I took on a customer project to help me get money for my own..

I put this in another thread, they suggested I ask a few of the 'Lude guys so i'm bringing it here.

So the motor is a JDM h22a (SIR) and the JOB STARTED as a simple head gasket change until he came to me and said he wanted to bump up compression with better heads. So I did some researching and asking around and came to two possibibilities..I wanted to run it by you guys and see what you think..


Choice 1 - Type S pistons...

Choice 2 - Mahle Gold Series Forged Pistons..


now i'm told BOTH of these can be dropped straight in without fear of wrecking cylinder walls..

Has anyone had any experience with either? Any ROD suggestions or should I stick with the stock rods?

 

Just so nobody thinks I haven't done reading..

Besides being a Honda Tech and having done a module or two about this particular car.

The Cylinder walls in the H-Series motors have Nikasil in them, i think FRM sleeves (Which are actually STRONGER then most sleeves including Iron ones). In any case, the problem this presents lies in..

1)Honing - As you can very well HONE away the FRM material leaving a bare, ineffective cylinder wall

2) Forged pistons - MORE SO, the RINGS in them which can utterly DESTROY the walls.

Now, where i'm confused in all of this that since the actual PISTON doesn't touch the walls, but infact the RINGS do, why would it matter what type of piston you use? Why sleeve the block at all? The FORGED pistons, PISTONS, would never actually be touching the wall at all..

So if instead you got like..Ceramic Coated PISTON RINGS, like the ones used in the Mahle piston..why couldn't you get away with running JE-Forged Pistons in the JDMh22a (Closed deck, SIR)? Not that i'm ATTEMPTING IT..but From what i'm seeing the Mahle Pistons are IDEA or this block after their revisions, but i've read about FAR MORE power being made with the JE Forged Pistons, so of course i'm liike...ok...Forged Piston...FRM Compatible Ringset...green light?


See what i'm gettin at?

 

I built my H23VTEC with type-s pistons, worked out very well. I've done some work on a Mahle build but didn't assemble it, to my knowledge its still running with no issue, and plenty of people are running Mahle's with no issue.

 

Either piston is fine, I have used both with very good results. There is also a Honda Service Bulletin advising that you don't need to hone for new rings as long as the cylinder walls are in good shape and not out of round. Check it out.