How do you set up camshaft to crankshaft timing on a 350 Chevrolet?

Answer 1

Depends on whether you're just talking about lining up timing marks, or whether you're talking about degreeing a hi-performance or racing camshaft. The former is pretty easy and straight forward, the latter is more involved and requires you to have a degree wheel, TDC stop, a dial indicator with 1" travel, and a fixture to mount the dial indicator in such a way as to measure the valve opening and closing events, and you need to to know how to use this measuring equipment.

When degreeing a camshaft everything is referenced from Top Dead Center (TDC) and if you don't know how to find this exactly then everything else will be off.

To find exact top dead center you place a TDC stop on the top of the #1 cylinder (if the engine is in the car with the heads on the TDC stop screws into the spark plug hole and this entire operation is much more cumbersome than if you were doing it to an engine on an engine stand), then you bolt a degree wheel on the front of the crankshaft, then you turn the engine *by hand* (NOT WITH THE STARTER! NEVER EVER USE THE STARTER WHILE A TDC STOP IS IN PLACE -- Disconnect the battery before you even put a TDC stop in place!), turn it by hand until the piston is up against the TDC stop and then mark the degree wheel where it lines up with a pointer that you can fabricate from a coat hanger or piece of wire, then you turn the engine backwards until the piston is up against the TDC stop again and mark the degree wheel again, exactly half way between those two marks is TDC, so for example if the degree wheel reads 41 degrees BTDC on one side and 39 ATDC on the other you have to move the pointer one degree and check again until it reads exactly the same on both sides of TDC. Then remove the TDC stop and make sure you do NOT move either the pointer or the degree wheel until you've finished degreeing the cam -- otherwise you have to go through this routine again to find exact TDC.

***This is also the best method to see if your timing pointer and harmonic balancer timing marks are right***

Most camshafts have a sheet with the valve timing and of course if you know what you're doing you can deviate and run the cam timed wherever you like. You have to start somewhere so just put the cam in and line up the marks on your timing chain, gear drive, or belt drive -- whichever you are using.

Put a lifter in the intake lifter bore and if the head is on put a pushrod in, then line up your dial indicator over the pushrod so it moves when the lifter/pushrod moves. Now slowly turn the engine over and when the lifter is just short of the top of it's travel you zero the dial indicator and mark the degree wheel, then roll the engine over slowly past full lift until the indicator comes back to where you zeroed it as the pushrod/lifter is just starting to move back down on the closing side of the cam lobe and mark the degree wheel again. Exactly half way between those two marks on the degree wheel is your intake lobe centerline. Example: Suppose the degree wheel reads 85 degrees ATDC on the opening side and 135 degrees ATDC on the closing side -- 85 + 135 = 220... 220 / 2 = 110, so the intake lobe centerline is 110 degrees. If it's not where you want it you'll have to advance or retard it until it is. You can do so with bushings in the cam gear or multi-keyed crank gears, etc.

Then check again.

There's other methods as well, for instance some cam companies say to degree their cam by the .050 opening point so you zero the indicator over the pushrod and turn the crank until the lifter/pushrod has moved exactly .050 from the closed position and read the degree wheel. Most however use the Intake lobe centerline method explained above.

Have fun!