rb25 pistons

[crccustoms]

why if you can use the same pistons for the 25 and 26, do they have different part numbers for the same bore? i have been pricing my 25 and noticed that two or three companies had that, and i remember hearing that they were the same pistons some where... maybe i heard wrong? any help would be appreciated!

[Carl H]

rods are interchangable between motors, pistons are not.

[Darius]

You physically can interchange the pistons, but the RB26 pistons with an RB25 crank will result in a really low compression ratio like 8 to 1. Not desirable for a street car.

[l0nestar]

To help you with your query and as an addendum to Darius reply.

Yes, the diameter of the piston is the same, BUT the location of the wrist pin is different and the other remaining critical dimensions are different. So you have 1 of about 9+ dimensions that are the correct. Esto no es bueno!

[Coolwhip]

as well, if i'm not mistaken, a RB26 rotating assembly (pistons, rods, crank) in a RB25 results in pistons extruding from the block deck a few millimeters?

[crccustoms]

thanks all for giving me that, im new to the rb's but learning and info like this is gold!!!

[crccustoms]

hey coolwhip do you have any IM such as aim or yahoo

[Darius]

as well, if i'm not mistaken, a RB26 rotating assembly (pistons, rods, crank) in a RB25 results in pistons extruding from the block deck a few millimeters?

You can put an RB26 rotating assembly in the RB25 and it will match up perfectly. But if you put RB26 pistons on RB25/26 rods, then the pistons will sit recessed in the bores at TDC by (1.21mm if I remember right). Now putting RB25 pistons on a RB26 crank will push them out of the bores that same dimension, but who the hell would ever do that?

My original plan was to source an RB26 crank and use the RB26 rods and pistons, but I couldn't find the crank (And NO that's not what she said). Now I can get one for cheap but already have the entire engine built...Timing sucks sometimes.

Like I said before, the RB26 pistons are far superior to the RB25's and I happen to have find a set in my basement that is now for sale for $150. LOL shameless plug.

[Shocker]

You can put an RB26 rotating assembly in the RB25 and it will match up perfectly. But if you put RB26 pistons on RB25/26 rods, then the pistons will sit recessed in the bores at TDC by (1.21mm if I remember right). Now putting RB25 pistons on a RB26 crank will push them out of the bores that same dimension, but who the hell would ever do that?

My original plan was to source an RB26 crank and use the RB26 rods and pistons, but I couldn't find the crank (And NO that's not what she said). Now I can get one for cheap but already have the entire engine built...Timing sucks sometimes.

Like I said before, the RB26 pistons are far superior to the RB25's and I happen to have find a set in my basement that is now for sale for $150. LOL shameless plug.

Yup thats how I have mine done, 26 rotating assembly in the 25 block, no issues mate. Drove her last night.

[jdmser]

[QUOTE=Darius] Now I can get one for cheap but already have the entire engine built...Timing sucks sometimes. QUOTE]

Wanna hook a brotha up? I just so happen to be in the market for a RB26 crank.

[Coolwhip]

Yea I know all about the swapping of the internals, just couldn't remember if the 26's went in or came out. :P