Spitfire 76 spitfire overdrive test question

[sabot]

Hi guys, is there anyway to test an overdrive unit and the solinoid when they are out of the car before they are reinstalled?
thanks tom

 

[DNK]

Didn't Tom just ask this?
Think Randall answered

 

[sabot]

i believe his was for a tr car,
is the spitty not different?
i thought i had read somewhere, here?, that there was a way to bench test 1 or both of the components, before installing them.
trying to figure out why it won't ingage.
tom

 

[DNK]

They are a different deal, but the workings I would think would be the same. Just a guess

 

[TR3driver]

Later Spits used a J-type OD, same as later TR6. Some minor differences (like the pressure and maybe speedo drive) but basically the same unit.

You'll need some way to drive the overdrive/gearbox, and preferably a pressure gauge with the funky adapter. Also need a source of 12v for the solenoid.

I think Jay Holekamp (sp?) is still selling the gauge & adapter for around $50; no doubt there are other sources. For motive power, I use my 1/2" drill motor coupled to the input shaft with a short length of straight radiator hose & some clamps. Others use various pulley arrangements and old washing machine motors or whatnot.

For a J-type, you first spin it up with the solenoid not powered, and observe that it builds around 20 psi of residual pressure. This may take a minute or two, as the oil fills the passages and the air bubbles bleed out. Then apply power and check that the pressure rises to the correct value. My documentation says 320-350 psi for a Spit, but it's possible that was revised later. You should also be able to hear (or feel) the change as your motor accelerates the output shaft.

Check out the Buckeye Triumphs site, they have some excellent articles on the J-type, including testing and troubleshooting.

 

[sabot]

got the o-drive tester,
thanks tom