Hello Dieselers,
It appears that I will have to replace the IP timing gear because of wear from the vacuum pump bearing. Maintaining timing is my main concern. The procedure from the book is to 1) move engine to 15 deg ATDC. 2) Fix cam gear and timing device with a cable strap. 3) Remove chain tensioner and remove bolt for cam gear. 4) Remove cam gear. 5) Remove timer. 6) Lock IP. 7) Install timer. If in steps 4 and 5 when the cam gear and timer are removed, how does one maintain timing? Seems to me that the cable straps must be cut. It may be obvious when doing but I don't see it now. Thanks for any help.
D.

Here's the skinny:

1 Set engine to 15 atdc

2 Lock the injection pump. (there is a 17 mm plug on the side of the pump. when removed you have access to the shaft that turns in the pump. at or near 15 atdc there is a small horizontal protrusion that can be held by a dowell with a slot cut into it. fabricate a tool to hold that protrusion centered to the access hole and make sure no matter what it doesn't move. if it does you're {more}screwed)

3 make (paint) a mark on the cam gear while at 15 atdc lining up with the tdc mark on the cam cap

4 remove the chain tensioner and cam gear. run a zip tie through the chain on the tensioner side and secure it so the chain isn't allowed to drop into the crankcase.

5 if your engine has a sheet metal "basket" held by 3 10mm bolts under the vacuum pump remove it.

6 remove the bolt holding the timer to the pump, note left hand threads

7 cut a soda can apart and get a good sheet of aluminum. slide that sheet between the chain and advancer and then slide the advancer out (ya know this might not be necessary with the cam gear out, if it gives ya any trouble use the soda can trick) care should be taken not to let the chain drop down into the pan where it can bunch up on the crank gear

8 reverse procedure to install taking note of the following: the left hand bolt should get loctite and on most models is a stretch bolt (should be replaced)

good luck

Thanks again duxthe1,
When installing the new IP timer gear, is there an index pin or groove or whatever to align to the old timer's position?
D.

Nope there are a lot of very fine splines but no indexing point. The older 617's had them but not the newer 603's. The pump's only indexing mark is the raised tab accessible through the plug in the side. When centered relative to that hole it indicates start of injection for the first cylinder. Really the most important thing to consider when installing the timer is to make sure there is no slack in the chain between the timer and the crankshaft gear when the timer is installed.

The position of the timer is not important, what is important is the position of the injection pump when you tighten the left hand thread bolt. When this bolt is tightened the IP pump should be locked at the assembly point and the engine should be at 15ATDC.

I don't think I'd try this job without the proper factory tool that locks the pump into place - when I bought mine it was only $25 from the dealer.

I don't see any reference to the the left hand thread bolt being a stretch bolt or loctite requirement upon re-assembly, the assembly torque spec is only 40-50 NM. I reused my bolt and did not use loctite.