Michael’s Blog

Many years ago I picked up a very unusual, at least unusual to me, model of an Austin Healey 100. Although it is the most cheaply made tin model one could imagine the detail in the original lithography is amazingly detailed.

I would love to know more about it…If anyone knows more about this kind of model please comment below.

The model is about six inches long and 2 1/2 inches wide.

2 Comments »

Any comments in the space provived below would be welcome.
After fighting with the cart springs on the back of AHX12 and other Healey race cars for many years I have decided that the time has come to get this monkey off my back once and for all. The rules for the modified class for Targa Newfoundland permit changing the type and positions of the springs and shocks, but prohibit replacing live rear axle with an independent rear end.
Although it would appear that a De Dion system would be permitted the work involved in designing and developing such a system appears to be a little daunting to say the least.
I have decided to stick with the old spiral bevel BN1 type axle for the present (read watch this space) and build a four link system incorporating coil-overs which will decrease the unsprung weight at the rear by quite a bit and give me a degree of adjustability which is unobtainable with the original Hotchkiss system.
I intend to build a small subframe assembly just forward of the differential which will be welded to the main chassis rails. I will use the upper radius arms which duplicate the BJ8 style and add lower arms to replace the leaf springs.
The finished job will look like this, although in this rendition I have drawn the coil-overs as the blue shocks because the springs take so long for my computer to render.

In addition to this I have modified the rear chassis to incorporate a dip much in the style of the BJ8.This modification will allow an extra 1.75” of rear suspension travel, something desperately needed for big bumps and “landings” in Newfoundland.

One problem that a four link system can present is incorporating anti-dive / anti-squat into the design without producing chassis roll induced oversteer. To put this into more simple terms it is desirable to design the suspension such that the car does not nose down on braking or nose lift on acceleration. These reactions, which can be quite significant, tend to destabilize the car and make control in extreme situations difficult. Modern suspension systems incorporate geometry which reduces or eliminates dive and squat and this is what I intend to do to achieve this.

At normal ride height I have designed the arm positions as above.
Under acceleration the diff housing will tend to rotate clockwise. This action will produce a tension in the upper arms the vertical component of which will tend to lift the chassis producing the anti squat. Should the car actually take on some squat (i.e. chassis moving away from the axle) the angle of the upper arms will increase and therefore the relative vertical component of the tension in them will also increase to minimize the squat. The angle of the lower arms will also increase and the vertical component of the compression in them will tend to induce squat, however the rate of increase of this force will be lower than that of the upper arms producing a net lifting force on the chassis.
Under braking the diff will tend to rotate anticlockwise and the vertical component of the compression in the upper arm will tend to force the chassis down. Should the chassis actually rise relative to the axle (dive) the vertical component of the tension in the lower arm will end to pull the chassis down replacing the force lost by the decreasing angle of the upper arms in a similar fashion to the squat scenario described above
The big issue however is the fore and aft position of the axle in a turn.
This is how I see this scenario.
If the chassis moves closer to the axle (suspension compressed {outside of turn}) neither arm will adopt an angle which will move it nearer to horizontal; thus they will both effectively become shorter. These arms becoming shorter will move the axle forward on the outside.
If the chassis moves away from the axle (suspension extending {inside of turn}) the upper arm will become closer to horizontal increasing in effective length as the lower arm gains angle and becomes effectively shorter. These length changes will near enough cancel each outer out resulting in no change of horizontal position of the axle on the inside. I realize that the axle will have a tendency to rotate different amounts at each end under this scenario but I think the rubber bushings used on the forward ends of the lower arms will have sufficient compliance to accomodate this
My expectation is that the nett result in a turn will be that the outside end of the axle will move slightly forward while the inside stays close to its neutral position the result of which will be chassis roll induced understeer which is what I want to achieve.

5 Comments »

If you have ever wondered what it is like to run a Targa Stage here is your chance.

This is a picture of my buddy Dick Paterson’s very hot 1959 Mini “Betty” taken by Gordon Sleigh. You can see the rest of Gordons pictures at : http://pics.spoon.org/Cars/Targa2006/

The following is a video from the inside of Betty while Dick and his Kiwi co-driver Tony Mattson hot shoe it through the very tight Brigus stage in the 2006 Targa Newfoundland. They were one of only two cars that managed to “clean” the stage. See the results here.
Turn up the sound and enjoy the ride.

13 Comments »

When the workers on the BMC assembly lines assembled Austin Healeys I’m sure they were told time and time again to put a dab of grease on the master cylinder clevis pins before installing them. These are the little 5/16″ diameter pins which form the attachment between the pedals and the brake and clutch master cylinder push rods.
Probably, when the “governor” was looking these little items were dutifully coated with some sort of grease however, most of the time, they were slipped into place without so much as a sniff of lubricant of any sort.

The sad fact is that it takes longer than the warranty period for something like this to wear out to the point where it is noticeable so I’m betting that the practice continued unchecked throughout the 15 years of Healey assembly.

The result is that after a considerable mileage these un-lubricated pins get badly worn.
These are a couple of examples that I removed from Healeys over the years.

Unlike modern cars the braking systems in Healeys, and for that matter most cars built before 1968, were designed with no duplication meaning that if one brake component failed the entire system failed. After 1968 all North American market cars had to have  “tandem” braking systems but, interestingly, this duplication does not include this little item, so failure of this pin can still cause total brake failure.

Another interesting thing about brake systems is that for the most part they are used very gently; after all vigorous application of the brakes usually makes passengers nervous. The only time that brakes are applied hard is during a “panic” stop and that, of course, is when components are subjected to the greatest loads and failure produces the most serious consequences.

I’m constantly amazed that I have never heard of an accident having been caused by brake failure attributable to the shearing of one of these pins. I’m sure that there are plenty of MGB’s and Healeys and Triumphs running around, all of which use the same system, with pins as worn as much or even more than those shown here.

If you drive a high mileage British Sportscar this winter may be a good time to check these out.

3 Comments »

From the 1967 New Zealand Motor Racing Annual.

4 Comments »

I was going through a pile of old photos a few days ago and came across a picture that someone gave me about 15 or 20 years back.

I apologize to the person who took the time to bring it to me, but I do not remember who it was. I do recall that the donor was someone from the Southern Ontario Austin Healey Club and that he had brought the photo to me specifically to ask if I had ever seen a Healey model with this rear suspension system fitted to it. I also recall that this was all rather secretive in that the person involved had apparently found this Healey in a partially finished state with this suspension. 

There are a number of very interesting features in this picture and I only wish that at the time I had followed up on it. The things that I find very interesting are:

1) Careful examination of the top area of the photo confirms that this is almost certainly a Healey as the standard cross brace section of a Healey’s frame is visible.
2) The frame sections are made from what appear to be sections of Healey frames. If someone other than the factory was going to do this to a car it would seem unlikely that they would have had access to sections of Healey frames or have bothered to replicate them.
3) It has inboard drum brakes indicating that this project was probably undertaken before inboard disc brakes were more common.
4) The suspension arms are very unusual yet quite clever in that the wheel would experience no camber change throughout its entire range of movement. This would not perhaps be ideal because some camber change upon compression is desirable to counteract the effects of body roll but with a little tweaking this could probably be built in.
5) I don’t recognize the differential unit but do note that it has a U bolt style universal joint yoke on the drive shaft connection. I think these are more typical on American style drive shafts.

If the person who gave me this picture is out there and on the list I’m sure we would all like to hear more about it or perhaps if anyone has any knowledge of a factory project of this type.

6 Comments »

WHY CONSIDER IMPROVEMENTS  
Although I seem to have gained a reputation for being somewhat of a Healey modifier I still believe strongly that a standard Healey in good mechanical condition is a fine car to drive and preserve, and I only offer what follows in response to several enquiries that I have had on the subject. I do not consider myself to be an expert, but I have some experience and what follows is based upon that; furthermore I’m sure that most of what I’m going to say will be obvious to those who have considered the subject in any depth but, for those who haven’t, this should be a good starting point .
Because the big Healey is the epitome of a “sports car” it is not unreasonable to think that perhaps it should handle in a sporting like manner.  It is pretty disappointing to take your car out to a friendly gymkhana or similar event and find that no matter how well you drive 1200c.c. rice rockets are completing the course in half the time it takes you and your Healey.  What I’m describing below should result in some respectable improvements and is, for the most part, easily reversible; I’m not advocating modifying the car so dramatically that it looses its classic appeal.

SOME BACKGROUND
Up until 1965 all big Healey’s used the same suspension which dates from 1952. Many of the components were probably designed for a cars built immediately after WWII.  The rear suspension of the big Healey is an interesting study in design compromises. In the interests of styling and to minimize manufacturing costs Donald Healey opted to use a rather outdated “under slung” ladder frame for the 100. I’m pretty sure that the Healey was the last mass produced car to use this design. One of the most demanding compromises which has to be addressed with this type of design is the spread of the main frame rails. Positioning the frame rails far apart improves the rigidity of the frame but places some major limitations on the suspension. With the Healey I believe the spread of the frame rails was determined by the front suspension and that the rear was built around the result.

UNDERSLUNG FRAME 

The problem with the under slung design is that the available suspension travel is limited by a factor of the distance from the underside of the rear axle to the ground. In the case of a Healey the total travel available is less than 12 cm.  Common practice in suspension design is to maintain the car’s normal ride height at or slightly above about mid travel. This means that the axle has only about 6 cm of available movement either up or down, and that is not very much. If you watch the suspension of a car driving next to you some time, you will see that an average car uses 10-15 cm of travel along a relatively smooth piece of highway.
The Healey design did produce a “firm” ride but, for cross ply tyres, which were all that was available in those days, the suspension was reasonably adequate.

HEALEY SUSPENSION IN THE 21ST CENTURY
Radial ply tyres became commonly available in the early 1960s and their improved grip means that they can generate forces in suspension systems that are substantially higher than could be generated with the bias or cross ply tyres. As a result, with good tyres and  some not very aggressive driving, the body roll of a Healey can be quite significant. Body roll in itself is not necessarily a bad thing, but it can have some negative effects when it causes excessive changes in camber of the wheels. i.e. their inclination relative to the ground.
However in the case of a Healey with its under slung frame, there is another major problem in that the body roll can be so significant that the rear frame on the inside of the turn rises sufficiently to contact the axle, which in turn lifts the inside tyre off the ground.

WHEEL LIFT

This has two immediate effects. Firstly the inside wheel spins because it cannot transfer the engine power to the ground and secondly the back of the car tends to step sideways. This sideways stepping is because tyres, particularly radial ply tyres in motion, behave a little oddly. Explained in simple terms, two tyres carrying 500 pounds each will have considerably greater resistance to side thrusts that one tyre carrying 250 pounds and the other carrying 750 pounds or in other words lift off one rear wheel and because the load on the rear tyres is suddenly transferred completely to the outside tyre things go very pear shaped indeed.

THE FIX
To rectify this situation we have several options.
1. We could fit stiffer springs. The problem is this would result in an even harsher ride, possibly okay for a smooth race track but definitely not ideal for street use.
2. We could increase the available space for rear axle travel. This is the solution that B.M.C. adopted in 1965, but it required some fairly extensive frame modifications which are out of the question for most people.
3. We could add roll stiffness to decrease the amount of body roll in turns and this is the course we will pursue here.
 
INCREASING ROLL STIFFNESS

Roll stiffness can be easily increased by installing anti roll bars. The front of a Healey already has an anti roll bar and you can stiffen this a little by eliminating the softness of the bushes or considerably more by fitting a thicker bar. Increasing the front roll stiffness  results in the outside front wheel supporting more weight in the turn and the car staying more level however, as a result of the uneven tyre loading thing mentioned above, this change alone will produce massive understeer. Understeer, for those not familiar with the term, means you turn the steering wheel but the car to a greater or lesser degree carries on straight ahead. 
To achieve the desired result roll stiffness has to be increased both front and rear, and then balanced between ends to keep the tyre weights where you want them through the turn. When this is done correctly the weight transfer in the turn will be evenly distributed between the front and rear wheels and this will produce the maximum grip.
SOME THINGS TO CONSIDER
1) Increasing roll stiffness will have a detrimental effect on the way the car negotiates one side bumps but a further modification; fitting tube shocks will improve this dramatically.
2) Installing most of the available rear anti roll bar kits involves welding to the frame.

(I have developed a design for a rear anti roll bar which requires only the drilling of 4 holes for installation but as yet I have not had an opportunity to test the design).

REAR ANTI ROLL BAR SYSTEM UNDER DEVELOPMENT

3) When it comes time to make adjustments remember; the stiffness of an anti roll bar increases as the fourth power of its diameter so a very slightly thicker bar will be substantially stiffer.

I hope that all helps.

18 Comments »

Upon the arrival of winter the GMDS* required that the wheels with snow tires be fitted to her 1997 Dodge Stratus. In the past I have run the car up to Precision Sportscar and done the job on a hoist in the warmth of the shop. This year I thought I would save some time and do it right here in the driveway.
Of course I don’t have an impact wrench or a floor jack here but the car comes with both a wheel wrench and a jack so how hard could this be?
Turns out that changing the wheels over wasn’t a problem at all. The problem was getting the jack back into its stowage position in the trunk after the job was done. Definitely one of the worst pieces of design I have ever come across.
With the jack removed this is the scene with which one is presented when attempting this task”

Quite obvious is the keyhole shaped slot in the jack mounting bracket welded to the trunk floor. The head of the huge carriage bolt slips into the keyhole slot providing an anchored thread to hold everything down. The instructions are glued to the underside of the trunk floor panel. Doesn’t look too tough eh?

Position the carriage bolt, slip the jack into position and lock it there by extending the jack a little, then drop the wheel and other bits on top after which everything is held down with the big wing nut, which by the way has to be run down about three inches of poorly cut thread to achieve its purpose.
Well there is a problem. The position of the head of the jack is determined by the two little tabs which engage into cutouts in the jack’s base. When installed the head of the jack prevents the carriage bolt from sliding into the slot of the keyhole.

In the picture above I have done my best, by flipping the jack over and then skewing the head to the left, to make things fit, but as you can see the carriage bolt won’t even start to enter the slot of the keyhole.
I had noticed that the jack was loose in the trunk when I went to get it out and I don’t think it has ever been used or for that matter correctly installed. My first conclusion was, as usual, that I was doing something wrong and, against my better judgment, I decided to refer to the instruction sheet (real men don’t do instructions). After reading them several times, as far as I could figure, the instructions suggested that I do exactly what I was attempting to do which was proving to be impossible. By this time I was getting bloody cold in the windy -2C weather and I wanted to suggest that the person who designed this system do something to him or her self which is probably physically impossible and definitely very painful.
So I got out the handbook and took it inside to see if it was any more informative.  It wasn’t.
I thought that maybe I had the wrong type of jack, but it is the same as the one in the instructions.
So what is the problem here?  If I can’t figure out how secure the jack how is my dear wife going to manage on the side of the highway and furthermore page 122 of the handbook features this big warning.
 

My guess is that the individual who designed this installation was just too damn lazy to get off his ass and actually try to install the jack into its mount when the first cars came off the assembly line and I’m betting that there are thousands of Stratus’s and Cirrus’s out there with their jacks loose in the trunk.
I thought, just for comparative purposes I would check the jack stowage arrangement in my winter beater 1996 Subaru Outback Wagon. I had the jack out and back in correctly secured in its stowage inside 30 seconds, no carriage bolts, no wing nuts, no plates, no cover supports, you just couldn’t do it wrong.
So what does this all mean…really?
I think it is a very good illustration of why the U.S. car makers can’t sell their cars outside of North America and why they can’t compete with the imports inside.  If they can’t design a satisfactory jack stowage system then how are they doing on the rest of the car; what about the steering linkage and those brake hoses. Has anyone actually checked them in service or, like the jack stowage, do they move on to the next project and hope that any faults get picked up in a recall.
My wife’s next car won’t be a domestic.
* General Manager Domestic Services
        

4 Comments »

Those of you who have been paying attention will have noticed that in my previous post I lamented the fact that we were unable to get more than about 6000 r.p.m. out of AHX12’s engine. I’ve done a lot of reading on that subject since we did those dyno tests and now have a better understanding of what we were up against and now, upon reflection, it all seems very simple. In my earlier days of “hopping up” engines, as it was called back then, we had no idea why our 750c.c. side valve Austin Seven engines would not exceed much more than 4500 r.p.m.

  Even down hill with a stiff tail wind the old bombs would top out at about 80 m.p.h. and nothing we did, short of dropping them off a cliff, would make them go any faster.  

  The general consensus among the more learned of our friends was that we had reached 3000 feet per minute average piston speed. Theories abounded as to why this number could not be exceeded but most were based around things like “the ring package would stop working” or “there would be uncontrollable blow-by” or “the rod bearings couldn’t handle anything more”. It always struck me as strange that we didn’t see a lot of evidence of this. Excessive blow-by would surely have been indicated by clouds of smoke and although we had the occasional cases of engines “putting a leg out of bed” as it was called back then that was usually because someone forgot to check the oil. 

  The engines just wouldn’t go any faster. It seems that we were somewhat off track and the real explanation is far less complex. 

  To develop power an engine has to ingest a gulp of air (which contains a bit of fuel). The force to get this air into the combustion chamber comes from the good old 15 p.s.i. (pounds per square inch) of atmospheric pressure. What the atmosphere has to do, when the inlet valve opens, is accelerate a slug of air through the port, past the valve and into the cylinder. The problem is that although that slug of air doesn’t weigh that much 15 p.s.i isn’t that much of a force. Everyone knows that the rate of acceleration is proportional to inverse of the mass being accelerated and the force accelerating it. In simple terms the old atmospheric pressure can only push so much air down that port in a given amount of time. At 6000 r.p.m. the piston moves from the top, essentially where this process begins, to the bottom, where it ends in 1/100^th of a second. That isn’t that long. Now there are a bunch of “mitigating circumstances” but when you get right down to it that is what has to happen. Things can be improved a bit by making the valves open longer and further, or cleaning out the ports and fitting bigger carburetor throats but the fact remains that 10,000r.p.m. just wasn’t going to happen on a long stroke 750c.c. side valve. Once the engine needs more air to go any faster it changes from a blower to a sucker and that is that.  We were up against the same problems with AHX12. We had pretty well doubled the power from the original 92 b.h.p. and to go much further we would have to tap Bill Gates for an engine development program loan and as far as I know he isn’t a petrol head.   

4 Comments »

The cam we were using for the first run of AHX12 in 2002 and 2003 was designed and built especially for the engine by Dema Elgin of Elgin Cams.
We had asked Dema to build us up another more aggressive cam because we felt the dyno results on the first one he supplied produced may have been part of the reason why we only managed to get about 165 BHP from the engine.

I felt that we should, with no decrease in torque, be able to move the power band up the rev range a little and thus get closer to the 200 BHP that I felt the engine was capable of.
As it turned out the cam really didn’t have the desired results and although we managed to get up to 178 BHP after spending all day on Barry Sale’s PHP Racengine’s dyno we were unable to make the engine rev higher and the power still dropped off at anything over 5500 RPM.
During the 2003 event we started having some oil pressure problems. Sometimes it was low sometimes it was high but it was not consistent and we couldn’t establish a pattern at all. We finally put it down to dirt in the oil pressure relief valve because after we cleaned that out all was well for a while but, eventually, the problem returned and it was time to investigate further. When we pulled off the pan we found that it was filled with steel flakes and upon further examination we found that several of the cam lobes were very badly worn, and this after only about 2700 km of use.

I was some upset when that cam went south, particularly after all the trouble I had taken to install and break it in correctly and the additional expense we had incurred to use Valvoline Synthetic Race Oil but concluded that perhaps we were overstressing the lifters with the added lift.

Prior to the 2004 Targa I rebuilt the engine with the cam that Dema had originally supplied and we decided, for no particular reason to use Valvoline VR1 20/50 Race Oil. This time we had no cam problems even after the engine ran 10 km with no oil!!!

Well recently I received a copy of an article written by Keith Ansell of Foreign Parts Positively Inc. and it looks as though VR1 may have been a good decision. The general gist of the article is that the quantity of EP additives in modern engine oils is being decreased markedly because these chemicals reduce the effectiveness and eventually damage catalytic converters. This is not such a problem in modern engines with roller cams and rockers but with our old flat tappet technology this spells disaster. Fortunately it seems that the VR1 still has the higher EP content as does Redline but they seem to be the only oils which do. Keith has promised to send me an updated version of his article as soon as possible which I will post here for those interested.

With a 100S head, diesel crankshaft and Elgin cam this is pretty well a unique engine. I’ve never heard of another like it that’s for sure. After some very hard racing miles including one seizure and 10 km at race speeds with no oil the engine was due for a rebuild. The block I originally used was bored out so far that some of the repositioned head studs, required for the “S” head were very close to the cylinders. The replacement block has 3.45” bores and the stroke is still 3.996” bringing the capacity down to 2490c.c. but hopefully resolving some of the head gasket issues that have been causing some reliability problems.   

14 Comments »