You plop down big bucks for a fresh GoWesty rebuilt engine, get it installed, and... your shop just can't get it to run right. The compression and leak down test good (they should—it's a fresh engine, after all!), and there are no strange noises, knocking or otherwise. The shop tech says, "You know, it might be the cam timing..."
Every so often, we get a report from an installer of one of our engines that they just cannot get it to run correctly, and they suspect the cam timing is wrong. It is, in fact, possible to assemble a waterboxer and get the synchronization between the cam and crank gears wrong—but it is extremely unlikely, and here's why:
In this photo of the cam, you can see the timing dot at 9 o'clock (circled in red):
You can also see the slot in the "face" of the cam, and this slot drives the oil pump. It is lined up with the timing dot.
Here is a photo of the crank gear, where you can see two dots opposite the woodruff key slot (circled in red):
When assembling the engine, the dot on the cam gear is placed between the two dots on the crank gear. At this point, the cam gear mark, crank marks, woodruff key/slot, and oil pump drive groove on the face of the cam are all lined up perfectly with the engine block halves' parting line. In the next step, the engine assembler has to rotate the crankshaft 90 degrees to make sure the cam and crank gears did not slip any teeth after the engine block halves are together (and the dots are no longer visible). All you have to do is rotate the crank back 90 degrees and make sure everything lines up the way it should.
This is relatively simple, but some people just have to check it for themselves—because, well, they just cannot get the engine to run right, and they are convinced they have exhausted all other options. (How do you figure out which component is causing the problem anyway?!) It must be something wrong with their new GoWesty engine—probably the cam timing, right? (Wrong.) But if you absolutely must check the cam timing, here's how to do it without removing the engine and tearing it completely apart (which would void your warranty, so don't do that!):
- Remove the pulley, coolant X-pipe, and oil pump.
- Rotate the engine so the oil pump drive slot on the cam is straight up and down (6 and 12 o'clock) and lined up with the engine block halves' parting line.
- Check the woodruff key/slot on the crank—it will be very close to 12 o'clock and lined up with the case halves if the cam/crank gears are synchronized correctly.
Note: There are 25 teeth on the crank gear. The cam/crank gears can be off by increments of only one entire tooth—no less. You are not looking for a very slight amount of off-vertical—it will be way off if the cam/crank synchronization is not correct. The woodruff key/slot on the crank will be off vertical by 14.4 degrees for every tooth that is off between the cam and crank. If it's only off one tooth, the key/slot will be off-vertical by 14.4 degrees to the left or right. If it is off by two teeth, the slot will be off-vertical by 28.8 degrees. Three teeth and the woodruff key/slot will be off-vertical by 42.2 degrees. As a reference, 11 o'clock and 1 o'clock on a watch dial are off-vertical by 30 degrees. Thus, two teeth off and the crank slot would be pointing to either 11 or 1 o'clock.