Swain PC-9 Piston Coating

[robertg]

Is this just a break in coating like a Vertex piston, or is it more permanent?

[MICK]

Permanent. Good stuff.

[robertg]

I found this on the Swain web site.
Unlike the simple “break in” skirt coatings that are now being offered by piston manufacturers and OEM’s, Poly Moly™ is designed to be a permanent solid film lubricant coating. PC-9™ is Swain Tech Coatings' latest generation of piston skirt coating. PC-9™ has the same low friction properties of Poly Moly™, but PC-9™ is even tougher.

I wonder how much weight it ads to a piston? I think I am getting my crank balanced at Surf & Turf and they need the weight of the piston. I doubt if it would be more than a gram or two?

[MICK]

Well beings how STR is going to have your piston on hand to balance your crank it shouldn't matter. If it's a little heavier they'll make the necessary adjustments, if it's alot heavier...you get the idea.

[robertg]

STR said they don't actually need the piston, just the weight of it with the rings, circlips, pin, and bearings. I have two pistons, and one is four grams heavier. I'm going to have to call then again and see if it matters.

[MICK]

I figured as much, but this is how I see it...

You're paying good $$ to have the crank balanced. It ain't cheap, and god only knows your crank could be pretty well balanced already. Don't pay the money if it's not going to be done 100% correctly. Send STR the coated piston, you wouldn't send a jug off to be bored without the piston would you? Simply tell the machinest 90mm? No you wouldn't...I hope. I see this as being no different. Your scales and theirs could be off just slightly, they may misunderstand you over the phone or the tech could misread the phone operators hand writing. When balancing a crank comes down to grams, off just a couple and you paid for nothing. Let the tech use his own scales and read his own hand writing

[robertg]

I know my weight will be right because that's what I do for a living. My problem is first I have to send out the piston for coating, and I am getting the cylinder plated so they definitely need the piston for that. None of these people ship to Canada so I have to get everything shipped to my USA address. I guess the turn around time must be shorter this time of the year, but it won't be until spring until everything is done.

[seanmx57]

Send the piston and crank in 2 boxes. Just ask Stevo to send the piston to the plating guys. I would hope he is willing to take real good care of you with all the work he's gotten in the last year from 500's.

I bet the PC-9 doesn't weigh enought to matter. From what I'm currently understanding changing the piston weight after the "balance" will just change the sweet spot where it's perfect to another rpm. In this case a gram or 2 wouldn't change the RPM enought to notice.

I'd do the head and piston dome as well with TCB.

powerseal USA will plate that cylinder with a torque plate if you provide it.........Might as well get it nice and round.


I guess you didn't sell that sweet bike?

[robertg]

Send the piston and crank in 2 boxes. Just ask Stevo to send the piston to the plating guys. I would hope he is willing to take real good care of you with all the work he's gotten in the last year from 500's.

I bet the PC-9 doesn't weigh enought to matter. From what I'm currently understanding changing the piston weight after the "balance" will just change the sweet spot where it's perfect to another rpm. In this case a gram or 2 wouldn't change the RPM enought to notice.

I'd do the head and piston dome as well with TCB.

powerseal USA will plate that cylinder with a torque plate if you provide it.........Might as well get it nice and round.


I guess you didn't sell that sweet bike?

I didn't really try that hard to sell it. I'll sink another couple of thousand more in to it this winter and probably loose interest in again in the summer. Still a lot cheaper than owning a snowmobile.

I'm going to send my cylinder to Eric Gorr to get plated, and he's going to machine the base down also. If I get the piston coated, I'm going to get the dome done also. I never thought about the head.

[seanmx57]

Good luck getting EG to plate it if it's the stock iron sleeve. AP sent jug to EG within the last 6 months and EG couldn't get the coating to stick.

powersealUSA and millieum would be my fist 2 choices in that order only because powerseal will do it with a T plate.

[robertg]

Does Eric Gorr actually do the plating himself? I wanted to use him because he is pretty familiar with the CR500.

Good luck getting EG to plate it if it's the stock iron sleeve. AP sent jug to EG within the last 6 months and EG couldn't get the coating to stick.

powersealUSA and millieum would be my fist 2 choices in that order only because powerseal will do it with a T plate.

[seanmx57]

I can't remember if it's US chrome or some other outfit that he works with. I just would NOT trust my jug to some one that had "problems" getting the nikasil to stick. I'd want someone familar with nikasil work on an iron sleeve........

CR500's are not complicated. powerseal USA does machine work as well as millieum I think. I just like powerseal because they used my T plate for the bore/hone process even though they told me it was a waste of time.

[Roostius_Maximus]

call Nick JR at LA Sleeve, he knows how to coat the cast liner, and can refer you to the material and person to do it. tell him u were talkin with me about the 500 stuff, should get a laugh