does anyone know where i can recoat my rotor housings?

i read on some thread that someone had their housings "hail coated"

i want to get mine coated to flatten out the lips on the edges of the housings

 

Are you rebuilding your engine? All of these procedures (which I think you mis-read heard wrong) require you tearing your engine apart and rebuilding it. Not a task for the beginner... Just FYI.

There are places that will put a new coating on your rotor housings... but, nobody really trusts them. I believe pineapple racing does it and has a "perfected" technique. Most people buy new housings if they want a better housing. Another option is nitriding. Its a method of rehardening the surface of the housing.

The lips on the housings I can ONLY imagine are referring to the exhaust ports.... lots of people when they port their engine will add a bevel to the edge of the exhaust port to possibly prevent an apex seal from catching and breaking.

Good luck?

 

I think the lip he is referring to is the groove left by the apex seal (the small piece), on the edge of rotor housing

 

o sorry, yes i do have my engine dissassembled and my rotor housings in the garage.

The lips i meant was the chrome flaking from the sides of the housing face and the groves made on each side of the housings surface.

 

http://www.jhbperformance.com/products/rotorhousing.php

 

Before considering JHB take a look in the Good Guy/Bad Guy section of the forum. JHB has terrible customer service, people have received housings back that were NOT the ones that were originally sent to JHB. Someone sent in ported housing and got someone elses stock port housing back. That guy then had to port the housings again and the JHB coating isn't the easiest thing to port thru. I don't know about you guys but that would **** me off immensely. I had contemplated sending 3 late D series 20B housings to JHB but after reading about them in the GG/BG section I dunno if that will ever happen.

 

Although it would **** me off if I sent ported housings an got stock housings back it could be an honest mistake... Alot of times when a company does a lot of one kind of work like transmissions, rebuilt engines, etc.; they will have some finished products sitting on the shelf... When they receive the unfinished product, they begin working on that product... Meanwhile, they just take the finished product off of the shelf and send it back out... This saves a lot of time... They may have done this and not realized what they where doing...
I have never used this company and am not really standing up for them... I am just offering a possible answer to why the guy got someone else's housings... I personally have heard through Pineapple that it is bad to buy resurfaced housings... I would not do it...

 

JHB is the only place that i know of that does the coatings, and yes check the good guy/bad guy section first before ordering yto know what to expect.

about sending out unported housings vs stock port housings, that is a pretty lame excuse for product swapping. they have to initially inspect the housings they were sent before they would send out a set of finished housings to make sure they won't get stuck with junk housings and at that point they would have obviously seen that the housings were ported. if they make it habit to just do parts swaps then they really should make it policy to not send parts you expect back or expect that they will have a number of pissed off people on their hands.

 

What about NSC coating? (Nickel Silicon Carbide composite)

I hear its pretty good and i found a place in Canada that does it in manitoba.

http://www.mt-llc.com/technology/index.shtml

 

NickelSil coating has been used for 2 decades in 2 stroke motorcycle engines, however i do not think it would be able to stand up to the abuse in rotary engines. in piston engine applications the bore does not take a lot of lateral abuse like there is in rotary engines.

 

Has any member used the recoated housings from JHB? I remember when they came out they claimed alot better housing life.

 

but still stock rotor housings are chrome plated, and NSC coating is 2 or 3 times stronger than chromium. So if chrome is subjected to lots of lateral abuse used in stock rotor housings and is weaker than NSC shouldn't NSC be better?

 

Our housings aren't just chrome plated, its some other nickel alloy (blanking on the exact name right now) that is super hard. The way I see it is that if it can last several hundred thousand miles, its good enough for me.
As for JHB, Blake at pineapple swears buy the Cermet coatings they do, but I don't know how much you can trust his opinion since he profits from sending housings to them. I have mentioned it to another engine builder I know and said to stay away because there have a been a few instances where the motor was torn down after 10k miles and the coating was coming off. I think I saw something about it gg/bg, but I dunno.
For me, when I do my "good" rebuild I am just going to get brand new housings from mazda. If you race/auto-cross your car you can get them for a little cheaper through www.mazdamotorsports.com

 

not to support or deny anything but just because someone found the coating flaking off doesn't mean "the process" is a bad thing. If anybody doesn't do the coating properly it can fail. We DLC coat some of our engine parts for our race engines, we had reliability issues using one of our providers. The DLC coating would start flaking off after about 15-20 laps in to an endurance run on the dyno. We switched to a new DLC coater and havn't had a problem since. Some of the parts we where replacing every race from our previous supplier we now run for several races and even then only replace them because we are paranoid about metal fatigue after so much abuse even though dimensionally they are good as new.

I'm sure the same goes for Cermet or NickelSil just because someone took appart one engine and it was flaking doesn't mean it's a bad thing, it's more likely someone skrewed up somewhere. Much of this technology originated fromt the aerospace industry and I don't think they are going to risk running a coating that may flake on a turbine spinning at supersonic speeds.

 

From what I've heard thats exactly right, Kyrasis6. I wasn't meaning to say the the process it bad, just that JHB might not be the best at it. For all I know the stuff with JHB was early on and they have since fixed any issues they have, I dunno. Its just that the cost savings is very small over new housings. I can get brand new housings for a little over 80 dollars more than having them resurfaced at JHB. ($392 vs. $308) When you figure in the price of shipping them to Canada and back, there's even less of a price advantage. For such a small amount of money saved, why risk getting something that could potentially fail?

For those wondering about the price of the housing, you can get the rear s4 turbo housing for $392 and change from mazdamotorsports.com if you are registered with them. The rear housing of an s4 turbo is actually cheaper that the rest of the FC rotor housings. It will work for NAs but you have to plug the coolant feed at the top (or is that on the front rotor...) plusyou don't have to grind out the baffles to port the exhaust.

 

Not to jack your thread but where would be the most trusted to buy brand new housings? Need 2 for my rebuild.

 

Kevin Landers was the one who originally found the bad batch of rotor housing coating by JHB and i would trust his findings on it, though he admitted it could have just been a bad batch and an isolated instance but JHBs poor track record also showed that not to be the case. be very weary when dealing with JHB.



only one way to find out right?

 

yep i think i will do it cuz right now my housings have about a .5mm grove on the sides, and i want the surface to be atleast flat

 

That's pretty deep. What did the corner seals look like when you pulled it down? It's worth giving it a shot I suppose. I wouldn't use a new rebuild kit on it at first though. Throw something together from old stuff and pull it down after 1000 miles or so. You should be able to see some signs of pre-wear if it isn't going to work. Wouldn't want to jack up a new kit by experimenting.

 

what do corner seals have to do with rotor housings? you mean the corner peice of the apex seals?

 

Yea the round pieces at the corners of the rotors.

 

ya the "round pieces at the corners of the rotors" or corner seals looked fine with no odd wear. But i don't think i had any role in making the groves on the sides of the rotor housings, which is probably the corner pieces fault

 

I was told by JHB themselves that some VERY large name builders also had bad batches of housings, I was just the first to use and report them.

I now have some JHB cermet B housings on the shelf and would be willing to sell them outright with no core exchange if someone were interested, at about the same cost as shipping to jhb/jhb's charges/return shipping on your own housings, plus no risk of 6 month turnarounds or losing your existing housings. I might even do a core exchange for credit if your housings are decent. I have checked a couple of the last batch I got and they appear to be flat and useable this time. One set is already ported. Contact me with your needs and I'll let you know what I have.

 

Bringing this thread back from the dead. was researching NSC and apparently it can be used in rotary engines.

"Nikasil was introduced by Mahle in 1967, initially developed to allow rotary engine apex seals (NSU Ro 80 and Mercedes C111) to work directly against the aluminum housing."

 

"Nikasil is short for NIckel Silicon Carbide. Silicon carbide is a very hard ceramic (much harder than steel) that can be dissolved in nickel. The nickel solution can then be electroplated onto the aluminum cylinder bore. The piston rings will then rub off the exposed nickel, leaving a very hard layer of silicone carbide to protect the aluminum piston from direct contact with the aluminum cylinder. With this setup, the engine tolerances can be much tighter for better performance."

Sounds like the nickel is only used to allow the mixture to be electroplated on. What about spraying on straight SiC with plasma sprayer?