9" ford axel shafts

[kiwicar]

Hi all
I have spent rather too long on the strange engineering website going through their catalog and my brain hurts.
http://www.strangeengineering.net/catalog/index.html
The reason for this is as follows, I have a 9" nodular iron case with a heavy duty pinion shaft support that I intend using on the new project. This has billet steel bearing caps but these are 3" bearings so as far as I can tell this limits me to 33 spline shafts maximum, to go 35 I think I need 3.25" bearings and a new aftermarket case, this is ruled out for now on the grounds of cost.
Now for the bit that is taxing the gray matter, I need to get shafts and gears, but what do I get? I have a 31 spline spool in good, little used condition, this can be replaced with a 33 spline spool and the 31 spool sold for a a net cost of about £50 so if needs be, no issue.
Basically the cost of 33 spline and 31 spline axels seem to be the same but all the 33 spline shafts I can find are listed as 8.8 inch although 33 spline spools are 9" there don't seem to be 9" specific 33 spline shafts. Shall I just get 31 spline or go 33 and if I go 33 spline what do I actually get, are 33 spline axels bigger diamiter than 31 needing a bigger diamiter hole in the bearings, I presume so but is this the case but they don't seem to obviously list specific 9" 33 spline axel installation kits it is all doing my head in. Someone please help!
Best regards
Mike

[Magnetteman]

Give Andy at Robinson Race Cars (01256 880589) and have a chat with him.
He's a Strange dealer so he will know exactly what you're looking for and the best bit I've found with him is that he will always advise what's best for you and not what's best for his sales figures.

The good thing with Strange shafts as you've probably found out is that they are made to length with no cutting/welding or resplining cut down shafts.

[kiwicar]

Hi
Thanks I call him, I will need to get other work done on the axel as well and what you have just said he sounds like the someone worth talking to.
Best regards
Mike

[Coops]

i can totaly recomend Andy too.

[kiwicar]

Hi Tony
Is that where you are getting your bits from?
Best regards
Mike

[stevieturbo]

Going larger than 31 spline will limit LSD options. And yes a main reason is shaft diameter and bearing size on the diff housing.

But do you actually need larger than 31 spline ?


I hate spools !!!!

But any of the usual suspects will be able to make you any shaft size or spec you need.

[Coops]

Hi Tony
Is that where you are getting your bits from?
Best regards
Mike

yup

[kiwicar]

Hi Stevie
I should get about 470 ft lb torque out of the engine, if I run it on methanol as a couple of people are adviseing I could be looking at be looking at 580+. If the torque converter gives me a torque multiplication of 2:1, first gear is 2.03:1 and a 4.11 crownwheel and pinion I think I am looking at 9678 ft lb of torque into the rear axels as I launch. Now that is split across both axels but 31 spline axels seem to be rated at about 7000ftlb so I don't think that gives me much of a mergin. If I stick a blower on it later then then I think it will definately need more than 31 spline and I would rather spend money only once. As for the spool, it is only going to get run on the strip and on a dyno to set it up and at 168" wheel base I don't think an LSD will change the turning circle much.
Am I being overly pesimistic about the rating of the rear end?
Best regards
Mike

[stevieturbo]

Hi Stevie
I should get about 470 ft lb torque out of the engine, if I run it on methanol as a couple of people are adviseing I could be looking at be looking at 580+. If the torque converter gives me a torque multiplication of 2:1, first gear is 2.03:1 and a 4.11 crownwheel and pinion I think I am looking at 9678 ft lb of torque into the rear axels as I launch. Now that is split across both axels but 31 spline axels seem to be rated at about 7000ftlb so I don't think that gives me much of a mergin. If I stick a blower on it later then then I think it will definately need more than 31 spline and I would rather spend money only once. As for the spool, it is only going to get run on the strip and on a dyno to set it up and at 168" wheel base I don't think an LSD will change the turning circle much.
Am I being overly pesimistic about the rating of the rear end?
Best regards
Mike

What vehicle, what weight, what tyres etc ?

I drove with a spool for a few months, mainly as it was the cheapest route to a 31 spline rear as the diff I had ordered hadnt arrived yet.
Words cannot describe how horrible it was !!!

Motorway etc was fine. But low speed manoeuvres were terrible. Parking, turning. The car was very jumpy, turning circle was increased, it scrubbed the outer edges of front tyres like crazy.
On a handling track at Elvington, I could do nothing but go straight. I ended up through the cones at every turn !! I couldnt believe myself the difference it made.

On the drag strip, it made no difference whatsoever to my cars ability to go forward.

So it depends what you will be using for, and how often it sees the road. But for me, never again will I use one.

I also see a spool for the risks involved. Should one shaft break, what will happen ? All drive to one wheel. To me that spells crash.
I dont know of an LSD that would do the same.
Although on drag style tyres when moving about, the spool doesnt seem to be as much of an issue. The soft tyres take up a lot of the nastyness of the spool.
On road or track tyres, it is truly horrible !!

I use a Ford 8.8", 2.66 1st gear, 3.27 rear ( have used 3.55 in past ) and a Ford Racing Torsen diff. Car approx 1580kgs on MT DR's or similar.
When launching, I have twisted 31 spline Moser shafts, maybe by one spline or so.
I guess it is just luck that they never turned more, as it was by chance I had removed them and found the problem.

Oddly...I never did twist the 28 spline Moser shafts. I'm thinking that is because the shaft itself was thinner, and perhaps took part of the strain by twisting or springing ?

I'm now using Mark Williams 31 spline shafts, and so far no issues there. Although they were about 2-3x the price of the Mosers.
The only LSD option for a 33 spline shaft was a typical plate/locker diff which had a diff pin.
IMO any diff with a pin has a weakness, and I wasnt prepared to use one. The diff and gears may be strong, but Ive seen far too many diff pins fail. Thats why I wanted my Torsen diff.
So while I wanted 33, it was a no go for me. Plus the diff cage would be weaker around the bearing area due to the larger hole through them for the bigger spline.

WRT above, the 9" I assume is bigger all round, so some of those weaknesses might not be a concern.

But I hear what you are saying about wanting the strongest.

[kiwicar]

Hi Stevie
It is for a slingshot, should come out between 1400 and 1500 lbs, 168 wheelbase, tyres are 14X32" drag slicks, I don't think I will be worried about parking it it will never see the road (unless they start dragracing in Milton Keynes town centre!). Yes I think if a shaft fails it will be terrifying. The 9" is a nodular iron case that has billet bearing caps and a pinnion support that is the beafiest piece of engineering I think I have ever seen not fitted to a tank, I'll post up some pictures tonight.
I think some people run slingshots with open diffs, but that thought scares me as much as a broaken shaft, if it un-hooks one wheel as I chenge into top at over a 90 I don't like to think what might happen.
Many thanks for the reply this is new territory to me and I really value all input.
Best regards
Mike
PS there is a basic spec here http://www.v8forum.co.uk/forum/viewtopi ... 60&start=0

[stevieturbo]

Given it is a race car, biggest shafts make sense.

As for an open diff. If one part breaks or fails or if a shaft fails. All that happens is you lose drive.
Unless the diff pin breaks and locks the diff up, although thats less likely.

So I dont actually see any danger at all from an open diff. It would be totally safe in all circumstances.

But a spool with the biggest, strongest shafts is the easiest, and probably cheapest option.

Moser are about the cheapest shafts and would be more than up to the job. Pretty sure they give a lifetime guarantee on them. Although in my case it wasnt worth the hassle trying to pursue any warranty, as they simply were not strong enough for me.

[kiwicar]

Thanks Stevie
I think I shall go the big shaft and spool route, as you say I think it will be the cheepest. I have Strange end caps and a Strange axel housing so I think I will stick with them to avoid arguments about why what doesen't fit, although there seems to be a wider choice of 33 spline moroso shafts.
One last dumb question, what actually holds the shafts in the housing and there by into the spool is it just the press fit of the axel shaft into the bearing centre
Many thanks again
Best regards
Mike

[stevieturbo]

Spool and diff are no different in terms of shafts.

I know nothing about your axle, so cant say.

But some shafts are held in via a c-clip in a groove on the end of the shaft, which is located inside the diff.

Obviously a full spool wont have this ability. So in that case, a bearing is pressed onto the end of the shaft, and this retains the shaft in position.
But as I say, I dont know the exact makeup of your housing, or shafts.

Also see Tony;s thread. He's getting 9" ends welded onto his axle so that his shafts no longer use a c-clip.

I use c-clip eliminators which are basically press on bearing housings which then bolt to the axle.


If you must retain the c-clip for some reason, then a mini spool or half spool which is built inside the open diff casing might be another option.

[kiwicar]

Hi Stevie
That sorts it out for me, they must be held in by the press fit of the bearing on the shafts as there is no way to get a C clip into the spool. The casing is a heavy duty version of the standard casing.
Many thanks
Mike

[kiwicar]

I spoke to Andy Robinson, well had a long chat with him and his wife, both very helpfull and knowlagable people. the cost of 31, 33 and 35 spline shafts, spools and bearing set-ups are the same however going 35 spline will need a new centre section, that is £384 I haven't got to spend at the moment. I am going to go 33 spline, I shall get the spool and ring and pinion gear direct from Strange with a centre section bearing kit, this should save me about £180 over buying in the UK, it set up the myself and get ARRC to shorten my axel case and supply the axels.
Thanks to everyone
Best regards
Mike