TC steering

[D&J Edgar]

Was able to get some photos of the steering arm modification that I mentioned earlier. They are on our TABC Yahoo site as well as temporarily another site for those that cannot figure out how to get on the Yahoo site. Yahoo - http://groups.yahoo.com/group/mg-tabc/photos/album/1005772606/pic/list Album name is Steering Modification if the above link does not take you direct. Other temporary site: http://tcmotoringguild.org/steeringmodification/steeringmodification.html You can see how the arm is bent up (to in effect lengthen it from the hub center) and how the tie rod is mounted under the arm to achieve oil sump clearance. Does anyone have this on their TC and if so how does it compare in steering with a known original setup? And for you metallurgists out there, what is the proper way to bend these arms without weakening them? David Edgar, TC 5108 El Cajon, California

> -----Original Message----- > From: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] On Behalf > Of D&J Edgar > Sent: Tuesday, 3 August 2010 8:04 AM > To: TABC > Subject: [mg-tabc] TC Steering > > > Here is a new one on me. A TC owner was wondering about a steering > modification done on his old TC. He has since sold the TC and bought > another so description very sketchy to say the least. Back in probably > the > early 60s, an old time mechanic at Auto-Sport in the LA area told him > that > he had a modification he could do to the TC to make it steer better. The > mechanic said the steering geometry was basically wrong on the TC and > the > modification would fix it. He believes the left and right steering arms > were heated and re-bent but is not positive. The TC did steer better. > The > current owner (and in England) had someone quite familiar with TCs drive > it > and commented that it was one of the best steering TCs he has ever > driven. > > One thing that is for certain is that the rod linkage attaching to the > steering arms are now on the bottom rather than the top (as was > original). > Just to be clear, when I say steering arms I am referring to the arms > that > bolt to the steering knuckles and the tie rods mount on. > > Has anyone else has heard of this modification? My theory is that the > arms > were bent up which would in effect increase the measurement (lengthen) > from > steering knuckle centerline to the tie rods. This would bring the tie > rods > closer to the pan though so the reason for mounting the tie rods below > the > arms. > > I have asked for some photos that might show the arm profiles but not > holding my breath. The TC is currently owned by Trevor Minett in > England. > That is all I know. He does not appear to be associated with this list > but > perhaps someone over there knows him and can look at the car. > > David Edgar, TC 5108 > El Cajon, California > > [Non-text portions of this message have been removed] > > > > [Non-text portions of this message have been removed] > > > > ------------------------------------ > > Yahoo! Groups Links > > >

[Ron Benson]

Hi All, Not sure if it works on steering box's, but the way to remove "bump steer" is to shim up the steering rack thereby lifting up the steering rods. This is probably the same theory. Regards, Ron Benson TB [Non-text portions of this message have been removed]

[Bentley Lodge Goulburn]

"Ackerman" is the concept you describe, that is the wheel angle is appropriate to the radius, less on the outside, greater on the inside. "Anti Ackerman" applies a greater angle to the outside to compensate for its additional slip (slip angle being defined as the direction angle of actual travel less the angle of the wheel point). Effectively with anti ackerman the outer wheel points more towards the centre of the circle than it would with ackerman. -----Original Message----- From: Koons, Robert A. [mailto:Robert.Koons@dbr.com] Sent: Friday, 6 August 2010 1:20 AM To: goscory@ozemail.com.au Subject: Re: [mg-tabc] TC Steering When you say "anti- Ackerman", do you mean that the outside wheel in a turn has a smaller turn in angle than the inside wheel? Thanks. Bob Koons

----- Original Message ----- From: Bentley Lodge Goulburn [mailto:goscory@ozemail.com.au] Sent: Thursday, August 05, 2010 06:34 AM To: 'TABC' mg-tabc@yahoogroups.com> Subject: RE: [mg-tabc] TC Steering This could be a modification based on the Ackerman principle. This relates to the usual arrangement where steering arms not being parallel so that when the wheels are turned the wheels compensate for the different radii of the two circles they track. There is (or was) a theory in racing circles that anti Ackerman was advantageous because the slip angle of the outside wheel was greater due to the weight transfer to that side, therefore a greater angle was required to overcome the slip relative to the unloaded wheel. On that basis the benefits would only be realized under severe cornering conditions and could possibly make it appear worse at more normal speeds. This was around when I was racing Formula Fords on production radial tyres in the late 70s early 80s. Gos -----Original Message----- From: mg-tabc@yahoogroups.com [mailto:mg-tabc@yahoogroups.com] On Behalf Of D&J Edgar Sent: Tuesday, 3 August 2010 8:04 AM To: TABC Subject: [mg-tabc] TC Steering Here is a new one on me. A TC owner was wondering about a steering modification done on his old TC. He has since sold the TC and bought another so description very sketchy to say the least. Back in probably the early 60s, an old time mechanic at Auto-Sport in the LA area told him that he had a modification he could do to the TC to make it steer better. The mechanic said the steering geometry was basically wrong on the TC and the modification would fix it. He believes the left and right steering arms were heated and re-bent but is not positive. The TC did steer better. The current owner (and in England) had someone quite familiar with TCs drive it and commented that it was one of the best steering TCs he has ever driven. One thing that is for certain is that the rod linkage attaching to the steering arms are now on the bottom rather than the top (as was original). Just to be clear, when I say steering arms I am referring to the arms that bolt to the steering knuckles and the tie rods mount on. Has anyone else has heard of this modification? My theory is that the arms were bent up which would in effect increase the measurement (lengthen) from steering knuckle centerline to the tie rods. This would bring the tie rods closer to the pan though so the reason for mounting the tie rods below the arms. I have asked for some photos that might show the arm profiles but not holding my breath. The TC is currently owned by Trevor Minett in England. That is all I know. He does not appear to be associated with this list but perhaps someone over there knows him and can look at the car. David Edgar, TC 5108 El Cajon, California [Non-text portions of this message have been removed] [Non-text portions of this message have been removed] ------------------------------------ Yahoo! Groups Links

[RussWilson]

David, Did you ever get a good answer to your question about straightening the steering arm? The thread seems to have drifted, and I didn't see an answer. It seems possible that the modification could have been made only to reduce the steering effort, and that reduction might have produced the comment of "one of the best steering TCs" that you quoted. As you mentioned, the effective length of the steering arm would be increased by straightening it. This would provide greater leverage to the overall steering system. From rough measurements on my car, I guesstimate that straightening the arm would increase the distance between the drag link connection and the king pin axis by 20% - 25%. This would provide a similar increase in leverage and decrease in steering effort. Of course, it would also require more travel of the drag link to produce the same turn of the wheels, so the turning circle would be increased if the peg hit the end of the Bishop cam before the wheels hit their stops. If this was the reason for the modification, I think it was wrong for the mechanic to have said that the TC steering geometry was "basically wrong." It's not wrong, it's just what the factory chose in the unavoidable trade off between fast, responsive steering and light, easy steering. Russ Wilson Encinitas, California

> -----Original Message----- > From: mg-tabc@yahoogroups.com

[mailto:mg-tabc@yahoogroups.com ] On Behalf

> Of D&J Edgar > Sent: Tuesday, 3 August 2010 8:04 AM > To: TABC > Subject: [mg-tabc] TC Steering > > Here is a new one on me. A TC owner was wondering about a steering > modification done on his old TC. He has since sold the TC and bought > another so description very sketchy to say the least. Back in probably > the early OE60s, an old time mechanic at Auto-Sport in the LA area

told him

> that he had a modification he could do to the TC to make it steer

better. The

> mechanic said the steering geometry was basically wrong on the TC and > the modification would fix it. He believes the left and right

steering arms

> were heated and re-bent but is not positive. The TC did steer better. > The current owner (and in England) had someone quite familiar with

TCs drive

> it and commented that it was one of the best steering TCs he has ever > driven.

..... [Non-text portions of this message have been removed]

[D&J Edgar]

Russ (and all), Nobody has responded to if they have seen this set up or driven a TC with the steering arm modification. I agree with your analysis regarding effort and possible increased turning radius. I was hoping someone who has experienced it could comment. I also asked about the metallurgy in bending the arm and got one reply from a metallurgist: ========= I wouldn't venture a guess without knowing exactly what the arm is made of, and how it was originally fabricated and whether heat treated. Steel is very complicated stuff, easy to f**k it up. ============ Again for those that missed it, photos are posted on our Yahoo Group site: http://groups.yahoo.com/group/mg-tabc/photos/album/1005772606/pic/list Album name is Steering Modification if the above link does not take you direct. Other temporary site: http://tcmotoringguild.org/steeringmodification/steeringmodification.html And thank you Russ for the tour of your garage a couple months back. Your TC driver is great and I assume you have your disassembled TC almost together by now, right? LOL David Edgar, TC 5108 El Cajon, California

On 8/7/10 1:38 PM, "RussWilson" wilsonrs@ix.netcom.com> wrote: > David, > > Did you ever get a good answer to your question about straightening the > steering arm? The thread seems to have drifted, and I didn't see an answer. > > It seems possible that the modification could have been made only to reduce > the steering effort, and that reduction might have produced the comment of > "one of the best steering TCs" that you quoted. > > As you mentioned, the effective length of the steering arm would be increased > by straightening it. This would provide greater leverage to the overall > steering system. From rough measurements on my car, I guesstimate that > straightening the arm would increase the distance between the drag link > connection and the king pin axis by 20% - 25%. This would provide a similar > increase in leverage and decrease in steering effort. Of course, it would > also require more travel of the drag link to produce the same turn of the > wheels, so the turning circle would be increased if the peg hit the end of the > Bishop cam before the wheels hit their stops. > > If this was the reason for the modification, I think it was wrong for the > mechanic to have said that the TC steering geometry was "basically wrong." > It's not wrong, it's just what the factory chose in the unavoidable trade off > between fast, responsive steering and light, easy steering. > > Russ Wilson > Encinitas, California [Non-text portions of this message have been removed]