra cost why not seen I have a Rb25 block.

I'll plan for a complete RB25 build up on the block then after I get my RB20 running again.

Cheers,

Grippy

Create an account or sign in to comment

You need to be a member in order to leave a comment

Create an account

Sign up for a new account in our community. It's easy!

Register a new account

Sign in

Already have an account? Sign in here.

Sign In Now


  • Similar Content

  • Latest Posts

    • My guesstimate, with no real numbers to back it up, is it won't effect it greatly at all.its not a huge change in position, and I can't see the air flow changing from in turbulence that much based on distance, and what's in front of it. Johnny and Brad may have some more numbers to share from experience though.
    • Which solenoid? Why was it changed? Again, why was this done? ...well, these wear..but ultimately, why was it changed? Did you reset the idle voltage level after fitment? I'm just a tad confused ~ the flash code doesn't allude to these items being faulty, so in my mind the only reason to change these things, would be some drive-ability issue....and if that's the case, what was the problem? Those questions aside, check if the dropping resistor is OK ...should be 11~14 ohms (TCU doesn't throw a flash code for this) ~ also, these TCU designs have full time power (to keep fault code RAM alive), and I think that'll throw a logic code (as opposed to the 10 hardware codes), if that power is missing (or the ram has gone bad in the TCU, which you can check..but that's another story here perhaps).
    • Question for people who "know stuff" I am looking at doing the new intake like the one in the picture (the pictured is designed for the OEM TB and intake plenum), this design has the filter behind the front bar, but, the filter sits where the OEM duct heads into the front bar, and the standard aperture when the OEM ducting is removed allows the filter to pulled back out of the front bar into the engine bay for servicing, a simple blanking plate is used to seal the aperture behind the filter This will require a 45° silicone hose from the TB, like the alloy pipe that is currently there, to another 45° silicone hose to get a straight run to the aperture in the front bar Question: how will it effect the tune if I move the MAF about 100-150mm forward, the red is around where my MAF is currently, and the green would be where it would end up Like this This is the hole the filter goes through  Ends up like this LOL..Cheers    
    • Despite the level up question, actually I do know what that is....it is a pressure sender wire.  So check out around the oil filter for an oil pressure sender, or maybe fuel pressure near the filter or on the engine. Possibly but less likely coolant pressure sensor because they tend to be combined temp/pressure senders if you have one. Could also be brake pressure (in a brake line somewhere pre ABS) but maybe I'm the only one that has that on a skyline.
    • Pull codes via the self-diagnosis procedure. As far as I can tell this is just a sign of transmission issues but not a code unto itself.
×
×
  • Create New...