Piston Brand Identification

[GRace]

I am in the process of dropping a in a stock rebuild with arp hardware in the talon. For grins I opened up the old motor that was leaving glitter in the oil and I discovered that the pistons are forged. The numbers on the top of the pistons are:

6560M855

8236D

The wrist pins holes have slots for clamps, (whatever they are called) but the rods are installed just like stock pistons. I would love to know the brand of these pistons but I'm not sure if it would be worth tracking down new rings or if I should just use stock pistons as I have an evo III 16g.

 

[g4ebguy90]

Man, them valve reliefs are huge and that top piston crown is fricken thick... Man I want those.

Deff a High compresson piston.

Kind of weird there is no brand or anything.

 

[GLHS0658]

Wiseco

 

[6damian6]

quick google search:
Wiseco 6560M855 - Wiseco Sport Compact Pistons - Overview - SummitRacing.com

 

[e85_4g63]

Definitely NOT a high compression piston...

 

[shockracer]

Grats, sounds like a small lottery hit.

 

[CrackedDSM]

Damn, hell of a score. Now all you need if you ever want to build the motor is a good set of aftermarket rods and go.

 

[g4ebguy90]

If it was a low compression piston, why would it need them big valve reliefs? if the height of the piston would be lower?... Not to mention that summit racing ad, says those pistons do not have valve reliefs?

 

[CrackedDSM]

A high compression piston will have a raised dish way more than what you see there.

 

[g4ebguy90]

Yea but that piston is pretty tall. I would think, that would make a difference to.
What CR is it?

 

[CrackedDSM]

It doesn't really look that much taller than a stock 1G or 2G turbo piston. Wiseco's are a heavy piston, so it's how thick it's build makes it look tall.

 

[GRace]

Thanks for the replies, I must have typed in the number wrong in google a few times when I first started searching. Well I guess the smartest thing to do is buy a $300 set of rods and sell my stock rod piston combos which are brand new with arp bolts. Is it usually a big deal to find rings that will work for wiseco pistons?

 

[CrackedDSM]

I wouldn't necessarily sell them just yet, unless you plan on going above 500whp. The stock rods, especially with ARP rod studs can handle 400-450whp all day no problem.

 

[g4ebguy90]

Yea the rod bolts truly are the weak link.

 

[BogusSVO]

well if they hung the pistons like stok 1g, means that the con rod is press fit to the wrist pin.

trying to press the wrist pin out, so you can hang them on aftermarket rods with the wrist pin clips, the pistons may crack/break/deform while pressing out the wrist pin.

I would have them cleaned and mic'ed and run them on the rods they are hung on

 

[GRace]

Ok, I called Wiseco and they are 9:1 CR pistons. That's pretty high for me, I also think the wrist pins are slightly bent on a couple because they don't move very easily. I'm not sure if it's worth $200 (rings, pins) to have high compression pistons when 91 octane is pretty much my only option.

 

[BogusSVO]

I doubt the wrist pins are bent, more like oil varinsh build up on the wrist pin.

are you moving the rod side to side with the wrist pim?

or rocking the piston back and forth on the wrist pin?

 

[GRace]

I doubt the wrist pins are bent, more like oil varinsh build up on the wrist pin.

are you moving the rod side to side with the wrist pim?

or rocking the piston back and forth on the wrist pin?

They move side to side easily, it's the rocking back and forth. A couple of them are very stiff but they can still move back and forth.

 

[g4ebguy90]

High compreession it is....