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? about FLMs hybrid bulks

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k5floyd

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can you use any 1/8 diff set up or just the Hot Bodies diff with FLMs hybrid bulks? also i recently saw in RCCA magazine that losi has developed and automatic locking diff for their 8IGHT buggy. would that diff work with FLMs hybrid bulks? anymore information on this diff setup would be greatly apreciated. thank.
 
If you look at the diff gears that losi has, they are very small in relation to a standard 1/8 MT diff, or a general buggy diff for that matter. To me, they look a bit on the fragile side and may not take the abuse a MT will throw at them. With a buggy, you have a center diff and less rotational mass on the tires, so the forces that will go through the diffs won't be nearly as brutal as if they are in a solid center driveline MT.

They are a cool idea though. With sealed diffs, you can run heavy oil in them anyway to get a posi-traction type feel.
 
Not all diffs have the same mounting and overall dimensions. I contacted FLM when I did the conversion and the hot bodies diffs are the ones they pointed me to so that's what I got. Can't go wrong with the manufacturers suggestions if you ask me. I imagine there may be other diffs out there that will fit but I don't know which ones they could be.
 
ordered flms big block chassis, hybrid bulks, hot bodies diffs, and the outdrives needed all from rc-monster.

i got it all put together but my problem now is the pinion. when pushed all the way in it hardly makes contanct with the ring gear and easily skipps teeth when turned by hand. if i pull it out, the pinion shaft sticks out passed the slots in the output drive and the rear drive shaft just barely wont fit.

i guess i could grid the end of the pinion shaft down but would like to avoid that. what are my other options, if any? is there a way to shim the ring and pinion?


also reguarding my original post. i have since found out that flms hybrid bulks use mp7.5 and hyper 7 gears. both of which have aftermarket torsion or locking diffs available
 
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Yes, you could certainly shim the pinion gear so you get the proper mesh. I did not have any issue with my driveshaft fitting but I'm not using their driveshaft anyways.
 
where can i get a shim kit and where are the shims placed?
 
not really sure exactly where to get the shims. I do know the inside diameter is 8mm though. You place the shims behind the pinion gear inside of the diff case
 
that would just push the pinion further in and in doing causes it to hardly make contact with the ring gear and skip teeth. the mesh is good with the pinion pulled all the way out.
 
k5floyd said:
that would just push the pinion further in and in doing causes it to hardly make contact with the ring gear and skip teeth. the mesh is good with the pinion pulled all the way out.
Click to expand...

No, adding a shim to the inside behind the bearing will push the pinion closer to the ring gear and cause binding if it's shimmed too much. If your mesh is best with the pinion pulled out as far as possible then you simply need to make sure the pinion is out as far as you can get it when you tighten the outdrive down on it while making sure the outdrive is in contact with the outer bearing.
 
that is correct except i had the diff open and looked at it with the pinion pushed all the way in and all the way out. all the way in it moves AWAY from the ring gear. yes i mean away, because its perfect pulled all the way out but when pushed in it comes off the ring gear closer to the diff cup.

now if i have it pulled all the way out and the outdrive is contacting the bearing, the pinion shaft is just passed the slots on the outdrive thus causing the driveshaft to not fit.
 
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OK, I'm following... When you push the pinion all the way in, it actually begins to pass the ring gear teeth right? I remember seeing the same thing. I would mount the outdrive to the pinion shaft while the diff case is unassembled so you can make sure the mesh is lined up before closing everything up. You probably don't even need to shim. I did not put any shims in mine because the outdrive keep the pinion from entering the case too far
 
you got it now. but i have already done what you said and now the pinion shaft sticks out passed the slots in the outdrive which doesn't allow the driveshaft to slide all the way into the outdrive causing it to not fit.

its either the driveshaft fits and the r&p dont mesh

or

the ring and pinion mesh and the driveshaft doesn't fit
 
any other ideas besides grinding down the pinion shaft?? i guess i could get some custom outdrives and driveshafts. the help is much appreciated
 
OK, you're gonna need tio determine what exactly is causing the driveshaft to bind because you absolutely need to have a good ring/pinion mesh. Is it the overall length of the shaft?... in which you could simply grind down the tip a tad. That wouldn't hurt. Or... is it that the cross pins bind in the end of the outdrive slots?.. in which you could grind the slots a tad deeper. You're just gonna need to know which one of those is causing the binding when yor mesh is good.
 
it is the pinion shaft that sticks a tad too much out. i will grind it down. i just wanted to see if there were alternatives and to make sure it wouldnt hurt anything by doing that. thank you very much i cannnot wait to have this thing running.
 
k5floyd said:
it is the pinion shaft that sticks a tad too much out. i will grind it down. i just wanted to see if there were alternatives and to make sure it wouldnt hurt anything by doing that. thank you very much i cannnot wait to have this thing running.
Click to expand...

Should be fun. How do you think I feel? I've had that setup for at least 6 months and I'm still not ready to run it. What's your powerplant?
 
i eventually settled on the ofna picco .28. by far the largest motor I've ever owned. i have played with .18s and .21s way back in the day when the tmaxx was fairly new but nothing with as much power as this motor so I'm pretty excited to have this thing put together and running.
 
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