I need to rebuild the bottom end of my 555 and considering the Mahle Powerpak set. I do like the smaller ring pack.

https://www.us.mahle.com/en/motorspo...iston-kits.jsp

These have a Phosphate Coating on the whole piston and Grafal Anti-friction coating on the skirts.

I am pulling out a set of Icon forged with their skirt coating and want to try something else.

Thoughts on hard anodizing or other coatings on a marine piston.

I may order custom pistons for a 4.580 bore to save the block a little so I can get any coating done. Diamond are the only ones with a catalog 4.580 set that I can find, but they are blower pistons. I have used Ross and BME in the past for custom pistons in my drag motors, any recommendations?

Glad to see you back in the hood! Hope all is well out west. Maybe icdedpeeps will jump in with some feedback! If I recall he did or had something similar done.

These guys are the real deal. Just recently had them put a thermal barrier and skirt coating on my 11.1 side by side piston. Real nice work that stays put.

https://swaintech.com/

There might be some power in the metric ring package some of these mahle pistons use over the std rings BUT i'm not in love with there tiny profiled, lightweight skirts etc in a marine endurance engine. I have taken several engines apart with them in past year and they looked like ****. As far as factory skirt coatings, the in house stuff done on pistons you buy doesnt seem nearly as good as stuff that gets done by a 3rd party. Ive used swqaintech, line to line and component coatings on different pistons and stuff all looked pretty intact at freshen up time. I bought diamond pistons with off the shelf coatings and looked pretty beat up at 35 hrs (I was under the impression they SENT THEM TO LINE TO LINE but evidently not), the stuff mahle uses looked like crap in no time.
Id personally just order a set of 4.560 JE, pay the upcharge to have them bumped to 4.580, its like 80 or 100$ extra.

My first question would be why do you want to change ? If you got good service from the Icons why mess with something that is working ?

That being said I like the Mahle pistons a lot. I just finished a late model 5.7 Dodge Hemi engine with them and I am putting together an Oldsmobile and also using them. Like AF said they have very short skirts and I am not sure if I would want to use them in a marine deal. And for me the jury is out on the real thin rings. The Hemi had 1mm top rings and 2mm oil. I know they say they seal better but I dont know about the long term. A lot of modern automotive engines are having oil consumption issues and I don't know if the thin rings is a factor.

One more thing to keep in mind is the Mahles are almost certainly going to be a lot lighter so you will definitely have to rebalance the crankshaft.

Call Mahle and talk to them. The few times I have called them they have been very helpful.

This is a pontiac 455 I just tore apart with Mahle pistons that had 200 miles on it, now I wouldnt blame the piston design or manufacturing process completely on how bad this looks BUT the skirt is really small (picture makes it look much bigger then it is) AND previous builder put them in too loose. There minimum clearance on these is .0025 and maximum is .0033, these were in at .005 to .0055, there NOT going back in! I freshened my 1000+ hp blower engine around the 100 hr mark and the JE's with swaintech coating looked almost new fwiw.

The hard anodizing from Diamond is awesome. Any other coating jobs send to Swain Tech because I've never seen it come off. They're also very easy to deal with and have quick turnaround.

Looks like there were some other issues too. The second ring looks torn up ? It amazes me how many guys try to out think the engineers that design these parts. I had a friend at another shop call me a few days ago and ask about clearances the other day because they didnt want to believe that they could be that tight.

Proven help for the metric ring pack.

https://products.totalseal.com/gas_ported_rings

How did your ICON pistons make out? Where they forged? What was their run time?

I was looking at an ICON option.