A few rebuild ?'s

[spaugh]

Ok my car (91 TSI AWD) Jumped time last night. Pulled my head today and it had broke 7 of my exhaust valves and destroyed my pistons. Well the motor had been rebuilt before i got the car. Just found out they had put 2g pistons on on 1g rods. They where stamped .050. I have been looking around and i have not seen any performance pistons that were .050 only .020, .040 and .060.

My first question is do i need to by pistons for a 7 bolt since my rods have been modified?
Second is my only option to go with the .060 over pistons?

Thanks guys for the help.

I am pretty sure these Questions answer their selves but i just wanted to be sure before i go ordering parts.

 

[BrokenTsi]

if you're already .050 over, then I would throw that block in the garbage. I've never heard of anyone having a block bored over THAT much. Perhaps you should actually pull a piston out to confirm that. I doubt the block is any good, perhaps you can save the crank tho.

 

[anteversion]

4g63t cannot be oversized that much, .040 it's the biggest overbore size it can affors since past this size, it will became too thin between water jacket and the sleeve itself. And go again with 2G turbo pistons, many have done this before cause they wiil rise your compression ratio to 8.5:1 instead of 7,8:1 with 1g ones

 

[spaugh]

I actually found some wiesco pistons on extremepsi.com that were .060 over sized for 6 and 7 bolt. So those can not be used?

 

[ctcare89]

You can use them.
Some people feel .060 is too much and there isn't enough "meat" left in the block to keep it strong. They worry about the block getting damaged. Whether this is true or not I can't say as I have not done it, but if the parts are for sale then some has done it. Hopefully someone with first-hand experience can chime in.

 

[dsm-onster]

Considering the 4g64 and g4cs has the same casting as the 4g63 (same shape oil and water channels) and they are 1.5mm or 0.060" wider at the bore, then you're just fine with a bore at or below that number. It seams plenty for 600+ whp.

You need to buy pistons for a 2g not for a 7 bolt. The pistons are generation specific. The rods are different for 6 bolt, 1g 7 bolt, and 2g. 2g pistons require a larger wrist pin than 1g 7bolts or 6 bolts.

 

[spaugh]

Thanks for the info.

 

[spaugh]

Anyone actually ran a .060 over piston?

 

[spaugh]

Sorry guys just went and took a second look at my pistons and they are stamped 0.50 so this means that they are only .020 over.