Michael’s Blog

When we were in Victoria in March 2008 we stayed with long time friends Steve and Helen Pike in Bacchus Marsh. Steve has a Healey shop which specializes in Healeys with a particular emphasis on 100Ss!!!

He has restored many Healeys and the quality of the work he produces is second to none.

While we were there Steve showed me a prototype of the reproduction factory hardtop which he is now producing. I felt that it looked very good and Steve says that the production versions will look even better as they have done some more finishing on the mould since this prototype was produced.

Steve can be contacted at mclassic@bacchusmarsh.net.au

 Here are some detail pictures. I will look for some more and add them when I find them.

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Does anyone recognize this heater valve. I have several of these, acquired with a pile of Smith’s stuff  bought when they closed down their Toronto operation. They are brand new and I am loath to throw them out.

 They look vaguely familar to me but I just cannot remember what car I’ve seen them on. Unfortunately there is no part number on them anywhere and the lettering on the body reads:”USE SPANNER AS NEAR THREAD AS POSSIBLE”.

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So Judy and I have decided that the time has come to sell the old homestead and move to the sticks. We have pretty well had it with the traffic and the way our neighborhood is changing. We are only about 150 meters from Yonge St in the middle of North York which is one of the suburbs of Toronto.

I just went out to the street and took these two photos of the signs on the first buildings I came upon.

I must say I have a better understanding of why the French in Quebec have their “French Only” sign law although, I vehemently disagree with that. However…I digress….

As we have only ever owned one house and therefore never sold a house this is all a new experience.

The GMDS has commanded that the house has to be emptied out and all the junk disposed of so the house can be “staged” for sale. Of course by “all the junk” she really means all my stuff. Now I admit I do have a tendency to be a little bit of a “pack rat” but hey, when someone needs something I’ve probably got several, in various colours, in fact several in each colour but, if you need it,  …….. I’ve got it.

This of course means I have to sort through all my “stuff” and I have a lot of pretty neat stuff.

For example I’ve got a little cannon that someone gave me which is actually a pencil sharpener; now I don’t actually use pencils any more but ….. well….it just to good to throw out.

I’ve got a tin whistle,

I always wanted to learn to play the tin whistle, but ….well…..frankly I’ve got a tin ear and it doesn’t work with the tin whistle I guess. 

I’ve got some old tobacco tins,

and a piece of Cherub MkIV log

, I’ll bet you don’t even know what a Cherub MkIV Log is… well you can find out here: I’ve got another piece of the log as well but I’m not quite sure where that is. My Dad was the commander of some mine sweepers around New Zealand during WWII and he scored this log when a Panamanian freighter tried to cut across their bows out in the Hauraki Gulf. I can’t throw that out!!

I’ve got a pivot pin from the clutch in AHX12, my good friend Ian mounted it on a block of wood and presented it to me because this little part cost us a class win on the 2003 Targa Newfoundland.

I’ve got a “KING OF THE ROAD” car lamp, in fact I have 2 of those

and there is my Durant hub cap,

and that phone jack adaptor that I meant to take to New Zealand this winter to give to my brother in law Ian who lives in Abingdon U.K. because I’m pretty sure it fits a U.K. phone jack…he must need it.

Did I mention the genuine NOS Wipac reverse lamp from a Mini

or the wooden Yogi I bought on the beach for less than 1 cent on my first trip to Bali,

and then there is the spare battery for my first video camera.

The camera is long gone so I suppose the battery should go too but …you see….. you aren’t meant to put them in the garbage so I haven’t quite figured out what you are meant to do with them.

And then of course there are the heater valves. ….. Oh yes; the heater valves…

These are genuine Smiths heater valves, I have about 3 dozen of them……but I’m not actually sure what they fit.

Fortunately I found a solution on where else…. eBay …yes, I found and bought an old Smiths catalogue which, I should mention, is so big it almost takes up more room than the heater valves, so that I can identify the heater valves, then sell them on eBay, and then sell the catalogue and be RICH!!!!

Well, one of the types of heater valves was in the catalogue and I actually sold the one I had; another was in there as well but, it only fits a Commer Cob II, if you don’t know what that is don’t worry, you aren’t alone, and there aren’t a lot of people out there restoring Commer Cobs, let alone the Mk II version which, by the way, uses a different heater valve from the MkI and the MkIII. Mind you I did find a picture of a Commer Cob in my Dumpty Book of Motors which is on my bookcase.Whoooo …37 HP…I think I know why no one is restoring one!!!

Unfortunately the other types of heater valves, each of which I have about 30 weren’t in the book!!

Now all this stuff was just on one corner of my desk, and I’ve got the rest of my office, the store room, my workshop and the garage to clear out.

Better get on with it!!!!    Fortunately it is only a single car garage…which is another reason why we are selling the house…  

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For those who aren’t members of The Austin Healey Club U.S.A. and therefore don’t get the Austin Healey Magazine I have posted this article that I wrote at the request of Gary Anderson the editor.

Targa Newfoundland is a highly addictive event. Billed as “The Ultimate Motorsports Adventure“ the event is rapidly gaining a reputation as a test of endurance for man and machine. On the 2007 running of the Targa, Michael Oritt and I learned how challenging “The Targa” can be.

In 2003 and 2004, Blair Harber and I competed in AHX12, the 12th Austin Healey ever built, which he and I had restored and modified within the classic traditions for just such an event.

We achieved a Targa Plate both times for completing every stage within the so called “Plate Time.” But the organizers, knowing that the easiest customer to attract is one who is already converted, follow the traditions of the Alpine rally and dangle a Gold Plate in front of you as the award for completing three events within plate time. So, after a two year hiatus, the quest for gold was the carrot which drew me back.

After months of preparation we loaded AHX12 onto my special transporter, and with “Betty” – the ’59 mini campaigned by my brother-in-law and long-time friend Dick Paterson – on a trailer behind headed off on the 2100 km journey to St John’s, Newfoundland.

We arrived in St Johns early on Saturday 8 September and spent the rest of the day checking the cars over, completing the necessary formalities and calibrating our odometers in time to be ready for the Prologue on Sunday, 9 September 07.

Day 1: Prologue

The Prologue is really just an opportunity for the crews to shake down their equipment, and for the organizers to get some comparative times to set the start order for the first day of competition. In the right seat of AHX12 this year was Michael Oritt from Solomon’s , Maryland, an admittedly very “green” co-pilot.

 Although Michael had competed in a prestigious European event some years previously, performance rallying was to be a new experience. With its full cage and hardtop AHX12 is not the easiest car to get in and out of, so it took a few attempts to formulate an entry /exit procedure and, once Michael was comfortably installed, he was content to stay put as long as possible.  We had run through the first prologue stage the previous day as part of our mileage check; in fact Michael and I ran it about five times before we were happy with the calibration of our Brantz Rallymeter, so the prologue stages gave us the opportunity to make a start on sorting out terminology. Prior to the event I had tried to work out with Michael the terms he could use to consistently and quickly describe the turns detailed in the instructions. I don’t think I did a very good job because we were still working on this toward the end of the last day!

We made it through the two prologue stages without problems, and although a little apprehensive, felt we were as prepared as possible for the next day.

Day Two: Leg 1, North Avalon

For those not familiar with the format of this type of event, a short primer: The Targa consists of five days of competition. with each day including between six and nine “stages.” A “stage” is a section of road which is closed to the public with all the side roads and drive-ways taped off to prevent public access. Marshals are positioned along the route to ensure that the road is clear and that any spectators are safely positioned. Once this is all set up, the competing cars, starting at 30-second intervals, drive through the stage as fast as necessary to attain what is often an impossibly fast average speed. Each car has a driver and a navigator and the navigator is provided with a book of “tulip” diagrams which describe sections of the course which depart from the normal flow of the road. 

Sounds easy, right? …Wrong. The roads in Newfoundland are often very rough which, in addition to being really hard on the machinery, makes even reading the route book very difficult.

Unlike our 2004 start we actually turned the correct way out of the parking lot at the start this year…big bonus…and for the first three stages we did pretty well. The second stage was a bit of a wake-up call for us all and a sad day for Healeys.

As we lined up to start the stage, being the first Targa car for the day after the Touring class cars had been sent off, there was a little commotion among the marshals and the stage was held while an ambulance tore off into the course.Seconds later we were asked if we were ready to start and, despite my protestations that the ambulance must surely still be on the course, we were sent off into the stage.

 I found that I had to keep the pedal down fairly hard to maintain our required 78 KPH average sped through this windy and bumpy stage and then as we hit an enormous bump in a long sweeping left hand curve, which launched AHX12 into the air and threw us sideways several feet, I was startled to hear Michael shout, “ambulance.” I had been concentrating so hard on the road surface that I hadn’t even seen the huge white and red behemoth on the side of the road and only caught a fleeting but very up-close glance of it as we passed by with all four wheels off the ground To this day I have no idea how we missed it, but in the same instant I caught sight of the unmistakable profile of a turquoise Healey well off the road and bent over some very large rocks.

This car, running in the Touring class, was the only other Healey in the event and was severely damaged and had been the reason for the ambulance call. Fortunately. neither one of the father and son team of Ivan and Ian Shelton was seriously hurt but the Healey looked like it would need some serous renovation.

After we had passedthe stage was closed while the ambulance made its way off the course and then when it reopened one of the open class cars came to grief in the same spot.

Targa Newfoundland is indeed a tough event!!!

  The fourth stage, named Northwest Brook, proved to be our undoing. The stage was originally meant to be 31 kilometers long, but when we arrived we were informed that it had been shortened to only 13 kilometers and we were to start at the 18.6 kilometer mark. This change created some problems for us and within one kilometer we went off the road when we missed a left turn at the top of a crest. One of the disadvantages of running a Healey in this type of event is that the combination of long nose and low seating position makes seeing the road ahead very difficult as the car crests a hill, and it is that which caught us out. AHX12 gracefully flew over a large ditch on to a beautifully manicured lawn and landed on top of one of the two fairly substantial pine trees we had flattened.

 

 

 

Michael and I climbed out just in time to dive for cover as a Porsche 914 almost landed on top of us. Fortunately, he managed to miss the ditch and was able to carry on, though a little more cautiously. After a bit of a struggle we succeeded in extricating a slightly less pristine Healey from the trees and, after a quick check for damage, we managed to carry on through the stage.

 

 

Unfortunately that incident, as well as causing sufficient of a delay to put us firmly out of contention for a Plate, caused hidden damage which would return to haunt us later in the day.

There were only two more stages on that day, both of which we “cleaned” easily before starting out on a 120-kilometer transit to the town of Gander. As we neared the end this I made the fatal mistake of commenting to Michael: “I am amazed at how much abuse this car can take and keep going.” At that very moment, with a bump and a grind, a rear axle shaft broke, allowing us to just limp to the end of the day courtesy of AHX12’s Dana limited slip differential.

 

 

Our crew jumped into action and despite considerable difficulty, had the broken shaft out within a couple of hours while I phoned Toronto to arrange to have the only spare in the world flown out to us, a process which would take until well into the next day.

Day 3: Leg 2 – Exploits
It was a pretty disappointed pair of Healey enthusiasts who stood aside and watched as the rest of the cars headed of on Leg Two, knowing that we were out of the running; little did we realize that there was worse to come. The axle shaft arrived late in the afternoon but, when we went to install it there was more bad news: the entire axle casing had been bent in our “tree felling” excursion requiring that we remove the entire rear axle assembly and try to straighten the case before we could continue.    

 

 

Then, to add complications to the process the crew of “Betty” showed up with Betty on a flatbed truck. They had cooked Betty’s engine as a result of a serious water pump leak…the day was not going well

Once the diff was out we took it over to a nearby gas station where the resourceful mechanics used a pair of axle stands, a sledge hammer, a five-ton truck on a hoist and a large oxyacetylene torch to straighten the case.

 

 

They finished their work around midnight after which our youngest crew member and I worked until three a.m. to reinstall the diff, only to discover that the spare axle, shipped in from Toronto was too short for the modified differential.
   
Day 4: Leg 3 – Kittiwake
The next morning we pulled the axle out again and took it to a local machine shop where, using an ancient and very secret Kiwi technique, they lengthened it by half an inch! Sadly for us this process and the time needed to catch up on the rally, which by this time had moved 200 kilometers south to Clarenville, took up the entire day so we missed our second day of competition.

Day 5: Leg 4 – Heritage
We were up bright and early and off down Newfoundland’s Burin Peninsular for a long seven-stage day centered on Marystown. 

 

 

 

 

 

 

After so much rebuilding and patching I made a point of taking it easy for the first stage as the goal now was to finish.Nevertheless, AHX12 seemed to be handling and performing well, so we cranked the pace up a little for the next four stages, but during the fast Garnish stage the differential started to emit some new and rather alarming noises, indicating that all was not well. We managed to complete the short Fortune town stage but decided that we had best skip the last two of the day and head back to Marystown to investigate the problem before something failed
catastrophically.When we removed the differential we found that the crownwheel bolts had come loose. These were the original Healey 100 BSF bolts. They had stretched and were looking decidedly worse for wear. As we didn’t have any spares, I decided to apply Locktite and tighten them as much as I dared. The next day had seven stages and I was far from confident that these over-strained,  45-year-old fasteners were going to make it through.

 Day 6: Leg 5 – Avalon
Our accumulated penalties of the last three days had managed to push us down to 46th position out of the 53 cars still running and I stagger to think of the trials that those crews who were trailing us must have suffered!Now it really was a case of just making it to the end, and to add to our woes was a 190-kilometer transit to the beginning of the first stage. My concern about the crown wheel bolts was that a seized differential in the middle of a stage could have some fairly serious consequences and even before we had finished the transit the diff was starting to complain.Interestingly, one of the odd phenomenon of Targa competition is that if you try to drive a little slower than normal you are inclined to make mistakes so I decided to drive as quickly and smoothly as I could hoping that we could avoid mistakes and preserve our differential.

The first stage, Osprey Trail East, was an easy one which had been shortened and we breezed through with 33 seconds to spare.The second stage of the day, Spaniards’ Bay/Bishop’s Cove, was a really tough one. In previous years of the event some cars were “clean” up until the very last stages of the last day, so the organizers had decided to insert four stages with impossibly fast times to prevent a draw. We took 57 seconds of penalty but were still running. 

 

 

Two stages later we ran Brigus, a short fast town stage, requiring us to maintain an 84 KPH average. Incredibly, while trying to drive as smoothly as I could, we still managed to be one of only 12 cars which cleaned this stage and the two following ones. Unfortunately, this was followed by a 25-second penalty in the final stage of the event, during which we missed a turn and nearly took out a 15-foot-high rock.AHX12 had survived yet another Targa Newfoundland. Despite placing a rather ignominious 44th, we had still managed to win our class and at the gala were delighted to learn that our efforts to finish had resulted in our being voted the co-winners of The Spirit of Targa Award by our fellow competitors. The other winners were the crew of Betty who, after overheating and ruining one engine, trucked their car all the way back to St. Johns and worked for three days and nights to replace their fuel-injected, dry-sumped, crossflow-head engine with one from a regular Cooper S in time to complete the final few stages.

 

Once again Targa Newfoundland had confirmed its reputation as a tough but very memorable event. My calendar says I’ve got 353 days left to rebuild AHX12 in time for next year’s event.

You can view the complete results for the 2007 Targa Newfoundland here.

  

   

    

    

     

     

      

       

 

 

 

 

 

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To all who have taken the time to read my blog… click for a Merry Christmas greeting.

 It is a bit of a slow download so, please be patient….it’s worth the wait.

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I’m not trying to make things difficult but I have found that describing corroded or damaged body panels is impossible therefore I have decided to sell  the few that I have left in stock in restored condition only.
The restoration work has, or will be, done by a former employee who used to do all our metal restoration work using masses of patterns and bucks which he has accumulated over the years.

Such panels will be supplied in ready to install condition with hammered butt welds and no paint or filler.
Mounting holes in the replaced areas may have to be drilled, as variations can occur from car to car, and minor “spot putty” will be required during the refinishing process.
The insides are not usually completely stripped or cleaned because, if you require this, it is more cost effective for you to use your time rather than pay a skilled panel beater to do it.

I have a VERY limited number of most of these panels and when they are gone they are gone.
The prices for the restored panels are as follows
FENDERS
6 Cyl convertible front $900 (SOLD)
6 Cyl roadster front $900 (1pr & 2 left available)
4 Cyl front $850 (1 pr available)
BN2 & 6 Cyl rear $600 (3 pr & 7 left available) 1 pr completed
BN1 rear $650 (1 pr available) 1 completed
I have one new reproduction 6 cylinder right rear fender which, typically, does not fit.  Anyone can have it for $100 + shipping, but believe me you would be better starting off with one from a ‘53 Buick Special.
SHROUDS
4 Cyl front $2300 (6 available)
6 Cyl roadster front $2300 (7 available)
6 Cyl conv front (single light) $2700 (SOLD)
6 Cyl conv front double light $2900 (1 available) completed
4 Cyl rear $2600 (4 available)
6 Cyl 2 seater rear $2800 (2 available)
6 Cyl 4 seater roadster rear $2300 (11 available)
6 Cyl conv (early) rear $2900 (SOLD)
6 Cyl conv front (late) $3200(1 available) completed

For panels which are not in finished stock I will require a 50% deposit with each order.
Depending upon the amount of work we have ahead of us production of a finished panel can take up to 4 weeks.

As mentioned earlier if these panels have to be shipped there will be a crating charge which is typically $50 for fenders and $120 for shrouds.

You can download the full list here:

scott-morris-list-modified.xls

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Well my efforts to dispose of the entire used parts inventory have not been successful. I had expressions of interest but when it came down to it they just didn’t work out.
As a result I have reluctantly decided to try to sell what I can through this blog.

As can be imagined organizing and describing the parts is very time consuming, and my storage arrangements are somewhat tenuous but, we just have to see how this works out.
One of the more difficult issues with used parts is figuring out a fair price. This is because different people have different interpretations of the value of such parts. 

First you have the person who looks upon used parts the way they would view things at a garage sale or a flea market, and in some ways that is not unreasonable. The parts are used and it would be easy to imagine that I got them for very little and therefore they have little value.

At the other end of the spectrum is the true aficionado; this is someone who has seen what is available in reproduction parts and really appreciates originality. I guess I’m one of those.  

For those in the first category please consider this. In order for these parts to get to where they now are all of the following had to occur.
 The car from which they were removed had to be purchased and moved to our shop.
  The car then had to be disassembled, this doesn’t mean ripped apart, it had to be carefully taken to pieces while being very careful to not damage the more useable parts. The people doing this work were not “casual labour”, I tried that and everything got destroyed, so the disassemblers were, for the most part, qualified mechanics.
 The parts removed had to be cleaned and sorted into “keepers” and “chuckers” and we had to pay to have all the latter parts amd the carcasses dumped.
 Storage trailers had to be purchased and positioned on valuable land.
 Storage shelving had to be purchased and assembled inside the trailers.
 Storage containers has to be purchased and then the “keepers” had to be sorted and stored in the trailers, some for as long as 20 years.
 Now someone (me) has to photograph and document all the parts and put them up on the blog. 

So, when I say that a used thingamajiggy is $55, it is all of the above that is being paid for and …..we tried our very best to do it on the cheap!!  

So here are the rules:
1. The minimum value of an order is $CDN40. If you want something worth less think of something to add to it. To put it bluntly I’m not in this to waste my time searching out $2 parts that someone thinks are worth $0.50. I am 25 minutes drive from where the parts are stored so it is at least 1 ½ hours out of my day to search out an individual part.
2. Everything is sold as is and all sales are final. Ask me any questions you like and I will do my best to answer them. I know British parts pretty well and am usually aware of what is important but please ..ask.
3. Please try to be very specific about what you need. Include the make model and year of car and an accurate description of the part you need.
4. I will charge a packaging charge of $5.00 for articles under 2 kg and this can be as much as $150 for big things like major body panels and heavy bits, like engines.
5. I will ship all parcels of a size that they will accept via Canada Post I will get a cost for the postage and send this to you.
6. I would prefer that you make arrangements for the collection and shipping of larger items.  I can arrange for this but I will charge a service charge of 20% of the shipping costs.

If you are interested in a particular part please contact me at mailto:magicareprotect-usedparts@yahoo.ca and be sure to include what you feel is a fair price for the part.
Say something like: 
I’m interested in a Spitfire MkII cylinder head. The casting number on the head is 122322 and if you have one in good condition complete with valves and springs I will pay $100 for it.”

Additionally it would be VERY HELPFUL if you would use a brief description of what you need in the “Subject Line”

If you have no idea what the part should be worth let me know and I will try to figure out a fair price. I will try to make every effort to answer all enquiries but if you don’t hear back please try me again, I use a pretty aggressive spam filter and stuff gets lost.

Scott Morris has been good enough to re-arrange the list into a much easier format to search.. .. something for which I’m very grateful. You can download it here:

scott-morris-list-modified.xls

I will try to keep it up to date and add more pictures as I get the opportunity to take them. I will not be updating the list on my previous post.

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Thanks to the very welcome advice of Jim Hockert, Mike Gladwin, Bob Haskell, Richard Ewald, Dallas Congleton and Ken Freese, all of whom made very worthwhile suggestions, I think we have the problem solved. My idea of the tab washers became a non starter when I realized that I would be unable to get a socket on the bolt heads with them in place .
The solution that I have finally settled upon is a combination of recommendations and involves using Loctite, hardened (grade 8 ) washers and lock wire in grooves cut into the side of the cage.

As Richard suggested, it is very likely that the Loctite job that I did between legs in Marystown, Newfoundland, with the lack of a torque wrench, stretching bolts and insufficient time to allow the Loctite to properly set up was almost certainly far from satisfactory.
This time I have used new alloy steel bolts and Loctite 243, an oil resistant grade .  As recommended I spent lots of time properly cleaning the threads on the bolts and in the blind holes in the crownwheel before assembly.
Using a modified version of Jim’s recommendation I drilled the bolt heads and, with a cutoff wheel, cut slots between pairs of bolts to accommodate lock wire installed after torquing them to 45 lb ft.
I’m still debating whether or not to use J B Weld to “glue” the lock wire into the slots to preclude the possibility of it slipping out and getting damaged through contact with the carrier….stay tuned.
Again thanks to all who took the time to read my post and recommend solutions to this problem.

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As noted in my previous post one of the problems we had with AHX12 in the 2007 Targa Newfoundland was caused by the stretching of BSF bolts which hold the crownwheel to the differential carrier. These 50 year old bolts, made at a time when the quality of  fasteners available in Britain was not that good, were not up to the rigors of Targa.  

The rules for Targa Newfoundland read as follows:
The central differential housing must remain OES.
The carrier, ring/pinion, axles, and all bearings are free.
Mechanical limited slip differentials are free.
The diff in AHX12 is not your run of the mill BN1 unit. In my previous post I have explained how we have managed to retain the central differential housing but strengthened the outboard sections to resolve the problem of the inherent weakness of the BN1 style case.
The carrier is a standard BN1 item, however the cage is from a Studebaker Lark V8 and incorporates a Dana POWR-LOK 27 limited slip unit. In order to get this cage assembly into the BN1 housing we had to turn down the bearing mount on one end of it and install a BN1 style ball bearing there, and use one of the taper roller bearings from the Dana unit on the other end.

Next an annular ring was machined and welded on to produce a correctly sized and positioned mount for the 32 tooth crownwheel from the 3.55/1 ratio gear set. This is what the whole thing looks like with the crownwheel not installed.
With this arrangement the cage assembly ends up being very close to the housing and, as there was insufficient clearance for the heads of the crownwheel mounting bolts, we counter-bored holes to recess the heads below the surface of the cage.

As the crownwheel is on the right side, when these bolts started to back off, their heads contacted the carrier casting which in turn tended to loosen them further. The noise generated as their heads ground away at the cast aluminium carrier was quite dreadful.

In this picture you can see just how much material was worn away.

Now, as I’m rebuilding the diff unit, I am somewhat perplexed as to how to prevent a reoccurrence of this issue. Previously I had used Loctite and good lock washers to lock the crownwheel bolts but even though the real problem was initiated by the stretching of the bolts I’m not confident that this locking method is satisfactory.
In the original BN1 differential 4 two hole tab washers were used to mechanically lock the bolt heads but, because our bolt heads are recessed, that system won’t work.

After considering drilling the bolt heads and lock wiring them, or drilling the heads, tapping a small thread in the hole then installing a tiny Allan head screw into the hole to be tightened against the wall of the recess, the best that I’ve been able to come up with is to make some two eared tab washers like this.

The flat tab would project through the gap at the outer edge of the counterbore and the turned up tab would be pressed against a flat of the bolt head to prevent it from loosening off.
Unfortunately I’ve been unable to find a production tab washer of this type so it would appear that my only options are to grind and file some out of some 3/8” fender washers, very time consuming, or have them laser cut, very expensive.

Does anybody out there have a better idea…

6 Comments »

The Targa Newfoundland 2007 is over and it proved to be a very revealing test of my revisions to AHX12’s rear suspension. By reading my previous posts on the subject you will get an appreciation of why I decided to make this fairly radical change to the suspension and how I did it.

All in all the suspension system was a success. I managed to get quite a bit of track time with the car after the work was completed and, once I had managed to sort out anti roll bar settings and find suitable tires, there was no question that there was a dramatic improvement in the handling. Unfortunately driving around a smooth race track is not the way to test for Targa conditions. The roads in Newfoundland haven’t improved much over the last 5 years and at best they could only be described as “rough”. Frost heave is a big problem in the maritime climate and the damage that this causes to the roads is something that needs to be seen to be appreciated.It was not the rough roads however which proved to be a test of the new set up but a small “off-road excursion” on the first day of competition.This “incident” in part involved jumping over a rather substantial ditch before bowling over a couple of small pine trees and coming to rest on top of one of them.  

 The “jumping” part of course resulted in a “landing” part and it is that which, as is normally the case, caused the damage. Although we managed to get the car off the trees and continue on our way we were not aware that the rear axle casing was bent and that the axle shafts were being subjected to enormous stresses which would result in the failure of one some 200 kilometers down the road.

For those of you who have managed to stay awake this far here is an analysis of what actually happened.

You will recall that to install the coilover suspension I fabricated plates with gussets on them to pick up the lower end of the coilovers. This moved the point where the axle casing was subjected to the weight of the car inward about 2″.

This increased the moment about the wheel by about 20%. I figured that this in of itself would present no real problems. Little did I realize that the BN1 axle casing had an inherent design flaw. As depicted in the drawing there is a very sudden change in section of the casing about 3″ inboard of the spring bracket. This change of section makes the tube very weak at that point. For this weak area the additional moment resulting from the movement of the load together with the ditch jump was just too much and it bent at this point on both sides.

This bending caused the axle shafts to rub on a scroll seal which is inside the machined “snouts” which the rear hub bearings mount on. I actually had no idea that there was a scroll seal in there and cannot really figure out why it is necessary. Anyway this rubbing of the shafts on the seal must have been sufficient, after a long straight run, to heat up the axle shaft to the point where it was weakened and it broke.

In the photo below the difference between dimensions “A” and “B” is an indication of how much the casing had bent.

The BN1 differential is a spiral bevel unit and uses an Austin casing which interestingly is pressed from one piece of 0.140″ thick steel. When we had the diff out and in pieces on the ground one of the onlookers started taking photographs of the casing and studying it very closely. I got chatting to him and found out that he worked for a manufacturer of differential casings in Toronto. It just so happened that they were just “inventing” a completely new system of pressing out diff casings using one piece of steel and he was dumbfounded to hear that the same process had been used by Austin some 60 years previously!!

It was not until I got the car back home and took a look the axle casing on my 100S that I realized that the Healeys must have been aware of this weakness. The 100S differential although still a spiral bevel unit uses a casing which does not have this change of section, in fact the 100S axle casing doesn’t look like an Austin axle casing at all but appears to be a Morris pressing much like that used in the BN2 and later Healeys. These casings are made in the more traditional method using 2 halves welded together. I suspect that the 100S used a modified MGA casing. As I don’t have many spare 100S diff housings lying around I had to come up with a modification to strengthen what we were using in AHX12. I could have opted to install a BN2 type axle but the BN1 unit is considerably lighter and I have a substantial investment in special axle shafts, hubs and limited slip units which would not be of use with the BN2 diff.

This is my solution.

I have cut the original housing off just inboard of where it would normally contact the frame rails on full droop and replaced the outer sections with 2.5″ 0.187 wall welded tube.  

The original “snouts” from the old diff have been turned down and welded onto the ends of the new tubes after 4 laser cut brackets, with pick up points for the radius arms and coilovers, were installed. This is what the fnished job looks like prior to the installation of the hub and brake.

All this work should go a long way toward strengthening the rear end which of course wouldn’t be necessary if I would just stay on the road!!                   

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