Degree wheel kits come in...
Degree wheel kits come in many styles and sizes. Just remember, the larger the degree wheel, the easier it is to see and read the measurements, as they are spaced farther apart on the wheel. Horsepower by Hedrick's Mark Hedrick swears by this large Moroso unit.
Like most things we're not familiar with, many look at degreeing a camshaft as some sort of black magic voodoo that only the most expensive of engine builders in brightly lit "clean rooms" know how to perform. We can understand that ourselves because we were, at one point, on the same side of the fence looking in. We too wondered what the heck that big wheel on the front of an engine with all the tiny numbers on it meant when reading our car magazines. What do the numbers mean and why is the guy rotating it back and forth and what's the gauge on the top of the engine for? Sound familiar? Of course it does, and frankly, like asking for directions, the last thing a car guy is going to do is go to his other car guy pals and ask how to degree a camshaft for fear of having his man card revoked. No worries here, as we're about to go through the process, step by step, on this 331ci stroker that we tested at Horsepower by Hedrick in Jacksonville, Florida.
So why do you want to degree your camshaft during a cam swap or engine build anyway? There are several reasons why you'd want to take the time to do so, and honestly it's a fairly easy and quick procedure after you get the hang of it.
First and foremost, when you're building an engine or even just swapping a camshaft, you're working against a stack of tolerances. We've all seen the specs for an engine and they are never an absolute, but more of a "window" if you will, of what's OK. Engine blueprinting, which is a whole other story, is when you take those clearances and ensure they're even across the board (to put the definition loosely). If these machining tolerances were exact from engine to engine, then there'd be no need to degree a cam short of just wanting to advance or retard it on purpose. You'd simply bolt it in "straight up" as they say. But since engines are not that exact, it's a good idea to bolt up the degree wheel and make sure the cam you have is machined like the spec card says, and that any other engine parts, such as the timing chain, cam dowel pin, and crank keyway don't change what the cam specs should be. Essentially, you are verifying the valve opening and closing events are where they should be according to the cam manufacturer's specs.
Bolting on the degree wheel...
Bolting on the degree wheel is your first step. Since you will most likely be adjusting the cam timing (and/or replacing the timing chain and gears to do so) the timing chain cover and front engine dress is removed for access. This engine, being on a dyno, meant just the damper, timing cover, and water pump had to be extricated. If you're doing this in the car during a cam swap, you may need to remove other accessories for degree wheel clearance. Don't wrench down on the crank bolt just yet, as you'll be adjusting the degree wheel in a minute.
To determine true top dead...
To determine true top dead center (TDC) of the engine, you'll need to install a piston stop of some sort. If you're building your engine from scratch and don't have the head(s) on yet, it's easy to install a piston stop, such as the one we're using here. Alternatively, you can install a different kind of stop through the spark plug hole. The degree wheel kit's pointer can be installed now as well. Rotate the crank to approximate TDC, align the pointer with the TDC mark on the degree wheel, and tighten the degree wheel to the crank.
To determine if the cam timing...
To determine if the cam timing is within spec, you need the specs for the cam you have installed. The cam should have a cam spec card in the package, or worst case, most all cam manufacturers have their cam specs on their respective websites listed by cam grind. Here's the cam card for our Trick Flow Stage 2 cam, grind number TFS-51402001. Of importance will be the numbers in the "cam timing" section.
Degreeing your cam can also aid in engine performance by placing the cam's powerband where you use it most. When you see cam specs in a catalog or on a website, the powerband is often shown in a chart or simply listed as "2,500-6,000 rpm." Advancing or retarding the cam can move this powerband lower or higher in the rpm range as needed.
Advancing the cam will bring the power and torque in sooner at lower speeds, but you could see some loss of high rpm power and torque. When retarding the cam, you'll see the opposite, with low-speed power taking a hit to give you that higher rpm charge. Adjusting the timing of the camshaft is easily done on most Ford engines with an adjustable timing chain setup. The crank gear is machined with multiple keyway slots in it, and is marked with the amount of advance or retard, usually in two-degree increments, at each keyway.
Once you've determined the correction amount needed, or the amount of advance or retard you wish to run your new cam at, it's simply a matter of relocating the crank gear to the correct numbered keyway and lining up the cam and crank gears indexing marks. See just how simple the whole process is on this 331 stroker we're building.
To begin degreeing the cam,...
To begin degreeing the cam, true TDC needs to be verified and the degree wheel possibly relocated. Rotate the engine clockwise until the No. 1 piston contacts the positive stop you are using, and mark the degree wheel with a pencil or write down the degree measurement. As you can see here, we have a measurement of 31 degrees.
Now rotate the engine counterclockwise...
Now rotate the engine counterclockwise until you hit the positive stop again, and note the second measurement. In this case, we have come up with 43 degrees. Since the numbers do not match this means we do not have true TDC determined. To correct the degree wheel, divide the discrepancy in measurements by two. So, we have a 12-degree difference, meaning our correction is 6 degrees, or 37 degrees total (you add the correction to the small number and subtract it from the large number).
Carefully loosen the degree...
Carefully loosen the degree wheel and reposition it on the new degree marking, which as we previously noted was 37 degrees. Once you've locked the degree wheel back down you can rotate the engine clockwise again and verify you have 37 degrees as your reading when you hit your piston stop.
You can go back and forth...
You can go back and forth as many times as you'd like, but ensure when the piston hits the stop in either direction that the degree reading is the same. You have now found true TDC and the piston stop can be removed.
For enthusiasts doing a cam...
For enthusiasts doing a cam degree check in their home shop, a solid lifter, or a hydraulic lifter with the oil chamber filled with washers/nuts or epoxy is a simple way to take all play out of the valvetrain for measuring the cam lobe. At Mark's shop, he uses this nifty cam checking tool. It fits in the lifter bore in place of the lifter and comes with adapters for both flat tappet and roller camshafts.
With the tool (or your solid...
With the tool (or your solid lifter and dial indicator base) in place on the intake lobe, rotate the engine over by hand a few revolutions just to make sure the needle on your dial indicator moves smoothly, and the lifter (or tool) does not stick in the bore. If all checks out, you can continue by rotating the engine clockwise until the lifter or tool is on the base circle, or heel, of the cam lobe, and then zero the dial indicator as shown.