A bearing is a fairly inexpensive item so I will go ahead and replace it. My engine did come with the double rubber sealed bearing and shows no sign of leakage. At this point I am desperate so I will replace it anyway. Motor always stayed over 200* F during break in. I did my best to keep heat in the motor but still be rich during break in. Thanks for the advice.

I have not tried any higher nitro percentages yet. I was under the impression nova's were shimmed for 25% so I didnt feel running 20% would be an issue. It never has for any motor I run but I understand your point. I am running the stock C6 plug. I plan on putting the motor back together with a new front bearing and then going back to the track and re tune with a few different plugs.

I will try more nitro but but why not reshim for 20%? I say that as I am not the driver I used to be and 25-30% is a bit much power for me. What kind of clearance would I want for 20% ? Thanks.

well
 

In my experience the c6tgc plugs kinda suck for break in. The above mentioned using a c5 plug for that reason. The shimming is probably not as big of deal. I use a 97t plug for break in and then switch to a c6tgc.

These pro engines just isn't designed for low nitro %. I've tried soooo many things to get them run perfect with 0 - 20 % nitro, but they just don't run consistant. I know some drivers only runs 20% though.

Its not enough to reshim. Its something with combustion chamber size etc etc.

The factory shimming is for break in so no need reshim. Fuel 20% is good to go even lower percentage nitro. If not a fault plug then it the carb... Idle gap+lsn n over rich hsn

Yes you can pop an Avid in there for $10 and might just save you allot of headache, the guys are right about using a hotter plug for break in also & of course verify the plug is ok

Ive seen a few front bearings give this problem and they don't necessarily have to be leaking fluids to be giving running / tuning issues

Have you tuned the engine much since it was new on the crazy rich factory settings?



Dave,
FUSION X ENGINES AUSTRALIA

please do not use the avid front bearing , its not good

the avid rear bearings however are pretty decent

if your 17011 is not leakibg then its not the front brng

use a c5tgc glow plug

I recently had one that wasn't visibly leaking, but when I dismantled the engine it was like the inner circle of the 17011 bearing could wobble around in there.
I'm not sure I want to spend $30 on 17011 bearings anymore.. how much worse can the run of the mill 607 2rs c3 bearings like what Alpha use, really be?

its not "just" the bearing which pushes out oil or sucks in dirt , many dfrnt factors involved

the tko front are better than the avid front for sure

you can do what you wish but out of hundreds and hundreds and hundreds or more like thousands of engines I guarantee you will not find a better front bearing than the 17011

Dave, on my second outing with the motor I burned around another half gallon of fuel. By the end of the evening I found myself tuning for more performance. I am not a person who uses a temp gun. I go by smoke, sound, and performance. Out of curiosity I did use my exergen once, the motor made great power at 270* F. I have heard stories that these motors run between 300-340 when tuned. I couldn't imagine how much power I would have had running that lean. I did do all of my tuning on the same plug from break in. It also seemed the leaner I went that the motor was less likely to flame out.

Dave, on my second outing with the motor I burned around another half gallon of fuel. By the end of the evening I found myself tuning for more performance. I am not a person who uses a temp gun. I go by smoke, sound, and performance. Out of curiosity I did use my exergen once, the motor made great power at 270* F. I have heard stories that these motors run between 300-340 when tuned. I couldn't imagine how much power I would have had running that lean. I did do all of my tuning on the same plug from break in. It also seemed the leaner I went that the motor was less likely to flame out.

270 to 280 is about where you`ll be at after break in at full race tune after about 1.5 to 2 gallons. Anything over there is something wrong like drag on drive train. My btt would sing at 280, and did so for 8 gallons. Now my x5 is a screamer at 250. I only temp to make sure runs are consistent to make sure nothing has gone bad like a bearing or clutch setup.

but it´s so much difference in driving style isn´t it?

my friend and i switched cars last time out.
he didn´t manage to get my engine warm enough, it richened up a lot and i made his engine become way too lean. same track, same time!

my engine´s are always 15-20° hotter than his, just because i´m so hard on the throttle and he´s so smooth.

+1 :tire: