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Invincibleextremes

Ford Super 8.8 irs swap thread. Rear brakes too

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I never stopped working on this, and will see this through to the end.  

This is my son Luke, he is 9 months old, and was born with half a heart.  It's a rare condition called hypoplastic left heart syndrome.  It's fatal without emidiate surgery and even so it's an uphill fight to make it past puberty.  He's had several heart surgeries and his first one was the hardest, with his chest being held open for a week.

 

Reason I'm even bringing this up is to get the back story of what we're up against, and what has been taking so long.

 

While we as a family were in the hospital in San Diego for 8 months I spent a lot of time researching everything currently available for high hp datsuns and the prices, weak links and other issues i came across currently on the market.

 

I then dipped into my personal gun collection (which is a shadow of its former self now) and over time purchased parts for this conversion, while measuring and doing more research as I went along.

 

I just recently finished up the actual design and have test fit everything and plan to road test it all soon.

 

I just want everyone to know that any hold ups I have aren't because I'm vacationing in Europe or have lost interest in 240z cars or playing with other toys.

 

So long story short, if I can make this kind of progress while fighting the fight of my life, you can bet your butt I'm seeing this through.

 

And yes I'm seriously considering doing a tacked together kit as well for the diy types.

 

But just to make it clear, I will absolutely NOT be sharing or selling blueprints or CaD files.

 

I sacrificed what little bit of time and money I didn't even have to spare to bring something like this to market, and I don't intend to give it away.

 

It will be the cheapest, strongest and most versatile bolt in diff setup you can put into these datsuns.  But it wont be free.

 

And no, this isn't my first rodeo on bringing something to market where there was a need.  The 2014 mustang disc brake adapters I've designed for classic mopars have saved a few dozen people a total of 30k if not more so far.  And yes, have put food on my table and diapers on my kids when we needed it most.

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On 1/15/2019 at 2:54 AM, Invincibleextremes said:

The super 8.8 bolts in just fine.  Measuring the axles and will be getting them cut and splined.

 

What axles are you cutting? I thought the stock mustang ones were hollow.

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1 hour ago, zboi said:

 

What axles are you cutting? I thought the stock mustang ones were hollow.

They are, but they're not driveshaft style hollow.  Theres no reason to not cut them.  Btw, the right side is solid and the left is hollow.  You'll need two lefts and a right to make a set for the 240z.  The solid side axle tapers down and can't be cut and splined so i used it as a jig to measure the length needed.

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Quote

Theres no reason to not cut them. 

 

The validity of that statement depends largely upon the hardening done to the original shaft.  I would imagine they are induction case hardened at the splines only, so while it will be easier to cut down and remachine new grooves outside of the hardened shaft area, you consequently would have weaker splines.   Additionally, are you having the splines rolled or cut?  

 

Quote

Btw, the right side is solid and the left is hollow.

 

IIRC Ford used to run different diameter shafts to help counter wheel hop. (Of couse this does nothing for shaft strength, it just changes their torsional stiffness.)

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Cutting hollow axles isn't my first choice, but they're still head and shoulders better than what came in these cars.

 

Ideally i would ship out some solid shafts taken from a junkyard for cheap

And pay for the service of 4 ends to be splined...

 

This would still be incredibly cheap but give me some peace of mind.

 

The core axles themselves are 55 to 75 bucks per side.

 

The end plan is to just shell out the $1,200 for some 800hp axles plus 100 for them to be in a custom length.

 

This is still cheaper and stronger than anything offered before in a 240z.

 

But right now what ill be testing is just how much abuse the least favored setup will take before i have to either get the shafts replaced with solid cores or buy custom made shafts.

 

On monday I'll get all that figured out.

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@yellowoctupus is correct if they are case hardened. You'll need to determine that before re-cutting shafts. All of those half shafts are very poor designs for strength, lots of stress risers and improper sizing (thought the solid shaft has some elements of sound design which is why you can't respline them). They should look more like these for maximum strength. This design is not only substantially stronger and lighter but adds a "cushion" to the axle as it will wind up like a torsion bar rather than breaking and absorb some shock loads. The smaller diameter may be contrary to common belief of bigger is better but is actually stronger by quite a bit when done right. The production shafts are a for the masses piece that the beancounters dictate design to a large degree. Engineers throw mass at problems because it cheaper than better materials/design.

 

custom drive shafts

(Photo from http://www.westgarage.co.uk/forsale/kits/shafts.html, just the first image that popped up from a Google search, not suggesting using them at all)

 

Check with Moser Engineering or RCV. I think Moser will be your best price, RCV best quality. I would start with 4340 and use 300M for best strength materials - both are through hardened for proper strength, the 300M quite a bit harder. I'll be using 300M as I just don't want to take any chances. Moser has another alloy they use that would be a great starting point. I wouldn't be surprised if you could get a set of shafts from Moser at about 1/3 of your $1200 price. They will also do resplining. I have used them for both services, and they do quality work at reasonable prices. There are others out there that will do it for you but those are the first that come to mind. You'll be way better off if you get away from the custom car places and into the race and especially desert race crowd for this stuff.

 

The problem is getting from the Ford inner differential and outer hub splines to standard 930 or 934 CV joints. Once you do that the rest is easy. If you want to look at doing the inner and outers that way, @1969honda and I would be in for the inners for sure and possibly the outers if they are compatible with what we are doing. I'll help with the design if you want.

Edited by jpndave

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BTW, any re-spline work is most likely going to be cut, not rolled. Rolling basically forges the spline into the shaft but is for much larger scale production and would be near impossible on the hardened stock.

 

Moser would likely not have the reduced diameter on the shafts but again, price will be great for a custom shaft. For maximum strength, you need to step away from a lot of the stock pieces and prices go up. That's where the 930/934 CV pieces with corresponding stubs to hub and differential come into play. This is what DSS is doing for their super axles for the Mustang.

 

HTH,

 

Dave

Edited by jpndave

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4 minutes ago, jpndave said:

BTW, any re-spline work is most likely going to be cut, not rolled. Rolling basically forges the spline into the shaft but is for much larger scale production and would be near impossible on the hardened stock.

 

Moser would likely not have the reduced diameter on the shafts but again, price will be great for a custom shaft. For maximum strength, you need to step away from a lot of the stock pieces and prices go up. That's where the 930/934 CV pieces with corresponding stubs to hub and differential come into play.

 

HTH,

 

Dave

The $1,200/pair price tag isn't for shafts, its for the entire thing, 930 cv joints and all.  With 34 spline stub axles into the housing and 32 spline stub going into the hub bearing.

 

Totally agree with you on the smaller diameter full floater style shafts.

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Went digging in the junkyard today with the CV spider in my pocket.  

Turns out the 02 explorer has the same diameter shaft ends... but courser splines.

The good news is its a solid heat treated shaft and its the same thickness its whole length, necking down only for the splines.

 

I also called moser and talked to them about sending in a core shaft and paying for two pairs of CV axle spline service and they're happy to do it so long as they look everything over and it seams like it works.

 

Cutting the heat treating off the hollow shafts just wasn't sitting well with me.

 

I also discovered that the two left shafts are different on the ends in diameter and one had a slightly smaller cv joint pair...

 

I'm guessing i got one v8 shaft and the other from a v6 car.  Both are splined the same into the housing and at the hubs... but one is stronger than the other with bigger cv joints.

 

The left and right v8 shaft have the same size cv joints... its just the spare left shaft had some differences.

 

Going back to the junkyard tomorrow to compare my cv joint to the explorer outer cv. If they are the same internally i plan on building a hybrid cv.  But if they're different I'll pay for 2 pairs of spline service and know that I'll never have to worry about the strength of those shafts...

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Edited by Invincibleextremes
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Went digging in the junkyard today.  The hybrid cv joint idea is a no go, mustangs used 8 balls while the explorer (2004) used 6 balls.  Would have saved me $125 by not having to spline both ends.  But not a deal breaker.  Still much cheaper than the 800hp axles, just not as cheap as I'd hoped.  

 

 

Here is a picture that shows why i picked these axles as cores.  The shaft in the middle is the mustang one that i cut a section out of to make the perfect length.

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Edited by Invincibleextremes

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