Exhaust ports/Nicasil plating

[Bob Monkhouse]

I\'m just about to start porting our Grants engine and I\'m a trifle concerned about chipping the nicasil lining on the rotor housings. When I\'ve done these on bikes I\'ve usually had them plated after porting work is finished. One of the things I have done when working on a plated barrel is chamfered the port and then used an alu cut burr up to the chamfer. Whats the advice from anyone who has done work on rotor housings?

[Mazdarotaryparts]

Hi Bob,

I would say you have answered your own question sir :cool

[Bob Monkhouse]

My Hero ****************

[Carl]

The plating on the Mazda rotor housings is Chrome,not Nicasil.
Nicasil was used on NSU and Norton rotary engines.
You will find that you don\'t need to recaot,just blend and bevell particularly the closing parst of the ports.
Regards
Carl

[clive]

The plating on the Mazda rotor housings is Chrome,not Nicasil.
Nicasil was used on NSU and Norton rotary engines.
You will find that you don\'t need to recaot,just blend and bevell particularly the closing parst of the ports.
Regards
Carl

You will have to forgive Bob, he\'s a two stroke modifier :Giggle

Come to think of it though many two stroke bike companys have offered Nicasil as an upgrade over chrome or cast bores as being much more durable and from memory less friction so I wonder if any tuner has tried it on Mazdarotarys

[Bob Monkhouse]

I didn\'t think anyone would still be using chrome these days, nicasil has been recognised as a better coating for quite a while. Now we are on the subject, does anyone offer a repair service to damaged rotor housings? I should imagine they are a bugger to repair and reface though it would be interesting to find out if it can be done. Who gets the job of honing them!!!!!

[leon]

Bob, i\'ve never heard of anybody repairing housings before, on the US forums or UK that have been shot.

What would repairing a housing in theory entail?

Striping back the chrome plating to remove the damaged sections then resurfacing it within spec.  . .  If mazda can chrome them i cant see why they are -not- repairable but is it worth the time and money?

[Bob Monkhouse]

Dunno, damaged bike barrels are regularly repaired. First by de-plating then weld repaired then re-plated and honed. To do a rotary would obviously be more difficult but I don\'t see why they couldn\'t be done.Cost wise, a bike barrel is something like £100 ish to repair. This is a third or less the cost of a new one. Maybe its not cost effective to do the rotary housings.

[Carl]

The chrome that Mazda use is far superior than what either NSU or Norton did and works exceptionally well with the hardened apex seals that Mazda supply.
The chrome is not just plain chrome,there are tiny channells in it to retain oil for lubrication,and teflon coating in the ones from the 1980\'s and Graphite coating in the 90\'s till now,so quite an involved product really.
Regards
Carl

[Bob Monkhouse]

I had a bit of a discussion with El Presidente about apex seals this morning and,with the two stroke experience I have, piston rings in most-not all- japanese piston kits come with plated cold drawn wire instead of the heat treated CI rings. You can literally tie these things in knots and they won\'t break(they aren\'t much use after doing that though)! My thoughts are-do after market apex seals come similarly improved. This is(our Grants RX) the only rotary I have ever done anything with and I am at present, very low down on the learning curve( not to mention ****ting myself if I get anything wrong when I\'m putting the engine back together). I\'m also in need of some instruction on setting the car up when its back together, thats why I went to the expense of buying a gas analyser( a proper one not a gunson thing), but thats another thread I\'m sure.Thanks for the info Carl, it means I know a bit more than I did-More than Yesterday but Not as Much As Tomorrow( thats a famous quote by  er............ Me)!!!!!

[Carl]

I am happy to help you with any questions you have on your rebuild,just give me a buzz in working hours.
Regards
Carl