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EPS potential danger in Alpine (Alleged)

DanR

DanR

Diamond Level Sponsor
ATTENTION TO ALL Electric Power Steering Applicants

I wish to alert you to a potential danger with the use of the power steering in an Alpine utilizing the Burman box.

I just received this post from a fellow member of our club:

Guys, Just for info the steering 'experts' in the UK are completely opposed to fitting power steering to the Alpine system. Apparently it is completely unsuitable for it and trials with a variety of systems have resulted in cracked steering columns and Burman boxes. It is not an area that I have any expertise in but I just thought that I would mention it as it has been a topic of conversation here recently. They are not anti- power steering in general and apparently it works well on the Tiger set up but they say it is not suitable and potentially dangerous to put it onto an Alpine.

Tim R

This is/was the first indication to me of any potentially dangerous use of the EPS for the Alpine. Please be advised of the above warning as to its completely unsuitable use in an Alpine.
 
Bill Eisinger

Bill Eisinger

Platinum Level Sponsor
I'm not sure what to think of that....it takes the same rotational force to turn the wheels regardless of what's applying the force. I guess maybe if you have the EPS cranked way up perhaps the initial dynamic impulse could possibly cause some damage. I don't think I'm going to lose any sleep over it at the moment.
 
260Alpine

260Alpine

Silver Level Sponsor
It could be the old wore out stock steering box's that are the problem. I wasn't kidding when I mentioned replacing the stock box with a Vega box popular in street rods.
 
DanR

DanR

Diamond Level Sponsor
Jim, Before I order a new Vegas box, does anyone have an idea where to get a used one or a loaner?
 
260Alpine

260Alpine

Silver Level Sponsor
Dan, Ebay or wrecking yard. My idea is to cut off stock steering shaft and modify to fit a 3/4" DD to Vega box spline Ujoint. I think it's 5/8" x 36 spline. There is a triangular mounting plate StreetRodders use. That would be welded to a plate that bolts to the stock mounting holes. I doubt if the splines for the pitman arm are the same so probably interference fit and drilled for a tool steel pin. Of course, you would center for alignment and equal steering each way. I'll attach pics:
 
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DanR

DanR

Diamond Level Sponsor
My biggest concern is the distance it will stick out toward the header/engine from the Alpine frame....

The Burman is 1 & 1/2" with almost 2 & 1/4" back space.
 
husky drvr

husky drvr

Platinum Level Sponsor
260Alpine said:
Dan, Ebay Chevy Vega search. 71-74 used is same as aftermarket.Good price on a new one:
Click to expand...


260Alpine,

Have you found a Vega box with less than four turns lock to lock?

Also, does the shaft with the Pitman arm in the Vega box match the Burman box rotation with the same steering input? I didn't investigate that far when I realized that four turns L to L was the best ratio available.

Just curious,
 
260Alpine

260Alpine

Silver Level Sponsor
Don, I don't know if the stock Vega box is different but the aftermarket Speedway Vega box specs are 5 turns lock to lock and 20 to 1 ratio. StreetRodders love it for cruising and easy steering. Race cars may want a quicker ratio or Dan R's Electric Power steering.
 
260Alpine

260Alpine

Silver Level Sponsor
Don, Found out 20 to 1 is stock ratio too. Flaming River has a 16 to 1 for over $700 !!! Stock Vega pitman arm is 6" long. A longer Pitman arm makes higher ratio too.
 
husky drvr

husky drvr

Platinum Level Sponsor
Jim,

Considering the Alpine is supposed to be three turns L to L, four or five turns L to L will certainly reduce steering effort and required attention to steering input during cruising. I also suspect increasing turns L to L will reduce any desire of ever driving in a "sporty" manner.

It's not a matter of effort required as much as just not being able to steer fast enough to keep up with the required input.
 
260Alpine

260Alpine

Silver Level Sponsor
Cosworth Vega has a quick box of 12.9 to 1 about 2 3/4 turns lock to lock Very rare and a larger 525 box. Same bolt pattern as Vega box, larger spline size. Same specs as a power steering box used in Camaro/Firebird and GM midsize cars. The manual box in those cars and the S10 trucks are 16 to 1 and 4 turns lock to lock. I don't know if there is enough room in the Alpine for that one. 525 box :

Borgeson Universal 920040 Borgeson Universal Saginaw 525 Manual Steering Boxes | Summit Racing
 
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husky drvr

husky drvr

Platinum Level Sponsor
260Alpine said:
Cosworth Vega has a quick box of 12.9 to 1 about 2 3/4 turns lock to lock Very rare and a larger 525 box. Same bolt pattern as Vega box, larger spline size. Same specs as a power steering box used in Camaro/Firebird and GM midsize cars. The manual box in those cars and the S10 trucks are 16 to 1 and 4 turns lock to lock. I don't know if there is enough room in the Alpine for that one. 525 box :
Click to expand...

Jim,

If the 525 is the size of which I'm thinking, then you're right. There's probably no way it would fit even with an Alpine engine - in the standard location. On the other hand, I've wondered if it might be possible to install one in the front corner of the engine bay with a GM style system. Might have the possibility of circumventing the problems of a rack installation. Just dreaming - too many custom parts.

The one I had experience with wasn't built for longevity, either. It was worn out before 100k miles. I might still have it, but I think it's gone. I'll try to look for it. If found, measurements might be questionable due to the mounting flange being on the opposite side.
 
B

Bill Blue

Platinum Level Sponsor
Does lock to lock movement of the Vega box produce the same angular output movement as lock to lock in the Burman?
Bill
 
260Alpine

260Alpine

Silver Level Sponsor
Bill, Don't know the answer to that. Don, the 525 is a few inches longer than the Vega 140 box with a longer steering shaft. It is easier to find in a 16 to 1 or 4 turns lock to lock.
 
alsalp

alsalp

Donation Time
I did my own EPS on my Alpine and the box busted out the front. Luckily it was in a parking lot. I thought maybe I screwed up the modification. My theory was that I stressed by demonstrating it over and over without the car rolling. I have a replacement and was debating going to stock. It was nice while it lasted. I knew someone did a conversion here and was curious they had problems. Another theory was to prevent full power assisted lock up with limit switches.
 
bernd_st

bernd_st

Bronze Level Sponsor
As Tim R stated and because of some broken boxes the Brits made some calculations about how much torque load an EPS would add to our good old Burman steering boxes. The finding is even the weakest EPS would add around factor 3 vs. normal manual condition. So do not install EPS on a Burman box, it's just not designed for it...
 
Bill Eisinger

Bill Eisinger

Platinum Level Sponsor
I've discussed this with a number of people including a couple of mechanical engineers and am still struggling to see how/why the EPS is the culprit in the failures. The net torque applied to the box internals will be the difference between the column torque and the friction resistance of the wheels and steering gear regardless of whether it's applied by hand or EPS. The impulse or dynamic torque (or whatever it is called) at the instant of force application will certainly be higher and if the ball bearings or the races are worn or loose there can possibly be a twisting resultant which may be what is happening to cause the failure. If everything is tight and properly lubricated, there shouldn't be a problem.

The actual case breakage is another issue...these aluminum cases are pretty susceptible to hairline cracking over time and any excessive internal force can cause them to go. Certainly, moving the wheels back and forth while the car is not in motion can exacerbate the issue because the turning friction is much higher (turning the wheels hard stop to stop might also be an issue) but, again, it would be the same if the wheels are moved by hand...the EPS just makes it easier and thus the temptation is there to turn the wheel even when not in motion.

It seems to me that if there is any wear or sloppiness in the worm gear and bearings (or case cracks) these boxes will eventually fail anyway...the EPS just possibly identifies the problem a little earlier.

I'm thinking that our best answer is to figure out how to support the projects that the Brit's are looking at to have new boxes and/or replacement parts manufactured.
 
nsbluenose

nsbluenose

Silver Level Sponsor
When you are talking about the Vega steering box, are you referring to the 70’s Chevy Vega or an aftermarket steering box brand?
 
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