Help identifying a forged piston.

[NateCrisman]

Hey guys, I have a set of forged pistons that I need some help identifying the brand. There are no markings or ID stamps anywhere, so all I have to go on is "looks". I used to sell Wiseco and Ross pistons, they don't look at all like those. Maybe JE? The rods are crower, so maybe an old-school hint?

They came from the engine I pulled out of GVR4 828. They are 86mm dia at the skirt bottom. The block they were in had some half-ass stuff with welded cracks and orings on the HG surface. So I want to order a new ring set and have a different block bored out for these.

Pics:

yeah, they are a little scuffed. nothing horrible though IMHO.

The piston tops have an odd shape, the quench area doesn't go around to the sides of the piston, only the front/back. I'm used to looking at dsm pistons with a round dish type top.

This #1 piston has some little dimples like a ball got into the cyl, I think I can smooth them out with some sanding/filing.


Im intending to put these unknown pistons, along with the crower rods, knife edged 6B crank, ARP mains and put together a good "built motor" for my personal GVR4. I haven't been able to sell the motor as is, so I might as well use the good internals. Then I can hit it with a 200shot and worry less. /ubbthreads/images/graemlins/devil.gif

I'm picking up a 1g awd this weekend that needs a shortblock, the stock motor from my gvr4 can go into that car, which is a fix-up-to-resell type car.

 

They look like they seen some detonation. JEs all have the JE stamp on the inside, so maybe CP?

 

[NateCrisman]

Ok so the list of "can't be"
Ross
Wiseco
JE

Can anyone else strike a brand out?

 

[NateCrisman]

Quoting Jonvr4:
They look like they seen some detonation. JEs all have the JE stamp on the inside, so maybe CP?



As for detonation, that didn't cause those dimples. There are matching perfectly round impressions in the cyl head that came off this motor, "something round" got into that cyl and bounced around a few times before getting out the exhaust. Seems like a tiny ball bearing or something like that.

The other 3 pistons are perfect on top. The top outer edges are all smooth, normally with detonation issues, the edges are rough.

 

Ross pistons have Ross cast into them, JE's have JE, weisco have coated skirts don't they?

 

[EMX5636]

Yeah, def not either of those three... Might be CP or Mahle...

 

Mahle have a phosphate coating I think. They also have a very small skirt, so not Mahle. Arias?

 

[NateCrisman]

CP pistons catalog

After hitting a bunch of mfg websites, I'm thinking they are likely CP pistons.

 

What do I win?

 

[3rdstrikedsm]

That area where the damage is will cause detonation, I would get a replacement for that one.

 

[NateCrisman]

yeah, I think I should be able to sand down those pits without losing much material.

 

[fivestardsm]

Quoting Jonvr4:
Ross pistons have Ross cast into them, JE's have JE, weisco have coated skirts don't they?



I belive that the older wiseco's did not have the coating on the skirts like they do now.

Unless you are sure that they are CP, you might want to check speed pro (A.K.A. sealed power). The tops look like a set I use to have in a s.b.350 years ago. I have another set of the Speed pro in my Ford 302 and they are coated on the skirts.
You might check Keith black. I know their are more out there, I just cant think of them right now.

 

[prove_it]

I don't think that Mahle prints anything on their pistons, but they dont have that kind of top. If they are CP they must be from a while back. If the engine was still running good, they must be a good brand.


Maybe they were made up in Iceland?

 

[curtis]

Hey Nate looks like we both have the same mystery pistons

click me

I was told mine were CP's only difference I see from yours and mine the sides on the dome are cut out on yours. My guess it was custom to lower the CR down to 8.0 / 7.5 range on yours

 

[bigblock4g63]

Quoting NateCrisman:
CP pistons catalog

After hitting a bunch of mfg websites, I'm thinking they are likely CP pistons.

i dont think so. cp as a stamp on the bottom

 

[NateCrisman]

That pic of a CP piston is all cast/forged rough finish on the inside. My pistons are all smooth machined finish on the inside.

hrm...
the thing that makes me still think CP is there is a groove cut between the top and middle compression rings. CP lists that as a "feature" in thier literature, and Iv not seen anything like that mentioned by another brand.

either way, rings are relatively generic (So I have been told now). Ill measure the existing rings and ring grooves, and have my machine shop make a recomendation to replace them if need be.

 

Not Mahle's. Thats all i got.

 

[bigblock4g63]

Quoting NateCrisman:
That pic of a CP piston is all cast/forged rough finish on the inside. My pistons are all smooth machined finish on the inside.

hrm...
the thing that makes me still think CP is there is a groove cut between the top and middle compression rings. CP lists that as a "feature" in thier literature, and Iv not seen anything like that mentioned by another brand.

either way, rings are relatively generic (So I have been told now). Ill measure the existing rings and ring grooves, and have my machine shop make a recomendation to replace them if need be.

 

[bigblock4g63]

it could be a srp piston .. they are the lower line of je

 

[bigblock4g63]

and for the win the piston is a roller wave




Quoting NateCrisman:
Hey guys, I have a set of forged pistons that I need some help identifying the brand. There are no markings or ID stamps anywhere, so all I have to go on is "looks". I used to sell Wiseco and Ross pistons, they don't look at all like those. Maybe JE? The rods are crower, so maybe an old-school hint?

They came from the engine I pulled out of GVR4 828. They are 86mm dia at the skirt bottom. The block they were in had some half-ass stuff with welded cracks and orings on the HG surface. So I want to order a new ring set and have a different block bored out for these.

Pics:

yeah, they are a little scuffed. nothing horrible though IMHO.

The piston tops have an odd shape, the quench area doesn't go around to the sides of the piston, only the front/back. I'm used to looking at dsm pistons with a round dish type top.

This #1 piston has some little dimples like a ball got into the cyl, I think I can smooth them out with some sanding/filing.


Im intending to put these unknown pistons, along with the crower rods, knife edged 6B crank, ARP mains and put together a good "built motor" for my personal GVR4. I haven't been able to sell the motor as is, so I might as well use the good internals. Then I can hit it with a 200shot and worry less. /ubbthreads/images/graemlins/devil.gif

I'm picking up a 1g awd this weekend that needs a shortblock, the stock motor from my gvr4 can go into that car, which is a fix-up-to-resell type car.