Okay, so at the beginning of tonight, we set out to time my friends 96 12v. followed directions to a t. The first time around, we didn't get the timing quite as high as we had wanted, only 14.5* and so we decided to go a little bit higher. Now when we crank it up to around 16.5 degrees, 6.5mm of travel on the dial indicator, when we pull the timing gear off the shaft, the shaft rotates and the dial indicator drops more than 3mm, leaving us at roughly 7 degrees timing. Has anyone had this happen or heard of this happening? Is our dial indicator broken or does the shaft have that much tension on it, that it is slipping back.

Also, when we first measured the amount of movement we had, before trying to time the truck, it was only 3.66mm which is almost 0 timing. Might the timing have slipped that much. The only problem the truck is having is that it smokes a lot, and doesn't get great milage.

Mods, #0 fuel plate, AFC, 3k GSK, Starwheel, turned a little, and 370's.

Any suggestions on what to do now?
Thanks guys.
Sean

 

Try putting the gear on just tight enough to turn the shaft so it doesn't snap to hard when you pull it off, yes its common for it to bounce back like that when you pull the gear (if you ever seen how steep the lobes are on the cam you would understand). As far as the timing slipping that much I have never seen it but I have heard of it happening. Make sure you clean the pump shaft and gear really good with a electrical contact cleaner or brake clean and let it dry before you reinstall the gear. I also use a new lock washer every time as well.