.30 over pistons???

[turbocreeper]

i currently have a block with 2g .20 over pistons. it was a newer rebuild. my problem is i have a nice scratch in my number 1 cylinder which i tried to hone but it didnt help. what i need to know is can i bore it another .10 and find a .30 over piston tp put in. i know they make .40 over but i dont really want to go that big. will it make a big differnce to have one cylinder .10 or .20 bigger then the rest?? what are my options?? thanks for the help.

 

[99gst_racer]

Don't run (3) .20 overs and (1) .30 over. If you need a .30 over in that one cylinder, then just bore them all out and run .30 overs in a cylinders. Otherwise it will never balance.

Kinda like running all different size tires. Yeah, it'll roll, but it will always pull one way or the other.

You will have problems with different weighed pistons and different bore sizes. Definitely match them all up.

 

[99gst_racer]

PS - Who's doing your machining?

 

[turbocreeper]

Paul from Accu-Pro race engines in Newaygo. At first he said we could sleeve the cylinder and bore it back out to .20 over, then he came up with that idea. Im unsure what to do. Those pistons are brand new.

 

[turbocreeper]

I havent heard to many people even talking about sleeving these blocks. Can we do this to our blocks?? Ive got another block but I already have so much time, effort and money into this one.

 

[99gst_racer]

If I was you, I would just go .30 over across all 4 cylinders or use a different block. I wouldnt try to bandaid it in any other way. Does Accu-Pro have a torque plate for the 4G63?

 

[2-0turbo]

i currently have a block with 2g .20 over pistons. it was a newer rebuild. my problem is i have a nice scratch in my number 1 cylinder which i tried to hone but it didnt help. what i need to know is can i bore it another .10 and find a .30 over piston tp put in. i know they make .40 over but i dont really want to go that big. will it make a big differnce to have one cylinder .10 or .20 bigger then the rest?? what are my options?? thanks for the help.

What is your compression? Don't go on a visual clue to decide if you need to overbore and put in larger pistons. Use data (wet/dry compression test) to make your decision.

 

[turbocreeper]

well because the car was smoking pretty good, i dont think i need a compression test. its got to be a good .05 deep. thats the whole reason for tearing it apart again.

 

[2-0turbo]

well because the car was smoking pretty good, i dont think i need a compression test. its got to be a good .05 deep. thats the whole reason for tearing it apart again.

Well now, that was information I didn't have. Smoking at idle or constant while going down the road? Mitsubishi engines are notorious for eating valve stem seals and smoking during vacuum conditions. If it is just during idle, I'd say it's your seals. If it is a constant stream of smoke while driving, I'd say you're correct and you need new oil control rings (aka a rebuild).

 

[oddrob]

The blocks can be sleeved, we've done it with no troubles. You can get 30 over pistons, just do them all the same.

 

[turbocreeper]

Who sells the .30 over pistons? I found one place, but there has to be more. How does the sleeving work? Do you bore the cylinder more, press the sleeve in, bore again to fit my .20 over piston? Is that how it works?