-xlr8planet-

iTrader: (3)

First of all I have to thank Marc at JHB for all the help he provided. Without him I probably would be a long long long long way from having a running 7. Marc really went the extra mile to help me out.

I got these in 2005, but due to the wonderfull world of south american customs restrictions, I got them ........ yesterday

Before you guys mention it, one of the housings looks brand new, the other does have a few things but nothing that could compromise compression.

This 12a housings seem to be from a 79 or 80 engine right? Mine is 81 and Im not familiar with these. I know I should plug the holes for gas recirculation, but... should I remove the sleeve? Im not sure how to port these.

That brings another question: can you port coated housings? I dont want the coating to flake

t-von

iTrader: (8)

I remember reading in the past that is was better to port before you have them coated. Things could have changed since then.

couturemarc

Marc here, Your customs in Argentina must be really awful!! At least you did finally get your parts.

You can port a cermet rotor housing without any problems. The only reason we have cautioned people about this is that its not like porting chrome. The cermet is harder than chrome and regular die grinder tools will tend to break and chip the coating rather than "cut" through it. This is why we have to use Diamod stones and tooling to finish these housings. You should use a diamond burr if you can to port cermet housings, anything else, including carbide will not be able to cut throught the coating.

Some other forum members have had success with a variety of other techniques as well; i believe i recall Kevin Landers saying he used a sanding drum and it worked quite well?!?!

All in all you just have to take your time and realize that what you are trying to cut is very very hard. Trying to force an agressive carbide burr on this material will cause problems.

As a side note i will be devoting more time over the next few months to trying to answer more of the questions on the forums, happy to help out where we can.

Latin270

Customs is a JOKE! I know guys who could have drove that to you along w/ tons of other things from Canada, through US, Mexican and C/S.American borders in about a week! lol Housings look goos BTW.

diabolical1

iTrader: (3)

question: which coating is that? A or B? those parts look great to me. i was going to caution against the porting now (vs. before), too, but i guess you can't get any more accurate than the horse's mouth. so as long as you can get the correct tools, port those suckers and post pics. damn, 2 years??? kinda made my 5 month wait for a flywheel seem petty. you, my friend, are hardcore. my brother ...

-xlr8planet-

iTrader: (3)

Marc!!!

I got the brochure you send with the housings and I will be making copies to take along with one housing to the Argentinian rotary shops I were able to find so far. Hopefully I might be able to send some bussiness your way.

I cant thank you enough for what you did for me.

If theres anything else I can do for you just name it

DarkKnightFC

Hopefully marc can chime in here. I am assuming he can speak for JHB. Have you had any complaints of the housings chipping or entire pieces flaking off EVER? Take for example the last part of this thread https://www.rx7club.com/showthread.p...66#post7342066

Chris

djseven

iTrader: (56)

Ive ported these with a sanding drum and it work really well. It definately takes some extra time to get thru the cermet coat. Buy lots of sand rolls because it will eat them quickly

couturemarc

Hey Chris,

Yes, happy to comment on whatever... especially when its asked in an objective mannor (thanks).

I have personally seen only 1 rotor housing flake any amount of cermet, ever. All in all we have had a return rate of less than 1% since 2004. This includes a bad batch of housings that occured in late 2005 where we were made aware of an issue and recalled the entire batch (this accounted for about 6% for that year). We halted production until the issues were worked out, this obviously caused some prolonged delays in orders and some frustration.

Of the pics from that link, one is familiar. I was personally contacted by someone claiming he had a JHB housing with a flake. I asked when he bought the housings, he did not buy them he bought a car that he was told had them. I asked if he knew who built the motor or who he bought the car from so that i could track down where the housings came from. No information was provided.

I asked the owner if he could send me pictures of the housings that would clearly show the surface so that i could asses the failure mode. I warned that housing damage that orrued from rotor to housing contact, apex seal failure or foreign debris would not be covered by our warranty. I also explaind that i wanted a point of reference in the pictures so that i could tell what part of the housing i was looking at, like a port or plug hole or something. So even though there was no reciept, he did not buy them or anything like that we still agreed to look at it. Fair right?

The pictures we got were very blury and poor, like from a cell phone or something. The housings were covered in oil and i could not see anything on the trochoid surface. I asked for better pictures of clean housings and these were never sent.

Cermet rotor housing fail differently than chrome housings. Just like ceramic apex seals fail differently than Mazda apex seals or other metal seals.

If a cermet housing gets hit by the rotor due to bearing failure or shaft flex, the coating will get scuffed like a chrome housing but sometimes it will also hit hard enough to fracture the coating. If the coating gets fractured it can flake. Make sense right!

Cermet is not AS pliable as a metal like chrome. It will give and flex very slightly but not the same amount as metal. If a rotor housing gets severly twisted this could also happen i presume (but i have never seen it happen yet).

It really appears that the kid that bought the car with the engine in question got screwed or just had bad luck. He perhaps got in over his head and got a car will all kinds of aftermarket goodies on it that he did not fully know how to tune. Either he or the previous owned damaged this engine accidentally or knowingly, who knows. Bottom line is that we would have considered honoring a warranty depending on the failure mode of the housings but the owner did not persue this option. Generally, but not always, this indicates to me that someone is simply testing the waters to see how easy it might be to get replacement parts for free. Once they find out that they have to send the housings in for inspection and that we WILL test them to find out why they failed they somehow then recall that it may not have been the housings fault and decide to save the shipping dollars. 99% of the time a legitimate claim will not be halted by a request for clear pictures of clean housings. Everyone, including myself would be pissed when facing a rebuild, and most of us have been there more than once. And when broken parts come out of an engine its obvious you should ask questions. Facts that we know for certain are that a flaked cermet rotor housing is 99% of the time evidence of another problem and almost never the root cause of a problem. Think back to all those old 12A housings that make good compression with half the chrome missing from them and these never broke any apex seals.

In most cases like this Chris there is more to the story when you scratch below the surface.

calculon

iTrader: (29)

Marc,

I'm glad that you are on here speaking on behalf of JHB. In my research, I've found very little info from the horse's mouth. Can you please respond to THIS THREAD? Presently, what are your expected turn around times supposing I wanted MY housings back?

Thanks.

couturemarc

Hi Ryan,

Happy to comment on this as well. To put it straight forward, turn around times are not fast for this type of CUSTOM process. Our original website stated 6-8 weeks, this was if everything went more or less according to plan. In some cases the parts would get done sooner but if something did not go right or there was a flaw we would ofter re-do the part and this would of course add time. Also, in the first couple years of offering this service we did not stock large quantities of raw materials, chemicals and what not as they are very very expensive. Same goes for diamond tooling, its very "finiky" to work with and expensive to replace not to mention the turn around time for custom diamond tools (3-6 months).

NOW we have changed operations to better meet the demands of 80% of our market and most of the readers on sites like this. If your rotor housings have not been doweled, peripheral ported, water jacket mods or anything crazy like that we offer stock housings that we have already coated in all 3 coatings that are sitting in inventory ready to ship. This means that you do not have to send in your housings or ship anything to us, you just buy cermet housings and then if you like port them for your needs.

We still do the custom housings and we are setting firmer start and finish dates for the batches so that we can give a much more accurate timeline to the customer. For example, we are trying to do 4-6 "custom batches" this year. Basically this means that if you send your housings to us just before we start that batch you can expect to get them back 6-10 weeks after.

We currently have hundreds of housings IN STOCK, so for most of you there is no wait at all, and to further simplify matters all stock is being held in California. This means that there is no longer any border crossing to get housings, no added taxes or duties or brokerage. We feel this system will address many of the concerns of our customers.

To summarize Ryan, we are planning a batch of custom housings to start mid Feb 2008. These customers would get the parts back around mid April 2008.

slo

iTrader: (1)

Where in California are the housings, I would love to come look at them in person.

couturemarc

Northern California

Unfortunately since they are not being held in our facility they are not available for viewing. I will be taking several high res. pics of some of the housings that we still have in stock in Winnipeg, i can post these if you like as well as some more high res pics of the used cermet housings and ceramic apex seals we have, is there interest in this?

impactwrench

Yes post pictures please.

couturemarc

Did you see the examples of new and used cermet housings we had on display at Sevenstock?? i will take some fresh pics and post them sometime this week when i can.

slo

iTrader: (1)

What I would be interested In, and willing to pay more for
(if reasonable).

Would be detailed, High res pics of the actual housings I would be receiving where I to purchase a set of housings.

DarkKnightFC

Thanks for your reply marc, I was certain there were some underlying things that were the cause. And it makes sense that the material is more brittle than normal metal. But thats usually the case with super hard material. I have a set of cermet A housings in my closet that I'm about to couple with some NRS seals and I don't want to end up breaking them because of a small chip in the face of the housings. They do have a couple of small imperfections but I bought them from Kevin @ RR and I trust his judgement.

couturemarc

i have a few pictures, its really hard to get good detailed pictures of these parts with the glare and reflectiveness. Going to try again soon after getting some advice on camera setting and such.

This one is a shot of a cermet A rotor housing with 80k miles on it using NRS 3mm 2pc ceramic apex seals;

http://i34.photobucket.com/albums/d1...arc/part07.jpg

Here is a shot of the matching rotor with ceramic thermal barrier coating from the same engine (80k miles)

http://i34.photobucket.com/albums/d1...arc/part21.jpg

something new we showed at sevenstock X, might as well show it here too since many have been copying it already... Here is a new cermet X rotor housing with an added 3rd, far trailing spark plug. This one also gives an idea of the finish of a new cermet housing.

http://i34.photobucket.com/albums/d1...arc/part15.jpg
http://i34.photobucket.com/albums/d1...arc/part17.jpg
http://i34.photobucket.com/albums/d1...arc/part16.jpg

NoDOHC

Marc:

What is the purpose behind the far trailing plug? Very high RPM ignition?

I think what slo is asking is that you send pictures of the actual housings that he will receive. I would like the same. If I were to pay $1200.00 for rotor housing resurfacing, I don't think that is unreasonable.

Barring that, if I send in my housings and ask for the same ones back, the turnaround time will be long, but I will get the same housings back, right?

Thanks.

couturemarc

NoDOHC,

The FT plug idea isn't original to JHB, it was used on the R26B engine and was found to deliver better fuel economy (upto 10%) and as a side benefit slightly more power 2-3% iirc. This whole idea seemed to be forgotten until we started to play with ways to "add" a plug to existing rotor housings. The R26B engine uses different rotor housing castings that are intended to facilitate the use of 3 plugs and thus have the upper dowel higher in the casting. To get the right placement on standard casting you have to cut into the dowel pin area and this makes things tricky. After i shared some pics with a couple builders the copycats did what they do...
OUR intent here was to produce some R26B "replica" housings with the same port timing on intake AND enhaust (you can't copy exhaust without re-coating the rotor housing... and of course this is our speciality).

http://i34.photobucket.com/albums/d1...arc/part18.jpg



As for the pictures, for a small fee we can have someone take pics of the actual parts you will get but more importantly we have a very thurough inspection process where notes are taken on every aspect of the rotor housing and then it is given a rating. Anything with a flaw that will affect engine life or function is scrapped. Anything with a "cosmetic" or non functional flaw is sold at a discounted price and a very clear description of the flaw is on record (these tend to sell very very fast!!!).

If you do send your rotor housinsg in to get done and are willing to wait, you will get yours back. We are set up to run a "custom" batch every quarter.

Hope this answers yours and others questions!

BEX

i'm thinking about getting some cermet coated housings but i am concerned about one possible problem the coatings might present:

i've read that the ceramic metallic coatings are better heat insulators than stock chrome so they help keep heat from compression and combustion from transmitting to the actual rotor housing irons..

if this is so, wouldn't the cermet coating also insulate the rotor housings from transmitting heat to the coolant passages? or do you (JHB) not coat the coolant passages?

if you do normally coat the coolant passages, are you (JHB) able to custom coat rotor housings that i send in so that the coolant passages are not coated?

i hope someone out there is still reading this thread. thanks for your input guys!

couturemarc

Hi Bex,

Sorry I have not been able to answer your question sooner, JHB was awarded a military and remote regions sustainability contract that has taken up 100% of my time from January until now.

Your question is a good one but also has some simple answers;

Cermet coatings, as used on the rotor housings, are not insulators. They will conduct heat in a similar way as the chrome plating.

Secondly, if you wanted to not have the coolant passages coated (although there is no advantage to this) we could do this for you at a small extra cost for the extra masking of the part.

It seems as though there is a lot of interest and curiosity about "HOW" we remanufacture rotor housings. Now that I have some free time again I will begin posting videos that show how this process is done. I was thinking about doing this on YouTube with several 5 - 10 min segments, any other suggestions??

Happy to answer any other questions any of you have.

BEX

Marc, thanks for the clarification. also, videos would be great (youtube or download for me).

swbtm

iTrader: (2)

Similar to everyone else, I'm planning on building a 12A turbo that I would like to be everyday reliable running 12-15 psi minimum for many many miles... none of this 10,000 miles then rebuild junk.

If you have created and posted videos on you tube or anywhere please let me/us know. I'm always interested in new toys.

Thanks for the info