knowledged RB25/26 builders please help!

[DETurbine]

Ok I have some more questions for you guys, just to get everything cleared up, becuase I keep hearing different things from a bunch of knowledgable people. Would rather here it from those that have done this before. I am going to be taking the block to the machine shop and will be ordering my RB26 rods this week.

I am going to be putting some RB26 rods in my SII RB25DET, so here are the questions I have for you guys:

1.I have been told from some that these will fit right in with no modification or grinding down and then from others I have been told that the rods are not a perfect fit and that you will have to grind away the rod slightly. Does anyone know which is true?

2. Do all (R32-R34) RB26 rods fit the same?....are they all the same?

3. Doing RB26 rods in my RB25, should I get the RB25 Wiseco's or the RB26 Wiseco's?....or are they all identical?

***(becuase from what I know Wiseco makes 86.5 and 87mm in the RB25's, but with the RB26 they only make the 87mm......that would creat a problem, becuase I do not want that low of a compression ratio...which from my knowledge...doing Wiseco 87mm for the RB and running a 1.2mm head gasket will creat a 7.9:1 compression ratio (which I am wanting more of a 8.3:1- 8.5:1 ratio))

[BBQ]

It depends on the RB26 Rods you are talking about, Are you doing stock Rb26 Rods or Forged rb26 Rods?

I know that Stock rb26 rods fit, with out any problems and Crower Forged Rb26 Rods fit with out any problems into an Rb25 Block, You have to make sure you get stock rb25 bearings though.

If you don't want to change your compression to much, then don't go 87mm bore. Go either standard bore size if you can find forged pistons to suit or just go .20thou over. And with a 1.2mm head gasket you will still be around the 8:5 to 8:3 compression region.

I personally would go arias forged (stock Replacement) pisons, as they are identical to stock in terms of dish wisco pistons. Wich will have an impact on compression.

You also have to look at other factors, Eg what size turbo you are bolting on and how much boost you want to run, to be able to determine the best size head gasket or the best suited bore size.

[DETurbine]

I am talking about stock RB26 rods. So it doesn't matter what gen I get (R32-R34) RB26 rods...they should all work fine in my SII RB25DET?

I am going to most likely going to have to deck the block and mill the head a good .5-.8mm, to get that compression up. Wiseco's make some great pistons for the money, the only down side is that for some reason they make it dished which will throw it at a 7.9:1 c/r. Decking the block and milling the head down a little should put me around 8.5:1+.

I would go to another piston, but the Wiseco's are $650 (US currancy) and after that comes the CP which runs $780, but I have heard more positive feedback from Wiseco then CP.

For the turbo I am going to be running a T61 with a .83 a/r. Is capable of 700hp, so the top end is not going to be the problem. I am going to have to make up for the lower end power, which I am going to be making custom intake manifold which will have some long runners and velocity stacks...to make as much velocity as I can to make some torque for the lower end.

[Jago]

aren't stock RB26 rods forged anyway? :S

[BBQ]

I am talking about stock RB26 rods. So it doesn't matter what gen I get (R32-R34) RB26 rods...they should all work fine in my SII RB25DET?

For the turbo I am going to be running a T61 with a .83 a/r. Is capable of 700hp, so the top end is not going to be the problem. I am going to have to make up for the lower end power, which I am going to be making custom intake manifold which will have some long runners and velocity stacks...to make as much velocity as I can to make some torque for the lower end.

I'm not sure about the R32 or the R34, but I know that the R33 will fit fine; I haven't compared the R32 or R34 rods against the R33.

I would think that the R32 and the R33 should be identical But the R34 I'm not 100% sure on, Maby some one else could confirm that for me?

As for the head gasket, if you’re going to be running such a large turbo, I would be looking at a different size head gasket? perhaps 1.8mm ?

As you will probably be running around 20+ psi ?

[R31Nismoid]

I am talking about stock RB26 rods. So it doesn't matter what gen I get (R32-R34) RB26 rods...they should all work fine in my SII RB25DET?

they will indeed.

SPHYNX[x']aren't stock RB26 rods forged anyway? :S

Nope, dont think so.

Just a better grade than 25 ones. They are also bigger if you compare them side by side.

Lot meatier around the link points

[C yar]

i have checked, and yes r32, 33, 34 RB26dett all have the same rods, part number 12100-05U01

[DETurbine]

Thanks allot guys for the help and information.

For the head gasket I am probably going to end up running a 1.2mm, from my knowledge and research you are more likely to blow a head gasket the ticker it gets.

[sweetr33]

think its got something to do with what pistons u chose to buy as appose to what size the gudgeon pin is. I got Ross forged pistons for mine and had to machine out the little end to fit the gudgeon pin in.