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Monkeysmate
04-02-2016, 08:37 AM
I'm about to start rebuilding the gearboxes on our buggies and I would appreciate any top tips before I start.
I have some specific questions...
1. Should I grease the idler shafts?
2. Should I grease the gear teeth?
3. What's the difference between the clear and the black grease? Why black grease on the thrust bearings?
4. What's the benefit of the alloy idlers?
Stupid questions no doubt, but I'd value your advice.
Thank you

Clive Loynes
04-02-2016, 10:16 AM
I'm about to start rebuilding the gearboxes on our buggies and I would appreciate any top tips before I start.
I have some specific questions...
1. Should I grease the idler shafts?
2. Should I grease the gear teeth?
3. What's the difference between the clear and the black grease? Why black grease on the thrust bearings?
4. What's the benefit of the alloy idlers?
Stupid questions no doubt, but I'd value your advice.
Thank you

Hi,
My take on this would be as follows:-
1 I wouldn't bother. They just support the ballraces and there is no sliding or rolling friction on the shaft itself.
2 Yes. All the gear teeth in the box are making use of the same grease, it gets smeared from one to the other. If you load the teeth on the idlers the greas will be transferred to the layshaft and diff very quickly. The first time that you take it up to speed the excess will plaster itself on the inside of the casing.
3 The greases that are preferred for thrust races tend to have an extreme pressure additive. Some of them are black.
4 The aluminium gears are stronger but make sure they are lubricated. I have seen posts from people who know about these things recommend that the white POM gears are used as a first choice. I have used those for about three years without a problem. I would be worried about two aluminium gears running together. It is usually best, with metal gears, to have dissimilar materials rubbing against each other.

Allan1875
04-02-2016, 10:26 AM
Space the idler closest to the layshaft closer to the spur side by about 0.3mm to stop plastic Pom gear getting destroyed by the protruding bearing.

Clive Loynes
04-02-2016, 11:10 AM
Space the idler closest to the layshaft closer to the spur side by about 0.3mm to stop plastic Pom gear getting destroyed by the protruding bearing.


Or just fit a 5x10x3 bearing to the layshaft.
http://www.rcbearings.co.uk/index.php?route=product/product&path=4_10&product_id=1596

Monkeysmate
04-02-2016, 11:11 AM
thanks guys.
Is there a particular type of grease for the gear teeth? or is this less important?

Clive Loynes
04-02-2016, 11:46 AM
thanks guys.
Is there a particular type of grease for the gear teeth? or is this less important?

I use a general purpose lithium based grease but I'm sure you will be able to find something far more expensive in a model shop. :)

I'm in the process of fitting an Avid aluminium layshaft and multi-plate slipper to my Evo. I will use the POM (Acetal) idler gears with that.

I have some aluminium idlers that someone gave to me but I have never used them. The aluminium wear surfaces are usually hard anodised and you want to make that surface last as long as possible. For that you need everything to be clean and lightly greased.

If two gears are correctly meshed, the faces of the teeth actually roll across each other and there is no sliding friction. But nothing is perfect in this world. :)

Monkeysmate
04-02-2016, 12:22 PM
Thanks for the replies... i was also trying to avoid using the expensive mini tubes from the model shop...

Ta
Tim

Pitman Ed
04-02-2016, 12:34 PM
Clive, is there an Avid layshaft that fits, or are you modifying one to take the Avid slipper?

Clive Loynes
04-02-2016, 12:58 PM
Clive, is there an Avid layshaft that fits, or are you modifying one to take the Avid slipper?


I'm adapting the Avid shaft for the Kyosho.

Allan1875
04-02-2016, 07:32 PM
I'm not a fan of the ally idlers, the gearbox just isn't as smooth and I have tight spots in my mesh.

I stripped the pom idlers on a jump landing but that was before I knew about spacing the idler or getting the new bearing.

When you grease the idlers, I suggest clear/white grease over black grease. Black tends to be thicker and will cause a little drag in comparison to the white. Be careful though, as some white grease is really thick too!

Dadio
27-02-2016, 01:33 PM
Thanks for the contens of this thread ,I just fitted the narower bearing to the lay shaft on mine ,that probably saved me premature gearbox rebuild .

Clive Loynes
27-02-2016, 02:36 PM
Thanks for the contens of this thread ,I just fitted the narower bearing to the lay shaft on mine ,that probably saved me premature gearbox rebuild .


Great! :thumbsup:

Dadio
02-03-2016, 11:35 AM
Just a quick question ,there's no standard cover for the pinion and spur gears and mine might be used off road so I modified one off the rear motor gearbox but did I realy need a cover or would the gears be OK uncovered off road ?

Clive Loynes
02-03-2016, 12:11 PM
Just a quick question ,there's no standard cover for the pinion and spur gears and mine might be used off road so I modified one off the rear motor gearbox but did I realy need a cover or would the gears be OK uncovered off road ?


From a wear point of view they would be better covered, especially if you are running in dirty/dusty/wet conditions.

If you are racing then they must be covered. They will do very nasty things to a marshal's fingers if you are a bit early on the power. The BRCA rules require that they are covered.

I don't understand why you say that there is no standard gear cover. The body covered the gears on the pre-Evo car and that meets the BRCA requirements and keeps most of the dirt out as well. The Evo has a separate gear cover.