Speedo mystery
 

My 1928 pheaton is up on jackstands . The body is mounted and is in the process of being painted . The engine and driveline are complete or is that is complete HHHMMM . Anyway I decide to run the motor up and check all systems . In first gear the speedo remains moribund nary even the vaguest twitch the same in second gear .Change into high gear and speedo works just fine even at 3 MPH at idle with spark fully retarded . As both rear wheels are off the ground I can engage top gear without going up through gears or go up through the gears in any order but no matter what the speedo only works in top gear,nice and rock steady . This car has the 14.9 small bore engine and multidisc clutch . 4.55 rear end and 9/41 speedo drive cap . The transmission and driveline run fine with no weird noises.So experts out there in international Model A Lnd what think thee ???. Its got me beat . As I will only need a speedo in top gear any way I will most likely leave it as a curiosity.

John in sunny blustery fluffy white clouds 68 degrees Sunday morning England

Re: Speedo mystery
 

John: It sounds like the speedometer drive is only engaged in high gear. You can test the speedometer unit by driving the speedometer cable from the lower end with a reversible drill. If the speedometer head acts properly then the problem lies with the adapter unit on the torque tube, or the driving gear on the drive shaft. I recently took apart a rear end for a customer that was missing the thrust washer and snap ring at the front end on the drive line. This allows the spiral gear to move up and down the spline, possibly disengaging the gears. Very loose pinion bearings will have the same effect by moving the whole drive shaft.

By pulling the speedometer drive assy off, you can stick a screwdriver in the hole and pry back and forth on the drive gear to make sure that it is tight and where it is supposed to be.

Re: Speedo mystery
 

Is this the John from "sunny" old England. If so, nice to see you posting again.
Paul in CT

Re: Speedo mystery
 

John . Great to see you back on here, Problem with the speedo is the engine , It does not have enough power to drive it plus with that low rear end it can,t get up enough speed to register on the speedo ??? If the drive is engaging, disconnect cable from speedo & check its turning, if good has to be in the head, tried another speedo ? Was great to catch upwith you both in March. Derek spring is coming here & the salt is calling.

Re: Speedo mystery
 

And now a short video to illustrate the puzzle

http://youtu.be/n8WSWZHa-n8

How goes it Derek? All packed?

Re: Speedo mystery
 

Andrew, Not yet still 4 days away .Have quickchange rear now to fit in the bag also.Least the baby has arrived , hope its not rusted up, I must be careful on fire up as it normally turns the other way down under ??? Hope Dad can sort the speedo out.