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HPI Trophy Truggy and Buggy Owners Club!

henzy190

By henzy190
in Buggies, Truggies & Stadiums

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dazp1976 Proficient

dazp1976

Posted
Posted

Aye, everything appeared to look normal, main gears at both ends were seated fine and the wee bars that go threw the cups were intact, the "planet gear" (the little ones) again were sitting in the correct locations, the bars that they go on to were again undamaged. When you remove the pinion gear and place the big internal gear from that back into the diff, apply a little pressure with your thumb and turn the other cup, you can feel the gear moving as it is suppose too, also putting the gear back into the pinion and holding it while turning the pinion cup, you can see/feel the internal gear turning with the cup

 

the internal gears

 

 

 

Allan

Sounds a strange one that. The only issue I've had using the hard gears is the housings shrinking a bit with heat and grabbing the gears locking them up. With the steel ones I had what you are saying kind of happen, the gears looked fine by eye but looking closer the larger outer ones had worn down slightly on the teeth and didn't bite. Are the little washers still there behind the little planet gears? Housing warped at the bearing end? Correct thickness gasket used on the end? If these are fine I would have said it's wear on the larger ones as it doesn't take much and they do look fine just looking at it by eye.

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pug=309 Explorer

pug=309

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Sounds a strange one that. The only issue I've had using the hard gears is the housings shrinking a bit with heat and grabbing the gears locking them up. With the steel ones I had what you are saying kind of happen, the gears looked fine by eye but looking closer the larger outer ones had worn down slightly on the teeth and didn't bite. Are the little washers still there behind the little planet gears? Housing warped at the bearing end? Correct thickness gasket used on the end? If these are fine I would have said it's wear on the larger ones as it doesn't take much and they do look fine just looking at it by eye.

Ill give that a looky and see

 

Cheers

 

 

 

Allan

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pug=309 Explorer

pug=309

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I was thinking that. I use heatshrink for mine but it doesn't stay that well.

Ive seen proper looking cvd boots listed in the bay, but not like those, those ones do look like they'd stay in place better

 

 

 

Allan

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Sully Contributor

Sully

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Posted

Yep it's the heatshrink tubes, an idea from mydoddy69, they work well for me and not expensive.

@dazp, the link not working for me but will have a look around the site and see what I find.

P.s. The 17mm conversion set you sent is fitted and works great, thanks.

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stevo2551 Explorer

stevo2551

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I'm running standard on my buggy I think a 15/46 but I'll know for sure later on. Another stripdown on the cards, another front diff issue of some kind. This time it was 4wd off the floor but on the ground just rwd. Took a nose dive and then it was just tail happy after that...

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dazp1976 Proficient

dazp1976

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I'm running standard on my buggy I think a 15/46 but I'll know for sure later on. Another stripdown on the cards, another front diff issue of some kind. This time it was 4wd off the floor but on the ground just rwd. Took a nose dive and then it was just tail happy after that...

Hi bud. Sounds like the center or front diff spider gears worn out or the oil got cooked. If you proper thrash it I recommend putting 101142 hard gears all round if you haven't already. If running stock grease in the diffs then switch to oil as it gives the gears much better lubrication. The grease just gets thrown around on the housing. If you are using oil then go to a slightly higher weight to prevent the gears cooking.

Edited by dazp1976
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dazp1976 Proficient

dazp1976

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ayup! 

 

is it true the the savage bulletproof diffs fit the trophies? and what exactly is diff shimming and is it important (sorry noob alert)

I have heard that they fit but haven't tried it myself. I do have 1 sitting here that has knackered screws so I might have a look but I think they would only use the alloy case. 9/29t won't be any good and the drive cups are either 9 or 11mm and the Trophy shafts have a ball end of 7mm thick with a 13mm pin length so it would rattle about a bit.

Shimming is very important to get a good mesh between pinion and ring gear. If they are not close enough they WILL skip and eventually wreck the teeth and it won't take long to happen. Too close and they will bind causing excess heat in the diff and the motor. Generally 2 shims 0.2mm thickness are behind the pinion bearing and 2 shims 0.2mm thickness are on the ring gear side of the internal diff. Sometimes though the cases may differ meaning the diff has more lateral movement so more or less maybe needed. If you hold the pinion still on the output cup you should be able to wobble the internal part easily but very little before it hits the pinion tooth.

Look at the D8T manual from page 15 onwards (linked) it is way more detailed than the rtr manual and the parts are identical except for a different thickness pinion shaft.

https://www.hpiracing.com/assets/documents/instruction_manuals/67800-d8t-glb-m-v1.pdf

Edited by dazp1976
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pug=309 Explorer

pug=309

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I have an alloy "bulletproof) Savage diff, ichanged the outer gear for my lightning/trophy one and it fits, ill take a pic of 2 later for you (once i've changed the seals, oil and gasket)

 

 

Allan

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stevo2551 Explorer

stevo2551

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I'm thinking it could be the internals of the front diff ready for an upgrade as suggested daz, I've had it complety appart Andre times recently so it's all shimmed up nicely as far as I can see/feel. I've had her a while and had good use out of her so I think she deserves some new bits lol

Before I strip it all back, is there a way of testing the 'bite' that the diffs have separately? I know you can lift it up and turn a wheel to test, works fine like like this, so thinking worn rather than actually broken.

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dazp1976 Proficient

dazp1976

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I have an alloy "bulletproof) Savage diff, ichanged the outer gear for my lightning/trophy one and it fits, ill take a pic of 2 later for you (once i've changed the seals, oil and gasket)

 

 

Allan

Alloy housings and harder spider gears are definitely the way to go with these. I'm running the innovative rc ones on one of mine. I have a Savage diff lying around so I'm gonna have a look at that for the other one for something to do :)

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dazp1976 Proficient

dazp1976

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Are the dif internals the same part numbers? ie. Front and rear are the same, so if I got 3 sets of hardened then were on a winner?

Yes buddy. 101142 all round. The plastic housings are the same on all 3 diffs. Prices vary quite a bit so shop around. Lowest on ebay is

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