Spedo use
 

I'm wondering if there is a way to use the spedo from a 300D n/a in a car with a 3.07 diff (the one from a 300D turbo). I know how to modify the odometer gearing so that it is accurate, but is there any way to modify the spedo so that it reads accurately?

As it is now I assume that the spedo will read 45mph when it's doing 55mph.

No. Just use the correct speedo and change the odometer to match.

the speedo is a friction wheel design, no way to alter it from it's design. should be no problem finding a speedo from an 82+123 to fit in there.

Magnetic drive, actually.

82, 83, 84 300D used the 3:07 differential

85 300D used the 2:88 Differential.

Charlie

Thanks for all the replies. The problem is that the car is a 240D with a '82-'84 300D 3.07 diff. The spedo from a pre '82 300D n/a would look perfectly and would display a more realistic speed range (0-85mph).

So without serious modifications and making the spedo/odo unit less reliable I think I'm stuck using a 300D turbo cluster.

The turbo spedo will have the black center cap on the needle. I think the 240 uses the silver cap. some times the caps will come off easy. I have had a few fall off, think the glue has got old and lost it grip. or you can swap the needles.

before you pop the needle off. lift it over the resting peg, and see where it rests. should be a little white mark on the edge of the face. needle should line up with that spot. replace the needle in the same place, then lift it back over the peg. i had to redo my 85 a couple times to get it to read right.

you mention you want the spedo to look correct (85 mph). I have a 150mph in my 240D :D.

Charlie

Not always. I have a 115mph 3.07 speedo on my shelf with a chrome cap.