Have any of you guys seen a broken output shaft on a NP205?
The reason I'm asking is I'm getting ready to built my drop box and was thinking about building my output shaft the same size and splines as the 205 so I could use the same bearings and yokes,

I guess while I'm at it, what are the biggest yokes I can get for the 205? I don't know how true it is but I have heard they are limited to a smaller yoke, but you know how rumors go,

and one more thing has anyone run across a place I can buy sprockets with splines cut in the bore?

 

I remember seeing a catalog once that had a lot of specialty parts for mud racers in it, including a whole chain drive setup or you could get individual parts. I'm thinking they were called Power Pro. I also know a fellow racer that used NP208 parts to build his own chain drive system. He used two front output shaft/gear assemblies sandwitched over the driven sprocket. The 208 sprockets werent doing anything other than to provide a place to bolt the driven sprocket to(basically being used as a flange)

 

Not to detract from your thread, but did you ever find a supplier for dana 70 spools???

 

I talked to a friend of mine (local machinest) the other day, and he said he knows a guy (another shop) that may be able to build one, when I find out more I'll let you know, I have seen a couple trucks on the web that said they were running a D70 with a strange spool, but when I called strange they said they do not build much for the D70, so I asked them about a custom job and the lady on the other end said they can't do that, I think I got blown off,

I found the web page for power pro earlier tonight, pretty cool stuff, I like there chain kit, but their sprockets only go up to 26 tooth, I read somewhere that in a 60 pitch chain you would not want any less than 17 teeth on your sprocket so to make 2:1 I will need a 34 tooth lower sprocket,

Buy the way what size chain and how many row was you friend running, power pro says there kit is D60 (double 60) I was planning on running triple 60 but now I'm thinking that might be a little overkill, triple would help to keep from breaking parts, but a lighter rotating mass couldn't hurt either,

 

I remember a few months ago, there was a white *hevy on the cover of a mag, claimed he was running a spool in the rear 70. Makes me wonder if someone is actually making them or if people are just lying about it. As far as the chain size- Im not an expert on roller chain, but I do know what size 60 is, and I'm fairly shure he wasn't running 60, but it wasn't far off, probably the next smaller size. He was running double. Also, the yokes on a 208 are larger than a 205- I'm not for shure if the u-joint caps are any larger in diameter (I think they are though) but the cross is most definitely bigger. Were you going to make your chain drive an enclosed unit with oil in it???

 

Yes I am, just to give you a run down on what I'm planning right now (subject to change without notice) I have an input shaft from an NP205 that I cut the gear off of then turned down to 2.375" when I get my sprockets I'll finish the machine work, the top sprocket will be 17 tooth double 60, I'll machine the inside bore so that it has about .002" press fit then have 4 keyways broched in it to match the keyways that I'll put in the input shaft, after I'm sure it will all fit properly I'll press the sprocket on the shaft & tig weld it on, then for the bottom I was planning on building the output shaft so it would accept NP205 yokes on each end, then make the center of the output shaft big enough to have 1.75"x10 splines cut in it, that way I could use power pro's sprockets on the out put shaft, unfortunatley thay only go up to 26 tooth sprockets, that would give me a little over 1.5:1 reduction, but I can use their 17 tooth sprocket when I want 1:1, I'll probably order a 35T sprocket from a book I have and have the 1.75"x10 splines cut in it, I think it will be handy to be able to change my ratio fairly quick, (pull a driveline, yoke and cover, then slap in a different lower sprocket and chain, put back togeather and away we go), as far as the housing I have a sheet of .500" thick aluminum plate that I will use to build it, it will consist of a front with the sides welded to it and a back that bolts on, after I have that all assembled I'll set it up in the mill and bore the input and output holes to accept NP205 bearings and use the 205 retainers to hold them in, & since the retainers have the seals in them I won't have to worry about dirt and mud getting in the bearings,

sounds easy enough,

I think I'll order a couple sprockets from power pro tomarrow night,
Igot to thinking about the 205 output size so I mesured it and it is 1.375" the pinions it the dana 70 axles I'm running are only 1.25" so I think they'll brake before my out put shaft does,

 

I don't think that is necessarily true when my old truck had a np208 in it, but when I built the new truck, it has a np205, I am using the same driveshafts (but shortened to fit) with the same ujoints, spicer 1330s I think?, although my spare np205 does have the smaller yolks on it. and I can't remember where now but someone was making a 1350 yolk fo rhte np205.

 

No...one of the big outfits were indeed making D70 spools, but it was at customer request. I talked to them myself and priced them out and they were only a little bit more expensive than a "off the shelf" spool. I can't recall, but I think it WAS Strange. I know its talked about in an old thread on here somewhere with specifics. I think I even gave the phone #. Either they've discontinued the practice or you just talked to the wrong person? I would think the latter is more likely than the former since D70s are becoming more popular.

edit: heres the thread......I guess its not that old after all. Apparently they told fishy they'd do a custom one too:

http://www.fordtrucks.com/forums/sho...ghlight=spool+

On another note, I'd bet many of the rigs you see claiming to run a spool have lincoln lockers. Same effect...

 

I am running 1350 CV's on my 205 front and rear. you have to buy flanges to bolt on the CV heads.

 

Well I just orderd two sprockets 17T and 26T & a length of chain from power pro, tomarrow I'll order another 17T and a 35T sprocket from martin that will give me three ratio's to work with,1:1, 1.52:1, & 2.0:1,

I think I'll talk to Ron (the local drivline gooroo) tomarrow or the next day and see if I can get the spicer 1410 siries yokes for both the NP205 and the Dana 70 pinions if not I'll go with the 1350 siries instead, I can also see if he found anything out about the spool for a 70,

 

A few more thoughts- where did you hear that you should have at least 17 teeth on size 60 chain???? What gear ratio do you plan on running???? (in your axles, that is) I run 5.86 gears in my 70's with 38 inch tires and a 420 engine and high range is perfect- low side is just too damn low!!! I am concerned about your interchangeability of chain/sprocket combo's. Isn't there a good chance that when you go to change your gearing that the different chain and output sprocket will require a different centerline measurement between input and output shafts?????? Basically because there is no way to take up or let out any slack.

 

I don't remember for sure where I heard/read the 17T theory, but it was explained that with less than 17 teeth the chain has to basically bend around a tighter radius, (working the chain more) creating more resistance, also the smaller the sprocket, the less teeth meshing with the chain, I really do not remember if I read that some where or was told that (way to many numbers & theories running around in my head),

As far as gears I already have 5.13:1 in the front diff, right now I'm trying to decide if I want to match the front and rear or go a little lower in the rear, so the front is pulling, but the next ratio from 5.13 is 5.86:1, I don't know if thats going to be to big a difference or if it will work good, this will be working with 44" tires,

When I build my case I will base the centerline using a 17T top sprocket (input)
and the 35T sprocket on the bottom (output) and fab the case to work with that combo, then when I change ratio's I will leave the 17T sprocket on the top and put a smaller sprocket on the botom (ie 17T top & 26T bottom = 1.53:1) with the smaller sprocket there will be plenty of room since it was designed for a bigger sprocket, now for the centerline when I put a smaller sprocket on the bottom I will also have to put in a shorter chain to make up the difference in rollout of the bottom sprockets,

I would like to be able to change ratio's because the truck will be running several different events, (mud bogs will likely be 2:1 along with truck pulls, sand drags might like a little less reduction so 1.53:1 may work and for the local street drags I'll put on a set of 35"-38" tire and run 1:1) not to mention the tuneability of easily changed ratio will help dialing the truck in to it's true potential no matter what event I'm competeing in,

 

even if you swap chanes your going to need some typ of tensioner or make the outputs so they can be moved away or towartds the input. im not positive but i dont think you can buy half links for d60 chain, even if you could i wouldnt want to run them. so you are stuck with. so you are going to be limitted in length selection by arounsd 2 inches. this will not be a fine enough increment to tqake up enought tension in the chain and not rip either your chain apart from the whip or walk off of your gears AND RUIN THEM.

 

I just looked in the McMaster carr catalog and they show hlaf links available for D60 chain,

If everything goes good with the case and I cannot get the center lines close enough with the different comboes I'll have to look into a tensioner, maybe something spring loaded on the loose side while traveling forward, hmmm now you've got me desighning stuff when it's way to early to be thinking,

 

Fordman, would you consider the half links weaker & thats why you would not run them? if so then I now see you and wyldstallyn73's point, either way there's got to be a way to make it all work,