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BJ8 plus 55mph Front end shaking
- Thread starter thibault
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Balancing of driveshafts (prop shafts) is usually done by taking your own driveshaft to a local specialist rather than buying a completely new one.
RAC68
Darth Vader
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Hi All,
There are many components that can induce a vibration at just as many speeds. Given the structure resulting a not-so-stiff infrastructure design and the common skimping of structural welds to make quotas and sales, it is no wonder that our Healeys do not produce the vibration-free ride of todays cars. So, where do you start? Although the common components (wheels/tires/flywheel) were early appreciated potential culprits. However, less understood and appreciated are brake drums, drive shaft, and even engine components. Add to this list, the alignment of the front or how the rear suspension is set up nd tracking and you are well past the ability of many to understand the possibilities and correction.
So, what do you do if you have a slight shake at the magic 50 MPH-65 MPH range (or there about) after address the commonly faulting wheels, tires, and drums? First, if only a slight shake remains, I would enjoy my Healey as it was new and is now, only going further if the shake remained substantial. Addressing more subtly causes of shake will require the scarce experts who understand the technologies incorporated within the Healey and how these components interact within its structural architecture and build implementation.
Yes, it is possible to achieve a close-to-perfect stability ride from a Healey but I suspect would be more economical and assured from the replacement of the substructure with a new stiffer frame (i.e. Jule Enterprises). And to that end, would contact Martin Jansen (who I understand is not well and wish a quick recovery) for his knowledge and suggestions.
Just my thoughts,
Ray(64BJ8P1)
There are many components that can induce a vibration at just as many speeds. Given the structure resulting a not-so-stiff infrastructure design and the common skimping of structural welds to make quotas and sales, it is no wonder that our Healeys do not produce the vibration-free ride of todays cars. So, where do you start? Although the common components (wheels/tires/flywheel) were early appreciated potential culprits. However, less understood and appreciated are brake drums, drive shaft, and even engine components. Add to this list, the alignment of the front or how the rear suspension is set up nd tracking and you are well past the ability of many to understand the possibilities and correction.
So, what do you do if you have a slight shake at the magic 50 MPH-65 MPH range (or there about) after address the commonly faulting wheels, tires, and drums? First, if only a slight shake remains, I would enjoy my Healey as it was new and is now, only going further if the shake remained substantial. Addressing more subtly causes of shake will require the scarce experts who understand the technologies incorporated within the Healey and how these components interact within its structural architecture and build implementation.
Yes, it is possible to achieve a close-to-perfect stability ride from a Healey but I suspect would be more economical and assured from the replacement of the substructure with a new stiffer frame (i.e. Jule Enterprises). And to that end, would contact Martin Jansen (who I understand is not well and wish a quick recovery) for his knowledge and suggestions.
Just my thoughts,
Ray(64BJ8P1)
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I have a Jule Frame and it is solid, no scuttle shake and a real solid feel driving it.
Bob_Spidell
Yoda
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The current thread on available, crappy engine mounts got me to thinking: How much could drive train oscillations, transferred through the engine and transmission mounts, contribute to scuttle shake?
RAC68
Darth Vader
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Bob,
There's a more then average porbability that drive train vibrations could be both transmitted through the Healey's substructure, and even amplified by it, to give what we commonly refer to as scuttle shake. It happens that the brake drums were the unaddress and undescussed item that turned out to be a major contributor and that surprise discovery took the lions share of attention away from any other possibility.
Also, Steve Byers mentioned his efforts to reinforce the transmission tunnel opening in the fire wall and, back then, it was thought that that weak structure was the cause of scuttle shake. Martin Jansen mentioned the issue of rear wheel tracking, which he indicated would be improved by moving the front spring mounts 1/2" toward the center of the car, as a cause of scuttle shake. And, I can go on with other possibilities.
So, what is your pleasure? I have owned my Healey since new and have driven it throughout the country (i.e. "Route 66" like). I met my wife 2 years later and it was our first family car with my wife doing most of the Healey driving. I also took my Son home from the Hospital in a basonette on the folded down back shelf with top up (imagine doing that today). So, when I drive my Healey with the Beach Boys blasting through my sound system, a little shake does not deminish my youth regression.
And yes, I made a fixture that allowed me to have my wheels tires and drums spin balanced as a unit. However, although it worked quite well, the wheel and tire must be mounted in the exact same position with respect to the drum. That is why I would not recommend that approach to others.
However, when I completed rebuilding my Healey in 1989 or so, I had the wheels and tires spin balanced and the car was tight and solid at all speeds...NO Shake. It was over 10 years later that the car seemed to exhibit any shake and, from what Patrick posted, it probably was due to substructure beginning to relax.
Just my thoughts,
Ray(64BJ8P1)
There's a more then average porbability that drive train vibrations could be both transmitted through the Healey's substructure, and even amplified by it, to give what we commonly refer to as scuttle shake. It happens that the brake drums were the unaddress and undescussed item that turned out to be a major contributor and that surprise discovery took the lions share of attention away from any other possibility.
Also, Steve Byers mentioned his efforts to reinforce the transmission tunnel opening in the fire wall and, back then, it was thought that that weak structure was the cause of scuttle shake. Martin Jansen mentioned the issue of rear wheel tracking, which he indicated would be improved by moving the front spring mounts 1/2" toward the center of the car, as a cause of scuttle shake. And, I can go on with other possibilities.
So, what is your pleasure? I have owned my Healey since new and have driven it throughout the country (i.e. "Route 66" like). I met my wife 2 years later and it was our first family car with my wife doing most of the Healey driving. I also took my Son home from the Hospital in a basonette on the folded down back shelf with top up (imagine doing that today). So, when I drive my Healey with the Beach Boys blasting through my sound system, a little shake does not deminish my youth regression.
And yes, I made a fixture that allowed me to have my wheels tires and drums spin balanced as a unit. However, although it worked quite well, the wheel and tire must be mounted in the exact same position with respect to the drum. That is why I would not recommend that approach to others.
However, when I completed rebuilding my Healey in 1989 or so, I had the wheels and tires spin balanced and the car was tight and solid at all speeds...NO Shake. It was over 10 years later that the car seemed to exhibit any shake and, from what Patrick posted, it probably was due to substructure beginning to relax.
Just my thoughts,
Ray(64BJ8P1)
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Another theory about scuttle shake is the BJ7 and BJ8 are particularly prone to it due to the heavier windshield assembly attached to the scuttle. If you look at the 1965 Road & Track road test of the Mk III, they even comment on scuttle shake in a brand new Healey.
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There IS a solution: Do not drive between 55 and 65 mph.
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Also, the brand-new rear drums could have been out of balance.
OP
thibault
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Thibault - with the car on stands, I would run it without the drums - to make sure even the new ones aren't out of balance.
With the driveshaft out of the car, examine the universal joints on the driveshaft for play - if the needle bearings in one of them have disintegrated that would put the shaft out of balance. I had that happen on one of my Alfas. U-joints are cheap to replace.
With the driveshaft out of the car, examine the universal joints on the driveshaft for play - if the needle bearings in one of them have disintegrated that would put the shaft out of balance. I had that happen on one of my Alfas. U-joints are cheap to replace.
RAC68
Darth Vader
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Hi All,
Steve is correct. Since most parts suppliers have had little experience or facility checking supplier provided Brake Drums for proper balance, the safest response to a customer's inquiry is to say that "They believe the units are in balance". Also, since finding a servicer to check drum balance is difficult and costly, it is likely an misleading vender statement will never be exposed. As a result, the purchaser will continue looking for the source of their scuttle shake and eliminate the drums as a potential culprit.
I am sorry to say that I have little confidence in most parts suppliers providing new drums balanced drums … from my perspective, a possibility but not a high probability.
My thoughts,
Ray(64BJ8P1)
Steve is correct. Since most parts suppliers have had little experience or facility checking supplier provided Brake Drums for proper balance, the safest response to a customer's inquiry is to say that "They believe the units are in balance". Also, since finding a servicer to check drum balance is difficult and costly, it is likely an misleading vender statement will never be exposed. As a result, the purchaser will continue looking for the source of their scuttle shake and eliminate the drums as a potential culprit.
I am sorry to say that I have little confidence in most parts suppliers providing new drums balanced drums … from my perspective, a possibility but not a high probability.
My thoughts,
Ray(64BJ8P1)
Bob_Spidell
Yoda
Online
My BN2 shakes badly; but I attribute it to wheels that are likely way out of true. As I mentioned, my BJ8's shake diminished considerably with the latest set of Vredesteins; they were balanced by a motorcycle shop so that may have something to do with it, but I can't say for sure.
Our '65 Mustang convertible has significant, er, firewall shake.
bob hughes
Luke Skywalker
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Thibault
Do you know anyone with a big Healey that drives nicely? Borrow their wheels, it would give you an idea if the wheels themselves are a problem - I had mine balanced and the car still shook, I checked with a dial gauge and the wheels appeared to be true, car still shook.
Bob
Do you know anyone with a big Healey that drives nicely? Borrow their wheels, it would give you an idea if the wheels themselves are a problem - I had mine balanced and the car still shook, I checked with a dial gauge and the wheels appeared to be true, car still shook.
Bob
RAC68
Darth Vader
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When considering the cars (not only Healeys) that have scuttle shake, it appears that most are mass-manufactured with quite light substructure construction. Light construction would be more prone to stress-deterioration over time and less apt to constrain even slight running gear imbalances/anomalies. As a result, the appearance and severity of drive-induced shake would vary from car to car with age-since major reconstruction being a contributing factor.
Such stiffening understructure modifications as a Jule Frame or lesser frame-stiffening approaches ranging from angle iron welded to the transmission opening to foam-filling frame sections, have resulted in stiffening the basic Healey structure to the point of constraining or even eliminating shake at any speed. Shy from installing a Jule Frame or foam filling the Healey frame, it would be beneficial to collect the many structural reinforcements/stiffeners and evaluating their effects (hearing from an implementer).
Any thoughts,
Ray(64BJ8P1)
Such stiffening understructure modifications as a Jule Frame or lesser frame-stiffening approaches ranging from angle iron welded to the transmission opening to foam-filling frame sections, have resulted in stiffening the basic Healey structure to the point of constraining or even eliminating shake at any speed. Shy from installing a Jule Frame or foam filling the Healey frame, it would be beneficial to collect the many structural reinforcements/stiffeners and evaluating their effects (hearing from an implementer).
Any thoughts,
Ray(64BJ8P1)
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I have never experienced scuttle shake on my 100. Right after I purchased the car in 1998 I bought a set of 60 spoke Dayton wheels from British Wire Wheels and thereafter have always had wheels and tires mounted and balanced by Alan Hendrix. I have never done anything to the brake drums. I guess I am fortunate.
British_Recovery
Jedi Warrior
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Thibault,
Where have you placed the jack stands ? If there is no weight on the rear axle, the geometry might lead to vibrations.
Bob
Where have you placed the jack stands ? If there is no weight on the rear axle, the geometry might lead to vibrations.
Bob