Speedometers

[wedgewa]

Recently my 1980 speedometer (140mph replacement installed new in 1982) began to wobble between 60 and 70 mph along with a sort of barking howling noise from behind the dash.
So I greased the cable and reduced but did not eliminate the problem.
So I then replaced the upper cable with a new one and changed the problem to a new form. Less wobble and less noise but all the time at all speeds. And the needle doesn't drop to zero when stopped. It "rests" reading about 5mph.
OK - every Smiths speedo I've ever owned has ultimately failed entirely - some sooner than others. I've had them rebuilt and I've replaced with "new" (if that's even a relevant term anymore).

But can they be lubricated prior to failure? If so, with what and where that might not be obvious?

And the cables. Lots of mention about lubrication in the service data but not what to use. My original BL GT6 book says "grease" but is not specific. My original BL TR7 book is silent on the subject. "Experts" (you know - those people that hang around your garage) all have different opinions ranging from wheel bearing grease to cable lube that is some kind of liquid in a tube. What is it really supposed to be that goes into the cable housing?

Somebody here must know these things!

[FI Spyder]

Grease bottom two thirds or three quarters as the grease will work its way up. The problem is you don't want the grease to reach the speedometer. I'd say you can't go wrong with speedometer cable grease which you can buy at auto parts store. It is a light liquid, I'd say probably made of something like sewing machine oil (which doesn't congeal) and graphite.

You say you replaced the upper cable so I assume you have a service indicator. Apparently these can cause the problem and can be dismantled and cleaned to solve the problem but I haven't tried it yet.


TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra

[wedgewa]

Thanks for the first early response. The new cable arrived with some sort of grease already inside. I have some of the liquid tube of cable lube available so I think that's next.

But what about the speedo head itself? Lots of turning and whirling parts on the back. Many appear to have been lubricated when originally manufactured many years ago. Are there any that can be successfully greased or oiled at the owner level? If so, with what and where?

I too have read that it's possible to open up the service counter. But I haven't seen anything about what to do once it's open. I imagine it is at least similar to an odometer inside but without knowledge, I wonder if there's some tiny but essential spring-loaded part waiting for the opportunity to fly halfway across my garage and disappear forever!

Any personal experiences with the speedo head or service counter on the forum??

[Jolyon39]

Please take photoes (High shutter speed to catch flying parts...GRIN) when you open up that counter. It would be usefull information for many of us

[FI Spyder]

Somebody on this site had actually done it but can't find the post. Didn't mention anything about any internal bobby traps but caution would be the order of the day. Plan to do mine someday. (I have a new one as a spare just in case).


TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra

[kstrutt1]

I managed to get the one to work in my Landrover by taking it appart and giving it a good spray of WD40 for a few days, basically the original grease had all gone hard. Once this had softened everthing up I put it back together with some thicker oil, it's been fine since.

[wedgewa]

Progress Report:

Local speedo shop tested the head on their bench. It's fine.

Replaced the upper cable with new. Noise much worse without even installing the speedo head.

Much gritting of teeth. And no camera handy.

Removed service counter to my bench. The lower cable end was rusted to the drive spindle and difficult to pull out.

Secured the counter on level. Removed the 4 case screws while holding down the case top. It was trying to lift by itself. One corner screw had some red sealer on it and was harder to turn out.

There's not much inside. But Smiths did commit the sin of combining metal worm gears with plastic drive gears. And running metal hubs against plastic bushings without washers or bearings. All lightly loaded but still lots of wear. The electrical switch is magnetic and is melted into the case - won't fall out. There is a shaft with 4 small counter wheel drive gears that is held in place by spring tension. Took the top of the case off very slowly and everything stayed in place. Dust and crud everywhere plus some rust.

I did not experience flying parts until reassembly. 4 gears and a shaft went 5 directions. After probably frightening the neighbors with my language skills, I did recover them all. I suggest reassembly inside some kind of box!

I'm using the same types of silicone grease and plastic-compatible oils that I use in the drive lines of Lionel electric trains. They also share plastic and metal gears that are loaded more than the counter.

Time to put it back in and see whether I have a success story or just a bunch of used up time.

[FI Spyder]

I await the result with baited breath. No pictures while you were scrambling around the floor after wayward parts?


TR7 Spider - 1978 Spifire - 1976 Spitfire - 1988 Tercel 4X4 - Kali on Integra - 1991 Integra

[wedgewa]

Words to the wise: Don't procrastinate.

Lessons learned: (1) The Smiths service interval counter is a simple device and easy to open, clean and lubricate. (2) It needs to be opened, cleaned and lubricated sooner than 160,000 miles. (3) Waiting until it screams in pain will mean the plastic gear teeth and plastic bearing surfaces have worn beyond function. The best you can do at that point is make the screaming stop so it can die in peace. And you can drive in peace and quiet while averaging the various speeds indicated until the new counter arrives.

Or I suppose you could just get a longer cable and eliminate it entirely. Since the counters for the injected cars are still available new, I have one on order. I think I'll be checking the internal lubrication before it goes in the car. (Because of the "O" in NOS!)

[Jolyon39]

Where do you buy the counter from and can you buy the key to reset them to zero?

I want one for my TR8

Jolyon

[wedgewa]

<blockquote id="quote"><font size="1" face="Century Gothic, Verdana, Arial, Helvetica" id="quote">quote:<hr height="1" noshade id="quote"><i>Originally posted by Jolyon39</i>

Where do you buy the counter from and can you buy the key to reset them to zero?

I want one for my TR8
<hr height="1" noshade id="quote"></font id="quote"></blockquote id="quote">

The counter for fuel-injected TR7's is part number DRC2338 and is available from The Roadster Factory in Pennsylvania. The counters for carb 7's seem to be more difficult to find. I don't have a TR8 book so I don't know if DRC2338 is the one you need.

I have a reset key which came with a BL Emissions book I bought back in the 1980's. Not much to it and you can probably make your own. It's just a flat piece of metal shaped sort of like a key with 2 small pins at the working end. The pins fit into the 2 holes in the reset shaft that is located on the right side. So resetting works just like a trip odometer reset. There's no lock. Anything that will engage the 2 holes and turn will work.

[wedgewa]

Turns out the DRC2338 counter which was listed as available from Roadster Factory is NOT available. Their listing was an error and is being corrected.

Their suggestion was to eliminate the counter by using a 48 inch Spitfire 1500 cable - part number GSD410.

Or find a used counter that isn't worn out.....

[Odd]

I'd go with the longer one-piece speedo cable - most of us living outside of California do...