Jump to content
SAU Community

Recommended Posts

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

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

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

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

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

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

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

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

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


  • Similar Content

  • Latest Posts

    • Did this end up working? Did you take some pictures?
    • And finally, the front lower mount. It was doubly weird. Firstly, the lower mount is held in with a bracket that has 3 bolts (it also acts as the steering lock stop), and then a nut on the shock lower mount itself. So, remove the 3x 14mm head bolts , then the 17mm nut that holds the shock in. From there, you can't actually remove the shock from the lower mount bolt (took me a while to work that out....) Sadly I don't have a pic of the other side, but the swaybar mounts to the same bolt that holds the shock in. You need to push that swaybar mount/bolt back so the shock can be pulled out past the lower control arm.  In this pic you can see the bolt partly pushed back, but it had to go further than that to release the shock. Once the shock is out, putting the new one in is "reverse of disassembly". Put the top of the shock through at least one hole and put a nut on loosely to hold it in place. Put the lower end in place and push the swaybar mount / shock bolt back in place, then loosely attach the other 2 top nuts. Bolt the bracket back in place with the 14mm head bolts and finally put the nut onto the lower bolt. Done....you have new suspension on your v37!
    • And now to the front.  No pics of the 3 nuts holding the front struts on, they are easy to spot. Undo 2 and leave the closest one on loosely. Underneath we have to deal with the wiring again, but this time its worse because the plug is behind the guard liner. You'll have to decide how much of the guard liner to remove, I undid the lower liner's top, inside and lower clips, but didn't pull it full off the guard. Same issue undoing the plug as at the rear, you need to firmly push the release clip from below while equally firmly gripping the plug body and pulling it out of  the socket. I used my fancy electrical disconnect pliers to get in there There is also one clip for the wiring, unlike at the rear I could not get behind it so just had to lever it up and out.....not in great condition to re-use in future.
    • Onto the rear lower shock mount. It's worth starting with a decent degrease to remove 10+ years of road grime, and perhaps also spray a penetrating oil on the shock lower nut. Don't forget to include the shock wiring and plug in the clean.... Deal with the wiring first; you need to release 2 clips where the wiring goes into the bracket (use long nose pliers behind the bracket to compress the clip so you can reuse it), and the rubber mount slides out, then release the plug.  I found it very hard to unplug, from underneath you can compress the tab with a screwdriver or similar, and gently but firmly pull the plug out of the socket (regular pliers may help but don't put too much pressure on the plastic. The lower mount is straightforward, 17mm nut and you can pull the shock out. As I wasn't putting a standard shock back in, I gave the car side wiring socket a generous gob of dialectric grease to keep crap out in the future. Putting the new shock in is straightforward, feed it into at least 1 of the bolt holes at the top and reach around to put a nut on it to hold it up. Then put on the other 2 top nuts loosely and put the shock onto the lower mounting bolt (you may need to lift the hub a little if the new shock is shorter). Tighten the lower nut and 3 upper nuts and you are done. In my case the BC Racing shocks came assembled for the fronts, but the rears needed to re-use the factory strut tops. For that you need spring compressors to take the pressure off the top nut (they are compressed enough when the spring can move between the top and bottom spring seats. Then a 17mm ring spanner to undo the nut while using an 8mm open spanner to stop the shaft turning (or, if you are really lucky you might get it off with a rattle gun).
    • You will now be able to lift the parcel shelf trim enough to get to the shock cover bolts; if you need to full remove the parcel shelf trim for some reason you also remove the escutcheons around the rear seat release and you will have to unplug the high stop light wiring from the boot. Next up is removal of the bracket; 6 nuts and a bolt Good news, you've finally got to the strut top! Remove the dust cover and the 3 shock mount nuts (perhaps leave 1 on lightly for now....) Same on the other side, but easier now you've done it all before
×
×
  • Create New...