What size pistons are you using?

[Doward]

Just got off the phone with Aaron @ SCE, and we found a small problem - they actually have in their book, that the 7M-GTE has an 85.7mm bore. I pulled up the online TSRM, and corrected that with him, to 83.24mm maximum bore, stock pistons - and that Toyota recommends nothing greater than 83.74mm bore - anything bigger is supposed to be a replaced block.

Now with that in mind, I mentioned that an 84mm gasket would be about the biggest I'd go, as it's difficult to get any pistons greater than 84mm in diameter.

Wiseco makes an 84.5, yes. After a lengthy discussion (really cool guy, btw) I tossed out the idea of posting this poll, and giving him a link to it. With the lack of material between our piston walls, it is in everyone's favor to go with the smallest bore that will satisfy the greatest number of people.

Simply put, please select the piston size you are using in your rebuild.

 

[IJ.]

84mm JE's

 

[Doward]

I'm sending Aaron the link now. Let's get this ICS Titan rolling!

 

[IJ.]

Early blocks could be dodgy even at 84mm late blocks no probs at all!

 

[Doward]

I'm going 83.5, if that will be enough to clean it up. With over 700hp, I'd like to know I have as thick of a wall as can be.

 

[IJ.]

Yep good move I went with 17+ Ross for my first build on the new block then scuffed a bore and had to go to 40+

Bit of a "gotya" is the Cam pully tensioner!

NO MORE than 36ft/lbs or you'll distort the bore.

 

[Doward]

Yep, planning on that being in place with the torque plate I can't wait to get this block all worked over!

 

[Nick M]

Early blocks could be dodgy even at 84mm late blocks no probs at all!

This is why I always quote the manual when asked, .5mm over max. I asked around about the old HKS 85mm pistons. Some bad problems happened. The new block should be different. You are right.

 

[Doward]

Ha.. let this run over the weekend for Aaron.. I was pretty sure nobody had really gone over 84mm on their build

 

[jdub]

+17 Ross pistons here

 

[Doward]

Just posted this over at the 'other' site... It'll probably be locked, and I'll be banned :3d_frown: for bringing more innovation to the 7M aftermarket. Oh well

 

[CRE]

Might want to point this out in the original thread about the SCE Titan. The title's a little vague and those who are primarily interested might miss this.

 

[Doward]

Good point!

 

[lifted]

whats stock size? and if i was using stock size, could i use a headgasket with a larger bore.?

 

[ViR2]

yes u can

 

[tig321]

Early blocks could be dodgy even at 84mm late blocks no probs at all!

I assume your talking about the quality of the some of the early castings?
(Glad to see your back IJ, I have always found you and your posts very helpful)

Doward, I'm really hoping this goes ahead and with an 84mm bore. I would be very happy if there was something equivelent to the HKS Stopper available, but with a smaller bore. I don't want to use an 86mm bore gasket with 83.4mm pistons.

If it was an 84mm bore gasket could you still go with .040 over pistons to 84mm? What is the minimum amount of room you can have between the gasket and piston, since 7m pistons stick out of the block?

 

[lzalusky]

ROSS +17

 

[IJ.]

Tig: Thanks!

Late model "Heavy Casting" top early model "Light Casting" lower

 

[JustAnotherVictim]

83.5 Wisecos.

 

[Doward]

tig321 - due to the fact that you have to have some clearance for the piston, you can actually have the head gasket bore the exact size as your cylinder bore - this is optimal for a number of reasons