MTFCA Forum

My rebuilt Stewart 102 is bouncing between 0 and 40 MPH and it's not the speedometer's fault as it is silky smooth when using a drill (reversed) to spin it. The cable is clean, not kinked, and lubricated and the swivel appears smooth as well. Any chance it will improve with use?

I wouldn't expect it to improve without service. A dry cable is a common cause of that issue, as is a dry bearing in the speedometer head. Dry drive gears to odometer(s) can also cause it. A badly worn bearing could cause it by allowing the magnets to hit the drum. Beyond all that, dirt could cause it, including metal or rust particles stuck to the magnets. A broken or kinked cable might cause it, or a cable with a badly worn end. Excess lubricant that has worked its way into the speedometer head might cause it.

Thanks Pat, but I should have mentioned that it's a Russ Furstnow rebuild with zero miles on it (actually about 3 miles now). I found it at Hershey with a minor blem in the brass, but otherwise beautiful. I'm positive that the problem is not in the speedo head so it has to be something in the cable or swivel but both look great. It has a modern type cable ( maybe 3/6" dia) in an original heavy case. Neither appear to have any kinks or sharp bends. It it possible that the inner cable is too long causing binding??

Bruce Compton wrote: ↑

Thu Oct 27, 2022 6:43 pm

Thanks Pat, but I should have mentioned that it's a Russ Furstnow rebuild with zero miles on it (actually about 3 miles now). I found it at Hershey with a minor blem in the brass, but otherwise beautiful. I'm positive that the problem is not in the speedo head so it has to be something in the cable or swivel but both look great. It has a modern type cable ( maybe 3/6" dia) in an original heavy case. Neither appear to have any kinks or sharp bends. It it possible that the inner cable is too long causing binding??

A modern cable is closer to 1/8".
I normally line the inside of the original housing with 1 or 2 layers of plastic tubing. (The type used for ice makers, but in larger sizes.)
Your cable is probably whipping around in all that extra space.

Before you mentioned it, I would have suggested you call Russ F. He will likely pinpoint the problem from your description quickly with his vast experience.

Thanks John ; Sounds like the answer. Never occurred to me but it makes sense. I'll try that trick tomorrow. Thanks again; Bruce

I tried the plastic liner trick and it helped somewhat but it still bounces around. It even bounces when the car is stopped with the motor running and sometimes sits at 5 MPH with the car not moving. I may try repositioning the swivel so that the cable comes out lower.

I have put aside a modern type cable, with its housing, and both will fit inside the original cable housing. That way the modern cable is running I side it's own housing. I have yet to make the cable ends to fit my Speedo head.

Allan from down under.

Bruce Compton wrote: ↑

Sat Oct 29, 2022 11:58 pm

It even bounces when the car is stopped with the motor running and sometimes sits at 5 MPH with the car not moving. I may try repositioning the swivel so that the cable comes out lower.

If it also does it with the car stopped, how will adjusting the swivel have any effect? Call Russ Furstnow and ask him. I'm certain he'll know the answer.

Sounds to me like something's jammed up, maybe up in the head? Like was said, call Russ.
I finally got fed up with my Steward 26's trip meter constantly sticking when it rolled from 99 to 00 for the first 10 miles and sent it to him. Can't wait to have it back all feexed! Assuming it IS fixable!!

Bruce Compton wrote: ↑

Thu Oct 27, 2022 6:43 pm

I found it at Hershey with a minor blem in the brass,

My first thought is that it was dropped or something else unfortunate happened to it…

I can't imagine what would make it bounce when the car is not moving unless it would be severe vibration. How is the speedometer head mounted?

Yes, it has me stumped. It runs silky smooth with a reversed drill driving it, holds various speeds steady, and the odometer reads fine too. I was thinking that the cable may be a tad too long and binding or putting pressure on the speedometer input mechanism so was thinking of changing the position of the swivel to maybe change the angle slightly. I'm desperate so I'll try anything. The car runs smooth (for a T) with no more vibration that any of the other 6-7 T's I've had before, but today I'll disconnect the cable and see if it still acts up with the car not moving.Thanks for all the suggestions.

Does the swivel run smoothly? Do the road and speedometer gears mesh properly thru out the revolutions?. Cold also be the inner cable is binding and releasing inside the cable housing.
Of course if you experience the problem while the car is not moving, then it's got to be something in the head.

Bruce,

Did you "lay" the links in the cable before you attached the cable to the speedometer head?

Ken

I inspected the head and found that the drum was able to move at least 0.060" vertically. Against my better judgement I removed the tiny brass strip that holds the main shaft and bent in slightly to allow for only 0.008-10" of vertical movement , and the result is a much smoother reading, but it still bounces more than it should. It's way better at idle with the car running, but still moves a little. When I get more courage , I'll open it up again and try for a finer adjustment that calls for 0.002-0.004" , as I think I'm on the right track now. Working on this intricate device is a major challenge for me as I don't have much control or feeling in my hands. I'm waiting for a carpel tunnel operation in two weeks as well as a visit to a back surgeon to deal with bone spurs irritating nerves in my back. No fun gettin' old but my T obsession keeps me going. Thanks again for all the help and suggestions.

I've had the head opened up maybe 10 times now and have the problem almost beat. I'm changing the pressure of the brass strip over the hair pin and have now got it to the stage where the bouncing is almost eliminated but the speed readings are a tad low at 35+ MPH. The tiny brass plate just keeps the main center shaft from bouncing and apparently should have 0.002-0.004" clearance between it and the point of the center shaft. There does not appear to be a locating or centering spot in the brass plate so if it allows too much clearance the whole drum is allowed to tilt. I'm wondering if there should be a "jewel" at the top of the main shaft, or something to keep it located on center.

Ever try the original hooks / links instead of the cable. I have them in mine with no trouble.

Thanks Mark, but the problem is for sure in the head. I just need to find the happy spot with the pressure from the tiny brass plate.

There may not be one. Are you certain that here is no debris in the mechanism ... not even a tiny bit of lint?

I've not seen one of these yet that didn't have some degree of bouncing around in the speed indicating drum. They are not rock steady like "modern" speedometers.

Agree with Jerry. In addition, its a lot to expect accurate speed readings throughout the speed range. I think you've got it dialed in pretty well. I'd hate to see you screw it up by doing too much fiddling.

I have followed this thread with interest, having bought a Stewart head from Russ Furstnow at Chickasha in 2010. I have yet to pluck up the 'want tos' to carve a hole in the polished Blackwood dash of my tourer to fit it.

Duncan and Fraser offered Corbin speedometers on the model T's they sold. These are an instrument of far better quality than the potmetal units Stewart provided. Until I restored my D and F wide body roadster, I have never had an operational speedo in any of my T's. The Corbin unit I fitted to it works superbly. The frame of the speedo head is brass. The components built into it are like a finely made timepiece. The cable consists of links like the Stewart, but every second link is a steel casting with an eye on each end for the wire links, and two annular rings to act as bearings within the cable housing. The swivel is nickel plated cast steel, with a 1:1 drive ratio. Even if the housings wear, they are rebuildable. I have an as new one, and another for a spare.

In operation, it has a rock steady needle which arcs from 8 o'clock to 4 o'clock, indicating 0-60 mph. At an indicated 40mph, GPS
tracking gives 38 mph. I may be able to improve that with a different cog on the swivel, but I am happy as it is. This set-up was put together from parts accumulated over many years. They were cleaned up, re lubricated and linked up ready to go, with never a drama since being installed. I am Blessed!

Allan from down under.

Variations in tire pressure, wear, and make could account for an error that small.

Just to clarify, my problems with this speedometer do not have anything to do with Russ Furstnow's work or great reputation. Russ gave me a quote on a rebuilt head a few days before I headed to Hershey but I decided to wait to respond till after Hershey as I was also looking for a better swivel, driven gear and an "S" bracket. On the second day I found an excellent "S" bracket and the same vendor had a beautiful Stewart Model 102 speedo head for quit a bit less than Russ's quote (and no shipping problems and cost) plus it had a tag attached "rebuilt by Russ Furstnow". It appeared perfect, and was reset to zero miles. Upon testing the unit at home however the previously stated problems appeared and I have since contacted the vendor. To his credit he admitted that he may have been mistaken and that this particular unit may not have been rebuilt by Russ, although he had several others that had been done up by Russ over the last 20 years or so and quite possibly got them confused. I've tried to contact Russ, but have not heard back from him and will now deal with the vendor as I'm almost 100% sure that Russ didn't do up this speedo, or if he did, someone else has had it apart since.