rotaryPilot

Yesterday in a local rotary shop the mechanic opened a renesis with 5281 miles because the engine was low on compression and could not even start up.

History of the engine
-Mazda Oils change interval every 2000 miles (total 3 changes)
-Premix Saber pro at 1500miles, 180ml at each tank
-Failed once at ignition coils and flooded
-3 hours cranking (lot of batteries) in order to measure compression because local dealer did not how to measure compression
-hard use at track (twice a month this car had track day)
-using this car twice a week

Well after we opened up the renesis we found apex and side seals in perfect condition. Housings in perfect condition. Stationary Gear in perfect condition. Rubber seals in perfect condition, no leakage of coolant at all.

So what was the problem????

The mechanic assumed that finding everything in perfect condition the apex seals springs should have been stack due to carbon lock.

Well carbon was very black and was present only at the faces of each rotor but it was kind of soft and not hard like rock. The thing that made me suspicious was that the side seals springs were broken in two pieces. I knew that during track days this car was suffering due to excessive gas heat because the driver was pushing a great deal. So to have a side spring broken was a logical conclusion for me.

The broken side seals spring made me understand that compression was problematic. HOWEVER the mechanic told me that side seals springs do not play role for the compression because even that the spring was broken the two pieces were one next to other like forming one big piece of spring !!!

Mechanic claims that compression was problematic due to excessive carbon lock and supports that premix was responsible for this carbon lock

SO I am asking:

1) IS IT POSSIBLE A RENESIS WITH 5281 miles and 180ml of premix in each tank to form excessive carbon lock????
2) IS IT POSSIBLE TO HAVE A SIDE SEAL SPRING BROKEN and not losing compression ?????
3) IS PREMIX SABER PRO RESPONSIBLE FOR EXCESSIVE CARBON LOCK?


I will provide you with a lot of pictures I soon as I will get them.

bse50

180ml over 60lt of fuel is like not premixing at all!
Broken side seal springs should account for the loss of compression but only for their side of the rotor.

Anyway the driver is a dumbass, that engine was barely broken in.

G3tR3DDY2GR3DDY

iTrader: (8)

uh yea, why would you instantly start tracking a car thats not even broke in. obviously not properly.

Side seals never had a chance to seat properly to even get stuck.

I think this is just a stupid error not really a typical failure...

I8U

iTrader: (1)

^+1

Flashwing

There's pretty much two theories when it comes to breaking in a rotary motor. One would be that you should drive the motor from day 1 how you normally drive it (like a nutcase or whatever). There's another school of thought that proper care needs to be taken to ensure the seals are broken in properly and the motor has time to wear in correctly.

Frankly, I'd side with a proper break in proceedure with taking it easy for at least the first 1,000 miles. However, I've seen both done and both motors seem to be fine.

So who knows.

bse50

somebody also suggests to progressively raise the redline. Like keeping it below 4000rpm for the first 500km and then raising it 1000\1500rpm every 500kms.

This would ensure to properly bed the seals in and give them the time to adapt through the various rpms.

Anyway there's for sure a relation between break in and engine life, at least this is the case here.
I'll tell you more, non properly broken in engines tend to fail around the 45000mi mark. I believe that if the owner didn't break it in when new then he won't be so smart to let it warm and such though so who really knows?

rotaryPilot

Well the owner told me that he break in the engine for at least 1000Km.

Photos renesis ready for the opening.













Photos will follow with renesis opened

bse50

Wow, your camera has serious drinking problems!

rotaryPilot

the other photos will be of good quality. Those photos in the previous post was taken from a bad mobile phone camera

bse50

Good to know
Since you are in greece let me know if you need anything. I live in Italy.

nycgps

iTrader: (1)

side seals do effect compression #

and there was too little premix.

and he is pushing the motor too hard too fast ...

bse50

Amen, nycgps we often agree i see
wonder if this "rotary shop" knows the right tolerances etc needed for a good rebuild?

rotaryPilot

So why this engine had an average of 400KPA at each face of the rotors ? Everything apart carbon and broken side seals springs looked in perfect condition. No sign of detonation, nothing wrong inside the engine.

bse50

How many springs were broken? it could either be them sealing enough to get 400kpa or the extra wear caused by poor break-in, cold runs etc.
In 8000km or so you don't have the time to see noticeable carbon build up!

Nubo

Cause of failure = 3 hours of cranking?

Mazmart

iTrader: (12)

Did the car have 5k on it or is this a built engine with 5k?

Paul.

bse50

Paul, did you notice the rust on the exhaust manifold sleeves?

Mazmart

iTrader: (12)

It's hard to see much in his pictures.

Paul.

rotaryPilot

2 side seals springs. 1 side seal spring in each rotor. Both rotor had about 400KPA average in each chamber

rotaryPilot

Brand new car from Mazda dealer having total at the moment of failure 5200 miles. Mazda dealer refused to replace the engine under warranty because the owner had aftermarket parts like Revi, final muffler etc. So the owner went to a local rotary shop.

04RX8man

def not enough premix...and I also beleive that youneed to be easy with a cat/motor when breaking it in...not leave the dealership and drive to the track and beat on it all weekend with NO mileage on it at all...

rotaryPilot

More pics !!!!!










[b]

bse50

like a 50\50 wrong use and poor break in.
Maybe he didn't even wait to warm the car up...
GL with the rebuild though. I'm rebuilding an engine with 800 miles now. Poor block!

Mazmart

iTrader: (12)

Did the broken side seal springs show signs of unusual wear (Overly thin in areas) and did they look to be stacked or bunched up a bit?

Paul.

rotaryPilot

I can not say about the side seals springs wear because I did not examine them so carefully. I am not the rebuilder I was just a spectator during the renesis opening. However, I have noticed that it was kind of difficult to pull the springs up. They looked stacked on the rotor.