Stock pistons "rate ore hate" ?

[wparsons]

Originally Posted by seito23

Are the tolerances really so tight? I am in Florida, so, maybe not an issue. With new rings and a honed wall I am surprised a little

Forged pistons run smaller when cold, that's why they slap. Once up to temp they expand and fill the space better.

[Fricke]

Originally Posted by makinen

I'm on the almost same boat.
My list is,
Skunk2 rods
King's bearings
ARP head studs
Reimax oil pump gear
Main case bolts
Gasket set
GSC single valve spring kit.

One thing I have missed is thr tapered small end of stock rods and matched stock piston pin area.

Attachment 131637
Attachment 131638

But Skunk2 rods have this shape.
Attachment 131639

So I have to go to the machine shop to match the stock pistons.
Attachment 131640

that was a ripoff
I can understand why ( more material ) but is all the forged Pistons and rods that way, or is it heads up an be ceer full whit what Pistons and rods you buying, so that they match?

[seito23]

Originally Posted by wparsons

Forged pistons run smaller when cold, that's why they slap. Once up to temp they expand and fill the space better.

I was thinking of it like, Mike, from Moto East. A piston that has been given the proper tolerances shouldn't slap anything, except the competition.

If that is common place to get piston slap after building an engine, me personally, I would think twice about having a build done in the first place. I am building the motor to make sure it lasts and can withstand the extra punishment that naughty engine deserves :burn rubber:

[Fricke]

Originally Posted by wparsons

Forged pistons run smaller when cold, that's why they slap. Once up to temp they expand and fill the space better.

I don't mind the piston slap, have had 2 ej257 whit fully built engines
The first one whit a SC46 turbo I even drown in winter, djust added a engine heater = lots of fun
And they shut up when in operating temp
And don't mind it on this one, because more race car then street car, don't think it's going to be so much street driving from now on, the car is totally gutted and I have welded in a half role cage in it.
So no more stereo and sound deeding material.
Butt the point from the first case was, why Change something that's not going to be the weak point for the hp levels?
There so much more to throw money at

[makinen]

Originally Posted by Fricke

that was a ripoff
I can understand why ( more material ) but is all the forged Pistons and rods that way, or is it heads up an be ceer full whit what Pistons and rods you buying, so that they match?

I have been looked around forged rods on the market and found that all rods have flat small ends.
Skunk2 said that "a machine shop can taper them for stock pistons," in the mail reply when I asked.

[Xero-Limit]

Originally Posted by justinsstang

How much are the CP 10.5:1 you're talking about? I was thinking about going 11.0:1 when I build it, not sure the price difference between the two

Around 650 ish with rings. Factory rings cost 180 or so retail, so 470 is the cost difference when you factor that in.

[wparsons]

Originally Posted by seito23

I was thinking of it like, Mike, from Moto East. A piston that has been given the proper tolerances shouldn't slap anything, except the competition.

If that is common place to get piston slap after building an engine, me personally, I would think twice about having a build done in the first place. I am building the motor to make sure it lasts and can withstand the extra punishment that naughty engine deserves :burn rubber:

Forged pistons expand more, so when cold they have more slop. Once they're up to temp they're fine, but on cold starts they will make more noise.

[justinsstang]

Originally Posted by moto-mike

Around 650 ish with rings. Factory rings cost 180 or so retail, so 470 is the cost difference when you factor that in.

What kind of rings are you including with the pistons? For boost I would want stainless, no chromoly.

What kind of price would it be for the 11.0:1 from CP as well to compare the 10.5:1