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ENGINE TIMING

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joe christie

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WHEN YOU INSTALL CAM GEAR AND TIMING CHAIN DOES THE ENGINE HAVE TO BE ON COMPRESSION STROKE TOP DEAD CENTER? OR CAN YOU JUST INSTALL THE TIMING GEAR AND CAM SHAFT GEAR WITH THE TWO BRIGHT LINKS AND TIMING MARKS? SEND RESPONSE TO JOE CHRISTIE AT ARTISTICCPT@AOL.COM
 
Welcome to the Forum...but please STOP SHOUTING! (caps lock off,please).

Can't help you with your timing problem, but as for sending a personal note to you explaining how it's done....that kind of defeats the point of a forum. We *share* info here, so that *all* can read. We hope you'll be able to share some of your knowledge with us too.
 
The engine must be on TDC when installing the chain & sprockets to keep the relationship in phase. Check the chain it has 31 links so that the chain actually walks around the sprockets while keeping them in correct relationship with each other. This is done to spread the wear pattern evenly over all the sprocket teeth and chain rollers. Not sure of the math but a specific tooth and individual chain link roller only see each other once every 1,000 or so revolution not on each revolution as with an even number tooth chain were used.

Regards, Bob
 
If the marks are lined up the cam timing is good. I suppose the crank mark is lined up with TDC. It is not the crank that determines TDC compression or exhaust, though. That is the job of the cam. Turn the crank 360 deg and the cam will turn only 180. You needn't check to see if the piston is at TDC on compression. Get it off one tooth and it will still run, but with very little power. How do I know this?
 
Sorry for the delay, Dave. I forgot to check to see if there were any responses to my post.....
Here is what I tried to explain, but with little success: It is the cam that determines if the piston is at TDC for compression or exhaust. If not for the cam the valves are always closed and the crank doesn't know the difference from one revolution to the next. Put the crank timing mark in the 'up' position and align the cam timing mark with it and the valves will be in only one possible position (and I don't know if it is compression or exhaust). Only by turning the cam through 180 degrees will you be able to reverse the valve position, and if you do that your timing will be 180 degrees off (you can't get it to be 360 degrees off, by the way.--I just threw that in. Nobody indicated otherwise).
As far as the statement I made "how do I know this?" It is a mistake I made many years ago with my previous 100. I wish the misalignment had been as obvious to me when I made it as when I had to open it again to verify the problem!
 
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