Thanks for sharing your experiences. I will be trying swain or line to line on this next set of pistons.

I have used Icon's a few times and have no issues with the piston itself, and they are forged. Like other's have said the coating that comes on the pistons from the manufacturer comes off really fast. These probably have no more than 20-25 hours? I had pulled these before because of a bad block after a few hours and the coating was basically the same as you see here. Some of the coating looks like it chipped off and not wore off.
https://cimg7.ibsrv.net/gimg/www.off...62a146aeac.jpg

Yep, seems to be my experience too , when the manufacturer coats them and it comes as part of piston price, never last like when you pay swaintech, line to line, etc.

I had the tops done by SwainTech.. I should have done the exhaust valves too.

https://cimg8.ibsrv.net/gimg/www.off...22f8653001.jpg

Skirt coatings looking like that after 25hrs are totally useless and just a liability. Putting the coating into the oil, and messing up the piston clearances.

Thanks for the sitrep.

I have noticed the very short skirts lately too.

Mostly in car drag apps, and when I see them in the Offshore market I always wonder.

In the photo above, of the one w/the worn skirts, there is near no skirt bellow the bottom of the wrist pin!

All the skirt support is above the pin and that is where there is already increased clearance designed in for thermal expansion.

Add to this the variable of combust chamber design, piston dome design and plug location.

As in, how much of the combustion process is actually side loading the piston from the start?

And w/little to no skirt support bellow the pin to counter the above…….

The short skirts would make me nervous, especially in highly loaded, high torque scenarios.

I bet there is an Engine Masters episode on this????

If not, should be.

I completely agree with you. I got into boats after drag racing and piston design I have found to be an important part of the differences. I do not like the short skirt in my marine motors for the reasons you mentioned. High load and high torque over a long period of run time is tough on parts. This is what most of my cylinders look like. No crosshatch left on the loaded side.

I love Engine Masters, I have not seen this on one of their episodes and I think I have seen all of them.

https://cimg6.ibsrv.net/gimg/www.off...5bc637b3e2.jpg

I rebuilt a 454 EFI about a 2 years ago that had Icon pistons in it. It had over 500 hours on it and except for the one piston that got torched from a bad injector they all looked pretty darn good. I ended up going to the next oversize and put it back together. I have used them in several automotive engines and they seem to hold up just fine. They are not my first choice but they have some oddball combinations available that nobody else does.

What alot of guys forget on these marine builds is RPMS and usage etc, there not drag engines, there not sp[inning 7400 so using a ultra lightweight piston with virtually no skirt, profiled to nothing is ridiculous . Every time I see lightweight Mahle pistons or similar come out of a marine endurance engine I roll my eyes, I have BOXES of them and they always looks the same, lost ring seal, cylinders skuffed, skirts tore up.

I have seen every episode Engine Masters as well.

Started as magazine articles which I read every one off too.

I love the out of the box thinking by some of the teams.

Sometimes when you follow one sport/hobby long enough, you see status quo take effect as everyone accepts the long term narrative.

Then someone gets involved who was top of the food chain of their previous sport/hobby.

Normally, that’s when we learn.

Remember the PB and HB tech series where there was always someone writing in about the miracle motor in their boat that was slower than stock!

Their next door neighbor was a drag racer and helped them build the motor!
Etc.

Ports, valves, cam so big you could walk through them w/a wire brush to clean the carbon off the piston domes!

On the piston side loading, the auto OEMS used to (maybe still do) offset the wrist pins in the pistons to side load the pistons so they didn’t slap when cold.

A trick from Direct Connection back in the day was to swap the pistons from side to side to eliminate this.

I did this in my home brewed 7k 440 Chrysler in my Super Bee.

There are many, many, VERY smart, go fast boat motor builders on here that know what works and what doesn’t.

One of the fast guys around me, educated me 30 yrs ago about the difference between HP’s and torque.

He had 25’ Checkmates running 120’s back then w/motors w/less HO’s than the others but WAY more torque!

And they never broke!

Word!