What's the latest opinions on cermet?
 

I have a spare set of housing that are just worn out and was thinking of getting them coated with cermet. I think JHB is out of business, does anyone know of a place that does good work? I am sure like everthing else, the way its applied has alot to do with how it performs and how long it holds up. I have read alot of good things about it but never heard any long term results on an engine with it. Does anyone know how well this holds up? Its got to be something to it the 787B used cermet housings.

Comparing the mazda factory-backed 787B to some aftermarket process run out of a shed isn't the best idea IMO :)

As an engine builder with dozens of worn out rotor housings sitting around I've looked into it and based on all I've read determined that I did *not* want to bother.

I'd say you have a nice set of bookends if you clean them up a bit :D

It is disappointing that Cermet isn't a viable option. I worry about the availablity of new housings in the future.

Yet.

Someone will figure it out.

And they will be wealthy, very much so.

I've seen some cermet housings that are nearing final testing.

It was impressive.

In fact I may be beta testing a set here soon.

Keep us posted on the results. I saw a thread a couple of years ago from Pineapple Racing where they had put together a few engines that were cermet and they were all over 120psi. Never heard anything else tho. I may be wrong but didn't the cermet housing for the 787b come from a US supplier?

Has anyone checked if nikasil is a viable option?

I just tore my engine down (it had cermet B coated housings) as it lost compression. The coating as we are finding out is not compatable for long duration with anything but cermic apex seals. I had ALS seals and they were significantly abraided after less than 3000 miles. Of note is the compression loss was equally degrading on all six sides over time so it was not a problem with one single element. Of the few engines that are running the coating seems they are requiring rebuild after about 10K miles. I'm putting stock housings back in and new ALS seals as I write this.

Wow thats bad. Who did the coatings?

Need to correct an error the housings were cermet A coated. JHB did the coating. Some good info in this link: http://www.jhbperformance.com/downlo...ch02cermet.pdf

The ALS apex seals are not the hardest of metals and do not meet the criteria of greater than 60 Rockwell required for compatibility with the cermet A.

Bummer.

Thanks for the info!

There is almost nothing out there for experience based application data from the private sector.

Thanks again!

Was there any degradation to the cermet coating on the housings? any flaking or the like?

No degradation or flaking; the only damage was some minor scratching from the seal material rolling over.

https://www.rx7club.com/picture.php?...ictureid=24583

If the Cermet is so durable why doesn't someone just use this a throw some ceramic seals in? What I don't understand is why didn't you put it all back to gether and just use ceramic seals rather than using all new housings and re-ordering the super seals? Wouldn't it been cheaper to do it that way? And we'd have a good test.

I think Goopy Performance does this...

I dosnt say it on there site, but i know people who have had there housings "repaired" by them. I am unsure if it's with cermet coatings or something else? Anyone know?

i'm curious. is your objection with the quality of work done by companies/operations (such as JHB) or is it with the overall expense? i ask, because until i just read that they are out of business, i had planned a future project with a Cermet/ceramic apex combo, and the sole purpose of that was to build a fairly mild engine and see how long it lasted as a daily driver. obviously it would not be cheap, by any means, and i understand that it ceratinly would not be justifiable for the average person rebuilding an engine, but based on what i've read it seemed like a promising idea.

so i'm just curious where you're coming from. is it the fact that it's more efficient to just buy new housings and rebuild on "more conventional" apex seals or if it was something you came across that led you to doubt the workmanship of a shop offering a Cermet option?

From what Dr. Iannetti told me during a phone conversation awhile back, Cermet coaled housing should only be used in an NA application due to Cermet's thermal retention properties. This causes pre-ignition to be more prevalent. And yes ceramic seals should really only be used with Cermet house if longevity is your goal. Had a cermet/ceramic motor last for over 10K miles before it blew up from other circumstance.

JHB cermet B housing was used on that motor.

JHB "recommends"(saw it somewhere) the use of OEM seals with their coatings.