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
      4th gear sychro worn

      By GTSBoy · Posted

      Not R7R. Meant to type R&R, obviously enough.
    • GTSBoy
      R33 headlight relay conversion?

      By GTSBoy · Posted

      Bugger "making it look stock". I put one conventional internally fused Hella relay behind each globe. I just pulled the plugs off the back of the globes and built new loom segments with male and female plug parts to match up to the original loom and the globe, and used the original power wires to each globe coming from the switch through the original loom plug to trigger the relays. Ran a big fat (also separately fused) power wire across the front of the car to feed all the relays. It's as ugly as f**k, but it is wedged down between the headlight and battery on the RHS and the airbox and headlight on the LHS, and no-one ever looks in my engine bay, and on the odd occasion that they do I simply give no f**ks for what they think. Fully reversible - not that you'd ever want to. For f**k's sake. It's a Skyline. They made million of the bloody things. We've been crashing them into roadside furniture for 30 years now. There is a negative side effect to putting relays on the headlights. The coil current is too little to properly clean the contacts in the switches and they get blacked up and you have to open them up every couple of years and clean them manually. I have 25 years of experience on this point.
    • joshuaho96
      R33 headlight relay conversion?

      By joshuaho96 · Posted

      I was poking through the R34 wiring diagrams vs R33 and noticed that the R34 has proper headlight relays while the R33 is like the R32 and sends full headlight power through the headlight switch. I'm not afraid of wiring but I really would like to do this in a way that looks OEM (clipping into open positions on the OEM relay box) and also unlike the factory wiring which interlocks the high beam and low beam on the halogen series 1 GTR headlights I want to make it such that turning on the high beams keeps the low beams on as well. Any advice on how to locate the specific connectors + crimp terminals + relays I need? I was thinking one NO relay for low beams and another for combined high + low running off the factory high beam headlight connector. I don't really want to splice into a crusty old probably discontinued factory harness so fully reversible is my goal here.
    • sonicii
      HY51 Fuga Hybrid

      By sonicii · Posted

      Pretty sure they run the same engine as the Q50 hybrid which specifies 95 RON.  I ran 98 in mine for a while, but it made no difference in performance or economy, so I have been using 95 for the last few years.  I have never hit 6.0L/100km, but have returned mid to high 6 on the highway.  Being a hybrid, fuel economy is a lot more dependant on how you drive it.  At 110km/h, mine never goes into EV mode on the highway, so returns closer to 7.5L/100. urban driving can return low 8s if you are careful or over 10 if you are a bit more enthusiastic on the throttle.
    • GTSBoy
      4th gear sychro worn

      By GTSBoy · Posted

      About a quarter of what you want to do. It's only R7R, not R&dismantle&replaceparts&reassemble&R. ? It is stock. I already told you, you will NOT have broken those. It's f**king 4th gear for Christ's sake. You just chipped the teeth off.
×
×
  • Create New...