Nikasil liners with Chrome rings

Many people do not know that there are two different types of chrome rings. "PVD" infused chromium is fully compatible with Nikasil lined bores. But chrome plated rings are not compatible with Nikasil lined bores. The rings made by Wiseco and JE pistons are fully compatible with Nikasil lined bores because they are the "PVD" infused chromium variety. "PVD" stand for "physical vapor deposition".

I don't have anything to do with chrome plated rings. I only use the "PVD" infused chromium variety. This is important info because Norton cylinders are now available with the Nikasil lined bores and some people are confused about ring compatability.

See confirmation about "PVD" chromium infused rings below:

From NPR of America - "Gas nitrided steel is OK, also PVD chrome intrusion (chromium nitriding)". This info confirmed with “BG” at NPR of America ph, (562) 207-6882. Also confirmed with Keith at total seal. Also confirmed by the many thousands of Jap, Italian and German bike owners who are running PVD chrome rings in their Nikasil cylinders.

Nikasil bores and other lined bores can now be easily repaired in Europe if anyone is interested.

n

Madnorton said:

Nikasil bores and other lined bores can now be easily repaired in Europe if anyone is interested.

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by who?

E.g. RAM (of Moto Guzzi fame) at como/Mandello del Lario, Italy.

Kind regards

Christian

Btw: they always were repairable in Europe fwiw know.

Nikasil cylinders is not something I find needed. The +.020 bore on my ‘72 750 was done in 1998 and have +40,000 miles. I just bought a bore guage. Piston to bore clearance is still .004” to .005”. Maybe the cost of Redline oil has been worthwhile.

ILLF8ED said:

Nikasil cylinders is not something I find needed. The +.020 bore on my ‘72 750 was done in 1998 and have +40,000 miles. I just bought a bore guage. Piston to bore clearance is still .004” to .005”. Maybe the cost of Redline oil has been worthwhile.

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Its about cooler running cylinders and tighter clearances. With graphite coated pistons you can install the pistons with .002" clearance to the coating.



I have alum cylinders with iron sleeves and the leak down test is at about 1 after 50,000+ miles - even so I would expect less wear and more longevity with Nikasil bores as shown below.

Got it….thanks. This is for Commandos that are raced? For me I think I’ll be dead before my cylinders wear out.

ILLF8ED said:

Got it….thanks. This is for Commandos that are raced? For me I think I’ll be dead before my cylinders wear out.

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Street or race. Dead or alive.

Not too long ago I pulled the heads on the Vin at 55,000 miles from the 2003 top end rebuild. The cylinders had a max of 1 thou taper.
Hastings Piston Ring Co. recommends a rebore at anything around 12 thou max taper.
If I can get back to doing about 4 or 5 thousand miles per year, it should take about 120 years to get to the Hastings number.
I'm thinking I'll do a pre-emptive rebuild at the sixty year mark.
I'll be 126 years old and really won't want road trouble at that point.
Same with the Nortons, will throw all new stuff in at that sixty year mark, need it or not!

Glen

I just called Wiseco and JE (again) and now they are telling me that XC chrome faced top rings are compatible with Nikasil bores. Chrome faced rings do seem to work well with Nikasil and a couple AHMRA bears racers have been running them for years with good results (as in wins). But NPR (nippon) who supplies their rings says that XX rings are the prefered rings to use on Nikasil and XX rings are available on request. The XX rings have a gas Nitrided stainless steel top ring and are not chrome faced.

My guess is that what Jim is trying to do here is make sure he has rings and pistons to suit all available Norton barrels, so I think what he is saying, is he is contacting suppliers to identify any issues.

Read in context with the words from a supplier of Nikasil plated barrels!

The argument is over whether or not chrome faced rings can be used in Nikasil bores. Wiseco and JE say yes and send them out to their Nikasil customers. Andy of TGA says no. Total seal and NPR (Nippon rings) have given me conflicting info about which rings were PVD which has just been straightened out. The consensus is that Nitrided stainless steel XX rings are the best available choice but there has been no actual evidence that I know of showing any problems with the chrome faced XC rings.

In the real world of racing - Norton twin riders Matts Hall, John Snead and Stan Keys have all been running chrome faced rings in Nikasil bores with tight clearances for years with excellent results (see photos below).


John Snead




Matts Hall




Stan Keys