Bumping the IP timing one tooth

[RustyCaddy]

Hey Coaster.

What had happened, to be completely transparent, was that after setting the timing a few months back at all three points the non-TTY bolt holding the crankshaft gear to the crank had loosened and backed out.  Backed out quite a bit actually to where the timing was changing because the sprocket was loose (thankfully the crank gear has the old style woodruff key or it might have been close to grenade-ing).

After retorqueing the bolt to 137 ft/lbs the cam was slightly retarded at the back end so, without loosening the belt, i reset the cam by loosening the sprocket and turning the cam to realign with the plate in back . So the crank was still at TDC and the IP pin was locked. The timing went back to about where it had been before the crankbolt incident, or it sounds that way as i need to hookup the luminosity probe.  Now i think the pump is slightly advanced relative to the cam, but unchanged relative to the TDC mark on the flywheel.

Haven't had a chance to see how much the range of IP timing adjustment may or may not have changed. But doesn't the IP alignment move slightly forward relative to the motor rotation and the camshaft when jumping a tooth at the IP gear?

[Gizmoman]

Do the "D", get a new bolt, and never worry about it again.

[air-cooled or diesel]

^thats a TDI crank gear.

the non-TTY bolt holding the crankshaft gear to the crank had loosened and backed out.

^looks like he has a 1.6. get correct crank gear for what you have.

[ORCoaster]

The question is: 

But doesn't the IP alignment move slightly forward relative to the motor rotation and the camshaft when jumping a tooth at the IP gear?

Let me think and visualize this for a moment, If you had a properly timed engine and the belt jumps one tooth on the IP and the other two are still aligned at TDC where does that put you for timing of the IP?  The belt would have effectively moved in the forward direction which would put the location of the lock out pin where?  Just short of where it would go in the hole for a properly timed engine.  It would be like you loosened the IP on the bracket and pushed it all the way towards the engine, correct?  That is advancing the pump.  If you had enough of the slot of the IP you could just loosen the IP and the nuts on the back and pull it forward. 

Most of us don't have that luck because I think to get one full tooth of the belt out of the system we need all of that adjustment and I know I run my pump right about in the middle of the slot.  So I wouldn't get by with just pulling the pump towards the radiator.  Maybe my hardlines to the injectors actually are limiting the travel in the IP adjustment slots.  I don't normally take the upper clips off when doing a time on the engine.

So you have a Luminosity setup?  Which one?  The little battery powered box that turn the flash of the combustion into a signal that is then able to trigger a standard timing light?  Or do you have the Snap On meter that will tell you RPM and degrees of advance or retard on the face of the meter?  I have both and really like the Snap On method.  It is just getting the probe into the inspection hole that is a bit tricky for me.  The meter didn't come with that proper means of keeping it steady so I made an adapter for the cap that works fairly well once I wiggle the probe towards the flywheel.  The last time I used it the flywheel nicked the probe and I haven't sourced out the reason why it quit working for me.  I ended up going to Plan B with the other timing light method.

[RustyCaddy]

All good points!

What my mind is not sorted out on is where that puts the IP gear in relation to its pinned position. Mostly the feel of the IP gear to me is when i set up the IP for engine timing purposes the gear falls backwards slightly towards the engine.  So may be my thinking is wrong that if the IP is set with the pin and falls back sightly but the cam is slightly retarded at the same point then readjusting the cam with the belt tight would have the effect of taking out the fall back in the IP gear and IP internals.  Sounds like i may have that backwards then from what you are saying.

i have the snap-on luminosity probe with the snap-on adapter that goes into the timing plug hole (somewhere in the garage anyways)

[Gizmoman]

^thats a TDI crank gear.

the non-TTY bolt holding the crankshaft gear to the crank had loosened and backed out.

^looks like he has a 1.6. get correct crank gear for what you have.

Shows you how much (or little) I know.
I thought they would fit on a 1.6 once you did the work on the crank. I put one on my AAZ 1.9, again, not a 1.6

Using a new bolt is still a good idea.

[RabbitJockey]

the tdi gear will work on a 1.6 if you do the same machining required for it to fit on an aaz, unless if it is the older 1.6 with a wooddruff key, and i think they also have a 17mm crank bolt and the 11mm head bolts.

[RabbitJockey]

All good points!

What my mind is not sorted out on is where that puts the IP gear in relation to its pinned position. Mostly the feel of the IP gear to me is when i set up the IP for engine timing purposes the gear falls backwards slightly towards the engine.  So may be my thinking is wrong that if the IP is set with the pin and falls back sightly but the cam is slightly retarded at the same point then readjusting the cam with the belt tight would have the effect of taking out the fall back in the IP gear and IP internals.  Sounds like i may have that backwards then from what you are saying.

i have the snap-on luminosity probe with the snap-on adapter that goes into the timing plug hole (somewhere in the garage anyways)

talking about the cam makes everything confusing, and the cam timing is irrelevant to the pump timing because the timing of each is relative only to the crank position.

hopefully this helps... if the sprocket needs to turn clockwise in order for the lock pin to slide in then the pump is retarded, if it needs to rotate counter clockwise then it is advanced.

the springiness of the sprocket where it wants to rotate counterclockwise from the pinned position is the beginning of the ramp on the cam plate, which is essentially what you are measuring when you check the timing with a dial indicator.

[RustyCaddy]

Thanks RabbitJockey.  Looks like i was underthinking the topic.  Sorry to have ended up hijacking the thread.

Gizmoman, will look into the gear bolt. The motor is an early 1.6 with 11mm head bolts so i will need to source a TTY bolt, the diameter is different from the later crank bolts like RabbitJockey says but TTY would be a definite improvement over the reuseable bolt.

Will hookup the luminosity probe soon to see where things are at and maybe take a short video for the forum. The motor seems to have survived for now, anyways until i screw something else up 

[Gizmoman]

Best of luck Mr.
I'll be asking about changing the front main seal (engine in) in a post to come.

[RabbitJockey]

I had a crank sprocket come loose on my old 1.6 with the early woodruff let crank, the a lot for the key was a little messed up but not too much.  After getting a new sprocket and key it fit tight so I filled in the worn part on the crank nose around the keyway with some jb weld, then reused the bolt with red loctite.  I drove with that engine at least another 50k before it failed from other issues. So that should give you some hope, but if you can find a new bolt I would highly recommend it.