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Custom Spitfire Rear Axles

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Spitfirejoe Avatar
Spitfirejoe Joe Guinan
Fremont, Nebraska, USA   USA
1980 Triumph Spitfire 1500 "The Phoenix"
I bought this set of axles off that auction site, and I'm having trouble figuring out exactly what they are. I thought the donor parts might have been from a Chevrolet Corvair, but emails to a reputable and knowledgeable Corvair parts supplier indicate that they are not Corvair sourced.

I don't think these are especially unusual, and believe this was a common race car upgrade "back in the day" before we had the well engineered racing axle kits available. Those kits are pretty expensive, and have not proven to be without problems. I can use this set almost "as is", but it looks like I will be trying to complete a couple other Spitfires for racing purposes. I'd like to be able to replicate these if they prove to be less expensive. If I could figure out what car (or tractor, or whatever) they came from, I think I could get a few sets made up.

So - asking here to see if anyone recognizes these. What other likely suspects could there be for the original parts? Some Datsun, perhaps?

Short descriptions -
- stock Spitfire rear trunnions have been built up by welding on new metal and drilled out for a larger bearing
- the original 5 lug hub has been cut down and re-drilled to the Spitfire bolt circle diameter
- Bearing is a Hoover 5206-FF
- flange/UJ Yoke - "Spicer" with a "crown" symbol and "8" on the outside toward the UJ and "A4" and "L36" on the inside.
- Splined UJ Yoke - what looks like "8 A90" First character is hard to see - could be a "B".
- U-Joint says "Spicer USA" and "A3R96"
- Axles have no identifying marks

Any input welcome! Carter Shore and I have already discussed these, and he had a similar set mounted on his G Production Spitfire at one point. I should measure the original stud circle on those hubs... that might lead me somewhere.

Joe Guinan
Fremont, Nebraska



Joe Guinan
Fremont, Nebraska

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1964Spitfire Avatar
1964Spitfire Tim P
Santa Clara, CA, USA   USA
Here is an old thread about comp axles that may have some useful information.

HELP ID AXLE

Spitfirejoe Avatar
Spitfirejoe Joe Guinan
Fremont, Nebraska, USA   USA
1980 Triumph Spitfire 1500 "The Phoenix"
In reply to # 1301715 by 1964Spitfire Here is an old thread about comp axles that may have some useful information.

HELP ID AXLE

YEAH! I Think that may have given me what I need. Wow. Who'd a thunk Dodge Dart? I had tried several searches, but just never found anything that worked for what I was looking at. I thank you, Tim!



Joe Guinan
Fremont, Nebraska

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14GPDJENGINEERING Avatar
Silver Spring, MD, USA   USA
Joe,

I do not recognize the axle or the shaft yoke. The flange yoke is a stock Spicer part.

But the Spicer flange yokes have a larger bolt pattern than the Spit/GT6, so the holes have to be slotted. Also the locating shoulder is larger.

One solution is to cut a bigger recess in the inner axles.
Another was to cut down the shoulder on the flange yokes or cut it off entirely. Cutting it down often left no material at one spot.
I have some yokes that the Summit guys got from Spicer un-drilled, so they drilled them to the correct pattern & tig welded more material on the back of the shoulder, then turned down the shoulder.
A third option is to use an adapter plate between the inner axle & the Spicer flange yoke.

I have some spare yokes, trunnions etc. left (but no axles).

A major advantage of the better racing axles is the fatigue resistance of using chrome-moly alloys which the Corvair, Dart etc. did not use.

I will send more info in a PM.

Dennis



Dennis smiling smiley


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Spitfirejoe Avatar
Spitfirejoe Joe Guinan
Fremont, Nebraska, USA   USA
1980 Triumph Spitfire 1500 "The Phoenix"
"A major advantage of the better racing axles is the fatigue resistance of using chrome-moly alloys which the Corvair, Dart etc. did not use."

Well, there's the point I was missing in all of this. A little cognitive dissonance - hoping to avoid paying the full price of admission. I was hoping cheap was possible and defensible from a safety standpoint, but I realize there are always drawbacks to that approach. The use of the better alloys adds cost, but for an obviously good purpose.

I'll probably go ahead and use this set of axles on one of the Spits, but will probably bite the bullet and get some crack testing done before hand and after the season. A serious visual inspection after a race weekend will probably be wise. Very few races annually is the plan - maybe only three weekends a year - so I can probably get by while I save up for a couple of Joe Siam's kits.

Many thanks, Dennis. (And Tim, also - for leading me to this info.)



Joe Guinan
Fremont, Nebraska

clshore Carter Shore
Beverly Hills, Florida, USA   USA
I have a set of similar racing axles, acquired and fitted in 1972 (ISTR from Rick Cline).
These were referred to at the time as 'SAE axles', SAE being the vendor name.

Mine are 1 piece, 5 lugs welded and then drilled and machined for Spitfire 4x3.75" wheel.
The axles themselves are larger in diameter, but employ the stock inner hub, so different ball and roller bearings having same OD are used.
They use a larger UJ, with cups on the axle side yoke retained by the U bolt assemblies, and circlip retainers on the diff side yokes, that bolt up to Spitfire big stub axles
The axle ends are fine splined, and yoke is retained via a disk shaped cap that bolts into a hole axially threaded in center end of the axle.

Given that USDM axles of the day were forged, featured large fillet between shaft and flange, and lasted basically forever carrying weight and torque loads 5x
what even racing Spitfires on slicks could generate, I'm not concerned much about robustness.

When is the last time that you heard about a USDM car or truck snapping an axle, ever?

14GPDJENGINEERING Avatar
Silver Spring, MD, USA   USA
The SAE axles were the Summit Automotive ones I mentioned in the other thread. I sold many of their axle kits as a dealer for Summit in my Region.

"Looks like Summit Automotive axle (Akron, OH), made by Stan & Gary -- two Goodyear employees who were racing a Spitfire at Nelson Ledges. Early versions used Corvair axle, yoke & u-joint with Spicer flange yoke. Later they went with Dodge Dart axles, welding up the 5 stud holes then drilling for the Spitfire studs. Then they got a batch of unfinished ones to avoid the welding. This one is machined from the Dart axle. It is a one piece axle with bolt-on yoke.

Tim, yours is a Mueller with Spicer shaft yoke. I had the same problem with the yokes & I have seen one axle break.

I started out with GT6 axles on my SCCA GProduction '64, then Mueller, then Summit (Corvair & Dart), ultimately Bill Davis & I developed the first Summer's Brothers axles for 1500 FProduction & GP. These had much larger bearings with custom rear trunnions like the Checked Flag setup. Never broke a Summer's Brothers axle. Others have commissioned racing axles from Henry's & Strange."

As said, I have seen a Mueller axle break & I had a nearly new GT6 axle break at Summit Point in '73 -- was very lucky that time.
Also had a set from SAE that had a defect -- broke in the last turn at Road Atlanta in '78. That was a fun ride!!
Fortunately the break occurred between the trunnion & the U joint (at the snap ring groove) so the wheel did not separate from the car, it just flopped over on its face sending me sliding into the tire barrier. Lots of body work that time.

For that reason I recommend using a shrink fit collar to retain the large ball bearing rather than cutting a groove for a snap ring.

Another problem with the Mueller & SAE axles was that a lighter duty ball bearing had to be used. It was 1 1/4 ID with the same OD as the original 1 inch bearing. That is why a spacer ring was needed to fill bearing bore. These bearings do not last as long as the stock ones.

Joe,

Your rear trunnion has been welded to allow for a larger bearing, that is why we went with the aluminum versions.
If you are not using super sticky tires & have 100HP , just magna-flux the axles, install the best new bearings you can get & you should be good for at least five seasons.
Or you can get the u-joint parts from me & order axles from Summers Brothers or any other racing axle supplier.

Dennis smiling smiley



Dennis smiling smiley



Edited 1 time(s). Last edit at 2015-07-10 09:05 AM by 14GPDJENGINEERING.

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Spitfirejoe Avatar
Spitfirejoe Joe Guinan
Fremont, Nebraska, USA   USA
1980 Triumph Spitfire 1500 "The Phoenix"
"Joe,

Your rear trunnion has been welded to allow for a larger bearing, that is why we went with the aluminum versions.
If you are not using super sticky tires & have 100HP , just magna-flux the axles, install the best new bearings you can get & you should be good for at least five seasons.
Or you can get the u-joint parts from me & order axles from Summers Brothers or another racing axle supplier.

Dennis"

Good to know! I'm going vintage, so super sticky slicks aren't even allowed. Hoosier Street TD or Yokohama A008 seem to be preferred. 100 HP is probably the limit for my engines.

So that brings me back where I started. How can I recreate these animals cheaply? I'm trying to talk 3 to 5 guys from my local Brit Car club into joining me vintage racing Spitfires. I have one early Spit nearly brought back to life, another one waiting for major rebuilding, and a later one that is a great candidate for a third. $2000 for axles is tough to cough up.



Joe Guinan
Fremont, Nebraska

clshore Carter Shore
Beverly Hills, Florida, USA   USA
Dennis,
thanks for sharing the history and details on these axles.
I had tried searching before without much success.

OK, so here's a wacky alternative, I had thought about repurposing some 'Wide 5' hardware.
Versions of these are seen on many stock car racers, and are quite robust.
They employ a pair of tapered roller bearings similar to those on front wheels, except inner are 3.346" diameter and outer are 3.125" diameter (!!!)
A unique feature is 'floating' hubs, where the bearings that support the wheel loads are taken by an outer tube (typically the live rear axle housing) and a separate inner axle that delivers drive torque.
The wheel and drive stresses are separated, so snapping a drive axle does not result in losing a wheel.

On a Spitfire setup, this would require an long outer tube that carries the wheel stresses, with a bearing/seal located somewhere close to the UJ.
This bearing/seal would see only rotation due to torsional flexing of the inner drive axle with respect to the outer tube.
Because of the lever ratio between the outer wheel bearing, the vertical link pivot, and this inner bearing, radial loads would be perhaps 1/10 wheel loads.
There is the issue of thrust loads from cornering, etc, but again there is virtually no actual rotation, so a collar or ring might be used.

Of course the wide 5 components are much larger and beefier, so fitting them could be a challenge, but similar configuration with smaller bits that fits Spitfire wheels could be doable.
Nearly everything would be custom of course.

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1964Spitfire Avatar
1964Spitfire Tim P
Santa Clara, CA, USA   USA
Joe,

I went through this decision a couple years back. My old school comp axles had issues. There was play between the spline and yoke, both rotational and lateral. Once I pulled the axles a friend with a big lathe confirmed one was bent. I probably could have fixed these issues, but felt I'd still have an inferior design that would continue to have issues.

I ended up biting the bullet and buying comp axles from Joe Siam/Chequered Flag Racing. I've met Joe a couple of times at vintage races, and he's a good guy and knows Spitfires and racing prep. He has a small stable of Spits that he maintains for vintage racing.

I know it's a bit spendy but it's buying some peace of mind, and consider the high cost of a DNF. Spread the cost over 10 years, and think of it as $150 - $200/year.

Give Joe Siam a call, if you are interested in buying more than one set, you may be able to work out a deal.

Regards,
Tim

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