front cam chain tensioner

[spawningvat]

Here's the history: My cam chain skipped and bent the #2 exhaust valve. I pulled everything necessary to get the head off the engine. I replaced the valve, reassembled everything, and set the valve cover on the engine.

Heres the problem: The valve cover does not lay flat on the head. It is held up by the front cam chain tensioner/supporter/runner. It is the slightly curved plastic piece that sits vertically at the front inside the engine. It has 2 circular ears that hold it in place level with the top of the head. Well mine is up about 1/32" of an inch.

Does anyone know if it can be snapped in incorrectly at the bottom of the engine? Any pictures of this joint?

So far I've tried tapping it down, pressing it down, lifting it about 1/4" and shoving it down, and threatening it. I've spun the engine over with no problems, and no funny noises, but i don't want to button it up and then have leaks and/or bent covers.

Any advice, pictures, hints, or ideas?

Thanks in advance.

/s/ Sean

[bwringer]

What sort of engine are we discussing? 1943 Hupmobile?



Assuming it's a GS of some sort, the front blade generally wants to sit a little tall in the slot, but can be pushed into place with finger pressure, and is held in by the valve cover. So your situation ain't right, unless you left out the head gasket or something.

If it wants to sit taller, the most likely explanation is that the cam chain isn't completely seated around its sprocket on the crankshaft. Place some tension on the chain by hand and rotate the crankshaft a bit. You might feel the chain drop into place, and you should be able to push the tensioner blade into position.

The cam chain can also get bunched up around the crank in unexpected ways -- once you feel like the chain is seated on the sprocket, rotate the crank another turn or two while keeping hand tension on the chain and feeding it through.

[spawningvat]

oh yea...

... the bike model helps. Its a '79 550e. It has the stock 8 valve engine in it. The head gasket is in place. The chain is currently under tension and the timing is set correctly. Even still, that front piece won't fall into place.

I'm wondering if there are multiple lower positions for that front guide and i'm in the wrong position? And being perfectly honest, I had those cams on and off too many times to count, and really don't want to have to pull them again. Maybe, just maybe, someone had this same problem, and knows what/how to fix it.

/s/ Sean

w/ a '79 550e

[Guest]

could the skipped chain have done some other damage, possibly to the housing of the said tensioner blade

[gustovh]

The front slipper is not in correctly. If it is not seated properly in the bottom of the engine, no way will the valve cover seat properly. remove it and try reinserting the slipper, you should be able to seat it with finger pressure. You will know when it is proper, it will be flush with the top of the head and the valve cover should lay flat. Another thing to look for is the tac gear mateing with the cam properly, if it doesn't the valve cover will not lay flat either.

ask me how I know.
V

[rphillips]

Be sure there is plenty of slack in the cam chain, on the front side while trying to get this resolved.

[POULSEN]

I don't have any other suggestions than already stated. But I hope a few pictures of my GS550 '77, could help you. The construction is fairly simple:


and a photo of "3" and "4":

and with the chainguide inserted:

Since I obviously have the head and cylinders off rigth now, let me know if You want additional photos or measurements.

Best Regards
Stig Poulsen

[spawningvat]

Poulsen: Those pictures are excellent. I found the microfiche but it wasn't detailed enough. However, your pictures are extremely detailed. The bike is all back together, and running beautifully. I didn't notice any blatant oil leaks. Here's the completion thread:

http://www.thegsresources.com/_forum/showthread.php?t=122056

Thank you for the help.

/s/ Sean