poor judgement

got some new diff casings and diffs of ebay, and fitted them with a set of hd gears in the rear.

i managed to drill the centre shaft with a 2.5mm drill bit, after grinding a small flat on the end. a cen hex pin is a nice interference fit. it drills easier than u would expect, i used a hand electric drill and a pair of pliers... the shaft flops about a bit in the front cup, as its missing the "ball" part of the bone end, but i reckon a bit of fuel hose stretched round it will cure that.

engine mounts are done, but with a 18t pinion on the 47t spur, the flywheel is just catching the diff casing - need a 20t pinion really, but i killed my last one... i may well take some off the flywheel to cure it.

pics if u want em when my cams batts are charged.

still need a brake cam and fuel tank, rx, and thats about it i think. hey i said it was a back burner...

Scouser

Definitely post some pics mate. If you think about it, now that CEN has put the FF on the back burner, the people here on this forum are in fact the cutting edge of CENs' development of the Fun Factor series of cars. Worrying really!!

rolland

CEN is definetly getting a whole lot of R&D for free thats for sure. Hopefully they will use some of our ideas and suggestions when they re-build the FF's.



rolland

poor judgement

gotta say i havent seen cen on here for a while... again... dunno where jeremy went with his competition ideas etc - shame really.

anyway, some pics. nothing that new really, just refined what i had done before. the drivetrain is now rock solid and very smooth. once i get it finished, i will strip it back down and get pics of anything in particular that u may want to see etc. not that there is anything particularly clever, holes where just drilled where bits fitted with many original holes being used. shame i had to cut such a large clearance hole for the spur tho - its bigger than i need as i changed my mind about how i was going to mount the diff half way thru... typical...

rolland

I hope that is the Rally chassis and not the JT chassis that you are gringind holes into.
I saw a complete center diff section for a ofna buggy on ebay a while back and it started to give me ideas about my stock chassis.


rolland

You must have been posting the pics while I was typing.

alvinl

Sorry if this is a really stupid question. What is the advantage of a center diff? It looks like the weight distribution is better and I am guessing better strength in the divetrain. I ask because i honestly don't know. Thanks.

poor judgement

yea, i still have to edit a post to get pics up for some reason...

mmm an ofna centre diff would open up a lot of possibilities, i have looked at that option. in the meantime i just about have all the cen bits, so i guess we will find out if it actually works soon... famous last words...

alvin - a centre diff is supposed to make the car handle better and allows independent front and rear brake adjustment... personally im just doing it cos i cant stop fiddling...

edit - sorry it just read wrong...

rolland

A center diff in theory will apply power to the front or rear diff that has the most traction. It will also free the front end up while cornering and on hard braking. It also has the benefit of a front and rear brake so these can be adjusted to apply more braking to either the front or rear independently or simultaneously.

With the Ofna center diff it is sealed so it can be tuned with different oils and the spur gear selection is greater. I will have to search to see if I can find one with the 2 speed setup. I'm not ready to give up the 2 speed, I really like hearing the little bugger shift.

rolland

alvinl

Thanks for clearing that up for me. I knew there had to be an advantage to using a center diff because I see a lot of vehicles utilizing it. It would be nice to see CEN take advantage of all the free engineering going on here. You guys are doing some ground breaking things with these cool little trucks...

rolland

They might get around to the FF after a while but right now there priorities are the Matrix, Mini Madness, and the Genesis. With the release of the Madness and the Matrix coming up is why I think they haven't been around lately. Or Jeremy could be on vacation.


rolland

poor judgement

ive never seen a 2 speed centre diff myself

the only way i can figure out a 2 speed centre diff setup, that will work on the funfactor using mostly standard parts, involved a drive shaft running inside another, tubular driveshaft, which kinda put me off... for now, might look at it again once this single speed is done tho

Scouser

When you have finished drilling holes in the stock FF chassis and everything is working as you like, send the chassis plate to the blokes at Highpath and get them to cnc you a brand spanking shiny new one made from something a bit more durable than the stock CEN ali. That is a big flywheel hole and a very powerful engine, could be a bad mix for such a soft metal! The centre diff is looking brilliant though mate, stick a patent on it and sell it back to CEN!!

poor judgement

might ne a bit too pricey for the chassis mate... bummer.

right, i guess it was bound to happen sometime - im thinking of putting a centre diff in my mt. its just "too much wheelies and trying to keep hold of it" for my liking now, the novelty has worn off... dammit, getting it to full throttle in 1st to try to find 2nd is hard enough... found 2nd - wish i hadnt... no crash but man its silly. i need more control, and a 2 speed isnt really necessary - it gets too far away too quickly to drive safely (for the trucks health not the tourists)

soooo, i reckon i can gat an ofna/hobao centre diff to fit the 2 brake seats - hello dremel... this would mean a good selection of hard as nails spurs and pinions, 2 brake discs - maybe 4, and still retain the option of swapping back to the 2 speed if i want to...[X(]

im pretty sure it will have crossed a couple of u guys' minds - any thoughts or ideas?

Scouser

I did think of merging some buggy diffs to the FF but my line of thinking was front and rear diffs so as to allow stronger diff gears and thicker driveshafts etc. A full on centre diff would certainly solve your wheelie problem, have you thought about the placement of the throttle servo? If you can get this to work it will be a huge step forward for thr FFs handling.

rolland

I have converted my MT over to buggy diff cups, cvj's, nuckles, and wheels. So far it was a fairly easy swap and the hadling is unbelievable. The T-Maxx diffs are almost the same size as the MT's diffs. It migh be possible to use the Maxx diffs but so far I have had no problems or adverse wear on the stock diffs with the hardened cross shaft so I am not going to try to convert them until I have problems with them.

Instead of trying to adapt the Ofna center diff to the FF brake seats why not use the whole Ofna center section. Like something pictured here.
http://cgi.ebay.com/Ofna-differencia...QQcmdZViewItem
or
http://cgi.ebay.com/New-Ofna-1-8-Sca...QQcmdZViewItem
I can't post the all of the links because of the number of items but if you went this route you will be able to have the front and rear brakes.


rolland

Scouser

Yeah, that's definitely the way to go. Its going to make the diff much more stable having it in its own casings rather than two CEN brake seats and it comes with the brake connections and shoes included, winner!

poor judgement

i hear what ur saying, but the height of the bearing in the brake seat has to be spot on with the height of the bearing in the rear diff to work the way i have the centre shaft set up.

im looking at possibly using 2 cen alloy brake seats. one will need a bit of dremel work for sure, but the rear seat should be fin as it is. they are a good bit chunkier than the plastic ones u see...

as for front and rear independant brakes, ive already sorted that with the 2 cen seats. plus - as one of the seats is staying in the original location, the mounting holes are already there and in the right place etc.

besides - ive got a hobao/ofna centre diff on the way now, along with some 1/8 buggy wheels and tyres - gotta see what rolland means about the wheels...

having said all that - the complete ofna diff/brake setup does look nice! ah well, i guess we will see what happens.

still very open to ideas tho guys

poor judgement

hmmm suppose i could just use the ofna diff and seats with a dogbone shaft at the rear of it, i found that they are easy enough to make up. i have enough shafts here that i could use... could even have a cvj on one end...

ill see how the diff offers up to the cen seats, if its too much work to do it so that its got a very good chance of holding together, then i will grab the ofna seat setup to try too - i can always sell it on i guess if its a no go.

ill ask the sellers about uk postage, cheers for the links, they work out real cheap with the exchange rate. [8D]

Scouser

I was going to say, if you got the complete centre diff set up and the height was a little off, a cvd would go some way to negating any problems with power transfer. The Savage has a relatively large drop in distance from the centre gearbox to the front and rear diffs yet the dogbones cope with it no problem.
If this set up works with CEN brake seats though then its all the better for retaining its' 'CENness'. Two alloy brake seats though at £42 a pop, its a pretty expensive diff this eh?

poor judgement

looking at the truck again, it would mean a good bit of chopping to get the ofna seat over the engine plate, but then it would be in the way of the engine mounts. i need offset seats like the cen ones - remember my flywheel clearance probs? theres just not the space on the chassis to do it any otherway... i dont think...

£42? nah, i got mine a lot cheaper than that mate - i aint completely insane. one is in the post, the other is on the truck but needs drilling and tapping - threads are pretty shot, gonna go to m4s - should hold it well!

Scouser

Got to ask, how is the chassis holding up with all this cutting and drilling going on? That aluminum is pretty soft to begin with but are you worried about it giving up on you?

poor judgement

its a bit floppy now aye... with the top m3 chassis stiffener its better, but if that gives then its dead. im just messin about, if it works out then i have the choice of standard, homemade or custom chassis - could just buy a 1/8 tho... or leave the damn thing alone...

crashing isnt high on the agenda tho, and i have an obstacle free area to bash in, and its stiff enough to cope with that, so it should be good... hopefully

would be nice to have a blank jt chassis - fat chance of that tho, so just makin do [&o] lol

rolland

The chassis is just a flat piece of aluminum that is cut out and them bent up. It would be rather labor intensive as far as the cutting but not that difficult to do your self. You could also scribe the aluminum and give it to a neighbor hood kid to cut out in shop class.

The Ofna seats I believe are shorter than the CEN ones. If you make a spacer to acommodate the height difference you can include the offset that you need to get the correct clearances. Or you can use a 60+tooth spur (which is what I believe they come with) on the center diff with a 12 or 13 tooth clutch bell.
As long as there is no binding on the dogbones the angles should be no problem.


Crashing is never on anybody's agenda but when you least expect it happens. A cartwheel at 40mph is potentialy as devastating as hitting a curb.

I'm pretty sure you won't be dissapointed with the buggy wheels and your axles will thank you.



rolland

Scouser

Buy a 1:8? You thinking of getting a buggy then?

poor judgement

maybe.. or a truggy... got more 1:1 stuff to be getting on with tho really, for the time being at least...