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Cermet Housings? Worth it or not?

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Old 12-13-07, 04:44 PM
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Wrkn Toyota, Rootn Wankel

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Cermet Housings? Worth it or not?

I've seen some members saying that the JHB Cermet Coated Rotor Housings were a raw deal and worth crap...

I haven't tried it myself... but I am very interested in the idea of getting them in the future for an engine build.

So I figured, let this be a place that we can post our opinions and experiences with the Cermet or coated housings?

You know for the better good of all us rotorheads?
Old 12-13-07, 05:11 PM
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I had a 12a 1/2 bridge done with cermet b. engine needed to be torn down at 10k km due to coolant loss(not related to cermet coating, a pinched oring -it was built poorly and it will be the last rebuild That I buy, know i have the tools and the knowledge and experience with rebuilding), never reasembled because of major flaking of the cermet in both housings, from my one experience I would not get them coated again. I hope this was just my experience with the stuff. I had it chose to go cermet after doing resaerch that pointed to it being a good choice.
Old 02-27-08, 07:05 PM
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Wrkn Toyota, Rootn Wankel

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Hmm... I still am interested in having this question explored...

So...

BUMP!
Old 02-27-08, 07:11 PM
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I have a set of 12a housings.

Lets hope I can build the engine soon and let you know.

I posted pics in ROTARY PERFORMANCE
Old 02-27-08, 07:15 PM
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Wrkn Toyota, Rootn Wankel

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Alright! thanks Xlr8! I will definetly like to know how that works out!
Old 04-08-08, 12:17 AM
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Just deciding to bump this thread because I never really got all the information I was looking for and I was wondering if Xlr8 had any updates...

so if you guys have any input on the benifits or downsides of cermet housings please post!
Old 04-08-08, 03:38 PM
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The downside of cermet housings is the rediculous amount of flaking after a very short amount of time.
Old 04-09-08, 10:13 AM
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no updates yet.

Porting
Old 04-09-08, 03:57 PM
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Wrkn Toyota, Rootn Wankel

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Aww!!! Hurry up and coat it! my future Renesis depends on it! LOL

:P
Old 04-09-08, 05:10 PM
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I will step in with opinions and heresay.

Firstly WHY do you want cermet housings. They are expensive and from looking around the longevity seems to be a HUGE issue.

Mazda designed their housings out of specific materials and did a dam fine job IMO.
I would think you would better spend less money by buying new housings directly from Mazda. But this is just me.

Alot of guys with various engine configs run high rpm, high boost, thrash their engines to **** and still the mazda components hold up decently well. I think they speak for themselves, where as the cermet coated ones do not.
Old 05-28-08, 01:19 PM
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i've been reading around about people's experiences with the jhb coatings and this is the trend i'm seeing:

12a housings that are coated have some rate of flaking and make some very upset 12a costumers of the coatings

however, 13b and 13b rew housings that are coated do very well and make a lot of customers very happy.

so here's my educated guess on the whole "is cermet good or bad" topic:

to my knowledge 12a housings are aluminum and 13b rew housings are iron. aluminum expands much more than cast iron at higher temperatures. cermet is very hard but brittle too. so it's possible that:

aluminum coated housings are much more likely to "flake" especially when their owners run into coolant problems like Clearkut's did.

cast iron coated housings are less likely to "flake" because cast iron doesn't expand much, even when its overheated, so 13b rew coatings have a much lower frequency of "flaking"

in fact, the only instances of flaking i have read about were from 12a housings. another thing to note is that i have only read about flaking issues from cermet b coatings not cermet a or x coatings.

again, this conclusion is derived only from extensive searching.. i have no first hand experience with the stuff and could be wrong.

if anyone has any experience or evidence to prove otherwise, PLEASE SHARE IT! i am looking into getting coated 13b coated housings myself but waiting to hear from more ppl's experiences.
Old 05-28-08, 02:23 PM
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Yeah, I am looking more for 13B applications... particularly the Renesis, but I think that the housings are the same material as other 13B's...

This is mostly research for a future swap I am working on. I heard both good and bad about cermet coatings so I was curious what the deal was.
Old 05-28-08, 02:24 PM
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Umm to my knowledge all mazda rotary engines have aluminium rotor housings... Correct me if im wrong
Old 05-28-08, 02:33 PM
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From what I remember reading about the Rotor housings... They are constructed out of aluminium and then have a steel insert that is "cast" into the inner part of the housing which is then coated in chrome.

I am not familiar with 13B housings though...
Old 05-28-08, 02:44 PM
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Originally Posted by BEX
i've been reading around about people's experiences with the jhb coatings and this is the trend i'm seeing:

12a housings that are coated have some rate of flaking and make some very upset 12a costumers of the coatings

however, 13b and 13b rew housings that are coated do very well and make a lot of customers very happy.

so here's my educated guess on the whole "is cermet good or bad" topic:

to my knowledge 12a housings are aluminum and 13b rew housings are iron. aluminum expands much more than cast iron at higher temperatures. cermet is very hard but brittle too. so it's possible that:

aluminum coated housings are much more likely to "flake" especially when their owners run into coolant problems like Clearkut's did.

cast iron coated housings are less likely to "flake" because cast iron doesn't expand much, even when its overheated, so 13b rew coatings have a much lower frequency of "flaking"

in fact, the only instances of flaking i have read about were from 12a housings. another thing to note is that i have only read about flaking issues from cermet b coatings not cermet a or x coatings.

again, this conclusion is derived only from extensive searching.. i have no first hand experience with the stuff and could be wrong.

if anyone has any experience or evidence to prove otherwise, PLEASE SHARE IT! i am looking into getting coated 13b coated housings myself but waiting to hear from more ppl's experiences.
Have you really compared a 12a rotor housing and a 13b rotor housing?
Old 05-28-08, 03:38 PM
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Recoated are so close to new$$, so I just bought new
Old 05-28-08, 03:59 PM
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some peoples kids man...*sigh*
Old 05-28-08, 04:20 PM
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Originally Posted by yetterben
some peoples kids man...*sigh*
Waz dat suppozed ta mean?

(yes I did the ghetto teen speak on purpose :P)
Old 05-28-08, 09:21 PM
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Originally Posted by EpitrochoidalPower!
Umm to my knowledge all mazda rotary engines have aluminium rotor housings... Correct me if im wrong
the 13b rew rotor housings are aluminum .. i was incorrect about that. i probably was thinking of a portions of the rotors themselves. 13b rew rotors have a cast iron lining in them i think.

however, the theory behind why cermet coatings might "flake" is the same... if the aluminum housings get too hot they will expand more than the coatings making the coatings flake.

also, i've heard that stock chrome lining "flakes" too. so those of you who have had cermet flake, have you run stock housings in the same conditions (i.e. coolant loss and overheating conditions, etc.) to know if cermet coatings are any worse than stock linings?
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