420SEL Timing Chain: I'm Stuck!
 

OK, I have all four pins out of the two left-side upper guides, and I can't get either one out past the chain and sprocket. The chain has some slack in the approaching side; there are several protuberances in the area which hang up the guide and I can't quite slip it out. the outside guide looks impossible; maybe once I get the inner guide out, the chain will slack enough to let it pass. If anyone can offer advice, now's the time. In several years of reading about this repair, I have never heard this difficulty asked about nor mentioned. Now I stop to eat a steak and asparagus, and wait for the Marines.

IF you've removed the cam followers, and IF you've removed the tensioner, it isn't a big deal to remove the gear and the chain. The reason I mention this is the chain is going to need some slack for the gear to go forward (this is how I did mine). If you didn't remove the tensioner AND the cam followers, there won't be enough slack to do this without possibly operating the valves on the RH side (very very BAD).

Before doing this, mark plainly and indelibly a line on the gear and chain. I thought that I did, but the chain metal is pretty tough, and I almost lost the mark. Marking both sides at this time would not be a bad idea.

The bolt comes off with a little "oomph". To brace it from turining CCW while breaking loose the bolt (obviously, turn the cam AS LITTLE AS ABSOLUTELY POSSIBLE) I used a large screwdriver through the cam gear hole with the top on an inner ridge of the head. I braced it again this way when tightening. You will want to TORQUE this bolt to the proper spec after replacement!!!

I was so paranoid about dropping the plastic parts down the engine that I put small wires through the holes where the pins were so they couldn't fall in without me being able to fish them out. Keeping the pins in a little to hold them will work just as well.