Keep Blowing/melting gears

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PlymouthRC

PlymouthRC

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Hi All,

I was wondering if anyone has had the same problem as me.

I keep either melting or exploding, or breaking teeth on my MCD gear box. It is gear "C and "D" .

I run 30/33 on the outer 2 and 24/25 on the in 2 (the 2 I have problems with).

I thought it was because I have worked the 26 Zenoah engine to the hills (raised compression, enlarged ports, bored out carb, etc) but at the weekend I put in my standard 23 Zenoah with standard muffler and did the same again.

Please can someone shed some light on why this happens and how I can sort it. I have spoken to some FG and MCD suppliers and they do not know anyone else having the same problem.
 
PlymouthRC said:
Hi All,

I was wondering if anyone has had the same problem as me.

I keep either melting or exploding, or breaking teeth on my MCD gear box. It is gear "C and "D" .

I run 30/33 on the outer 2 and 24/25 on the in 2 (the 2 I have problems with).

I thought it was because I have worked the 26 Zenoah engine to the hills (raised compression, enlarged ports, bored out carb, etc) but at the weekend I put in my standard 23 Zenoah with standard muffler and did the same again.

Please can someone shed some light on why this happens and how I can sort it. I have spoken to some FG and MCD suppliers and they do not know anyone else having the same problem.
Click to expand...
Absolutely it is a problem, you need to install 23/26 gears in C and D location. THat will eliminate your problem. I couldn't get a tank out of the plastic C and D gears.
 
Looks good, wish I had the money to do that.

Anyway do you mean run all four in steel or just the two I keep blowing?
 
PlymouthRC said:
Looks good, wish I had the money to do that.

Anyway do you mean run all four in steel or just the two I keep blowing?
Click to expand...

A few tips for you that should reduce the chance of melted gears -

1. Bodyshell - remove the four side windows (I assume you have a Race Runner). This greatly improves airflow and lowers the temperature under the bodyshell.

2. If you install new plastic gears run them in!!! Take it easy for the first 10 minutes - no hard acceleration just low speed runs.

3. If you have the cash the 23 and 26 teeth steel gears even when used with the stock plastic gear plate are a worthwhile upgrade.

An alloy gear carrier plate like the Vertigo Performance one pictured above helps with cooling and the transmission will be smoother running but it is not essential.

I have been racing and bashing MCDs for over two years and the best combination I have found to date is 30/33 gears in plastic with 23/26 in steel and a plastic (yes plastic) gear carrier plate.

This combination was used by Ian Oddie (2005/6 largescale world champion) in his Race Runner even though the buggy was being raced with one his 6.2 hp engines installed.....

Clive
 
Thank you for your advice.

On the cooling side, I have Pull start window open and the top air scoop. The thing is I can do this even with the shell off so there is all the cooling in the world.

The general gear ratio I race on my track is:- A to B 24/39, C to D 25/24

The big thing that has always confused me is I NEVER have this problem with my On Road MCD and my old Blueline Monster (do not run this one that often).

Good to hear I do not have to get the metal gear carrier as I know that is serious money, but I will look at getting the steel gears.
 
Hi Clubin,

I have been pricing up the steel gears and the alloy gear carrier like yours, it costs a fortune!! I have working out the carrier and steel gears works out at about £260.00 :helpsmilie:

There is no way I can afford that so I am going back to what I know best, being an ex-boater I have learnt to make my own bits. So I am going to see how much I can make my own set and from my experience I will be able to do it a lot lot cheap than £70.00 a pair.

I will keep you all posted on what I find and do with the gears.
 
HI Guys,

Just a quick one, I have just run a whole day and got through a tank and a 1/2 racing without getting through any gears and I did something simple.

I had 2x 25 tooth gears so put them on, they where tight for the first lap but after they had shaped themselves together they went quiet and went well.
 
HI Guys,

I have an update, I think I have found out why I am now getting through the gears were as in the beginning I did not.

I was about to try the new gears and have noticed the standard gear plate is worped resulting in the shafts not being parallel.

Other than getting the expensive alloy gear carrier is there any way to sort this probem?
 
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