SPF Speedometer Issues

T

Tony R

Hello All,

From the beginning the speedo in my SPF jumped erratically and now it has stopped working, have any of you seen this probelm and what was the fix?

When I talked to Ohltoff they said they had a set of gears as an add on the fixed the erratic reading, anybody installed those pieces?

Tony R.
 
C

chuck smith

mine read 30 percent higher speed than actual, so I got the Olthoff gear reducer. usually an erratic speedo means the cable needs lube, use automatic tranny fluid
 
M

Jack

in another post, a motorcycle chain lubricant made by "Gunk" was recommended.
This is good stuff and comes with a "wand". Better than trying to soak your cable with ATF (also a good lubricant for speedo cables).
 
kgschrader

Kirby Schrader

They're mostly silver
Lifetime Supporter
Since my final drive is a 4:22, I too had the higher speed indication. Olthoff supplied the gear reducer and it fixed the problem.

Or did.... On the way home from work last Friday, my speedometer stopped working. When I removed the cable at the ZF, the cable checked out fine.

I removed the reducer and its input was no longer talking to its output. I took the reducer apart and found that the input and output shafts have the gears pressed on. Except the interference fit wasn't enough. The gear was turning on the shaft.

FWIW,
Kirby

chuck 1 said:
mine read 30 percent higher speed than actual, so I got the Olthoff gear reducer. usually an erratic speedo means the cable needs lube, use automatic tranny fluid
Click to expand...
 
M

Lynn Miner

The Olthoff reducer will correct the 30% error. The jumping needle is usually a sign of the cable being too tight at the transmission connection point (Olthoff will warn you of this if you buy his adapter). The fact that yours has stopped is a good indication that the cable has broken. My cable broke after 800 miles. It broke about two inches from the speedo because the cable made a near 90 degree bend and the radius was way too tight. I solved the problem by (luckily) getting a new cable under warranty from Ian at Dynamic and then installing a Stewart Warner 90 degree gear set on the back of the speedo. No more kinks in the cable - runs smooth now.
 
B

Rich E.

Initially I had problems with speedo. It would jump like crazy. I had the 90 degree SW unit and the Olthoff correction gear. At about 750 miles the speedo cable broke. Sent the speedometer, cable, and reducer gear, including a elevations diagram and basic schematic of the routing to a speedo shop in W. Hollywood Ca, that specializes in these speedo's. They ended up replacing the actual cable with a larger diameter (less flex) therefore much less bounce and changed the length. Speedo is now smooth as glass. All for roughly $100. If your interested I'll look up the name from my reciepts

Rich.
 
T

Tony R

Hi Guys,

I have a 3:77 ring gear , does that mean I do not need the gearing to correct the readings?

Just came up from the garage looking at both ends of the cable, nothing obvious.

How did you replace the cable once you bought the new one from the speedo shop in N. Hollywood, it looks to be non-serivce friendly ?

When removing the cable getting to the back of the speedo it seems to be a task removing the dashboard.

Is Ian still with the folks in Ohio or has the entire organization been dissolved ?

Thanks in advance for your responses.

TR
 
S

Mike Christian

getting to the back of the speedo is a bitch. I removed the fuse cover and worked one hand through there and one from the underneath. choice words were said.
 
P2164

Jack Houpe

GT40s Supporter
I had a problem with my speedo from the factory, seems who ever installed it bent the cable at 90 on the speedo head. When I hooked everything up at the transaxle and drove off it sheared the cable. I then decided to remove everything and ordered a electronic unit that looks just like the original but has better back lighting at night. it took all of 2 hours to install. All you have to do is mark off 2 miles press the cal button at the start and finish of 2 miles and its calibrated. No more cable problems and you can also order a custom dial with Smiths on it if you want. The head was $269 and the pick up unit was $149 which goes where the speedo cable hooks to the transaxle.
 
T

Tony R

Hello All,

Thanks for the responses and great information.

This is a great place for GT40 info, tips etc. etc.

Jack, That sounds like the right way to go where did you get the bits and pieces and how did you run the wiring from the transaxle up to the dash?

TR
 
B

Rich E.

I would have to say that if North Hollywood speedo wouldn't have been able to fix the problem with the peices at hand I would have gone the electrical route like Jack. North Hollywood speedometer would have been able to get all the stuff for swap too.

Rich.
 
P2164

Jack Houpe

GT40s Supporter
You can order online the 4 inch programmable speedometer from Gauges, Custom Gauges, Tachometers, Speedometers by SpeedHut Go through there custom design on line ordering process and they will get it out to you in a week.

Now if I had it to do all over again I would not have purchased the pick up adaptor. The speedometer accepts signals from any pulse signal from 2 volts to 100 volts, 500 to 250,000 pulses. So I would have just purchased a crank sensor off a ford or GM, fabricated a bracket mount and used the bolts for the CV joint as a reference pick up. This will save you over $100 dollars but if you want the unit I have then you can purchase it from www.speedometersolutions.com or call and ask for Roger Luckow @ 414-463-6660. Tell him you need the unit for the Pantera ZF, its not $149 like I thought its $126 including freight. I will post a pictures today of the head unit and the pick up.

I just ran the wires through the hole where the brake line goes through the firewall and then under the center consol cover up to the dash. You might want to purchase a multi strand cable and run it, when you see the difference in night lighting you will want to change all the gauges. All the gauges from Speed Hut are electronic and use sender units.
 
Last edited:
mtrusty

Mike Trusty

GT40s Supporter
Lifetime Supporter
After seeing Jack's installation I decided to do the same thing. The only comment is that they will not put the "SMITHS" logo on the dial. The lawyers will not let them. Other than that the gauges that Jack recommends are first rate high quality units. They even have carbon fiber cases and are much shallower than the original style gages. I now have a complete set of SMITHS gauges if anyone needs them.
 
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