Degreeing Cams

[Rat72]

I'm installing a new cam in my BBC. I thought I would try something new and degree it but between tools and hassle, I wonder if it's worth it? Comp Cams says they advance all their cams by 4 degrees. So the stock options are 0, 4, and 8 degress unless I use cam degree bushings. Is it really worth the $100 in tools and time to do this. I would be done by now if I just lined up the marks and called it good?

Oh, and what is this cam button they talk about in their install directions. The motor didn't have one of those before, is it needed?

Thanks,
Whit

[Kid]

if it's worth doing, it's worth doing right.
Degreeing the cam is just 1 of many things to varify when building, blue printing a quality motor. Sure a motor will run with out being blueprinted, (or degreed) but there is a reason when 2 motors of the same size, 1 will perform better than the other.
Cam, crank, timing gear machining tolerances all contribute to the cam timing relative to crankshaft. "Degreeing" the cam measures this acumulation of tolerances, then with offset keys or bushings, you can get the cam installed where it was designed to be relative to the crank & ignition timing.

[OleBlue69]

It's your call. If you're going to be drag racing, then you will want to degree the camshaft. If it's a streeter, then not necessary.

Changing the cam advance is basically like changing what rpm range your "powerband" is at. So if you retard the cam slightly you're powerband would go up in rpm range, and advancing it will give you more bottom end. Wait that may be backwards, I'm tired so I'm getting confused. Somebody correct me if I'm wrong. But regardless if memory serves me right changing the cam degrees by a difference of 3-4 makes a difference in about ~500rpm I think. So no major change in performance characteristics.

Well I'm tired and might just be getting you more confused, so I'm going to call it a night... Hope this helps.

[Billla]

The short answer is no, you don't need to degree a cam if you are installing the cam in the stock position. You should align the timing marks and turn the crank until the marks line up again to be SURE you've correctly indexed the sprockets.'

The cam button they're talking about is a bearing that fits on the nose of the cam to keep it from walking back and forth in the cam bore. The question of needing it or not depends on the cam, the use and the front cover you're using.

[Rat72]

Both recommendations are logical. I've looked into degreeing the cam and it looks like a reasonable effort. But the bigger effort seems to be installing the springs. The kit came with springs and I have the tools to pull the springs and measure the heighth. Again I'm tempted to leave it alone. The current spings are matched for the old cam and are dual spings to support .560 lift. The new cam is only .520 lift and my guess is that the old springs would work just fine. Is it worth the effort to replace them with the matching spings I got with the comp cam kit. Install is easy but installing them to the correct height may be an issue. Should I expect a problem? Will I be adding shims or grinding out the base?

Thanks,
Whit

[Billla]

There are a lot of variables on the springs to consider - installed height, seat pressure, open pressure, etc. I agree that you SHOULD be OK, but if I was building an expen$ive BBC I wouldn't skimp on the work to replace the springs. Why not just use a spring compressor to swap out one spring and see if there are any fitment issues?

Originally Posted by Rat72

Both recommendations are logical. I've looked into degreeing the cam and it looks like a reasonable effort. But the bigger effort seems to be installing the springs. The kit came with springs and I have the tools to pull the springs and measure the heighth. Again I'm tempted to leave it alone. The current spings are matched for the old cam and are dual spings to support .560 lift. The new cam is only .520 lift and my guess is that the old springs would work just fine. Is it worth the effort to replace them with the matching spings I got with the comp cam kit. Install is easy but installing them to the correct height may be an issue. Should I expect a problem? Will I be adding shims or grinding out the base?

Thanks,
Whit

[Rat72]

Originally Posted by Billla

There are a lot of variables on the springs to consider - installed height, seat pressure, open pressure, etc. I agree that you SHOULD be OK, but if I was building an expen$ive BBC I wouldn't skimp on the work to replace the springs. Why not just use a spring compressor to swap out one spring and see if there are any fitment issues?

You're right, it won't take much effort to see see if I'm on track. Crap, this is exactly the way I started a total rebuild on the last motor.

Thanks.
Whit

[Billla]

Originally Posted by Rat72

You're right, it won't take much effort to see see if I'm on track. Crap, this is exactly the way I started a total rebuild on the last motor.

Thanks.
Whit

ROTF, L! Sorry, Whit - I know the "while I'm in there" feeling. Go to change a spark plug and all the sudden the distributor is on the bench torn down ;-)