FG diff internals

[mooman007uk]

tried the fg diff gears today...had to take a bunch of the shims out..one in the bottom of the case...none in the ring gear or on the spiders:surprise: so will have to monitor it for any galling on the case..guess if it wears a groove in the case then i can put shims back in, what i should do is dremel a touch off each side so i can get the shim behind the spider gears
the dogbones are too short for the fg cups so a 2-3mm spacer behind the wheel axle at the back...they'll work up front no problem with the cvd's (and probably with dogbones with the short arms...i'll try one in the back to see if it'll still need spacers

http://i729.photobucket.com/albums/ww294/mooman007uk/nutech%20parts/DSC01642.jpg

with the bone shoved fully into the outdrive

http://i729.photobucket.com/albums/ww294/mooman007uk/nutech%20parts/DSC01643.jpg

bone all the way in diff cup

http://i729.photobucket.com/albums/ww294/mooman007uk/nutech%20parts/DSC01648.jpg

[Clubin]

Just might work! I sure hope it does, that'll be a bulletproof setup.

[grfilipp]

is there a position that the doge bone stays in the cups? like if you center it for example. there are some elcon conical springs that would keep it centered.

[mooman007uk]

if you centre the bone then it's not quite long enough on both sides and the ball part isn't in the slot in the cups so with springs or ear plugs it'll still get spat out

I came up with a simple solution and now i get full compression and droop and the bones are just peachy..about 1.5mm back and forth play at full drop and a tiny bit at full compression...at ride height there's about 1mm play...took it for a quick blast once i'd finished and everything seems 100%...now just need to get a few tanks on it to see how things hold up.

i just used washers to space behind the outdrive and one behind the diff cup. I tried a cvd and they're the same length as the bone so this spacing will work for those too but isn't needed in the front...seems though the bones are same front and rear the distance between cups on the rear is 5mm more than the front????

http://i729.photobucket.com/albums/ww294/mooman007uk/nutech%20parts/DSC01656.jpg

http://i729.photobucket.com/albums/ww294/mooman007uk/nutech%20parts/DSC01653.jpg

http://i729.photobucket.com/albums/ww294/mooman007uk/nutech%20parts/DSC01657.jpg

[Pipeous]

Excellent Smithers

[Clubin]

Nice work moo! Don't tell NuTech, they'll copy it. LOL And you won't get credit.

[mooman007uk]

i got some new fg diff cups today from high performance in Alberta..big thanks to them for a price that couldn't be beat for us Canuckians...fg have actually changed something:omg: a first i 20yrsLOL cups now have a wider bit on them as in pic and are 1mm longer which is a bonus

i did suggest to nutech ages ago that this mod using smartech parts instead might be they way to go...

you can get the smartech innards and cups for $88 for two sets and shipped from vision racing in hong kong...cheapest on the planet.
I'll keep the nutech bits up front for now...I've enough nuey diff parts to last a while

http://www.davesmotors.com/s.nl/c.885035/n.1/it.A/id.1924/.f

[Clubin]

Mine were the original style and after a bunch of worn out dog bones, and 5+ gallons of fuel I bought new ones. FG has been making them like that for 2 years already, they are stronger. They are indestructible. I have only ever broken one, and that was one of the old style out drive cups. The diff internals and the idea of the splines is awsome. Easy to get more fluid in.

[mooman007uk]

so got my cvd's today, had to take one washer out the outdrive side and add a smaller shim and threw in the new cups...oh so nice to be able to just slide them out...i should now have a near bullet proof rear end. whole drivetrain is now silky smooth
i now need to find bigger/fatter orings for the inside of the case...my diff still leaks out both drive cups and i have 2 orings per side stacked at the moment but with no big outdrive shims/washers inside it seems to have sped up...easy to refil now but leaks are a pain

at ride height
http://i729.photobucket.com/albums/ww294/mooman007uk/general/DSC01660.jpg

full stuff

http://i729.photobucket.com/albums/ww294/mooman007uk/general/DSC01661.jpg

full droop

http://i729.photobucket.com/albums/ww294/mooman007uk/general/DSC01662.jpg

[VancouverHobbies]

Hey Moo you best paint those cups bright orange, hate to see it ruin your day when one goes flyin and you won't be able to find it :damn:...all that claimed power you have going through them cvd's :beta:

[mooman007uk]

only flyin it'll be doing is flyin past your insect and smutty mongrel thing LOL

hopefully next weekend i'll be down to give some flyin lessons:dance:

[Clubin]

Insect. LOL

[mooman007uk]

ran yesterday at gas jockeys and not happy with the fg cups...the rear arms flex enough when tumbling and cartwheeling to allow the cvd ball end to pop out...happened a few times...lost one new cup straight away...so going back to the nutech hard cups and may try double pinning them and leaving out the spring for some extra strength...will see how it goes. the fg cups need to be 2mm longer and it would be perfect...

[Pipeous]

or longer cvds/bones I guess. couldn't you just tack something like an extra sleeve on the cups?

[mooman007uk]

if the cvd's are longer they'll bind in the diff cups when the suspension is compressed...fg's don't have as much articulation and the cups are a bit short..thought about tacking something on but to make it strong enough it'll get the cup cherry and bugger the hardness up...i had tried more camber to keep it together but think that's what broke my rear hub and stretched an upper arm ball joint about 5mm...suspension bound up and something had to give...
Scott had no issues at all yesterday despite some exuberant driving:beat dead horse: I'll go back to the nuey stuff, i've only broke one pin in 30 tanks or more so they hold up fine...i just had to fiddle...as you do... and my fiddling was the root of most of my downtime....d'oh...had to try it though cos would have been the ultimate setup

[grfilipp]

have you thought to install the front arms/hubs at the back also?
i have a titan that has that exact problem (as it lacks the spring diff) and i am working at the moment on installing the front suspension at the back as i never poped a cvd at the front. longer cup or a shimed cup just binds when fully compressed or extended.
my understanding is that the problem is the geometry of the arms/hubs that forces the cvds to travel that much in and out of the cups.

[mynameismud76]

Thinking about getting rid of the spring thing in cups.

Got some centre diff cups from FreePrawn to drop in the rear, might work. The spring thing binds too easily after muck gets in there =(

Might just work =)

[grfilipp]

but isnt the spring that prevents the pop out problem?

[mynameismud76]

Yes I guess that's the reason behind the design, but sometimes when compressing the cups, it doesn't spring back out again..too much dirt? cup shaft warped (possible, when rebuilding rear diff, the cups felt a little reluctant to go back in)?

Personally, perhaps I run too much camber (have photos to support this..LOL), I've yet to have a bone pop out on me..fingers crossed LOL.

[grfilipp]

i believe that the problem is that the hubs "tilt" line is further out than the cvd/dog bone one. so when the arms move up and down the shaft is too short at the end points of travel. the front suspension keeps the tilt point of the shafts closer to that of the arms ( the cvd seats inside the hub).that is why the spring is needed( when it works).
what i am going to try is either install the front suspension at the back or a combination of front arms and custom hubs.

[Pipeous]

that's what the droop screws are for... to limit downtravel.

[grfilipp]

mt arms are too long for droop screws to make a difference. too much flex. alloy arms maybe. straps or something like that also might help but i never liked the idea.

[grfilipp]

well i went i ahead and tested my idea and it worked.
i installed front arms at the back and made some custom hubs.
with stock parts when the suspension travels down the pin moves away from the diff cup, when it moves up it goes in. that travel (on a titan at least) is maybe 5 mm and that is alot. when tried to put some washers it just binds when going up.
using the front arms and making my self some hubs i minimized the in out travel in the diff cup. the arms are around 7mm shorter so the hubs have offset that make for that distance by moving the inner bearing more to the inside so the distance at the end is the same for the cvds to work. usually i would loose a diff cup every time i would make a sudden turn with some speed and the truck rolled. yesterday i went through 2 tanks of fuel without the slightest problem. no matter what i did to the track nothing popped.
i will post some photos later.
hope it helps if the problem is similar with the nutech as well.

[grfilipp]

http://i598.photobucket.com/albums/tt70/grfilipp/TITAN/IMG_0406-1.jpg

http://i598.photobucket.com/albums/tt70/grfilipp/TITAN/IMG_0407-1.jpg

[mooman007uk]

I abandoned the fg stuff, cvd's kept popping out so i put nuey stuff back in...also changed the pivot points on the rear upper arms so there is less in and out travel of the pin in the slot...had a quick run yesterday and all seems well