A question to all you engine builders out there, dos anybody know why ceramic seals would brake in the turning stages at around 7k rpm if every thing else is ok like turning, A/F ratio, timing, clearances and there ware no sighs of detonation what els could cause the seals to brake. all 3 seals broke for the second time on the front rotor so i dont know why it is happening we think it may be faulty seals but i find this hard to believe as this is the second time this has happened after the rebuild of the engine and runing in, the car has a half bridge and a single turbo and all the other normal upgraded things so what could be causing them to go.

cheers

Erdin

 

What exactly do you mean by "turning stages"?

I suppose if you're using 3mm seals it could be that the rotors weren't machined out precise enough, but that usually causes them to "stick", not break. I just had 2 piece 3mm ceramic seals installed in my Pineapple engine sourced out by them. Where did you get yours? Too bad they don't come with x-rays to show structural integrity like the old Ianetti's did. How much damage did they do to the engine when they let go??

 

sory it should have read tuning not turning the rotors ware not machined cus i used the 1 piece 2mm seals on the second engine.

 

Sounds like the "tuning" is being done very poorly. What kind of ecu are you running and how is the car being tuned?

 

the ecu is is the PFC it is being tuned on the road with a wideband i thought it may be the tuning too but my engine builder has more then 20 years of experience plus he sade when he opened the engine up there ware no signs of detonation.

if any body has any ideas please do share

 

What is the condition of the rotor in the front housing? ANY "roll" in the "edges" of the apex seal slot can be more catastrophic to ceramic than metal. Detonation would not be evident as the breakage could be due to purely mechanical stresses. The "roll" would account for the fact that only the front housing and seals were affected.

 

Are all the injectors working equally well? Maybe just maybe one of the front ones isn't working well and you are getting less fuel in there.... your overall AFR would appear to be OK since it would represent the AVERAGE of the two rotor chambers. Maybe the rear rotor is running 10:1 and the front is 12:1? Just an example.

Another thing I would look at is the porting to make sure it isn't too extreme causing something to bend/break/snag and cause your problem.

B

 

Are the little things like the Fuel injector Defusers ok?

I cant belive this guy would miss somthing like Rotor Wear?

What about Oil Injectors? They working ok?

Being Ceramics when the engine went last time what was replaced? Also was it on the same Rotor?

Chris

 

Erdin,

Man, I'm so sick for ya!

I can't believe you have had another serious problem from one of the most experienced engine builders.

Gutted for you mate....

Jus

 

I know Jus i cant believe it either iam not having much luck at all, iam gona make a point of all the comments of the members and ask him about it to see what he says but iam sure its not tuning but i could be wrong.

 

ok guys i spoke with my mechanic there was no signs of roll in the edges of the apex seal slots. All the injectors ware working fine cus he checked them cus he also thought it my be this. regarding injector defusers the 550cc injectors do have defusers but the 1600 dont have them or are not need, cant remember all of what he sade regarding that. oil injectors, ware ok cus there ware no signs of wear in the engine. when the engine was replaced larst the rotor housing, apex seals, side seals and both rotors ware all replaced.

 

If everything checks out ok mechanicaly and you're 100% sure that it's not tuning then do yourself a favor and put the motor back together with factory apex seals untill at least you figure out what the problem is. At least if you break the factory seals the damage would not be as great as with the ceramics.
Which manufacturer Ceramics are you using?

 

iam gona have someone els check the maping to be on the safe side if it checks out ok il do just that.

 

As above. Put in stock Mazda seals and try again. Are you running the engine in at all or just giving it 7k rpm on a fresh build. Are there holes in the map. You may be accelerating through a lean spot that hardly registers on the W/B. Have you data logged any of the tuning. What wideband are you using.

 

iam gona have an other tuner look at the map to be on the safe side il have to ask my mechanic what widebend he is using, iam gona be away for 4 weeks so il have to carry on looking into things when i get back. i did put 1500m on the engine befor any tuning was done do you think i should put more since iam useing ceramic seals.

 

I would certainly check the map and wideband. It will only take a small detonation to damage the engine. You may only notice when its already too late!

 

It happens to the best of them Jus :-(

Nice to see this ones name's not being slated on the UK forums, isnt it? Shame the rest arent as lucky!

Rich

PS Erdin - dang - sounded like you were getting sorted when we spoke quickly at TOTB the other week. Gutted mate :-(

 

I'm sure your in "safe hands" with the current mechanic, as I've said before "one of the most experienced". But as Rich said "it can happen to the best of them" but I think it's too early to say this, as it sounds like no one has established the cause.

Most important is ACTION!

What is the situation? Do they still have the car and are they still trying to rectify? Or have you taken the car away? Is anything covered under warranty?

As I'm sure they will be working hard to rectify.

As crispeed wrote, try the steel seals and wide-band mapping, wouldn't hurt getting a second mapping opinion as well, when she is all running again.

Hope it works out for ya soon erdin, a gutted jus....

Jus

 

Maybe something to do with the porting?? Maybe.. Just a guess I dont know a whole lot about this just thought i would throw it out there.

 

Hi Erdin,
I have built a half bridge port on an FD that has been absolutely caned,ask Rich and co,(He has borrowed it to scare the locals)
At the moment it is still running having done somewhere between I think 8000 to 10000 miles.
During this time it stated life with stock twins with 280 rearwheel hp and is now running a single of unknown origin.The car is Geffs at GPA in Portsmouth UK.It has been on trackdays and competed at TOTB 2.
The seals are 2 piece 3mm Mazda.
The Iannetti's are very good but the 2mm are weaker than 3mm by a considerable margin,also 1 piece are stronger than 2 piece.For high output turbo applications Dr Iannetti reccommends 1 piece seals of 3 mm type.
I have built a number of engines with Iannetti seals with no problems so reccommend them highly.Choice of steels for the halfbridge was purely economic.
I know the builder of your engine personally and he is more than capable,as has been said previously it can even happen to the best of us.When it does if everyone had your attitude that would be great.I am sure that you will get it sorted soon.
Kind regards
Carl

 

Erdin give me a call as soon as you get back mate.

rgds

 

Guys it means alot to me that you all taken time to replay to my post and belive me i know my mechanic is one of the most experienced in the uk his worked on my car since i bought it two years ago and i will continue to bring my car to him, he has always given me good advise when ever i needed it and my car is still in his hands iam purely looking in to all the resons why the seals may have broken and going back and cheacking with him to see what he thinks, il probably go back with the 3mm seals now.
thanks again guys, il be away as of tomorrow so il have to carry on when i get back.

 

I look forward to seeing your car up and running soon.
You will be well pleased with the result.
Kind regards
Carl

 

How about seal to groove clearance, length clearance?
How much boost? What is your rotor housing minimum thickness and how much less than "A" point? At 420 celsius a 13B ceramic seal grows approximately 0.004"

 

iam not sure about the clearances il have to talk to my mechanic about that but i will be up grading the ecu cus i dont think its tuneable enough for a brideged engine.

regards
Erdin