De-glaze of nicasil bores

[MartinB]

Hi Guy,

I need to de-glaze the nicasil bores of an engine I am currently building in order to fit new pistons and rings and wondered if I need to use any particular grade/material of flex hone (or similar)?

Thanks

Martin

[Guy Croft]

I don't know enough about this to comment substantively, sorry.

My guess is that the coating - if honed - will be removed completely and the matching of rings to coating is very critical.
The only people I know of in the UK who might be able to advise constructively on the overhaul might be Poeton Coatings , but they may well say the liners need to be rebored and recoated - and no doubt will want to know about your rings and their suitability for the new coating - which may well not be Nicasil, I don't think they use it.

http://www.poeton.co.uk

GC

[MartinB]

Thanks Guy,

The new rings are to suit the nicasil bores so shouldn't be a problem.

I will see what I can find out and post it here.

Martin

[robert kenney]

Nickle Silicone Carbide coating can be honed but because it is extremely hard requires diamond matrix hone stones to machine hone. This is if applied on steel. On aluminum I would NOT hone at all. The bore must be free of ridges or steps ETC for machine honing. I would recomend hand deglazing only in any case.

This process is used on most air cooled aircraft engine cylinders in stead of nitriding and under those circumstances I only hand deglaze to speed ring seating but it is not required. This also opend porosity previosly covered by varnish from running and helps carry and hold oil during break-in. This would be more critical on aircraft due to severity of service and not so on water cooled in my opinion.

For hand deglazing, green Scotch Brite seems to leave a nice finish. I have also had good results with gray. Again, very light and even and, with some light oil or solvent then follow a proper cleaning regime to remove all residue.

HTH
Robert

[MartinB]

Guy,

I have found that Flex Hones are available for nikasil bores, they are aluminium oxide instead of the normal silicon carbide. I have ordered one and am waiting for it to arrive, I will post results.

Regards

Martin

[Chris S]

I use the Flex one . A few seconds on the coating is enough to bust the glaze . This nikasil stuff is TOUGH. Use a bore guage to check the result after if you're worried. The bikes I work on all have nikasil barrells. It rarely goes wrong.

Chris

Edited by GC