Can someone explain degreeing cams

[Oceanside78]

I've watched a few YouTube videos and I'm still slightly confused. Some of the terminology used it out of my league. What are the benefits VS negatives? I see great gains from doing it, why doesn't everyone do it??? Is it that difficult to do?

Thanks gents

 

[Dark02Pony]

in simple terms..degreeing a cam is getting the cam and the crank rotation synchronized. This is pretty much getting your timing set. Not degreeing it will result in either retarded or advanced timing.

 

[oldmodman]

A cam need to be linked to the crankshaft. Generally with a chain, but sometimes with a toothed belt.
There is one "factory correct position" to install it in. Generally signified by aligning two dots. One on the cam and one on the crank sprocket. As you go up in complexity to a single overhead cam, and then to double overhead cams (like the Cobra & Coyote) it gets more complex but still follows the same rules. A small change in the advance or retard on even a set of stock cams can make a large difference in cranking pressure as measured by a compression test. that's why some terminators were HP freaks and some were lower on HP output. The factory cam gears were not the most precisely machined parts in the world.

Now it gets a little (or a lot) more complicated. If you are trying to tune a motor do something other than what the factory desired you can retard or advance any cam. In a multiple cam engine you can retard or advance either the intake cam or the exhaust cam. Some cam designers will give you specific, non factory methods of installing their particular cam.

Plus cams can be adjusted to make more or less horsepower, more or less emissions, better or poorer mileage. It is always a trade off. More horsepower might (or might not) mean more emissions, less mileage and so on.

This just touches the surface. Cam design and performance is a skill that is only learned by experimentation. If you are building an engine and have your heart set on "doing cams" I would talk to your engine builder. Then talk to everyone that you know that has built their own motor. Then talk to the special custom cam department at several cam companies.

At about this time in the project you will feel like just getting drunk.

Wait until sober to make your cam decision.:-D

If you are just going to install a set of stock cams in a mildly modified engine just get the factory service manual and follow the installation instructions.

 

[Oceanside78]

in simple terms..degreeing a cam is getting the cam and the crank rotation synchronized. This is pretty much getting your timing set. Not degreeing it will result in either retarded or advanced timing.

I mean, I get all that (the basic stuff) I just don't understand why people install cams, then when asked, say the didn't get them degree'd. Isn't that just leaving a lot of power on the table for whatever reason?

 

[Oceanside78]

A cam need to be linked to the crankshaft. Generally with a chain, but sometimes with a toothed belt.
There is one "factory correct position" to install it in. Generally signified by aligning two dots. One on the cam and one on the crank sprocket. As you go up in complexity to a single overhead cam, and then to double overhead cams (like the Cobra & Coyote) it gets more complex but still follows the same rules. A small change in the advance or retard on even a set of stock cams can make a large difference in cranking pressure as measured by a compression test. that's why some terminators were HP freaks and some were lower on HP output. The factory cam gears were not the most precisely machined parts in the world.

Now it gets a little (or a lot) more complicated. If you are trying to tune a motor do something other than what the factory desired you can retard or advance any cam. In a multiple cam engine you can retard or advance either the intake cam or the exhaust cam. Some cam designers will give you specific, non factory methods of installing their particular cam.

Plus cams can be adjusted to make more or less horsepower, more or less emissions, better or poorer mileage. It is always a trade off. More horsepower might (or might not) mean more emissions, less mileage and so on.

This just touches the surface. Cam design and performance is a skill that is only learned by experimentation. If you are building an engine and have your heart set on "doing cams" I would talk to your engine builder. Then talk to everyone that you know that has built their own motor. Then talk to the special custom cam department at several cam companies.

At about this time in the project you will feel like just getting drunk.

Wait until sober to make your cam decision.:-D

If you are just going to install a set of stock cams in a mildly modified engine just get the factory service manual and follow the installation instructions.

So, if you install cams, and you use the factory setting, how do you advance timing based on cam position? I mean, I'm not super newb, but by no means an expert. I've always though timing could be advanced/retarded via tuning. Is that a different form of timing? Are you basically just making minor adjustments to get the valves opening sooner?

 

[Oceanside78]

At about this time in the project you will feel like just getting drunk.

I LOL'd hard at this

 

[95gts5oh]

You're just making sure the cam in synced with the crank based upon the valve events given for the cam at .050 lift. Or intake centerline if you choose that, which I don't use. When checking your cam you may notice that you don't have to advance or retard the cam at all if the valve events are within a degree of your intended specs. Honestly it's not hard to do at all, setting up the dial indicator is the most annoying part to me. The last one I did I advanced it two degrees only to find out I needed a bit more clearance on my intake ptv so I retarded it back to 0 or factory "dot to dot" for more clearance. All my specs are still within 1 degree of what was given to me so it's good to go.

Some people advance stock cams for more performance, it's hard to say how much it will actually help but I've heard it does.

 

[thomas91169]

So, if you install cams, and you use the factory setting, how do you advance timing based on cam position? I mean, I'm not super newb, but by no means an expert. I've always though timing could be advanced/retarded via tuning. Is that a different form of timing? Are you basically just making minor adjustments to get the valves opening sooner?

Ignition and fueling timing is what you are changing while tuning.

Cams are mechanically driven by the crankshaft.

You can make very small changes by advancing or retarding cam timing, which will make valves open sooner or later, depending on the results you are going for. There is lots of science behind advancing or retarding camshafts.

Yes, if you throw in aftermarket cams at factory timing, you are leaving power at the table, because degreeing cams allows you to gain some power depending on your setup.

 

[Oceanside78]

You're just making sure the cam in synced with the crank based upon the valve events given for the cam at .050 lift. Or intake centerline if you choose that, which I don't use. When checking your cam you may notice that you don't have to advance or retard the cam at all if the valve events are within a degree of your intended specs. Honestly it's not hard to do at all, setting up the dial indicator is the most annoying part to me. The last one I did I advanced it two degrees only to find out I needed a bit more clearance on my intake ptv so I retarded it back to 0 or factory "dot to dot" for more clearance. All my specs are still within 1 degree of what was given to me so it's good to go.

Some people advance stock cams for more performance, it's hard to say how much it will actually help but I've heard it does.

....I've got so much to learn...

 

[Oceanside78]

Thank you for the replies though. I'm just lost in the sauce. I'm a hands on/visual learner but I don't know anyone local who can show me how it's done. The mystery to me continues lol

 

[95gts5oh]

So, if you install cams, and you use the factory setting, how do you advance timing based on cam position? I mean, I'm not super newb, but by no means an expert. I've always though timing could be advanced/retarded via tuning. Is that a different form of timing? Are you basically just making minor adjustments to get the valves opening sooner?

Cam timing and ignition timing are separate things, you advance or retard the cam using adjustable cam gears/timing sets. On the timing sets the crank will have many keyways that you'll place on the keyway of the crank at TDC. Usually they're marked with a dot which is commonly referred to as "Dot to dot". Well to advance it you look at the crank sprocket and find the keyway marked 2A, to advance it 2 degrees, and slide that on your crank. Then your goal is to match the dot on the cam gear to the crank gear. The dot on the 2A keyway is moved slightly from the factory dot in order to advance the cam. Now this is from a pushrod engine point of view, I haven't degreed a modular yet but it's roughly the same way. And yes you are basically adjusting how soon or late the valves will open and closed when you play with cam timing.

Ignition timing can be changed with tuning but not cam timing.

 

[Oceanside78]

Gotcha, that makes a little more sense, thanks