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Old 07-22-2008, 08:51 AM   #9526
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Originally Posted by Sp Racer View Post
We had this problem, but I'm happy to report it seems to be solved.

Check out the following...
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.
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#2 - Make sure your clutch is not slipping - it heats up the clutch bell and then melts the gear ( very common )
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hope this helps!

You know, thinking about it, that does ring a bell. My clutch was engaging real late (when first started the car won't move up until close to half throttle), and I almost burned my hand when I touched the clutch bell gears by accident. Since the clutch timing seemed to loosen up as it heated up I left the engagement timing alone, but definitely looks like something I should check.
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Old 07-22-2008, 09:02 AM   #9527
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Originally Posted by PrimeAKF11 View Post
You know, thinking about it, that does ring a bell. My clutch was engaging real late (when first started the car won't move up until close to half throttle), and I almost burned my hand when I touched the clutch bell gears by accident. Since the clutch timing seemed to loosen up as it heated up I left the engagement timing alone, but definitely looks like something I should check.
try reducing yr clutch gap and end-play...u may want to check yr spring preload too.
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Old 07-23-2008, 08:49 AM   #9528
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Ok, the hot-clutch-bell-melting-the-2nd-spur theory is getting to be more convincing. Took the clutch apart, and guess what, the shoe had partially melted and warped . I had just eyeballed the clutch gap and endplay when I was building the car, but when I actually took a vernier caliper to it today, I found them to be WAY off. Explains why the clutch was engaging late and heating up excessively on the raceday .

I still find it hard to believe that a clutch bell can heat up to the point that it weakens a spur gear (and eventually stripping it), but I am going to fix what I see and give it a test run when the gears get here.
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Old 07-23-2008, 10:43 AM   #9529
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Quote:
Originally Posted by PrimeAKF11 View Post
Ok, the hot-clutch-bell-melting-the-2nd-spur theory is getting to be more convincing. Took the clutch apart, and guess what, the shoe had partially melted and warped . I had just eyeballed the clutch gap and endplay when I was building the car, but when I actually took a vernier caliper to it today, I found them to be WAY off. Explains why the clutch was engaging late and heating up excessively on the raceday .

I still find it hard to believe that a clutch bell can heat up to the point that it weakens a spur gear (and eventually stripping it), but I am going to fix what I see and give it a test run when the gears get here.
I want to ask...after the 2nd gear stripped, hows the 2nd gear look like..? Mine is like, where it stripped, were like the 3/4 part of the whole width of the 2nd gear, the side is toward the 1st gear side...and, the 1/4 width of the 2-speed were NO TOUCH (toward the engine side)...since G4RS clutch housing and the 2nd pinion gear is 1 piece design, there is a very good chance the HEAT from the 2nd pinion gear MELT the 2nd gear especially the area that has a full contact between the 2nd pinion gear and 2nd spur gear..

But...my 2nd gear, were melted within 2 laps after started the engine....and my clutch gap, was 0.4-0.5mm....I used this setup all the time.

On my serpent, that used full size pitch (not 0.8 module) I have yet melted or stripped any gear...

I still want to find out does my engine was shifted...stripping 2nd gear happened to a lot of current cars, most common on Mugen, and some on NT1.
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Old 07-23-2008, 02:06 PM   #9530
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Ill have a look at post the details tomorrow when im in my workshop.
Possibly take a pic too.

Quote:
Originally Posted by keavze View Post
just want to ask: what's the size of the stock brake piston?
also what's the size that you used? i've trying to find one that fits...
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Old 07-23-2008, 02:17 PM   #9531
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The problem is that too much clearance on the 2 speedshoe makes the clutch engage to aggressively and in some cases with a harder spring tension the shoe doesnt engage properly with the 2 speed housing causing a heat build up from it slipping.
Sometimes it sounds like a inconsitent change too sometimes early, sometimes later.

Cant speak for the RS but some had the same hassle with the G4S.
I add 2 washers/shims between the 2 shoes to keep the clearance closer to the 2 speed housing.
Make sure the shoe is set as close to teh housing as possible.
Also look at how the bearings seat in the 2 speed housing sometimes they wear or dont fit snug so the housing wobbles a bit.
Also the grub screw that keeps the tension on the cam that screws into the shoes, swap them out for slightly longer ones and put some superglue or loctite as they come loose often.
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Old 07-23-2008, 03:50 PM   #9532
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Quote:
Originally Posted by PrimeAKF11 View Post
Ok, the hot-clutch-bell-melting-the-2nd-spur theory is getting to be more convincing. Took the clutch apart, and guess what, the shoe had partially melted and warped . I had just eyeballed the clutch gap and endplay when I was building the car, but when I actually took a vernier caliper to it today, I found them to be WAY off. Explains why the clutch was engaging late and heating up excessively on the raceday .

I still find it hard to believe that a clutch bell can heat up to the point that it weakens a spur gear (and eventually stripping it), but I am going to fix what I see and give it a test run when the gears get here.


Get yourself some of the "red" colored throw-out weights - it seems like they slide better and give you a more even clutch engagement.

You cannot run more than about 0.7mm clutch gap on these UFO 2 clutches
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Old 07-24-2008, 04:02 AM   #9533
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OK the balls i am using similar to these in this pic are 6mm OD and the flat side sits against the brake pad.

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Old 07-24-2008, 07:50 AM   #9534
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Quote:
Originally Posted by Solara View Post
...after the 2nd gear stripped, hows the 2nd gear look like..? Mine is like, where it stripped, were like the 3/4 part of the whole width of the 2nd gear, the side is toward the 1st gear side...and, the 1/4 width of the 2-speed were NO TOUCH (toward the engine side)...But...my 2nd gear, were melted within 2 laps after started the engine....and my clutch gap, was 0.4-0.5mm....I used this setup all the time.
That was exactly how it looked when mine stripped. 3/4 of the 2nd gear toward the 1st gear was crushed, the rest 1/4 on the motor side still had some teeth remaining.

Hmmm... so it's pretty common huh...
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Old 07-24-2008, 08:32 AM   #9535
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Quote:
Originally Posted by razzor View Post
OK the balls i am using similar to these in this pic are 6mm OD and the flat side sits against the brake pad.

thanks razzor, will try it out next time when i rebuild my rear differentials...
too lazy to dismantle the rear parts now.
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Old 07-24-2008, 09:53 AM   #9536
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Quote:
Originally Posted by PrimeAKF11 View Post
Ok, the hot-clutch-bell-melting-the-2nd-spur theory is getting to be more convincing. Took the clutch apart, and guess what, the shoe had partially melted and warped . I had just eyeballed the clutch gap and endplay when I was building the car, but when I actually took a vernier caliper to it today, I found them to be WAY off. Explains why the clutch was engaging late and heating up excessively on the raceday .

I still find it hard to believe that a clutch bell can heat up to the point that it weakens a spur gear (and eventually stripping it), but I am going to fix what I see and give it a test run when the gears get here.
I've spent many hours on this problem and from the warping of the clutch shoe which you have indicated it may be the positioning of your motor. I found that some motors do not properly align because the backplate screws interfere with side brace on the exhaust side of the kit. On my G4RS this caused the bell to bottom out on my 2nd gear spur. 1 it tilted the bell to one side and engaged the clutch unevenly which caused the shoe to appear warped and 2 this generated alot of heat and woul eventually lead to failure of the 2nd gear spur. I resolved this issue by milling out 2 notches on the side brace where the engine backplate bottom screws were hitting. The other thing I did was go to the KFactory 2nd gear pinions. The gear is a little wider and covers the 2nd gear spur better. I have since had no problems. Prior to this I had made A-mains at several races only to get knocked out due to 2nd gear spur burning up. Hope this helps.

G4RS
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Old 07-24-2008, 11:11 AM   #9537
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Quote:
Originally Posted by Speyederjedi View Post
I've spent many hours on this problem and from the warping of the clutch shoe which you have indicated it may be the positioning of your motor. I found that some motors do not properly align because the backplate screws interfere with side brace on the exhaust side of the kit. On my G4RS this caused the bell to bottom out on my 2nd gear spur. 1 it tilted the bell to one side and engaged the clutch unevenly which caused the shoe to appear warped and 2 this generated alot of heat and woul eventually lead to failure of the 2nd gear spur. I resolved this issue by milling out 2 notches on the side brace where the engine backplate bottom screws were hitting. The other thing I did was go to the KFactory 2nd gear pinions. The gear is a little wider and covers the 2nd gear spur better. I have since had no problems. Prior to this I had made A-mains at several races only to get knocked out due to 2nd gear spur burning up. Hope this helps.

G4RS
You know what, I JUST figured this out, and was about to do a search on the forum when I saw your post. You are absolutely correct, two of my backplate screws (on my OS 12TZ) are hitting my side braces, preventing me to get proper clearance on the clutch bell side. I only noticed it after trying to feel the clutch endplay with the motor mounted on the car. Hey where did my clutch endplay go? ohhhhhhh...



Fortunately my cousin owns a small milling machine, so I am probably going to head over there tonight and get the brace modified. Thanks for the advice!!!!

Last edited by PrimeAKF11; 07-24-2008 at 11:25 AM.
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Old 07-25-2008, 12:35 PM   #9538
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Hi All,

Going somewhat 'Off topic'..........

I had a chance to spend some time testing different set-ups along the lines of an idea I've had for some time.

I've always thought we run our cars far too stiff (spring wise I mean)
I've also thought that we run our shock oils far too light.

Anyway. At the recent Byrons race at Joliet Illinois I had the chance to test my idea out.
The track is very smooth and flat. I ran 1.3mm (15LB) springs. and began using heavy oils in the shocks. I ended up with 80WT Losi oil. Thats about 1070 cps. In both front and rear of the car.

The car was very stable and very "flat" on the race track. Had very little roll as would be expected.
The camber of both front and rear had to be altered because of this too.
Camber ending up at -0.5 to -1 Degree at the front and -2 to -2.5 degrees at the rear !
Also the rear toe ended up at only -1.5 degrees which is not unheard of, with a front toe of +0.5 degrees.

The tire wear was very low and the car felt good. What was another side benefit was when the traction came up......and became very high. The car still handled very well. Even though others were suffering from traction rolling!
My roll bars were at a soft setting. Front: Flat and Rear: about 30 to 45 Degrees.
I ran softer tires (38 S Front and 40 S Rear) and still had wear comparible to others there.

After all this. I just wish now my ability to drive these cars was better...... lol.
Don't we all wish that?

I'm looking at going even softer on the springing and higher on the oils with probably the need for stronger roll bars required.

We'll see how it goes.

Regards and I hope others have a chance to try this stuff out and let me know what you think.

British Menace
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Old 07-25-2008, 07:28 PM   #9539
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Menace, will you have time to make it over to Toledo for the GLC next weekend?

We hope you can make a visit.
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Old 07-26-2008, 11:20 AM   #9540
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Quote:
Originally Posted by British Menace View Post
Hi All,

Going somewhat 'Off topic'..........

I had a chance to spend some time testing different set-ups along the lines of an idea I've had for some time.

I've always thought we run our cars far too stiff (spring wise I mean)
I've also thought that we run our shock oils far too light.

Anyway. At the recent Byrons race at Joliet Illinois I had the chance to test my idea out.
The track is very smooth and flat. I ran 1.3mm (15LB) springs. and began using heavy oils in the shocks. I ended up with 80WT Losi oil. Thats about 1070 cps. In both front and rear of the car.

The car was very stable and very "flat" on the race track. Had very little roll as would be expected.
The camber of both front and rear had to be altered because of this too.
Camber ending up at -0.5 to -1 Degree at the front and -2 to -2.5 degrees at the rear !
Also the rear toe ended up at only -1.5 degrees which is not unheard of, with a front toe of +0.5 degrees.

The tire wear was very low and the car felt good. What was another side benefit was when the traction came up......and became very high. The car still handled very well. Even though others were suffering from traction rolling!
My roll bars were at a soft setting. Front: Flat and Rear: about 30 to 45 Degrees.
I ran softer tires (38 S Front and 40 S Rear) and still had wear comparible to others there.

After all this. I just wish now my ability to drive these cars was better...... lol.
Don't we all wish that?

I'm looking at going even softer on the springing and higher on the oils with probably the need for stronger roll bars required.

We'll see how it goes.

Regards and I hope others have a chance to try this stuff out and let me know what you think.

British Menace
That sounds interesting!
Question for you...

Were you using a front diff or a spool? Could you share with us your diffs settings, front and rear?

Thanks for your suggestions!!
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