Tim,
If after testing you have problems with sealing & compression,
it might be an idea to get the Apex seals coated with something 'relatively' soft to give them something to key into.
If the grinding process is indeed as good as it looks, you may find that the tolerance in the apex seals straightness and surface doesn't match that of the housing.

If it works though you know where I'm coming for my racer engine.

 

Sorry, wrong numbers completely! I was looking at a reference gauge today and thought "what did I say in my post?" I was sure I was barking up the right tree when I posted... what a tit! But back on the subject, what Ra do you finish yours to? Or is that something you woudl like to keep a secret?

 

so what is the approximate power gain from a completely coated engine vs the same engine with no coating? take for example a streetported na 13B

 

I don't think I've ever heard of a spefic power gain. It helps reduce friction which should free up some horsepower, it also keeps more thermal energy in the combustion chamber which should help to combust a little more fuel. The main benefit is that if you blow a seal they can resurface the specific part of the housing for cheaper, rather than having to buy new housings.

- Steiner

 

I remember them saying that they put there full ceramic a coating in a 84 or 85 modle 1st gen that ran the quarter mile in 16.2 stock and after the full ceramic a coating it did it in 15.3.

If you look in scalliwags thread about resurfacing rotor housings, they have posted the percenteges of everything that comes with the coating.

 

My 12A turbo is running,with the cermet 'A' coated housings.After 10 miles the engine had 6.5 bar compression on all faces.Done 100 miles now,so will do another comp. test,I expect it has gone up.Engine is very smooth,and starts easy.It has large ports and a GT42 turbo.

 

sounds good

 

wow the A coating,,, wish i have the money to get that done
matt

 

great news Tim, please keep us updated as things develop, there are lots folks following this topic!!

 

Do you have your rotor housings back yet? How are they?

 

I was told this week, will post my findings as soon as i get them back
matt

 

I have done 500 miles now.Compression test showed 6.2-6.3 bar,so much the same as it was.Engine is running very well.

 

I went on a rolling road today to check the tuning,made 349rwhp,then did some adjustments and made less power.Car then would not idle,stalled,and was very difficult to restart.Did another power run,and made less power.Tried to do a compression test,but could not measure any.Had a look through the spark plug hole,and I could see the apex seals were badly scored,which basically means they are ripping off the 'indestructible' ceramic coating.
Drove home,did a comp test,I now have between 4.6-5.1 bar compression.One totally fucked engine.
Can someone tell me what exactly 'cermet A' is? I was under the impression it was the same coating Mazda used on the rotor housings in their Le Mans car,but if you read jhb's website,it doesn't exactly say that,just leads you to believe it.
All I know is that it is totally incompatible with Mazda seals.How can this be so if supposedly it has less friction.CRAP.
When I built the engine,I was concerned as the coating did not seem to be very hard at all,and concerned when after 500 miles the compression hadn't gone up.
I will have pics when all in bits,suppose to be drag racing on Sunday.

 

Ummmmmmmm

 

Hate to say it, but you were making some really good power until you "made some adjustments". My guess is that maybe you just pushed it that bit far & it has let go?

 

No,didn't push it too far,only 1.3 bar boost,engine ran happily at 1.6 bar before this build.
Anyway I have stripped my engine today,it wasn,t as scored as I expected,but most of the 'cermet A' coating has gone.It has simply worn away.This is similar to a housing I once had sprayed with molybdenum,but that did 7000 miles,the 'cermet A' has done 700 miles.
The coating that has gone has dragged around the side plates,they look scored and worn as if they had done 50,000 miles,not 700.
Confirmed my concern that the coating wasn't very hard at all.
Anyone have thoughts on this?

 

**** - not good Tim. I will watch for Marcs reply with interest.

 

hey tim,

I know your probably not in the mood but can you please reply to my PM I would appreciate it very much if you could help me out.


Cheers

pete

 

MY observation reading this thread, the 787B racer runs much lower chamber pressures than a turbo chamber on hi-boost, also tempeture would be alot higher than a N/A ,like the 787B , the hi-pressure gets behind the seal, apex, and pushes it outward at a much higher force, think about it! so far its going to be hard to improve upon mazda chrome impregnated with teflon system. Just a thinkin RON

 

I tried Ceramic coated rotors back in 98 ,detonated on first 12 lbs, assumption ,chamber temps were to hi for timing and A/F ratios, again im not saying it cant be done yet! but integrety is still the final question. RON some place I said try 18 lbs. for just a 1/2 hr. at full load. then we will have a good idea!

 

Tim Have you got a response to that happening from marc at JHB?

 

Please post pics of your housings if you have any.

 

Here is a pic of the best housing of the 2,it looked absolutely perfect when it went in,now what you see is mostly steel liner,700 miles later.

 

I was there when Tims car was on the rollers sounded good. Then the problems started. It lost compression totally our comp tester stops reading at 5 bar tims reads lower. The coating let go it is the only explaination. I say this cos my new engine has No comp same as tims( mostly due to the fact I forget to take the timing lock off the ecu when I gave it to a mate to run in) I made just under 400rwhp at 1.3 bar on a ported fc block with T04R, Tim Will make more and good luck to him. I am sorry that his test have failed but we all know that problem. Then again we will lurn from his experience. See you tomorrow Tim need the servo very melted. What a fun drive I have!!!

 

only thing i can think of is that they were ground wrong then coated ground wrong to match
and when they were reground (not at jhb) took to much off leaving to thin a coating.
hope this is the case or i will be in for the same thing with the ones i got done.
matt