Jump to content
SAU Community

Recommended Posts

my is engine knocked and a friend of mine has sn rb26dett in which he recently replance his stock pistons with forged ones, he said i could have the stock ones if i wanted. Has anyone tried the swapping rb26dett pistons into the rb25, what time compression could i expect, are the pistons stronger, any info would be appreciated.

Link to comment
https://www.sau.com.au/forums/topic/273433-rb26dett-pistons-in-rb25det/
Share on other sites

ok i have put the pistons in the block using rb25det rods and an rb25det crank, the sides of the pistobns however dont reach the top of the engine block, any idea how this affects the compression ratio

++++

hey kilo_gulf,

those two engines do have the same bore size but have a slightly different stroke.

rb25 has a bore x stroke of 86 X 71.7

rb26 has a bore x stroke of 86 X 73.7

take notice to the 2 mm difference in stroke.

THE PISTONS THAT CAME IN THE MOTOR ARE OK , THERE AFTERMARKET, I HAVENT BEEN ABLE TO IDENTIFY THEM, BUT THEY DONT HAVE A DOME ON TOP LIKE THE RB25DET OR RB26DETT PISTONS, THEYRE FLAT TOPS. I DID A COMPRESSION TEST ON THEM ABOUT A MONT BACK AND THEY AVERAGED BETWEEN 115 TO 120 PSI PER CYLINDER. I DONT KNOW WHY THE PERSON WHO BUILT THE ENGINE WOULD USE THEM MY GUESS IS NITROUS, IN ANY EVENT THATS WHERE I STARTED. THUS WHEN THE RB26 PISTONS BECAME AVAILABLE I JUMPED AT THE CHANCE HOPING FOR BETTER COMPRESSION BUT IT SEEMS ILL BE RIGHT WHERE I STARTED.

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

    • From the factory on RB26s there's a fitting on the intake manifold collector/"plenum" that provides pre-throttle boost signal. That's how they did it back in the day, I figure it's fine to replicate it.
    • I would be surprised if that wasn't the issue. It's probably telling you, that even if you remove the plastic liner, you may have some other clearance issues that may occur too in some scenarios. IE, tyre to guard. It looks like someone has already rolled the lip, but you may still have issues in the future IE, turning and hitting a bump etc. The fact it changes how bad it makes the noise when you are going backward vs forward is highly indicative that it's the tyre rubbing. They do make a terrible sound, even if you're only pushing a project car that has a liner hanging down on a tyre!   Has the car been lowered? If it has been, what is the measurement from the centre of the wheel hub to the lip of the guard straight up?
    • Summernats cruiser?
    • Mark's a bit smarter than people give him credit... He'd convince the person that is to become dead, to drive him to the forest first. That way his car has no evidence in it, and he's free to dispose of their vehicle permanently how he sees fit too...
    • But if you had to go bury a body in the forest, would you not put that in the boot? Most of them are >=90kg these days.
×
×
  • Create New...