Differences Between 1g and 2g Pistons

[Sk8er07999]

Ok beside the obvious 7.8 to 8.5 comp ratio and the thinner rod ending on the 2g's what are the physical differences. Like how can you tell the difference by looking at a set of 1g and 2g pistons? Reason I am asking is because my friend just ordered 2g pistons for his 1g. He can't tell the difference. He says the only thing that looks different is they are stamped differently. So how can I identify a 2g piston in a pile of 1g pistons? Thanks, Kevin

 

[zac83]

I believe the difference is: 22 mm wristpin bore in a 1g, 23 mm wristpin bore in a 2g. you have to get the 1g rods machined 1mm larger to fit the 2g setup.

 

[RoasT BeeF]

Thanks for posting this Kevin.

I am the one who got the 2g pistons. I thought that the 2g's were dome shaped. Maybe I am just crazy but I swear I saw a pic somewhere like that. The 2g pistons I got are dished and look exactly like my 1g pistons. Unless the deck height is different I dont see how they could be making more compression. I havent pulled the 1g pistons out yet so I guess that will be the only way to tell by measuring them. Just want to make sure I didnt get another set of 1g's that will be doing me no more good than what I already have. If anyone has some pics of 2g pistons or info please post.

Thanks

 

[dsmturboawd]

Originally posted by zac83
I believe the difference is: 22 mm wristpin bore in a 1g, 23 mm wristpin bore in a 2g. you have to get the 1g rods machined 1mm larger to fit the 2g setup.

i believe its 21 and 22, not 22 and 23.

 

[kpt4321]

They're not going to have a dome.

 

[keltalon]

Originally posted by Sk8er07999
Ok beside the obvious 7.8 to 8.5 comp ratio and the thinner rod ending on the 2g's what are the physical differences. Like how can you tell the difference by looking at a set of 1g and 2g pistons? Reason I am asking is because my friend just ordered 2g pistons for his 1g. He can't tell the difference. He says the only thing that looks different is they are stamped differently. So how can I identify a 2g piston in a pile of 1g pistons? Thanks, Kevin

the only difference i can tell by putting them side by side is that the 2nd ringland is a little thicker than the 1g but other than that the darn pistons looks as if the dish is the exact same dept! just my 2 cents

 

[awdEAGLEtsi]

pistons aren't the only thing that affects compression...the pistons could be almost identical and the compression could be way off.

 

[dsmturboawd]

good point. rings, head gasket, crank, etc plays a role.

original poster: i feel you have enough information in this thread to do what you need to do. if not, ill go look at my 2g pistons and 1g pistons and see what the simple differences are.

good luck.

 

[Sk8er07999]

We got it covered. There was no question about headgaskets or anything. Just pistons.

 

[awdEAGLEtsi]

well whats the difference between them...cause the other post said the bolts are stronger on the 1g pistons.

 

[dsmturboawd]

forget what you read in the other post about that.

 

[awdEAGLEtsi]

why? that doesn't matter?

 

[Defiant]

Piston bolts

 

[Sk8er07999]

Yeah I just got new arp piston bolts . :laugh:

 

[Topper348]

Could anyone take comparison photos if they have both laying around. The reason I ask is because i just found 3 oil squirters in my oil pan. They came in contact with the bottom of my 2G pistons. The squirters may have been installed at an incorect angle in the rebuild, but i just wanted to make sure that the skirts on the 2G pistons were the same as the 1g's.