Note: Everything that follows are the words of the one and only Bud Silvers.
Why install VW steering in place of BC steering on my MG-TC?
Three reasons: size, age/materials, and design. Handling is also a factor.
PLEASE NOTE: Those who dislike the VW steering and who favor the BC steering only talk about handling!
Above are the primary reasons to seriously consider changing the steering on your MG-TC (or TA/TB). If you are reading this page then please be aware that in my OPINION the VW system is greatly superior to the BC system and thereby SAFER! I believe this to the point that I have built over 50 kits to convert the stock BC system to the VW system. I have one in TC-1576 which I am restoring right now. The following is based on my experience and my interpretation of the two systems. The issues presented here are real and factual. I have partially supported my opinion with photographs. My primary concern is safety, not simply handling. I will say that handling is a part of the safety issue and handling is greatly improved with the use of the VW system. The feel of driving the car is not quite the same; it is improved. I have attempted to express my views in a honest and factual manner. While reading and viewing the following material you should make up your own mind and use your own experience to decide which system you wish to use. If you prefer to continue the use of the stock BC (Bishop Cam) steering, then PLEASE, at a minimum check your sector shaft and pitman arm for cracks or twisting frequently. I would recommend having both of those parts magnafluxed yearly or at least bi-annually. A better solution for those of you who wish to retain the BC box would be to replace those parts with newly manufactured replacement parts. These are available from Doug Pelton at From The Frame Up.
When I began this project back in May of 2007 I planned to build three conversions. One for me, two for local friends. I then decided to build a few more and sell them. There seemed to be a great demand for the conversion kits so I have continued to build them. My kits are now in use from coast to coast of the United States. There is also at least one in Canada. I believe all of those who have purchased and installed the kits are happy customers. One such customer on the East Coast was so happy with his kit that he sold two more kits to his friends. Take a second to check out The Motley Crew!
Thank you for taking the time to study this page and make your own decision.
Here is a picture of the VW steering box (on the left) and a BC steering box (on the right). The VW steering box is not very much larger on the outside. It is what is inside that counts!
If you find yourself concerned the larger box might look out of place in a TC here are some pictures of the VW box installed in a TC:
This picture above illustrates the size of a stock BC Pitman Arm compared to a stock VW Pitman Arm.
Above you can see what the VW Pitman Arm looks like as it is modified for the TC. The one on the left is a stock VW Pitman Arm. The one on the far right is a VW Pitman Arm modified for the TC.
It is also worthwhile to remember that the BC Pitman Arm has been known to crack where it clamps onto the sector shaft. Please note with this picture, that Pages 100 and 101 suggest that cracks can occur opposite the pinch bolt. This refers to the two points in the upper portion of the picture. I personally consider the two points in the lower portion of the picture to also be potential points for cracks.
Above illustrates the size of a stock BC sector shaft compared to a stock VW Sector Shaft.
The new VW steering boxes which I use in my kits are manufactured by TRW and built from modern steel, iron, and aluminum. They are brand new. On the other hand, the BC steering boxes were built in the late 1940’s from WWII surplus materials. That in itself does not make them weak, but it does make me wonder about the quality and consistency of those materials. By the same token the age of a piece of steel does not make it weak, but abuse and over-stressing over a period of time can cause metal fatigue. The bottom left picture is of a BC sector shaft that is twisted. This is probably the result of an attempt to turn the steering wheel when the car was not moving. Even the single twist in this sector shaft does not mean that it is going to break. What concerns me is there is no way of knowing how many times this particular sector shaft has been twisted. Repeated twisting will cause metal fatigue and breakage. The picture on the right shows a shaft that has not been twisted.
The BC steering box utilizes a simple peg which rides on top of a worm gear. When the worm gear is rotated, the peg is forced to move, turning the sector shaft and the pitman arm. There is a substantial amount of friction involved in this process since there is metal rubbing directly on metal. In addition, turning the worm gear tends to try to force the peg vertically up and out of the worm gear. This creates friction on top of the sector shaft as well. The Tompkins Kit relieves some of this friction by utilizing a thrust bearing at the top of the sector shaft. Here is a picture of the BC workings:
The VW steering box utilizes a worm wheel rather than a peg which interacts with the worm gear on the side rather than on top. When the gear is rotated the wheel rotates along with it, and moves the sector shaft and the pitman arm. Rather than rub together as the BC steering does, the VW steering rolls together. There is far less friction in this process since the wheel and the gear are rotating against each other rather than rubbing. Though turning the gear with this system does create some force trying to move the wheel away from the gear, with this system the force is horizontal and not vertical. The sector shaft is substantially more rigid in the VW system and therefore can oppose the horizontal force easily. The VW design allows you to turn the wheel when the car is stationary without fear of damaging something. I do not recommend doing this though, since it still puts undue stress on the rest of the steering and is not good on the tires or wheels.
The final issue that I will address is handling. It is interesting to me that the proponents of the BC system address this issue as if it was the only issue. The feel of the car is indeed lighter. It does not require as much force to turn the steering wheel with the VW system. In my opinion you do not lose the feel of the road at all. What you do is take control of where the car is going on the road. On October 26th, 2009 my friend Jim Goodwin sent an email to the TABC group which in conclusion said:
“…… Bud Silvers and I installed one of his kits at his house and I couldn’t be happier. It is amazing. All of the fun with none of the terror. My TC wants to go where I want to go now. No more arguing about the best line through a turn. No more changing lanes by blinking, we’re partners now, no shadows or ghosts can deter us. I tend to drive fast and I now have the confidence to go faster and farther from home, and will be installing seat belts soon. I’ll keep the stock bits for the next owner so he can relive those thrilling moments from yesteryear if he wishes, but I’ll never go back.”
Something that everyone should consider is that handling is a matter of safety too! Having a car that goes where you want it to is certainly important when you are on any road. Having a car that anyone can drive is also important.
It is impossible to say what the condition of your BC steering is. Certainly it was better when it was new, but with 70+ years behind your car, it now comes down to your best educated guess. Earlier I said if you prefer to continue to use of the stock BC (Bishop Cam) steering, then PLEASE, at a minimum check your sector shaft and pitman arm for cracks or twisting frequently. I would recommend having both of those parts magnafluxed yearly or at least bi-annually. A better solution for those of you who wish to retain the BC box would be to replace those parts with newly manufactured replacement parts. These are available from Doug Pelton at From The Frame Up. I firmly believe that checking what you have is imperative! It is not just your safety, but the safety of your passengers, and the safety of all those who you share the road with. It is your car and your responsibility. I did not start down this path to persuade people to buy my VW kits. If you wish to build your own kit I will help you without charge! I can make all the necessary parts for you to build your own and will supply you with those parts for as reasonable a cost as I can. I will give you the names and contact information for my suppliers. The TC is a hobby for me and it shall remain a hobby. I do indeed make a profit on my kits when I do sell them, but the profit is less than I would make for my labor by working for Wal-Mart, and there are no benefits, except to know that I have helped make another TC safer. This link is merely my conjecture regarding what would result of a steering system failure, i.e., further reasoning behind changing the steering in my TC to VW. It also explains why I put Bob Grunau’s spindles/axles on my front end.
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