90 Integra Head Build

[natt2000]

Yeah were aware that its the FRM sleeves, what were wondering is what the problem is. Pistons shouldnt touch cylinder wall, so im confused as to why a forged piston would be an issue compared to an oem one

from what i hear frm is very easily scared/gauged, while forged pistons are somewhat stronger.

"You have to look at why FRM & forged aluminum doesn't work. Cast iron has lubricating graphite flakes (or nodules, in ductile iron), and iron-aluminum interaction does not produce much galling. Aluminum, like stainless steel, is notorious for galling severely when it rubs on another surface composed of the same base metal."

stolen from HIprofile of Honda-tech

OT here http://www.honda-tech.com/showthread.php?t=2790459

i also hear it has to do with how aluminum expands compared to frm. i know some companies make forged pistons with special coatings, but not everyone feels safe with them, and have mixed reviews. if i were making an h22, i know i wouldnt feel safe without iron sleeves.

 

[DaddyBuiltRacing]

Yeah I agree that if i were to build an H22 it would be sleeved, just didn't know you couldnt run forged internals until today lol.

 

[hidenplanvew]

I know Mahle makes pistons for the frm but they are hit or miss. 600 for pistons that might fail or 800 for sleeves to be able to use any pistons and to be stronger its a no brainer... Thats what I had to do...

(FRM was a waste by honda and just a pain... The frm does crack and you start burning oil)

 

[natt2000]

yah, the mahle pstons have a coating that wears off after ~30k miles. they also dont like to be boosted for very long anyways.
frm was used because it has a much lower friction coefficient than iron sleeves.