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
      R32 gtr transmission strength, billet plate

      By GTSBoy · Posted

      Just put skinny tyres on it.
    • cosline
      R32 gtr transmission strength, billet plate

      By cosline · Posted

      Yes, I know🙄 but the sequential is not in my budget... don't want to reduce power neither, so looks like I'm stuck in the rabbit hole🤣
    • Piggaz
      R32 gtr transmission strength, billet plate

      By Piggaz · Posted

      You’ll be very upset when you bust that too not to mention the gearing totally sucks. Don’t do it.
    • MBS206
      R32 GTS (RB20DE) Injectors Replacement

      By MBS206 · Posted

      Is the panel filter one that is oiled? Have you ever cleaned or touched the AFM?
    • The Bogan
      NC MX5

      By The Bogan · Posted

      So.... the K&N air box thingo was too big, ended up gifting it to a mate, well, by gifting it he actually supplied food and beer at the pub,  which was nice, as it will not sit on a shelf in the garage for the next 10 years I did trim up some of the existing stuff to neaten it all up and gave it some wrinkle paint, unfortunately it currently has a used and abused mish mash of different types of hose clamps, 4 big fat T bolt type (shit), and a few normal clamps of vairing sizes and brands, but..... only until the 6 constant tension black worm clamps that I ordered from EFI solutions turn up next week Currently the current hose clamps are triggering me hard, LOL Is this the final version, probably not, I really want just 2 silicone pieces, a straight bit of silicone from the filter to the MAF is easy and will happen as soon as I head into Just Jap tomorrow, the problematic part is a 30° silicone bend from the MAF to the TB that I can connect the engine breather from the head, I found that there are bulk head fittings for boat bilge pumps that should work, but until I can get a 30° silicone bend the alloy pipe, and the 11ty thousand hose clamps, are there for the foreseeable future 4 hose clamps are golden, 6 are grudgingly acceptable, the 8 currently holding it all together is just taking the piss    I've also ordered 60 more retaining wall blocks for the front yard, I mis-gonculated the height that was required to get above the base of the Photinia's (red robin's) that are the hedge behind the front fence, currently it is 2 blocks high, and about 1/2 a block short, so going 3 blocks high will be above the base of the red robin's, and allow some room for mulch
×
×
  • Create New...