You can also spin it with a power drill. Put a 1/4" extension into the chuck (or if you have the proper 1/4"hex with a 1/4" square end you can use that) and spin the motor with the drill. still have to excite the windings or spin past ~2k rpm.

With zero charge volts it is either brushes or diode. I have an alternator guy, so I just take it to him. Had him go through the whole alternator on the GT. He replaced all the bearings, brushes and regulator and repainted the windings to prevent it from shorting. Cost me 160$. Well worth it to me. I had my hands full rebuilding the engine....

 

I think you got a good deal there. I tried Hilton's sugestion on my spare and saw about 8 or 9 volts but it does not spin too high using a piece of rope to accelerate it.

I am pretty sure it is the diodes that have gone given the low resistance to earth I measured. On my spare alternator resistance was very high. I checked the bushes on my spare unit and although some wear was obvious it did not look too severe.

I also have a feeling that some wiring is going to have to be replaced.

Regards

Fred

 

After some diagnosis concluded the alternator had gone so fitted the spare one- it still works thak goodness.

Now the wiring -basically the front engine harness is shot to some extent or other. Continuity checks did not reveal anything further after replacing the leads into 5 of the harness wires in the 14 pin connector as a temp measure.

For the oil pressure switch we fitted 3 separate wires external to the harness as a trial. The oil pressure indicator on the panel now works but there is an anomaly in that when the ignition is switched on the needle flicks over to full scale and when the engine fires up the gauge seems to show normal pressure indication behaviour.

Anyone any bright ideas as to why this may be? They fitted new terminals but resued the cover on the connections to the sender unit.

Regards

Fred

 

There are two independent units in the oil pressure sender unit - a variable resistance that drives the oil pressure gauge, and a simple pressure switch (earthed when there is no pressure, open when there is minimal pressure). It is easy to switch the wires...