Cam Degreeing-mystery?

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tooslow

tooslow

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If you buy a cam with a centerline of 108 why would you put it in at 106 0r 110???
Why not put it in at 108??
How do you no what to put it in at??
 
You need a degree set that includes a dial indicator, and degree wheel. I prefer the Mopar Performance degree wheel because you do not have to divide by 2 to get where the camshaft is. It is a 180 degree wheel and reds directly instead of a 360 degree wheel. Camshaft makers recommend advancing most cams mainly because people tend to choose too large of a camshaft to begin with and they know that most people will probably not degree the camshaft in. So, it gives the customer who just stabs it in "straight up" a decent running engine. It is important to also know that most camshaft companies grind 4 degrees advance into the camshaft to begin with. This is why it is important to degree a camshaft in for best performance. Because the camshaft can actually end up being as much as 8-12 degrees advanced when the ground in advance plus the recommended advance gets added together. I use a compression gauge in conjunction with a degree wheel to get the best cranking compression pressure. It has worked very well for me.
 
Technically, you're right.. Why not have what you wanted? In most cases, moving the cam a few degrees one way or the other will change the rpm and power curve in terms of flattening or making it more peaky. So moving the intake's installed centerline becomes a tuning tool. A way to play with the power curves.
 
StrokerScamp said:
You need a degree set that includes a dial indicator, and degree wheel. I prefer the Mopar Performance degree wheel because you do not have to divide by 2 to get where the camshaft is. It is a 180 degree wheel and reds directly instead of a 360 degree wheel. Camshaft makers recommend advancing most cams mainly because people tend to choose too large of a camshaft to begin with and they know that most people will probably not degree the camshaft in. So, it gives the customer who just stabs it in "straight up" a decent running engine. It is important to also know that most camshaft companies grind 4 degrees advance into the camshaft to begin with. This is why it is important to degree a camshaft in for best performance. Because the camshaft can actually end up being as much as 8-12 degrees advanced when the ground in advance plus the recommended advance gets added together. I use a compression gauge in conjunction with a degree wheel to get the best cranking compression pressure. It has worked very well for me.
Click to expand...

I should advance or retard the cam until i get the highest compression reading. This a good rule of thumb??
Do some of you guy's actually install the cam, put the engine together, drive it, then take it apart, change the centerline, and do it all over again?
Really??
Can't the cam manufacturer tell you what to install it at if you provide your combination?
 
I haven't kept up on this stuff, but once upon a time, maybe still yet, there was a manually variable cam tuning setup where you could go into the timing cover through removeable plugs and change the cam timing.

Years ago there was a centrifugal operated cam timing deal, "varicam?" that worked sorta like your mechanical advance
 
tooslow said:
I should advance or retard the cam until i get the highest compression reading. This a good rule of thumb??

Ehhhhhh....sorta. lol It all depends on what you're doing. You don't wanna keep advancin it til it won't ru on pump gas. MOST of the time, what will happen is you keep advancing it until the cylinder pressure drops off. BUT, depending on how the cam is ground, that don't always happen real quick. It's somethin you kinda have to have done a number of times to get the hang of it.

Do some of you guy's actually install the cam, put the engine together, drive it, then take it apart, change the centerline, and do it all over again?
Really??

No. Nodoby said or even implied all that. Like I said, it all depends on your level of skill. Most people simply degree the cam where the timing card says and leave it at that. And that's a fine way to do it. But there's more tweakin to be had usin that compression gauge in conjunction.

Can't the cam manufacturer tell you what to install it at if you provide your combination?
Click to expand...

It's all a "best guess". Every single engine is different. Even two built the same identical way using the same parts and same machine work. No two are the same.
 
67Dart273 said:
I haven't kept up on this stuff, but once upon a time, maybe still yet, there was a manually variable cam tuning setup where you could go into the timing cover through removeable plugs and change the cam timing.

Years ago there was a centrifugal operated cam timing deal, "varicam?" that worked sorta like your mechanical advance
Click to expand...

Several modern engines have that now. Variable valve timing of some sort. I know Toyota has had it since about 1990. You can still get timing covers like that.......for the chebbie of course.
 
Cam timing basically only affects where the power band is and when an engine makes its peak power. If the car is heavy and the converter isn't loose enough then advancing the cam can bring the power on sooner, or if it's got too loose of a converter or a too steep rear gear then you can retard it to make peak power at a higher RPM. You can't change it a lot though. Maybe 200/400 RPM.

If you install a cam ground on an 108 centerline at 104 then you have advanced the cam 4 degrees.

BTW the lobe centerline is the degrees between peak lift on the intake and peak lift on the exhaust, just wanted to make sure we covered the basics. :)
 
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