Numpty speedo fault question!

[Schrodinger]

I fear this may be a very stupid question, but here goes!!

The speedo on my S4 has stopped working, I'm happy enough getting it refurbished but I'm a bit worried about refitting it without knowing what caused the problem in the first place. My concern is that it started playing up the day after I topped up the gearbox oil and there seems to be some oil on the cable at the back of the speedo so I wonder if this has caused the problem. Has anyone else had anything similar or should I start believing in coincidences?!

I presume if this is the cause I also need to replace or clean the existing cable, does anyone have any advice on the best thing to do?

Many thanks for any help!
Jennifer

[Frank Howard]

Jennifer,

Oil on the cable is a sign of proper maintanance by the previous owner. If you get the chance, you may want to check that it is not broken and then clean and re-oil it with a light weight oil.

Pratically all Elan speedometers have failed by now for one reason or another. You can confirm that the fault lies in the speedometer by attaching a drill to the speedo input to see if you are able to make the speedometer and/or the odometer move.

Good luck,

Frank Howard
'71 S4 SE
Minnesota

[ppnelan]

It must be THAT time of year - my Elan speedo now has an inoperative trip & odometer, and my +2 one has stopped working completely...

At least the rev counters are reasonably stable, if not entirely accurate...

Matthew

[brassringfarm]

Jennifer - When I restored my Elan, my Numpty Speedo was jammed in side the speedo. When a drill was used to turn the speedo from the cable end - it would not budge. I took it to the local 'professional' speedo shop in Cincinnati where I lived and they 'fixed' it for $80.00. A year after the restoration the speedo stoped working again. I'm betting the professional shop just un-jammed it and never fixed the actual problem. Of course the right angle drive had broken the first time it went, along with the nylon gear in the tranny.
Net, this time I will send it to Nisonger's in New York and have it done right. (They redid my Tach and it looks and behaves like new)
Try spinning the tach with a drill on the cable first, as suggested. If it doesn't turn - then still check the right angle drive in case something broke there. They can be sourced several places.
A question I have: is the Right angle drive unit the same as on the MGB? or what other make?
Best of luck. The speedo is relatively easy to take out and fix!
Paul Zimmerman
65`S2

[tower of strength]

Raise the rear wheels off the ground and run the engine in gear, if the end of the cable that fits to the speedo is turning, then the instrument is at fault, if not, suspect the angle drive or a broken cable. the inner cable can be withdrawn from the outer and should have squared shoulders on both ends, If thats not broked, then the angle drive or the gear inside the gearbox has failed

Hope this helps

Mark

[miked]

Mark, not being funny here, but I think you need to qualify what you are saying here as even with the action of the diff' and only one wheel lifted the acute angle of the drive shaft do nuts do not lend them self to spinning. This is unless you mean to lift from under the A frame cross bar. This is critized as it is easy to bend the thin tubes of the A frame if you dont spread the weight with small board and keep it outboard.

Mike

[denicholls2]

I have no doubt that shops like Nisonger are capable of repairing your broken speedo. I know this because I am also capable of addressing the basic ills described here. But you don't need to go this route, you are a self-reliant Lotus owner and can fix it yourself!

I believe the most common fault is due to long sitting. This causes the brass bearing to seize either partially or completely. The added force required to turn the assembly then wears the cable and can damage the [delrin?] gears in the transmission that drive it. This is the common failure mode of the Europa speedo.

I DO NOT recommend the "insert a drill" suggestions above. Knowing there are delicate parts in an assembly, would you apply a power tool (electric jackhammer) to increase force and get them to turn, or would you seek the source of the problem first? A free assembly is easily turned by inserting a manual screwdriver of the right size, and can be turned sufficiently to determine both if the needle moves and if the odometer works. Using a power drill in the wrong direction may apply sufficient backwards force to cause permanent damage.

The part is easily disassembled. Twist the bezel to free it from the body, then remove the two screws on the back that hold in the mechanism and slide it out the front, making sure to keep your paws off the needle as you do so. (If you hit it accidentally, your readings will subsequently be off, but by a constant amount. Adjusting the needle to barely rest against its stop should get you within 5 MPH)

The one I looked in most recently had both a bound center bearing and had just started failing to operate the odometer. The center bearing was fixed with lubrication, the odometer by removing the dry-caked grease whice caused it to bind and relubricating it. I used white lithium spray grease. The odometer is triggered by a very delicate metal arm that ratchets through an offset cam, like a watch mechanism.

Checked by my GPS, both components are now extremely accurate and reliable.

I strongly recommend that you not let any of these failures go unaddressed for a long time, as stress damage to the related parts can result and may be much more difficult to repair. The Renault drive gears in the Europa transaxle, for example, are not the same as the parent R-16 and no longer obtainable.

[Schrodinger]

Thanks all for your help!

I've disconnected the speedo cable and the cable seems to be turning OK which is why I assumed it to be a fault with the speedo itself. I've now removed the speedo itself (which, as always, wasn't quite as simple as it should have been!) and there's really no need to go near it with a drill, any slight turn of a screwdriver in the input shows a significant erratic, non-linear response. Anyway, it has now been sent off to be looked at by those who know a lot more than me about these things!

I think I'll just stop worrying about what went wrong - unfortunately if something breaks straight after I've done any work on the Elan I just assume I've messed something up!

Thanks again!
Jennifer

[tower of strength]

Mark, not being funny here, but I think you need to qualify what you are saying here as even with the action of the diff' and only one wheel lifted the acute angle of the drive shaft do nuts do not lend them self to spinning. This is unless you mean to lift from under the A frame cross bar. This is critized as it is easy to bend the thin tubes of the A frame if you dont spread the weight with small board and keep it outboard.

Mike

fair coment Mike, I did this on a two poster ramp with my +2 and the backend did bang about a tad, but it was only for a few revolutions , just to see if the cable turned. I wouldnt recomend running the car through the gears like this though! I did a similar thing with my spitfire on chassis stands whilst messing about with the overdrive wiring, that was hairy!

Mark