Cam Chain Too Tight?

[luckynumber0]

Hey all,

Was in a great mood this morning as I began wrapping up my rebuild on an '82, which all began due to a worn cam chain guide. Everything has been smooth so far - cleaned everything like never before, replaced rings, replaced cam chain & guide, got barrels honed & head inspected/cleaned/valve job (inc. seals) at a very good machine shop, and have been taking my time with everything so as not to screw anything up.

Well, today everything went back together with ease but when it came time to put the cam chain on the cam, i noticed that when I aligned the crank to TDC via the rotor, the chain was not even. Luckily there seems to be enough for me to link them with the cam & crank in correct positions and on top of this the chain is much too tight to meet for the master link.

I read on here that the Athena head gasket from mike's is thicker than OEM, which would make sense because the amount of give that the two ends of the chain would need to meet is quite small...however it doesn't want to give.

I thought about taking the bearings off one side of the cam, linking them up, and then lifting the cam and shoving the bearings on once it clears.

Anyone have any experience with this? Also, did I fuck up putting on the new cam chain somehow if where they meet is not at the index mark on the cam when aligned in TDC?

 

[5twins]

The chain doesn't have to meet right over the index mark. It really doesn't matter where it links together although it's easier to work on it if it is somewhere near the top of the sprocket. Yes, a new chain will be very tight and will most likely need one end pried over that last sprocket tooth. It helps if you add some spacers to at least 4 of the long studs and partly bolt them down (you don't need the full head torque on them). You have a new base gasket too and all the parts are loose. You need to pull all that stuff down together tightly. Then the chain should go on for you.

 

[luckynumber0]

5twins -

That's a relief. Thank you for your ever-helpful responses.

Just out of curiosity, when you do top ends is it part of your method to wind up with the chains linking together at the top of the cam sprocket (for convenience)? I did the trick of linking old & new chain together and running it through because splitting the cases wasn't on the agenda. I'm wondering exactly where I made the blunder...

 

[5twins]

I don't think you've blundered. I try to get the chain to meet somewhere near the top of the sprocket but once it has met and you slip the master link in, you can rotate the motor a little and bring it right to the top to work on riveting the link. Like I said, it doesn't matter where you make the chain meet, as long as the notch on the cam sprocket is correctly pointing up (cam timing correct) when and where you fit the chain.

 

[XSLeo]

A new chain is packed with grease. This makes the chain tight at first. This helps prevent excessive wear at first running.
As the engine runs a bit the grease squeezes out as oil soaks in.
Go ahead and pull of the bearings on one side. Install the link in the chain. Then lift the cam back up and slide the bearings back on.
If might be a bit tough to lift it all the way back up. Use a large Phillips head screwdriver. I use a #3.
Once you have the chain and cam in place check the timing mark. The notch should be straight up. On the other side of sprocket is a dot or dimple, this should line up with the sealing surface.
Leo