Suspension Modifications to improve Handling and Roadability?

[John Turney]

...

John indicated that he tightened up his steering box and introduced some negative camber to eliminate constant steering corrections. Although there are a few things I want to address, there seems to be a consensus that a slight amount of negative camber is a good thing and would help eliminate the wander.

Since I can’t go overboard at this time with the expense, what is the recommendation on the most cost-reasonable approach that would provide a worthwhile adjustable camber implementation?

As always, thanks and all the best,
Ray (64BJ8P1)

Ray,

Negative camber increases the front grip, especially needed with a heavier front anti-roll bar. Verifying toe-in stopped the constant steering corrections.

 

[stretchit2]

Don't overlook the obvious. I have done Putzke shocks, Denis Welch steering box, Michelin XAS Tires, new tie rods, bushings, etc. But I recently had my 53 year old leaf springs replaced and wow what a difference.

 

[dougie]

Ray -

I would start with these: https://www.mossmotors.com/Shop/ViewProducts.aspx?PlateIndexID=75681 Easy install, good for about -1/2 degrees negative camber.

 

[RAC68]

Thanks Dougie, I can handle that.

All the best,

Ray (64BJ8P1)

 

[Frameman]

I've been racing my 3000 for over 30 years. I've considered every modification possible to improve handling. I've read every book I know of about how to make a race car handle. I've raced against and talked to Healey racers from around the world. I have never heard of anyone remotely suggesting that the rear spring front mounts should be moved inward. I routinely drive my Healey 130 MPH and more, depending on the length of the track, and the car is stable. So, what exactly would moving the front spring perches inboard 1/2" achieve?

A car set up for racing is very different than a car set up for the street. Race cars have roll cages which add to the improved handling of the car by controlling torsional loading. The suspension is set up differently for racing purposes. Therefore cannot be compared to a car set up for regular road use. The purpose of toeing in the rear springs is to maintain rearend stability. North American Auto manufacturers have been doing this since the 1920s. Healey started to do this in 1965.
If you go to our website there are pics of the undercarriage of my V12. The basic suspension is stock with heavier rear springs and 1" rear sway bar. We have a 1" sway bar on the front with stock suspension. The car is also equipped with rack and pinion steering. I have had this car over 150 mph and found it to be very stable and predictable. Once again because of the Jule chassis we are still not comparing apples to apples as with your car. The Jule chassis provides more rigidity as does your roll cage.
I think the suggestions put forward on this site have been good for people with stock Healey chassis. You can't do the same things to a stock Healey as you would a race car.
When doing suspension upgrades always consider the effects on torsional loading.
Marty

 

[RAC68]

Sorry to bring this up again but...

Yesterday I was with a very experienced automotive suspension expert who is also a British car enthusiast. As you would expect, I couldn’t resist asking some questions about my plan to introduce negative camber as a way to reduce high speed steering wander.

He responded with the very logical suggested that I first find out exactly what my present camber, caster, and toe reading are and how my rear wheels were tracking. Being aware that Healeys were only provided with a toe adjustment, he indicated this information and my driving objectives would determine what modifications could be required within the context of reasonable effort and cost.

He then brought up “Caster”. He described caster as the angle that the front suspension leans back (Positive caster angles) and that an angle of greater then 5 degrees will improve directional stability but increase steering effort. He thought the Big Healey had a small built-in positive Caster (specs indicated around 2%) and this is my major cause of wander at speed (by the way, an MGB has a 7% Caster with good directional stability).

Has anyone modified their Caster setting and, if so, how?

Thanks,

Ray (64BJ8P1)

 

[HealeyRick]

Ray,

I haven't heard of a lot of Healey owners complain of "wander" as opposed to "scuttle shake" My BJ7, with basically a stock suspension, tracks straight and true at highway speeds without any sign of wander. I'd suspect your problem with wandering has something to do with a suspension component being loose or worn, loose wheel bearings, a bent rim or really wide tires if you fitted those. Trying to change suspension caster where there's no built-in adjustment sounds like a tall order to me.

 

[Bob_Spidell]

I believe--someone correct me if I'm wrong--that whatever positive caster a Big Healey has is achieved by pushing the lower A-arm assembly forward. Of the two lower brackets, the rear is positioned slightly outboard of the front, causing the 'point' of the 'A' to be moved a bit forward relative to the upper mount (i.e. the Armstrong shock absorber). As you can imagine, this causes some binding which, I suspect, is part of the reason relatively soft rubber/steel suspension bushings are used (Note: I use urethane bushings in my BJ8). About the only way to increase caster would be to move the shock towards the rear, which would require some sort of offset plate or cutting and welding. I noticed the adjustable camber shock mounts we got from Kilmartin for our BN2 were sloped a bit towards the rear--though the rubber buffers were on the wrong side (another story)--whereas the stock mounts were flat to the chassis. I suspect this was to allow just a shade more pos. caster, or to relieve some of the built-in binding, but can't say for sure.

 

[RAC68]

Bob/Rick,

I had never heard or thought of adjusting the caster until it was presented. I have done more research since posting and found that, of the group of popular British sports cars, the Healey seems to have the least positive caster by quite an amount.

Rick, I would say my suspension is tight but I will be having the Healey aligned professionally to find out what my Caster, Camber, Toe, and what my rear wheel tracking is to compare it to model specs. My Healey has always required small but frequent steering corrections at speed since it was new and I have been told by others that I am not unique.

It turns out that high speed stability increases with the % caster and a target of 5% is desirable. Our Healeys have only 2% at best. Since I have never heard anyone address camber on a Healey, I was not confident that anything was ever done (as with the camber).

Bob, I was told that caster will also benefit camber as well but increase steering effort a small amount. Angling the shock plate and moving the lower arm pivot points would add caster. However, to move up to a positive 5%, have no idea the distance forward the pivots would need to move.

Thanks Guys,

Ray (64BJ8P1)

 

[Legal Bill]

For a street car, caster should not require any "adjustment" unless you have accident damage. If the caster angle is correct, then the toe in adjustment should result in a stable stright line.

 

[RAC68]

Bill,

I appreciate that the caster is not adjustable and should be at 2% if all is well. However, I was told that a caster in the area of 5% angle would be much more stable and hold its line at high speeds (but would increase steering effort). Since Caster and Camber were both fixed and a Camber mod now allows adjustment, I was wondering if anyone created a Caster adjustment as well.

I am not sure what the best angle would be for our suspension configuration. However, some of the more common British sports cars of the ’50s and ‘60s have caster angles of from 0% for the early cars (i.e. TR2/3, etc.) to 4% for some later models and topping out at 7% for an MGB.

Although my Healey is not bad at high speed, since new it has always required constant small steering corrections and I have wondered what could be done. Caster and Camber are settings I never considered as they were fixed and only started to investigate when a suspension expert brought it up. I also realized that I hadn’t gotten a professional alignment in decades, not to just adjust toe but to find out the real values of my car’s actual Camber and Caster angles along with how the rear wheels are tracking. I though getting the alignment would be easy but I am finding this a little more difficult as many have no interest in getting involved with anything but a modern vehicle where the information is in the computer and they just set up the machine and follow its dictates.

Well, that's it for me on this subject.

Enjoy your Memorial Day and Parade,

Ray (64BJ8P1)

 

[GregW]

You might be interested in reading about the build for Blair Harber's Targa Newfoundland race car.
https://www.acmefluid.com.au/larry/ahx12.html

 

[RAC68]

Thanks for the link Greg.

I love what Michael Salter has done to the front suspension of the Blair Harber Targa car he built. Fully adjustable camber and caster along with rack steering, coil overs, and disks and calipers all around….what more could you want. Just a little much for me to do on my car.

Thanks Greg, although I read it a while back, I enjoyed it more and gained more insights this second time…a real good read.

Ray (64BJ8P1)

 

[Legal Bill]

Bill,

I appreciate that the caster is not adjustable and should be at 2% if all is well. However, I was told that a caster in the area of 5% angle would be much more stable and hold its line at high speeds (but would increase steering effort). Since Caster and Camber were both fixed and a Camber mod now allows adjustment, I was wondering if anyone created a Caster adjustment as well.

I am not sure what the best angle would be for our suspension configuration. However, some of the more common British sports cars of the ’50s and ‘60s have caster angles of from 0% for the early cars (i.e. TR2/3, etc.) to 4% for some later models and topping out at 7% for an MGB.

Although my Healey is not bad at high speed, since new it has always required constant small steering corrections and I have wondered what could be done. Caster and Camber are settings I never considered as they were fixed and only started to investigate when a suspension expert brought it up. I also realized that I hadn’t gotten a professional alignment in decades, not to just adjust toe but to find out the real values of my car’s actual Camber and Caster angles along with how the rear wheels are tracking. I though getting the alignment would be easy but I am finding this a little more difficult as many have no interest in getting involved with anything but a modern vehicle where the information is in the computer and they just set up the machine and follow its dictates.

Well, that's it for me on this subject.

Enjoy your Memorial Day and Parade,

Ray (64BJ8P1)

Ray, you can just buy a toe-in stick and do it yourself:

https://www.amazon.com/Longacre-79620-Toe-In-Gauge/dp/B001NNFZ2Q

Or you can make your own for cheap if you can weld:
https://www.garagejournal.com/forum/showthread.php?t=121853

Honestly, toe in is very easy to measure. I think there are even instructions on the internet about how to do it with a curtain rod...

 

[dougie]

Bill -

If you can network with the British car racers in your area, I'm sure you could find a shop willing to do the alignment the right way.

 

[Legal Bill]

Thanks Dougie. I don't have any problem finding a shop that can do it. There is one three miles from my house. But if you have trouble finding one like Ray is and you don't know if your toe-in is correct, the bar works to within 1/32 of an inch.

Here is an older thread on the subject.

https://www.britishcarforum.com/bcf/showthread.php?93183-Toe-In-Out-measurement

 

[RAC68]

Bill,

I really appreciate your help but toe adjustment is not my problem. I am looking for an alignment shop (and think I have found one) to get accurate measurements of my camber, caster, and rear wheels tracking (i.e. what they would measure on a 4 wheel alignment). I want this information establish a base line on my suspension and to make sure the fixed settings are in spec. Since I haven’t had my Healey to a professional alignment shop for decades, I can only assume all is correct but I would like to validate that assumption.

By the way, I built and use Steve's design and find it easy and I think my implementation is accurate. I will find out when I have it aligned at the shop.

Thanks again,
Ray (64BJ8P1)

 

[Legal Bill]

Good luck with it, Ray.

 

[RAC68]

With all the discussions on handling, negative camber, toe-in leaf springs and the like, today I think I found the cause of my high speed wander complaint. As mentioned, I have always felt my Healey needed constant small directional corrections when traveling at speed and this was a condition that could become very tiring during an extended drive. Today I decided it was time to pack my front wheel bearings and, after jacking the left front wheel for removal, I noticed (for the first time) excessive end play. This was a new development to me, but since I hadn't overtly checked for this condition for quite some time, could have existed for who knows how long. After detecting the end play in the left front, I immediately checked the right wheel and no end play was detected.

Since the amount of end play was quite substantial, I expected to find that the bearing had somehow deteriorated with some physical indications. However, when withdrawing the outer bearing, no obvious problem was viewed and a thick and thin shim had been previously installed. Curious, and not having any additional shims on hand, I repacked and installed the same bearings with only the thick shim, knowing it would still produce a small amount of excessive end play. With the hub nut fully tightened and a substantial portion of the original end play eliminated, I decided to test the results with a drive.

The results, as you would expect, wandering was substantially diminished and stability increased. Since end play still is not correct on the left front wheel, I have ordered a new set of bearings and full compliment of shims. I expect to get them in the very near future and will install the new parts for, hopefully, even better directional stability. This may eliminate any need to install the parts purchased to produce negative camber.

Ray (64BJ8P1)

 

[DerekJ]

One of the reasons for the 'wandering' is the worm and peg steering system which is not as good as rack and pinion and has a dead spot in the straight ahead position. The new DWR steering box helps to eliminate this.