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Chilihook

Big Bear Build (Triple B)

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2 hours ago, Crash Cramer said:

Forgot to comment. You called the motor "no-name" and it is a bit far from the truth. That looks to me to be a Speedworks Monster Mash and it was made by Trinity I believe, BITD. :lol:

Yes, that was Dawn. I have heard that it promotes rust, but I made sure to do a light coat of machine (3-in-1) oil over the parts before they went back together. Hopefully that will do the trick.

That's exactly what it is! I have no knowledge of them at all. Is it worth keeping? I was going to try out the M480-RS that I have from my original BB in this truck...

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I will see if I can dig up the specs on that old motor, but yes, it is worth keeping. Go ahead and have the original motor mounted into the truck.

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The 480 motor is the version 1 origial motor.  My Big Bear is the version 2 that had the 540 motor. The version two had 3 bevel gear differential but I have not seen a replacement set available lately so I use version 1 , 2 bevel gear set. Yours is the aftermarket ball bearing differential.  Once my brushless motor and esc come in for my wt-01  I'm switching my big bear to the tamiya esc and the new 540 motor that was stock on the tamiya. Although if what I read is correct, the 25 year old silvercan 540 might be more powerful. Sorry for rambling, I'm still learning. 

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Couple of notes: the 480 might be a goner - it spins well and all, but the two leads have come off over time and took a good amount of the contacts with them. Maybe salvageable, I don't know.

Reassembled the rear end and transmission without any issue; the ball diff is smooth and silent - but when both axles are turned in the same direction, there's gear chatter and it occasionally locks up. During assembly, the pinion gear looked a little small to me, like the teeth wouldn't mesh with the spur gear well. So I'm going to have to disassemble it and do a little more checking of pinion gear teeth and numbers and such I think.

Oh, and the windshield is toast - anyone know where I can get another? Thanks!

IMG_4785.jpg

 

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try the link in my post it starts a cool gear generator. :)

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On 2/1/2017 at 5:12 PM, waterbok said:

try the link in my post it starts a cool gear generator. :)

Very cool! I have to take apart the transmission and get an accurate count of the teeth on the diff.

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Designed rear axle sleeves to have Suzuki Jimny rims and tires be a direct fit to the Big Bear.

Screenshot_1.png

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Alright, I got my 3-d printed axle sleeves today! I was very lucky and had all of my measurements spot on except for one - the inner diameter of the sleeve itself. It should have been at least a half mm bigger than I designed it. No biggie, I just reamed it out to size and it fits fine.

Using several bushings, I made an impromptu spacer for one of the front wheels to see how it looked and noticed that the front wheel is closer to the body than it ought to be. Pretty sure this is due to the offset of the wheels. Does it matter overly much?

IMG_4803.jpg

IMG_4804.jpg

IMG_4798.jpg

IMG_4805.jpg

You can see the offset difference below.

IMG_4806.jpg

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Actually, I can't see offset difference, but HA HA  my eyes are failing me. Perhaps a bird's eye view from the top with the car lined up with all those lines lined up to help see it. Still looking nice and at least you erred on the side of too small because it is easier to enlarge the hole than it is to shrink it.

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that doesn't look too bad, I was thinking that as the Big Bear tires are so big, the Tamiya ones might look a little small in comparison, but it looks pretty good, well done!

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nah, got some BigBear wheels laying around here and there's big difference in offset between the front bearingholder wheels to the rear "+" drive ones. Probably need to add an inch length for the fronts :) 

i see it's a common failure spot too, the long tube bearingholder can be ripped out of the wheel by impact

what's the weak point in the gears? got a bunch of gears that came with the wheels, should get around to sorting them out. Don't own any more Marui wrecks so got nothing to reference them too.

 

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I'm not sure what causes the failure of the stock gears, I would guess cheap materials and weak design. Although you'd figure with so few moving parts in the transmission that would be a strength, not a weakness. There is noticeable play in the transmission after it's assembled. No bueno.

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The v1 2 gear diff is a bit under designed and can't handle the stress

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22 hours ago, Chilihook said:

Couple more pics to show the difference in front and rear wheel track.

IMG_4815.jpg

IMG_4812.jpg

WOW, my eyes still work. Great photos and it still looks good.

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On 2/1/2017 at 4:55 PM, waterbok said:

Could you give me the tooth count and outer diameter of all the gears that way I could try to figure out what kind of pitch or mod each gear has.

My gues sofar is that the diff gear has 42 pitch and the motor pinion 48. (V2 has 32 pitch)

84Wuvk1QRlvtBRmIWgSahsWILvhYzYhBrEfz_LC1

RuxhtWhMigGhI0JAriCr4tAb2gjpvGc8-wnu7WJl

 

Took the trans apart again last night to try to figure out why the gear teeth were grinding/locking up on the Triple B. Got a tooth count on the pinion gear (18), the idler gear (32), and the diff has 60 teeth. I'm not sure, but something seems wrong with the diff. When the trans is fully assembled and one wheel is engaged, the differential is very stiff, it takes some effort to move it. While it takes effort, it does move freely, just stiffly. When both wheels are engaged, rotating forward or reverse the transmission seizes up and won't rotate the wheels. I think I have a spare set of original transmission gears that I might put in to see how they feel.

Does anyone have experience with these ball diffs who can tell me what they're like or how they should feel?

Thanks!

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Mmm motor pinion 18T and idler 32 kind of dont fit in my book, do you have outside diameter of the gears?

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I still have to get them - today being Valentine's Day though, the Mrs. probably wouldn't be too pleased if I went to the basement to play with my r/c, lol. The pinion gear is really small though... 99% sure that's where the issue is.

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16 hours ago, waterbok said:

Mmm motor pinion 18T and idler 32 kind of dont fit in my book, do you have outside diameter of the gears?

Pics of the measurements @waterbok :

IMG_4820.jpg

18 tooth pinion = 10mm

IMG_4821.jpg

32 tooth idler gear = 20mm

image.jpg

60 tooth differential = 38mm

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Bump!

Anyone have any thoughts on why the gear teeth would be chattering and or locking given these measurements and tooth counts for the gears?

Thanks!

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Thanks @waterbok, even with the cool link, I'm not sure what you mean. Would a 16 tooth pinion gear solve the problem or is it something that has more to do with the size of the teeth on the gear?

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These pics showed up on eBay.  You have to cut the stock axels to make the ball diff fit. 

IMG_1917.PNG

IMG_1918.PNG

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