TC Steering

[lasloja]

i understand the the TC steering has been discussed a LOT. But I was wondering if someone out there has done a conversion from the stock with a Thompson kit to something better? Are you satisfied with the upgrade? I am looking for someone in the western Pennsylvania region that has done this and is please. I would like to drive a TC with the updated steering before I do it. I have been in the Great Race for the last two years and have put around 8,000 miles on the TC in the last year an a half. The car is good but is there anything better? Thank you for your input.

[Duncan M]

First mistake was removal of the original rub plate (top plate) to install the Tompkins kit.

[lasloja]

Duncan,
Thanks for the reply. Have you an upgrade or are you still stock? I just want to see if there is anything better. As I said what i have now is not bad.

[Ian R]

I have just put a 1937 TA back on the road after 20+ years in a barn.
In my first drives after the refresh, I soon got fed up with the circa 45 degrees of free play at the steering wheel, combined with the very direct response of the TA..
I have a pukka Tomkins kit that my father purchased in 1991 for 30+ pounds but is still in the original wrapping.
An investigation shows that the whole Bishops Cam system needs just about everything being replaced or refurbished.

So I just purchased a VW kit from NTG in England.
Cost was about the same as projected repairs to the Bishops Cam.
I’m going to fit the VW system & then decide whether it is worth “refreshing” the Bishops cam system.

[Steve Simmons]

There are lots of threads where you can find opinions on this by using the search function, but what it comes down to is that they are just plain different. The stock BC box can be made to work very well if it is rebuilt properly and the entire front end is set up correctly. The front end of these cars tend to be very sensitive to things not being just right. But even set up perfectly, the stock setup won't be as stable and gentle to drive as a Datsun or VW box. That doesn't make one better than the other, just different. The added stability and ease of steering comes from using a lower ratio and more modern design in the gears. So while you do gain something, you also lose that sporty, aggressive ratio. I hesitate to say which is "better" because it's an individual choice. Probably the only real mechanical advantage is that the aftermarket boxes are far stronger than the original. There's virtually no chance of breaking one. The BC box should be inspected, especially the pitman arm, on a semi regular basis. The aftermarket boxes don't really require anything once they are set up.

[lasloja]

I HEAR WHAT WHAT YOU ALL ARE SAYING. THAT IS WHY I AM LOOKING TO TRY ONE OUT.
THANK YOU FOR YOUR INPUT.

[Norman Tuck]

Hi,
If you do ever get the opportunity to out the VW Conversion, I would love to hear your reaction.

Good luck finding a test car, and please keep us posted.

Norman

[lasloja]

Thank all, I will keep up updated. Again anyone that has updated the TC steering let me know where you are and If i can test it out.

[stephen stierman]

You know you can shim the box without the Tompkins kit. Have you set the steering up with the peg at the high point on the worm with the wheels centered? The peg can easily be replaced or rotated if worn on two sides. Set the toe in to 1/2" like the prewar cars instead of 3/8" it is transformative. There is always a bit of lost motion in the center, but the car should not wander from side to side. I drove a car with a VW conversion, it was an improvement, but with a bit slower steering. Changing the toe in improved my car so much that I forgot about doing a VW conversion entirely.

[jagman2]

steven
with 1/2" toe in , i would expect excessive tire wear on the outside. that setting is considerlably greater than
the 3/16" as stated in the instruction manual. how did you determine the 1/2" setting?
i am ready to set up my toe in on my TC and seems like there lots of opinions on this setting.
thanks.

[stephen stierman]

Look in any MG manual that lists specifications for TA, TB, and TC. The prewar cars were set at 1/2".

[jagman2]

guess i need a prewar manual for my post war TC. my instruction manual for midget (series TC) under general
data lists front wheel toe-in as 3/16" (5 mm)
cheers

[Ian R]

In another current thread about track rods joints, Steve Simmons provided a link to a paper about the steering system & how the TABC cars gain toe out with speed due to flexibility in the track rod ends & drag link ends.
The link is:
http://www.tcmotoringguild.org/techinfo ... native.pdf

So 3/16” static toe-in is going to get reduced with speed and given the grip available with modern tires & road surface compounds, it is likely that a TABC set at 3/16” static toe overall actually has some toe out at speed.
If the pre-war setting was 1/2” of toe in with the tires & road of the period, this setting has to be a starting point to maintain toe-in with modern grippier tires & roads. It would be interesting to try even more static toe in.

[stephen stierman]

I will tell you that setting toe to 1/2" was a transformative experience.

[Ray White]

I will tell you that setting toe to 1/2" was a transformative experience.

That is a most useful tip. Thank you Stephen.

Ray.

[stephen stierman]

Give it a try, if you notice no difference you can readjust. Yes, the steering box has a bit of free play at center, they all do, but the problem is with car wanting to follow every groove in the road surface because of the front end geometry. The vehicle should not be wandering this way and that. My Morgan has a Cam Gear steering box which is relative of the BC box, almost identical inside and a bit of free play on center also, but it still goes down the road in a straight line.

[Steve Simmons]

One note about wandering, the tire tread pattern plays a huge part in this. The original B5 pattern seems to be particularly bad at following the grooves in the road. Another note is to not fight it. The car will wander one way and then wander right back again. Anyone who has driven a Model T learned this one pretty quickly. You can always spot an inexperienced Ford T owner by the car darting back and forth even at low speed! They have an extremely aggressive steering ratio that makes a stock TC feel like steering a bus. But I digress...

[stephen stierman]

My TC was equipped with the typical Excelsiors. I will tell you that once I increased the toe to 1/2" there was no need to fight anything. It tracked straight down the road and following a line into a corner was even improved. I sold this car on BAT last Oct. and there is a driving video of some length in my ad if you want to watch it you certainly can. Black car, apple green interior.

[frenchblatter]

Surely one of the "charms" of the T series is the high-geared steering. If the car is set up correctly, which mine is (with 1/2" toe in) it drives perfectly well. I suspect that fitting lower ratio steering boxes is covering up incorrect joints. worn kong pins and toe-in etc.

[lasloja]

I hear what you are saying. That is why i would like to try the difference. As I said above I have 8000 miles in the last year and half with not issues. Tires are wearing perfectly even and car tracts fine, still want to try the difference. I am hoping that it is just a personal choice. Thank you for your input I really appreciate it.