We're not going to be able to gather any usable data from this motor due to an unknown history for 45k miles. That's certainly enough time to cause long term damage provided the previous owner didn't have good habits. At this point there are only a couple conclusions:

1. Despite increased viscosity and good engine care this motor still suffered noticeable bearing wear in places we expect to see it.

2. Due to an unknown history any good or bad habits cannot be concluded due to the possibility that the previous owner didn't care properly for this motor or otherwise operated the vehicle in conditions that caused long term damage.

I honestly say #2 is the best bet. Had OD been the only owner of this motor with a tracked history of care we could gather some useful information.

 

a fun thread start when im not in the states ...

I might have a meeting with the local rotary club, some have been turboed for long time,i will show those builders these pics and ask them some question

Btw, Damn, that knightsports supercharger is f-ing nice. And their race car .... I was like .....omfg the whole time ....

 

subscribing, it is a nice reading
nycgps where are you?

 

Im in hong kong right now

I also heard that there are quite a lot of engine failures in china, most of them due to bad gas = kaboom. Dont have this problem in hk tho

 

Im in hong kong right now

I also heard that there are quite a lot of engine failures in china, most of them due to bad gas = kaboom. Dont have this problem in hk tho

 

Bad gas? How bad of gas can they be running over there? Is this with NA cars?

Paul.

 

Supposedly it's hard to determine if the gas there is leaded or unleaded, and a lot of place try to save money and get gas from cheaper sources.

 

few things we can discuss?
1- Doesnt appear that i was having a lot of seal skip?
2-Sparkplug holes did not have cracks and I bet the apex seals were worn evenly--I have temps under control
3- seems water meth does help in keeping the engine clean--remember i am boosted so my a/f's are richer than oems --by some anyway.
4- I drove the engine for 100 miles on one rotor!
5- the good exhaust port wasnt bad

and this is MY 2nd engine with the same exact bearing wear. Regardless of history if there isnt a lubrication problem 2 engines of mine in a row had the same exact bearing wear would HIGHLY suggest a real problem.
I do not overtighten belts--use the 90 degree twist rule and i am not the hulk. Except in the eyes of my wife
OD

 

Can I put you on the spot Paul and ask you to confirm your related current stance on quantity of pre-mix per tankful, daily driver. I believe you indicated a lowering to 3.5 oz in part due to what you've learned on this and other engine autopsies. TIA

 

Here are a few more including apex seals which weren't bad (Other than the broken ones) although we don't reuse them so that I can show value in relation to Mazda's rebuilds which don't reuse them either.

I tried to show the one apex seal that had slight warpage but I don't think I got a good picture. One shot shows the Master's hands (He hates any pictures of him being taken).

Paul.

 

Yes, you can cause some extra loading of the shaft due to overtightened belts and a better viscosity helps to prevent bearing issues even in that case.

A Cobb could very well reduce the carbon creation through tuning.

Paul.

 

I went back and made a correction to the notes on the pics with the scarred rotor. That was the correct housing with a rotor from an FD engine we just built. The rotors from Olddragger's motor were both usable. I'll post pics of his rotors when they were prepped for reassembly soon.

Paul.

 

1/2 oz /Gallon is a good rule and I think that his carbon was due mostly to a/f ratios. Less is not a big problem since you're just supplementing an existing system. It's added benefit is a more complete coverage.

Paul.

 

I'd imagine pre-mixing with some sort of detergent would help to clear off the carbon too. If I am correct, MMO has some sort of cleaning agent, as does FP+.

I'm hesitant to think that pre-mixing or not would have helped this engine as it was a used engine. If a lot of that carbon was caked on before olddragger got it, the de-carbing and pre-mix might be solutions too late.

 

Most decent two-stroke oils will have relatively high deteregent levels anyway.

 

OK, that's 8 oz of pre-mix to a standard 16 US gallon tank (15.9, but who's counting). Thanks again.

 

His carbon buildup was not that bad and yes, there are methods of reducing it further.

Paul.

 

Here are pics showing items to go back together. We did all new bearings because we could. His rotor bearings weren't too bad.

Paul.

 

Here are some more prep pics.

Paul.

 

Paul do you have any pics of rotors from a renny that was premixed and well maintained?

 

starting to look good--may want to buy it back!
Jk but i do wish I could.

I can tell you my 1st engine was in much worst shape. Much more carbon, front stationary bearing was through the copper, rotor and housing unuseable, cracked leading sparkplug holes on both rotors, much more blow by evidence, even had heat markings on the e shaft.
I should have bought an engine from paul to begin with but my car was down and he didnt have one available at the time. Lesson learned.
Now i will definently use a vacuum oil catch can instead of a vented one. Believe that may help with carbon buildup a little more?

 

Nope. Since the motors that arrive at our store usually haven't had that treatment from their initial usage. This motor is closer to that and it's failure was due to a fluke lean condition. It's main damage item was one rotor housing.

Paul.

 

Oh okay. I am just curious if the use off premix is very obvious. OD, what do you mean about a vacuum catch can?

 

Here's the result. The finished product.

Paul.

 

The gas they sell in China's gas station were not even close to the rating on the gas pump. Its usually a point or 2 lower. thats why almost everybody have a few bottles of "octane Booster" with them whenever they want to visit the track (A lot of tracks in China), Yes its NA Rx-8 that has a lot of problems.

One way they do is they have to "Detune" the computer even further. the other way is, well, use a bottle or 2 Octane booster every tank.

Hong Kong doesnt have this problem, but there is no race track in Hong Kong, and the closest track is about 2+ hours from HK.

*P.S.* The track is domainting by GT-Rs, Evos, and STi.