Jump to content
SAU Community

Tomei Pistons

NYTSKY

By NYTSKY,
in Engines & Forced Induction

 Share

Recommended Posts

NYTSKY Grand Master

NYTSKY

Posted
Posted

I just found some Tomei pistons that i might purchase,but before i do i would like to ask some questions:

Its for an RB25DET

These are the specs of the pistons:

Bore: 87.0mm (Will this be big enough? Allowing for the bore to be honed.Or will i need to go 20thou over?)

Pin Dia: 21mm

Recess: Nil

Ring: Standard(I think this means they are not Titanium coated.But are still Tomei rings.)

CHEERS

Link to comment
https://www.sau.com.au/forums/topic/199167-tomei-pistons/
Share on other sites
NYTSKY Grand Master

NYTSKY

Posted
  • Author
Posted
bore size will depend a lot on the condition of your block. have you pulled the motor apart yet? your engine builder will be able to recommend which one to go for.

The motor is not apart yet.

I could only see that the seller only had the 87mm pistons,so i was wondering if this would be big enough,allowing for the bores to be honed.

Stock bore in a RB25DET is 86.5mm isnt it?

So having the 87mm pistons would allow for .5mm to be cleaned up.

or is this a too small of a margin to go off.

Link to comment
https://www.sau.com.au/forums/topic/199167-tomei-pistons/#findComment-3552156
Share on other sites
BLN215 Rookie

BLN215

Posted
Posted
Thats awesome.40thou is heaps i cant see why my builder would want to hone more than that.Motor is in great condition.

It'll depend on the condition of your bores as to how much will need to be bored/honed out of it.You'd be best to have the engine pulled down and inspected and/or machined before you shell out $1300+ for a set of pistons that you dont know if you'll need.

Just the way i'd do it :)

Link to comment
https://www.sau.com.au/forums/topic/199167-tomei-pistons/#findComment-3554956
Share on other sites
NYTSKY Grand Master

NYTSKY

Posted
  • Author
Posted
It'll depend on the condition of your bores as to how much will need to be bored/honed out of it.You'd be best to have the engine pulled down and inspected and/or machined before you shell out $1300+ for a set of pistons that you dont know if you'll need.

Just the way i'd do it :)

Well i want to buy the pistons anyway.I should think 40thou over for the pistons should leave plenty of room for honing.

Link to comment
https://www.sau.com.au/forums/topic/199167-tomei-pistons/#findComment-3554958
Share on other sites
NYTSKY Grand Master

NYTSKY

Posted
  • Author
Posted

The seller only sells the pistons in 87mm.So i think that the 40thou over will cover me incase of poor bores.If my bores are in good condiiton,would an engine builder charge more for the bores to get...Bored?

Link to comment
https://www.sau.com.au/forums/topic/199167-tomei-pistons/#findComment-3555149
Share on other sites
BLN215 Rookie

BLN215

Posted
Posted (edited)
The seller only sells the pistons in 87mm.So i think that the 40thou over will cover me incase of poor bores.If my bores are in good condiiton,would an engine builder charge more for the bores to get...Bored?

If your bores are in good condition then you'll be using an oversize bore you dont need too and wasting perfectly good metal that could be needed down the track.You may only need a 20thou over bore so your using 2 overbores when you dont need too leaving you with less life in the engine block/sleves.

But if your determined to get them go for it,just remember were only trying to help you out here.

Edited by BLN215
Link to comment
https://www.sau.com.au/forums/topic/199167-tomei-pistons/#findComment-3555158
Share on other sites
Beer Baron Grand Master

Beer Baron

Posted
Posted

always go for the smallest oversize possible. far better to pull down the engine first, inspect. then buy pistons to suit your new bore size. if there is nothing really wrong with the motor you should be going for 86.5mm bore. .5mm oversize.

Link to comment
https://www.sau.com.au/forums/topic/199167-tomei-pistons/#findComment-3555276
Share on other sites
NYTSKY Grand Master

NYTSKY

Posted
  • Author
Posted
always go for the smallest oversize possible. far better to pull down the engine first, inspect. then buy pistons to suit your new bore size. if there is nothing really wrong with the motor you should be going for 86.5mm bore. .5mm oversize.

In that case i think it would be a better idea to get the pistons in Oz then.

Link to comment
https://www.sau.com.au/forums/topic/199167-tomei-pistons/#findComment-3555283
Share on other sites
fEkuaR Experienced

fEkuaR

Posted
Posted
In that case i think it would be a better idea to get the pistons in Oz then.

Definately a better idea. Your engine would be absolutely stuffed if you NEEDED 40thou oversized pistons. Also if you dont go large oversize now you will be able to use the block again if need be in future re-builds. A block can only be taken so far out.

Link to comment
https://www.sau.com.au/forums/topic/199167-tomei-pistons/#findComment-3555635
Share on other sites

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
 Share
Go to topic listing


  • Similar Content

  • Latest Posts

    • GTSBoy
      R33 persistent issues. P/steering and lag/misfire

      By GTSBoy · Posted

      Power steering is probably because someone has nuked the HICAS CU and you no longer have the variable power asist doing what it is supposed to. How much boost are you running? You are aware that any more than 10 psi on the stock ECU is just asking for it to go to full R&R (that's Rich & Retard, which is effectively Retarded and Retarded!) which kills all the power. Depending on the exact conditions, it can just be runnign on the fat and stupid end of the maps, then the conditions change, you make a little more boost and the ECU goes into panic.
    • Kapr
      Freddy Plenum vs Genuine options RB25

      By Kapr · Posted

      @BuiltNotBought Just as GTSboy said.   If you want driveabilty and more low down torque..keep the stock runners. They are VERY good from a factory. I have them too on my RB25DET NEO and as a GTSboy i have fmic but with stock piping route(i have Blitz intercooler) Iam making around 320 BHP and the car pulls "hard" from like 2,5k all the way to 7k. I have it dyno tuned to mimic N/A power curve and making little less max torque due to the smallbox tranny. But driveability is very great. I had 350Nm below 3k so car feels very quick.
    • MissMintyR33
      R33 persistent issues. P/steering and lag/misfire

      By MissMintyR33 · Posted

      Looking to sort out a couple of issues on my skyline  It recently was rebuilt, however rebuilder long story short did not give two flying effs about the work he did. So moving forward it's running but I have two persistent issues 1) it has a misfire / lag type of issue (was at higher RPMs but I had a dead piggy back ecu removed which improved it) now it's not as bad but still does it at random, I thought it may have been a boost issue I'm running an older turbosmart dual stage controller, turbosmart told me to try running off gate pressure however it still has a lag at random times. It has New MAF, maf plug, coil packs, sparks, CP harness.. injectors tested and cleaned. Factory ECU. 2) Power steering issue. It is tight as anything. Flushed power steering, rebuilt my pump because the bearing was shot. Flushed again still tight (mainly when parking and going slow into my driveway etc)  No kinks in hard lines, replaced the lines I could see had cracks. Still tough to steer.  I was told to shim a coin and place into the solenoid plug? Is there anything else. My steering angle sensor also has a issue. It's a used one I replaced, does it need to be calibrated? I feel like I've tried everything and this car is my voodoo doll.   
    • Dose Pipe Sutututu
      Neil's R33 Gts-t Build

      By Dose Pipe Sutututu · Posted

      Holy shit... wow!!! I totally missed this
    • MBS206
      Dose's Sometimes DIY and Pay Someone Home & Boat Improvement Thread

      By MBS206 · Posted

      One main filter. Each tank has a prefilter to keep rocks and small children out, then the big main filter that also does water separation. Clogged the first one so bad it was like a rev limiter at 3200rpm. Literally just like dropping the throttle off and maintaining rpm!
×
×
  • Create New...