I just took the spark plugs out...

First three is front rotor and last two is rear rotor.

 

It looks like i have a bad front rotor? Or what do you guys think?

Olle

 

Pulled it out anyway...

 

Well, my guess is bad control ring on the front rotor... But looking at your car, if I could make a suggestion, I would ditch the greddy fmic. I had that thing back in the days and personally, I had more issues with that fmic than any smic (I had several different ones and now running Apexi FMIC).. just my advice..

 

Thanks!

Im gonna check all internal parts very closly. Hope i find something...

Im gonna stick with the Greddy FMIC becaus i just welded new intakeholes on it and made new piping to match with new vacholes. If im not satisfied with it i may build a v-mount setup next winter.

Hope to take the motor apart at thursday night or friday as im working loooong days tomorrow and thursday. Just got to sort a 54 mm socket.

Stay tuned

Olle

 

UPDATE

I took the motor apart last night and found that a apex seal groove on the front rotor had a long crack and a little hole in it. Just where the apex seal spring sits.

I think this is a perfect example of what could happen when you mill to 3mm apex, and do it on a rotor that have too little thickness of material under the spring. When the motor revs high and when there is alot of oilpreasure togheter with the thin metal this can happen. Also if the rotor is a little bit worn out it speeds up the process.

The sad thing in this is that i have worked so much in getting the car run good since my engine builder did the teardown and assembley of the motor last time i pulled it out and did not see this crack. So in a way i feel that i have been spending both money and time on something that my engine builder would have discovered in the first teardown. But i have been talking to him today and we have agreed on him balancing the new rotor im gonna use togheter with the whole rotating assembly and also check for clearance issues and if so also mill that rotor to the right tolerances for free.

Im also gonna let someone x-ray my rotors to make sure that there is enough metal under the apex seals so this wont happen again.

Here are some pics:

 

Other then this the motor looked fine. Im gonna tripplecheck all engineparts closely one more time to make sure there is no other problems.

One more pic of my bad rotor. You can see the two extra dowelpins in the background.

Olle

 

I guess I still get one right every once in a while. Sorry to hear though. Honestly the crack probably become larger after the second build. The few times I have seen this happen it was near impossible to see the crack with the eye. The rotor had to be pressurized to find the problem.

 

Yep you had right! =)

Honestly im kinda glad this happened becaus now i know what the problem is!

So overall its a great day!

Thanks for all help! Actually the help i got here was the main thing that i found the crack.


Olle Lindén

 

Just so you know there is no real reason to use 3mm seals any longer. The 2mm ALS along with some other 2mm seals can handle just as much abuse and make better compression and not wear the housings as quickly. Just something to consider.

 

Yes so ive heard. But if im gonna go with 2mm seals i have to change the other good rotor too and also get new apex seals... And thats more than i want to afford right now. Im gonna get a new rotor (second hand but good) and mill it to 3 mm apex. Then slam the engine togheter again and have a nice summer =)

But for my next build im more than positive im gonna use 2 mm apex. But then i might have a bridgeport too =) Ive seen a guy here in Sweden hwo dynoed 770 hp with 2 mm seals so i guess it works.

Now i have to sort a rotor and get all the parts balanced. Then im good for the summer. I hope ;-)