Narrowing a rear axle.

I've never done it, but I am a machinist and I can read, so lets hear it.

If I farmed the job out, what would it cost for someone else to do it?

Dan

Dan,

I don't know about $$ to have someone do this, but have a look at this link from the Alfa BB:

http://www.alfabb.com/bb/forums/spider-1966-up/16373-my-project-spider-veloce-v8-conversion-15.html

Starting on page 15 he describes the process he used to shoeten a Ford 8.8" to fit into an Alfa Spider. He made it look pretty straightforward (he went to Mosler for new axles).

I've never done it, but narrowing the tubes is just cutting and welding with the obvious fixturing and jigging. The axles themselves can also be done this way, but it's obviously riskier, and you can mess with heat treatments by accident. There was a Car Craft article a few years back about a firm who did this for people...

I've seen it done a couple times and it looks like as long as you can keep everything aligned right while rewelding you should be ok. The guy i knew had a solid steel rod about 1 inch in diameter with bushings that slid on it and fit in the housing ends to keep the ends in place and similar bushings to fit in the bearing caps in the center section.

I found a step by step with decent photos. If you can read you can cook, right?

http://www.carcraft.com/howto/ccrp_0801_rear_axle_modifications/index.html

www.pirate4x4.com will have all kinds of info in their forums, as it is very common in the 4x4 world. Cutting to certain lengths will make sourcing axle shafts much easier/cheaper.

Talk to Jensenman, I think he just did one.

eastpark wrote: Dan, I don't know about $$ to have someone do this, but have a look at this link from the Alfa BB: http://www.alfabb.com/bb/forums/spider-1966-up/16373-my-project-spider-veloce-v8-conversion-15.html Starting on page 15 he describes the process he used to shoeten a Ford 8.8" to fit into an Alfa Spider. He made it look pretty straightforward (he went to Mosler for new axles).

WOW!!! Should I applaud that guy's talent, patience or creative thinking?

Everyone should take a peek at this project. Serious.

i did it with a ford 8.8" for my opel gt challenge car.

i machined 4 alum. inserts and installed them in the bearing seats. i used a piece of 1" cold-rolled rod as a fixture. i took 3" off of each side. i actually had a 'straighter' axle than the factory. i remember measuring the factory runout at .007 or 8 or something. i got mine within .002 or 3

i took my axles to a guy who re-cut the splines on the end for me (and turned the groove for the c-clip) $100 bucks out the door.

i was lucky my axles didn't taper after the spline...alot of them do. you could fine some axles from a different rear end. 8.8 were used in everthing. i almost used a set from a ranger, but resplining worked out just fine.

haas

914Driver wrote: Everyone should take a peek at this project. Serious.

I did and spent the last hour or so reading through most of that thread.

914Driver wrote: I found a step by step with decent photos. If you can read you can cook, right? http://www.carcraft.com/howto/ccrp_0801_rear_axle_modifications/index.html

That's the article! Looks easy enough. Just be careful. Definitely challenge friendly.

sachilles wrote: www.pirate4x4.com will have all kinds of info in their forums, as it is very common in the 4x4 world. Cutting to certain lengths will make sourcing axle shafts much easier/cheaper.

Beat me to it.

I talked to a guy yesterday that's done three. He disassembles everything, whacks ___ inches out of each tube and welds it back together. Then he whacks the same amount out of the axle shaft, welds that back together.

I've seen the cars, they haven't fallen apart. It worked for him, was he lucky or are we over-engineering this?

Dan

~Here~ is a very good article on cutting down a rear axle.

914Driver wrote: Then he whacks the same amount out of the axle shaft, welds that back together.

Not sure I like that idea. Cutting and rewelding the tubes is fairly simple as described by several posts here. But cutting and welding the axle shafts sounds a little iffy to me.

If you are talking about a low power setup it might work. But resplining the axles won't create any stress points and would be much stronger.

aeronca's site link shows the right way to do it and that's how I did my RX7 rear axle. About welding axle shafts: your bud has been VERY lucky. I busted 4 before giving up and having a set resplined.

Think an RX-7 axle would put up with 300+ hp?

Dan

I think it would, particularly in a light car. The best thing about that page is that the basic idea and procedures is applicable to just about any stick axle.

Moser Engineering will shorten and respline axles. Dutchman Motorsports will too but their shop foreskin, er, foreman is a real butthead sometimes.

I could measure it up and find an index head and mill at work, but what's a ballpark price range for their labor?

Dan