Power Seal Nikaseal?

[channelcat]

PowerSeal says they can Nikaseal coat cast in iron liners. send them cylinders, striped of valve rod tubes,
and include pistons, and rings, and they will Nikaseal the cyinders to restore the ring end gap to whatever tolerance you want. for $220/per. My cylinders have so much wear I can feel it with my fingers. ring end gap is over 50% of spec. Bob Browder (?) said those production years, 77-78 could have have porosity in the casting, recomended not boring, and if a guy who could make money on the process says dont do it, I'll listen.
Bike runs ok, 50 mpg on the highway, but like 110 psi.
Anyone have experience with PowerSeal ?

[Strong Bad]

Porosity of a casting and the chance of increasing the porosity by boring is one thing, plating a cylinder with Nikaseal is another. Even if the casting was porous, one would expect that the Nikaseal plating process would fill the pores.

[caponerd]

I had contacted one of the companies that does nickasil plating last year to find out about the possibility of using nickasil plating to restore tolerance of worn out cylinders for my Royal Enfield vs sleeving.
One of them said they'd be willing to try it (might have been Power Seal), but they emphasized that the thickness of the plating would be limited.
They couldn't bring a worn-out + 0.040 bore back to standard size, but could return it to plus 40.
The price is higher than sleeving, but the advantages; better heat transfer from the piston to the cooling fins, and the longevity of nickasil (my R100RT is at 130,000 miles on the original pistons and bores) make it look like a better option.

Uh, hey, are you talking about a '77-'78 BMW? Woudn't it be easier to find a pair of good nickasil lined cylinders from a newer model?

[F_Sahms]

Two major advantages of nicasil are that (usually) it plates right on alloy, making heat transfer better, and it allows tighter clearances over iron liners. Plating an iron liner achieves neither.

If there's a later alloy cylinder that will work in your motor, get a pair of junk ones and have them nicasil plated. Millennium can do them for $200/hole.

[mark1305]

You may want to get a second opinion from Millenium Technologies. Never used them, but if/when I need Nikasil plating they are at the top of my list based on lots of feedback I've read over the years.

Don't know how thick they can compensate for, but talking with them once (and IIRC) the max scoring that can be restored is something like .007" deep on existing Nikasil cylinders. Don't hold me to that number, though.