Pelican Parts Forums - Help -Cam Sprocket Spacing off - chain cutting into case reinforcing ribs!

Help! When I opened the case on my 68 S engine to inspect chains and install tensioner safety collars I noticed that the drivers side chain was offset toward the passenger compartment so much that the chain was starting to saw through the case's two vertical aluminum reinforcing ribs below the tensioner. It has cut in to a depth of about an 1/8" for about 1/2" of each rib where it is (was) touching. Nor was the chain sitting centered on the chain ramps. Instead it was offset inward so that the outer edge was riding on top of the first of the two raised guides running down the middle of the ramp, instead of in the valley between them.

The PO had just done some tensioner work, I don't know why. (He is an engineer who had the car for 25 years and rebuilt the engine in the 1970s about 30k miles ago (90k total), so I had figured he knew what he was doing - oh well.)

Questions for any Pelican tech samaritans:

1) I am hoping that he simply installed the cam sprocket backwards and that flipping it will fix the problem - the chain is so far out of place I can't imagine it is just missing the spacer shims behind it. Can anybody think of any other causes ? ? ?

(I don't have the straight-edge alignment tool to measure sprocket offset from the layshaft, but after looking in BA's book, I am not convinced that I could effectively get such a precise measurement with the engine in the car anyway. I do know that my set up is wrong and figure anything that moves the sprocket outward is vastly better than what I've got!)

2) Can anyone confirm that I can get enough slack to remove and flip the sprocket by pulling the tensioner, but not the ramps, etc? Also, I really don't want it to slip off the layshaft gear - any hot tips to keep the links on the teeth down there while I am working up top ? ? ?

3) I guess I will also should check cam timing for safety's sake, but do I really need to do that if I mark the exact link and tooth where the chain sits in the sprocket now and return it there ? ? ? This really shouldn't change timing, if I can get the sprocket back on in the right orientation, should it ??? (Assuming it is in time already - this cylinder bank compression tested at 160 psi +/- 5psi for all 3 holes just a month ago (curiously, the other bank tested at only 135psi, but again +/- 5-7psi for all three! (But that is a separate post for another day. . .))).

But Wait, there's more!

I wonder what impact this had on the chain, ramps and my tensioner system:

The tensioner sprocket had unusual wear on its teeth that is not not matched on the other side (the teeth are shiny and skinnier at the tips, but don't look majorly worn, yet. The other side has no shine to it, and looks brand new). I figure I need a new tensioner wheel at a minimum, and probably should rebuild the tensioner too. Any thoughts here ? ? ?

4) The tensioner is part number 901.105.619.0L. Anybody recognize this? It isn't the latest "053" tensioner, though it looks a lot like it, but it isn't the earliest open style either. I thought the in-between version was an "049," but that's not the part number I've got - what else could this be ? ? ?

5) The part numbers are poorly cast and very hard to read due to casting flash, etc. - is this normal ??? The part numbers on the other tensioner stand out perfectly, which makes me wonder if the driver's side tensioner is a cheap counterfeit Taiwan piece that may have contributed to my problem, and that I should just replace with a new "053" and safety collars instead of rebuilding it. (I don't want pressure fed for a variety of reasons.)

6) The chain didn't appear to be injured, but it is a different brand than the other side. Passenger side says "Germany" on the links, Driver's side says "JWIS" or something like that. Am I crazy to think of re-using it? How do I swap in a new chain without splitting the case or throwing off timin ? ? ? Replaceable masterlinks seem shaky to me - are they ok ? ? ? Anybody done this ?

7) I have 6 brown ramps, which should be period correct from the 1970s rebuild. They appear fine, from what I can see. However, there are bits of what seemed like hard plastic up to 1/4" that look like they may be broken bits of ramp material in and around the around the chain area. Weirder still, the sump screen was absolutely clean. If the ramps were breaking up, or if old ones did before, would my windage screen keep these bits from getting down to the sump screen? I saw nothing on the windage screen looking up through the sump plate hole.

8) I have read posts about replacing the ramps without splitting the case, using angled needlenose, etc., but it seems like a nightmare! Anybody done this, and is it really that bad a job? ? ? Can I do it with the engine in the car, but the mounts and tray removed and the case on a jackstand ? ? ?

9) This may be my invitation to the upgraded and bushed late sprocket arm set up, but I am worried about throwing the chain alignment off even more by changing parts around. Also, can I change the sprocket arm without changing the tensioner, or vice-versa ???

That's all for questions, here's background for why I am not doing a $$$ rebuild (or why I believe I don't need to - please feel free to correct me!):

The car is solid overall, but is fairly tired and not original in many ways. I bought it for cheap to use as a guilt-free disposable drivers ed/mild race car ($7k running a bit rough, but a solid tub with a 68 S chassis number and all the right suspension/ brake bits for an S, and WITH a genuine running 901/02 motor with Weber IDSs). Despite all the weirdness described above, I think I caught the problem early enough before any permanent damage. I have enormous faith in the toughness of these engines as long as they are kept to the factory redline and fed cool, clean oil, so I want to keep this job as simple as possible, and only fix the chain situation if I can.
I work on the car in a friend's airport hanger and all my A+P certified mechanic buddies who work on Lycoming air cooled aircraft flat sixes have seen the damage. They tell me that because 1) the engine has good oil pressure 2) the cam lobes look beautiful - smooth, clean and not blued or overtemped, and 3) there are no other signs of oil/ heat damage or wear, that the engine should be fine without further overhaul. They tell me tales how much abuse both engines can take, and that any aluminum shards carved out by the chain shouldn't a problem because: 1) it is a small amount, 2) they should get picked up in the oil screen, then the filter, and 3) that even if some got through the filter to the pressure side, a few small aluminum shards are too soft and malleable to hurt the bearings! Yes, I know it sounds insane, but these are skilled people licensed by the FAA and working on your airplanes!

Any and all help (or reality check) you can offer would be much appreciated.

Thanks, and drive it like you stole it!
David