Do 4G63T's with 180K get by on a .020 bore, or need more?

[90gst_sean]

At the top of the cylinder I measured a .5 mm difference in round for all four cylinders. Thats about .020 of a inch I think. Will that be enough to get the cylinder back in good condition?

Is it common for a virgin engine that ran OK at the time of tare down with 180K to need a .040 bore job?

 

[dave99gst]

.5mm ? soo .019" ?
.020 should cover it. were do you get .040 ??

 

[90gst_sean]

If there was damage to the cylinder wall or it was really out of round, wouldn't you need to take out more metal to get the wall smooth again? That was were I came up with the .040 .

I was just wondering if .020 would be enough. I need to order my pistons before I have the block machined, right? It would suck to buy .020 pistons and find out that I need something bigger.

I'm deciding which of these three pistons I should buy. Mitsu 2G pistons & rings, Partsdino on Ebay sells ITM pistons that I've heard were OK for the price, or TopLine.

Are the TopLine pistons 2G compression?

Any thoughts on what would be the best pistons for the $$.

Any reason not to go with one or the other?

I'm running almost stock and don't plan to go over 375hp in the foreseeable future.

Thank you!

I almost forgot. What about the crank and rods? I have the motor on a stand and every thing is out. Should I have any machine work done to ether of them? Am I forgetting any thing important?
And I really don't want to eliminate the balance shafts... Should I really do it though?

 

[RedTalonTsi]

I had a running 180k virgin 6-bolt block I just rebuilt. I did .02 over with topline 2g pistons on my machined and cleaned up rods. If you are not planning on going over 400 hp I see no reason to spend a lot on forged stuff. The machinest I used could get a better deal on pistons than I could so....

Just my experiences, and I'm very happy with how it turned out, whatever you end up getting make sure you have the engine balanced, that is have each componant individually balanced all the way out to the clutch housing. I did and it purrs like a kitten at high rpms.

Later,
Dana

 

[dave99gst]

seeings how you will be taking the block to a machine shop anyways -
they will be able to answer the question as to if the block can be used or not.
(within .020")
thats one of those things you need to be able to measure in person and cannot be answered over the internet.

Id just take the block in and tell them you are planning on using .020" over pistions and want to be sure the block is useable. if it is.. then order the stuff and take it up to the shop to have the block machined. (yea, they need to have the pistions before any maching work is done.)

 

[90gst_sean]

Unfortunately I just read that last post. The shop I use is about 35 miles from my house. Throwing a engine in the trunk of my Honda was a new experience for me and not something I would have just thought to do to have something measured. After reading the first two post replies, I went ahead and ordered my pistons .20 over.

Now that the blocks at the shop, .20 may not cover it.

For anyone in a similar spot as me, and reading this looking for info. IF YOU REAM THE RIDGE AT THE TOP OF YOUR BLOCK, BE EXTRA SURE THE PISTONS YOU PLAN TO USE WILL COVER YOUR ASS!


If you know your going to replace at least the ring and maybe the pistons, you may be able to remove your old pistons from the block without using a ridge reamer. I'm no mechanic, force your pistons at your own risk, You still have to be careful.