Ok, right now the cam is installed in the engine, which is a 350 SBC block, and i have a question on how to set the cam timing. Now, I've read instructions on setting the timing, and setting it dot to dot on the cam sprocket vs crank sprocket. And when i do that, the number 6 cylinder should be at TDC on compression stroke correct? When i actually look at the piston position when taking the head off, the number six cylinder is not at TDC at all. And the number one cylinder is almost all the way down. When i turn the crank sprocket to the -4 degree mark and line that up with the cam sprocket dot, the number 6 cylinder is actually at TDC. Is this where i should set it to? Maybe im thinking about this wrong, but any help would be appreciated.

Thanks.

 

you need to loo kat the instructions that came with your timing set to know what key and mark to use. my guess is you're using the wrong mark for the key way.

 

well, im using a Cloyes True Double Roller Timing set, and the instructions specify that for factory specified timing, i should use the O timing mark on the crank sprocket, and line that up with the dot on the cam sprocket. Which is where the situation above comes into play.

 

Somthing's odd. #1 and #6 will always be in same position in their bores at all times (If one is at TDC the other will be, too. If one is at BDC the other will be too). Only difference is the valves- one is always 2 strokes ahead of the other- TDC compression vs. TDC exhaust, etc.

#1 is the front-most cylinder on the driver's side. #6 is next-to-back cylinder on the pass. side.

Now....

You should determine TDC of the #1 cylinder before installing the timing chain. VISUALLY make sure #1 piston is as close to TDC as you can determine by eye- your eye is better at this than you might think. The timing mark on the lower timing gear should now be pointing straight up at the middle of the cam (and the keyway in the crank should be pointing 45* to the left, directly at the middle of the #1 piston. ALL SMALL BLOCKS ARE LIKE THIS REGARDLESS OF YEAR OR DISPLACEMENT- you can rely on this rule-of-thumb.)

Now install the chain and upper timing gear with the dot pointing straight down, directly opposed to the dot on the crank gear. Roll the engine back and forth a few degrees either direction to make sure the dots "pass" eachother truly at the straight up and down position. If you're off by one tooth on the chain it will be obvious by doing this- they will pass eachother either significantly off to the left or right of true straight up.

NOW you have installed it correctly and you are at TDC of the compression/power stroke (on #6- both valves fully closed) or TDC of the exhaust/intake stroke (on #1- both valves slightly open). That is to say, correct at least as far as the timing chain installation is concerned. If you want to degree the cam to assure it's dead-nuts-on you can now do it and determine if you need a little advance or retard dialed in at the chain to hit the cam specs exactly.

 

Didn't you mean the keyway should be pointing 45* to the RIGHT at the middle of the #1? It really makes a difference when people are bolting things together based upon what you type.
The Cloyes set can be set up for 0' or +4 or -4 or +8 or -8 degrees cam timing. It has to do with the 3 keyways and the "triangle" the "dot" and the "bar" timing marks.

 

Thank for the great explination. I made sure that the #1 piston was at TDC, then checked where the mark on the crank sprocket. it was dead on where the -4 degree mark was though, im assuming the sprocket might have just been put on with the wrong keyhole. But the notches on the crank, where the sprocket slides over is pointing directly to the #1 cylinder. And yes supervisor42, i do believe he meant to the right, not left. After i put the chain on, i checked by rolling the crank, and making sure the marks passed each other correctly, and they did. So everything seems good to go on that part now, and thanks again guys.