Jump to content
SAU Community

Recommended Posts

Hi guys, long time reader here first time poster

I've got a r32 gts25 sedan that i've sold my 20det setup (284rwhp if anyone cares) to build a RB30det, so far i've got a garret truck turbo, similar size to 3540, rb30e bottom end and r32 25de head, gtr valve springs, oil pump collar, just buying up the bits as i see them basically

I've also aquired a set of 26dett pistons, I've tried searching and haven't found a definite answer to if i can use them or how much work is required? i have a set of 30e pistons to which i'll use if the 26's arent any good, basically what i'm asking is  a) how hard are the 26 pistons to fit, and b) is it worth it?

thanks in advance guys. I'm sure i'll have many more questions as the build progresses

Cheers :P

Link to comment
https://www.sau.com.au/forums/topic/262171-rb30-gtr-pistons/
Share on other sites

Pretty sure you have to use RB30 pistons as their pin heights etc are to suit RB30 rods & crank..

cheers for the reply, so i cant use 30 rods with 26 pistons? i havent had a chance to measure anything up yet, was trying to avoid wasting my time if people already knew the answers haha

might have to take them into work and whip up some drawings to see if its a suitable option,

Not sure on the exact differences, I'm using RB30 spec forged pistons. You might find that with 26 pistons on 30 rods on a 30 crank that you could be smashing pistons into valves.. need an experienced RB builder to answer that :P

cheers guys, turns out one of them is poked anyway so ill prob just stick with the 30 pistons, on the subject of 30 pistons, i've got a set that i had ultrasonically cleaned, when they came back they had lots of pitting in the top of the piston, im assuming its just bad casting/ has anyone else had a set that were the same? i tried to take a pic but it wont pick up the detail- aka budget camera

That pitting is probably from detonation..

I was hoping that wasn't the case but had my suspicions, picking up another motor tomorrow hopefully the pistons in that one are better, first motor had a bent crank (god knows how) so i had to buy a whole new motor to get a new crank, what a mission just to get more power!

Bent cranks are quite common in i6 engines.. just make sure you get all your clearances checked and machine appropriately.
 

it had about 0.3 bend in it, decided to try another as its cheaper to get a new one than grind, bit of a gamble to but its a low k's engine so should be ok

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

    • So I'll put filler past the repair area a bit to make sure I don't miss anything. Then I'll block it until it's almost level, put the guidecoat, then keep blocking until it's gone. Then it's still wavy.  In regards to hitting the panel, I saw this video might give more context - Skip to 0:47 he knocks it down. But yeah I'm sanding until the guidecoat is gone then checking because otherwise my filler is still well above the bodyline. Unless what you're saying is I should put guidecoat around it early, surrounding the filler then stip once it's gone?
    • I refreshed the OEM injectors with the kit and connected it up. It now ideals okay even with the IACV removed. Driving still has the same cutoff issue like the 550cc injectors so the issue is somewhere else. I bought FPG's Fuel Pump Hanger. I will be installing it next, but it is not as straightforward as I thought it was with my limited wiring knowledge and no instruction on the specific model I purchased (FPG-089). I also got the incorrect billet clamp as I could not find info on the OEM sizing.
    • Stop looking at the garage floor, and turn the radio up a bit louder if there's any strange noises...
    • No. Turbo shuffle and surge/flutter are not the same thing. Specifically, on a GTR, turbo shuffle has a definite meaning. On a GTR, the twin turbos are assumed to be the same thing and to operate the same way, exactly. In reality, they do not. Their exhaust sides are fed and exhaust a little differently, to each other. Their inlet sides are fed and exhausted a little differently, to each other. Consequently, when they are "working" they are often at slightly different points on the compressor map compared to each other. What this means, particularly when coming on boost, is that one of them will spool up and start producing extra flow compared to the other, which will put back pressure on that other compressor, which will push the operating point on that other compressor up (vertically). This will generally result in it bumping up against the surge line on the map, but even if it doesn't, it upsets the compressor and you get this surging shuffle back and forth between them That is "turbo shuffle" on a GTR. It is related to other flutter effects heard on other turbo systems, but it is a particular feature of the somewhat crappy outlet piping arrangement on RB26s. There are plenty of mods that have been attempted with varying levels of success. People have ground out and/or welded more material into the twin turbo pipe to try to prevent it. Extending the divider inside it works, removing material doesn't. There are aftermarket replacement twin turbo pipes available, and these exist pretty mush purely because of this shuffle problem.
    • You can temporarily* use lock collars to keep it in place until you can do the bushes, back the nuts off, slide them in, snug back up. *temporarily is often for ever
×
×
  • Create New...