Why you want to "degree" your cams...

1. Which piston do you check for TDC?

A: You do one piston per side. That is all you need. You can choose which one, does not matter. But most people choose 1 on the right, and 5 on the left.

2. At PM (TDC) with the cams journals all lined up is that the compression stroke?
A: That is correct. Cams lobe pointing up meaning both valves are closed as the cylinder fires.

3. Is there a commercial degree wheel that is know to fit without modification on a 308 series car?
Summitracing.com. $25 gets you the 10 inch one.

4. Which valve lobe do you check and how, when and where exactly do you check it?
You do not check the valve lobes. You place the dial indicator stem right over the shims in the buckets. You do not measure valve lift per se, you measure valve shim depression caused by the lobe as they push on the shim

5. What is the deal about switching shims.
A: When the valves are adjusted properly, there is a gap between the cam shaft and the valve shims. Switching valve shims to a thicker one eliminates this gap for the purpose of doing degreeing work if you are using the overlap measurement method. Then you have to swap the shim back out. When you do the center line method as I outlined above, you just leave the original shim in place.

6. If you only check one lobe per shaft which ones are those in each bank.
A: Pick one piston, then you check both valves on that piston. You are basically assuming that the factory has done its job in manufacturing all the lobes relative to each other. That is all you can do.

If I am going to hav to do this I want to do it right. So far after 15 years everything I have done on the car has made it better. I have never touched the cams as the car ran so well and the marks were off just enough I am a sure the last owner had this done. But with my reconditioned camshaft, I have been advised to do this procedure. The car ha been apart for 15 months so might as well do it before it goes back together.

A: 15 months, well what's another day?

 

Hey Guys,

Are the timing marks on the cams and caps specific to each engine? I mean, are they marked after the engine is assembled? If so, this would mean that the marks would not be accurate if a cam (or cams) are replaced, right?

I installed euro cams on my USA '78 GTS. I know I should degree the cams, but even if the marks line up, if the marks are specific to each engine, then these marks would be useless, right?

Thanks

Henry

 

I am guessing here henry but the NOS cam I got had a mark on it. I would imagine when they were made they would have gone into a gig for stamping???? This is very confusing to me, not sure what I will do....

 

All cams have a mark on them for first assembly so that the valves and pistons don't meet up. After that, if you want to, you degree your cams to get perfect timing. In 355s the factory technician even put a chisel mark on the final timing locations on the cams.

 

OK, so the cam markings are not specific to each engine. So to recap...the markings are more or less a guide, but usually very close. The only way to know for sure is to degree the cams.

 

camshaft changes are mainly the work of a professional. we lesser experienced ones shouldn't try anything fancy with that.