All out D80 Mods????

RyanB

RyanB

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Aug 10, 2006
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Hey Guys, my current project is running a Dually D80 (We can run larger axles, but honestly...I don't really see the point up here in Ontario on our less than perfect tracks as I never once had a problem with the old truck and that motor was putting out way more torque with the twins.

Anyway, I know the typical norm with upgraded axles, driver plates, welding the diff to the tubes. I will be running a spool and 5:13 gears, but my main thing I hear about all the time and have yet to see any real good pics explaining this better are the girdles and custom covers to load the bearing caps.

Anyone have any picks or more info on the covers and what it takes to put one together? I just starting drawing up the actual bolt patern profile on Acad last night so I can get the girdle waterjetted and need to know which direction to go after that.

Thanks in advance...RyanB
 
Here is the one like I build. It has a 1/2 inch flange. and the shell is 1/4 with 3/8 reinforcement where its needed. I have the ability to do any custom work you need on these. The bearing preload bolts are backed out in this picture, they arent that long when they are torqued.


diff.jpg
 
Not right now. There is nothing special on the inside if that is what your wondering.
 
alright, sound good. Here is another question, in doing some searching I came across some mini-rod guys that are having the exact same problem with there D60 rear ends. Just wondering if anyone has done anything like the picture below. Its not really a truss, but pulls the spindles and tubes back in towards the diff almost compressing the ring and pinion further. Anyone know anything about this???
 

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I expect it could be done, but I would think the pinion would flex before the ring gear.
 
Where do most 80's break? does it break the pinion, or does it have problems with the ring trying to push away from the pinion?

I am not sure where they are breaking in the hot 2.8 trucks or 3.0 trucks running them.

i just thought if you could machine the case to install a brass thrust button it might help keep the ring gear from pushing away fromt he pinion under heavy load.

maybe its not needed, just throwing the idea out there.
 
I personally feel that the way the beefed up cover design is a better idea than a thrust button, a thrust button would possibly be a wear item and that presents oil contamination issues.
 
getblown5.9 said:
Where do most 80's break? does it break the pinion, or does it have problems with the ring trying to push away from the pinion?

I am not sure where they are breaking in the hot 2.8 trucks or 3.0 trucks running them.

i just thought if you could machine the case to install a brass thrust button it might help keep the ring gear from pushing away fromt he pinion under heavy load.

maybe its not needed, just throwing the idea out there.
Click to expand...

From what I have read, I believe the carrier pulls out of the case which is why all of the covers/girdles I have read about are interested in keeping the caps in place.

Also, from what I have read, the Rockwells have the issue of the ring gear flexing away from the pinion which is why some kind of snubber is beneficial.
 
Replace the cap bolts with studs from ARP In the D-80. Also i checked into putting the thrust bolt in an 80 like the old corp. HO 72's have, and their isn't anywhere for the bolt to ride on the back side of the ring gear. In the HO 72's, the ring gear sticks out from the carrier about 1", witch is were the thrust bolt rides to keep the ring and pinion from seperating.
 
Just a thought....never hurts to brain storm a little bit. In this super thick girdle from the other post mentioned above
photo_3-2.jpg


could you also run a set of bolts on an angle in towards the side of the bearing caps...think of it almost like splayed main bearing caps on say a big block Chevy. Just a thought, but that could put side to side pressure on it. I know the bearing cap isn't very large though so Im not sure if would work.


Just thinking out-loud!!!

Ryan
 
hey Ryan - other than say Erin - are there any tracks around here tight enough to bother a 10.25 , D80, or GM 14 unless one bounces to hard?

I cant think of any.

The carrier caps are the weak point on most rear axles as they are very thin dead centre of the cap in some instances

The thick plate over the back of the case will stop most of the case flex, and certianly the axle truss should get most of the rest

this is old drag race and mud bog 101 stuff

We never welded the axle tubes because cast steel doesnt hold welds well

Instead we drilled and tapped thru the holes in the case on each side, threaded the tube and used a bushing, bolt and washer to lock the axle tube and case together
 
Ryan I think you have some good ideas. Im thinking of doing something like this, though maybe a little cleaner with heims instead of top links. Like ken says its done lots on drag cars.

Ken trust me you can weld to a cast rear centersection just fine if you know what your doing, though i have seen the bolt method as well. Imo welding is the better bet though.
 

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brushpuller said:
Replace the cap bolts with studs from ARP In the D-80. Also i checked into putting the thrust bolt in an 80 like the old corp. HO 72's have, and their isn't anywhere for the bolt to ride on the back side of the ring gear. In the HO 72's, the ring gear sticks out from the carrier about 1", witch is were the thrust bolt rides to keep the ring and pinion from seperating.
Click to expand...

I also had the same idea and after 2 years it broke the cap in half!
 
After all this custom and big money parts wouldn't it be less costly to just run the Bigger rearend?
 
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