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I was driving my car 86 GTV6 2.5L) on the highway today when all of a sudden it started to run really badly.I made it to my garage and started searching.What I found was that my ignition timing was way off.I brought everything to TDC compression No.1 and removed the timing belt cover on the pass.side.I checked and confirmed that both cams are where they belong but the dizzy/oil pump drive had skipped a few teeth.I checked the tensioner with a mirror,mechanical type, and the setting arrow is where it's supposed to be.I also looked to see if the spring was broken - it seems OK.Next I pulled the dizzy and checked to see if its shaft spun freely - it did.My oil pressure has been good and steady so I don't think the pump is seizing ?.I also checked that the nut which fastens the pulley was tight - it was.I reinstalled the dizzy in an appropriate location and the car ran fine.
So now I'm wondering what to do ? I've pretty well made up my mind to replace the belt and tensioner even though they have less than 10K miles on them.Anybody have any ideas why this would have happened ?

I would be surprised to see that the belt skipped at the dizzy gear and not at the cam...if it did LUCKY YOU! There is almost zero resistance at the timing pulley in relation to the cams...so a slip here is really strange, esppecially if you were just driving along and everything is in good mechanical order...

do you have belt covers on...maybe a little stone got up into the belt??

I have oil type that is now non-adjusting...It is set just slightly loose at startup but when engine warm, tension is correct

Yes I have full belt covers.I too am very suprised that the distributor drive would skip and not the cams - Alfa mystery

Check the belt teeth?

I've looked very closely at the belt and its teeth seem to be fine.I'm starting to wonder if it's possible for the distributor to seize temporarily due to heat ? I believe that its bearing surfaces are simply bushings but I could be wrong ?

Murray,Check the bronze drive bush..Take the gear and move it latterly..
If it moves quite a bit,bingo..thats your problem.It will move while driving and that will cause a skipped belt..

Thanks Barry.This bronze drive bushing of which you speak - could you describe exactly where I would find this. From what I can remember the gear that drops into the head and engages the drive pully shaft is steel but my failing memory could be playing tricks on me

Murray,Its the bush in the cylinder head in which the oil pump drive and distributor drive gear shaft goes through..Grab the oil pump drive gear and wiggle it back and forth..Remember the belt is still attached so you will need Arnold muscles or a small prybar to move it..
..actually,with the belt attached it should move pretty easily..

The gear actually cants over slightly and this shaft and bush wear in the lateral direction ,same as the pressure from the belt riding on it...

Your more confused now than ever,huh?

Murray,Its the bush in the cylinder head in which the oil pump drive and distributor drive gear shaft goes through..Grab the oil pump drive gear and wiggle it back and forth..Remember the belt is still attached so you will need Arnold muscles or a small prybar to move it..
..actually,with the belt attached it should move pretty easily..

The gear actually cants over slightly and this shaft and bush wear in the lateral direction ,same as the pressure from the belt riding on it...

Your more confused now than ever,huh?

Ok Barry I got it ! (item A) Thank you. I'll report back once I've stuck my finger in the hole

Uh,Murray,its item "b"..

Ok Barry - guess I didn't get it I'll try giving the pully a good wiggle.