in line coating on piston skirts

[chevy art]

anyone have any positive or negative info on inline piston coatings. i had my forged pistons coated with about .008 on the skirts . its a spare block which will not be used for a while. any suggestions on first startups or breaking in the pistons to the cylinder walls? anyone know of any problems with this product? thanks Art

[Tom68]

anyone have any positive or negative info on inline piston coatings. i had my forged pistons coated with about .008 on the skirts . its a spare block which will not be used for a while. any suggestions on first startups or breaking in the pistons to the cylinder walls? anyone know of any problems with this product? thanks Art

0.008 or 0.0008 ?
I got some Cleveland forgies skirts built up with a blue coating because the pistons had been fitted race loose and then a bit looser, that's well over 10 years ago, motor still running and quiet, doesn't do a lot of miles though.

[BOOT]

Can't rem where but I saw something not long ago bout some piston coating clogging a dry sump pick-up and they kept having to pull the pan to clean it out. IDK who did the coating or much else tho....

[Mark O'Neal]

If you are referring to Line2Line coatings. Yes it works and works well.

And if someone has a motor running .0008 piston to wall, I'd like to see the skirts after the first 30 seconds of running.

[Tom68]

If you are referring to Line2Line coatings. Yes it works and works well.

And if someone has a motor running .0008 piston to wall, I'd like to see the skirts after the first 30 seconds of running.

Poster said he added .008, how big was his piston to bore before. Rings would be busy sliding around in the grooves. Unless he was talking 0.008 millimeters.

Not that I'd try running a forged piston with 8 10th of a thou clearance, but J.E apparently would.

[Mark O'Neal]

If you are referring to Line2Line coatings. Yes it works and works well.

And if someone has a motor running .0008 piston to wall, I'd like to see the skirts after the first 30 seconds of running.

Poster said he added .008, how big was his piston to bore before. Rings would be busy sliding around in the grooves. Unless he was talking 0.008 millimeters.

Not that I'd try running a forged piston with 8 10th of a thou clearance, but J.E apparently would.

No, they won't. That piston has the equivalent of Line2Line, if not that. Since the coating establishes it's own "optimal" clearance, they can start it anywhere they want but that's not where it will run. I also don't see the point, as a correct shirt profile won't make noise at .0045. But Line2Line would have been wonderful in the '80s when we were cam grinding skirts at .008 to .012 instead of using Takasawas or Okumas and being able to shape them any way we want to.

My guess is he started at .010 to .012...but it's just a guess.

[1972ho]

Sounds like he just had his skirts built up to .008 of coating on a cleveland block so it’s more than likely a 4.030-4.040 bore if it’s a cleveland block.

[gregsdart]

I have a mopar block with pistons line2line coated to take up . 0043 extra from honing. They added coating to bring the skirt in at . 0025 clearance cold. The breakin procedure was a number if warmups and cool downs, then warm up and do part throttle pulls in steps, to gradually wear in the coating. With all i had done to that 550 inch motor i was hoping to see 900 hp. I got 926hp, and the vacuum pump was only pulling 2 or 3 inchs .

[chevy art]

it was around an 8 thousandths coating. what happened was i was having the 400 block freshened up. it was a 30 thousandths over original build, but the bores were all slightly different in size and maybe not parallel, so the engine builder honed the block to get the bores the same and thy came out to 40 thousandths over and now had all the bores the same. i got new dykes rings for it (40 thousandths over) and had the pistons coated to fit the rebuild(this was discussed by my engine builder and the guy a 2 line coatings). that is where this build stands now and that is why i am just asking questions about this product. thanks Art

[HDBD]

I use many KB forged pistons with line2line (L2L) coatings. I also have used Swaintech PC9.

L2L allows taking a worn piston and or bore (after honing), within reason, to be run when their directions are followed. The build up can be as little as .0007 and as much as .020". Measure the metal before coating at the gauge point. Add in the clearance required by the piston manufacturer and application, or greater if required to clean up the cylinders honing. Have L2L add enough build up to get to 0 clearance over the coating. The piston should slide in with a little resistance. If more clearance is needed use a Scotchbrite pad by hand on the skirts at the tight spot to get the piston to fit well. Follow their instructions for break-in. It will take a little longer to get the pistons to find their happy place than what it typically takes rings to break-in alone.