Did you degree your cam?
10-13-2008, 05:40 PM
#3
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No. I did not. I don't guess it is a must or I would have done it. If I was building a 1200hp motor and reving it to 9k rpm I would. For a daily I don't think it is a neccesity.
This is from cranes website...
What is Meant by Degreeing the Camshaft, and Why is it Necessary?
The term "Degreeing In Your Camshaft" means you are making sure the camshaft's position in the engine coincides with that of the crankshaft, so that their rotation is synchronized. This is the only way you will know if the rise and fall of the pistons properly matches the opening and closing of the valves, so the engine will run properly. A few degrees of misalignment can affect the engine's operation dramatically.
If the circumstances were perfect, one would only need to line up the marks on the timing chain sprockets and the cam would be degreed. In reality, you are dealing with a group of components (the camshaft, crankshaft, timing chain, and sprockets), all with their own standards and tolerances. If these tolerances stack up against you, it could throw you out of alignment. Without degreeing the cam you can never be sure that the parts are in correct position. If you have the tools and expertise, we always recommend that the camshaft's position in the engine be degreed in.
So take it as you will.
This is from cranes website...
What is Meant by Degreeing the Camshaft, and Why is it Necessary?
The term "Degreeing In Your Camshaft" means you are making sure the camshaft's position in the engine coincides with that of the crankshaft, so that their rotation is synchronized. This is the only way you will know if the rise and fall of the pistons properly matches the opening and closing of the valves, so the engine will run properly. A few degrees of misalignment can affect the engine's operation dramatically.
If the circumstances were perfect, one would only need to line up the marks on the timing chain sprockets and the cam would be degreed. In reality, you are dealing with a group of components (the camshaft, crankshaft, timing chain, and sprockets), all with their own standards and tolerances. If these tolerances stack up against you, it could throw you out of alignment. Without degreeing the cam you can never be sure that the parts are in correct position. If you have the tools and expertise, we always recommend that the camshaft's position in the engine be degreed in.
So take it as you will.
10-13-2008, 05:43 PM
#4
Yes, my LE1HL was off by 6*. My new cam was off by 4*.
The again, I spent money on a custom grind cam, so having ICL exactly as designed is important to me.
A retarded cam loses power down low, an advanced cam loses power up high.
In my case, the simulator projected a 13tq loss from the retard and a 7rwhp loss from the advance.
In some cases, an off-the-shelf grind actually produces better results when set advanced.
Granted, you'd have to degree it to know it was advanced in the first place.
The again, I spent money on a custom grind cam, so having ICL exactly as designed is important to me.
A retarded cam loses power down low, an advanced cam loses power up high.
In my case, the simulator projected a 13tq loss from the retard and a 7rwhp loss from the advance.
In some cases, an off-the-shelf grind actually produces better results when set advanced.
Granted, you'd have to degree it to know it was advanced in the first place.
Last edited by James Montigny; 10-13-2008 at 05:52 PM.
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10-14-2008, 01:38 PM
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its not about being serious either. i mean what if the company send you the wrong cam. you have a cam card, degree it and check and see if they made a mistake. it does happen
10-14-2008, 05:45 PM
#10
Offset bushing in the cam gear.
(essentially, you drill the hole bigger and the piece that goes inside offsets the pin forward or backwards)
Oddly enough, that's also how you degree a cam in an LT1.
http://www.compcams.com/Technical/In.../Files/145.pdf
10-14-2008, 09:36 PM
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I degreed my cam. Never did it before, but it was a good learning experience. It helped me understand more about what is going on with the motor, and cam profile. It also will verify that you are where you need to be as far as cam specs you ordered.
You want the specs you ordered right?
It is like measuring push rod length etc. Being precise is a good thing.
You want the specs you ordered right?
It is like measuring push rod length etc. Being precise is a good thing.
10-15-2008, 09:04 PM
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The gears line up with each other dot to dot, it's the cam you rotate.
Offset bushing in the cam gear.
(essentially, you drill the hole bigger and the piece that goes inside offsets the pin forward or backwards)
Oddly enough, that's also how you degree a cam in an LT1.
http://www.compcams.com/Technical/In.../Files/145.pdf
Offset bushing in the cam gear.
(essentially, you drill the hole bigger and the piece that goes inside offsets the pin forward or backwards)
Oddly enough, that's also how you degree a cam in an LT1.
http://www.compcams.com/Technical/In.../Files/145.pdf
and my cam spec'd out exact to what my card said?
10-15-2008, 09:13 PM
#14
That's awesome. I love it when that happens.
Good to hear you at least checked it.
For those who have not seen one. An offset bushing is nothing more than a little cylinder with the center drilled offset from the center.
You drill out the cam gear's drive hole so that the offset bushing fits inside, and the little hole offset from the middle
advances or retards the cam. I didn't quite understand how it works until I watched the machinist put it in.
Then it all made sense.
When I asked how many degrees off it was he looked at me and said "don't matter, you line the cam up and put in
whichever bushing fits" LOL ... I love crusty old machinists ... they have great senses of humor.
He's 100% correct, but still didn't answer my question.... kinda like calling Microsoft tech support.
Good to hear you at least checked it.
For those who have not seen one. An offset bushing is nothing more than a little cylinder with the center drilled offset from the center.
You drill out the cam gear's drive hole so that the offset bushing fits inside, and the little hole offset from the middle
advances or retards the cam. I didn't quite understand how it works until I watched the machinist put it in.
Then it all made sense.
When I asked how many degrees off it was he looked at me and said "don't matter, you line the cam up and put in
whichever bushing fits" LOL ... I love crusty old machinists ... they have great senses of humor.
He's 100% correct, but still didn't answer my question.... kinda like calling Microsoft tech support.
10-17-2008, 06:43 AM
#15
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Every one of the Bullet/Ultradyne cams I have degreed have came in with in 1/2 to 1 degree of where it should be.
One more thing, the lobes I use are assymetrical and will not "degree" the same way. Peak lift is gonna happen 4-6 degrees before the actual centerline. You can't degree the cam by using "peak lift method".
You have to degree it by using the opening/closing points. I suggest just aligning the @ .050 IVC point of the cam with the cam card.
The GM 847 is the same way. Peak lift method will show a 107 ICL but when you do the math with opening/closing pioints you see it is actually on a 111 ICL.
Degreeing a cam is often skipped but really needs to be done to make sure the cam (and everything else like crank key way, bottom gear, upper gear, etc), was made correctly.
This is the one chance to get the cam in the engine right.
Lloyd
One more thing, the lobes I use are assymetrical and will not "degree" the same way. Peak lift is gonna happen 4-6 degrees before the actual centerline. You can't degree the cam by using "peak lift method".
You have to degree it by using the opening/closing points. I suggest just aligning the @ .050 IVC point of the cam with the cam card.
The GM 847 is the same way. Peak lift method will show a 107 ICL but when you do the math with opening/closing pioints you see it is actually on a 111 ICL.
Degreeing a cam is often skipped but really needs to be done to make sure the cam (and everything else like crank key way, bottom gear, upper gear, etc), was made correctly.
This is the one chance to get the cam in the engine right.
Lloyd
10-17-2008, 08:19 AM
#16
My cam guy has a Cam Doctor so he verifies the cams before they ship, leaving his customers to only worry about the timing set really.
I did not degree it, friend was ggoing to bring the wheel from 1.5 hours away andwhen he forgot it I just said the heck with it and went ahead with the project. Seems to have worked out just fine.
I do know it is fairly common to find a degree or two of offset in the stock setup and I have heard of some big offsets in Comp cams.
I did not degree it, friend was ggoing to bring the wheel from 1.5 hours away andwhen he forgot it I just said the heck with it and went ahead with the project. Seems to have worked out just fine.
I do know it is fairly common to find a degree or two of offset in the stock setup and I have heard of some big offsets in Comp cams.
10-17-2008, 08:20 AM
#17
One more thing, the lobes I use are assymetrical and will not "degree" the same way. Peak lift is gonna happen 4-6 degrees before the actual centerline. You can't degree the cam by using "peak lift method".
You have to degree it by using the opening/closing points. I suggest just aligning the @ .050 IVC point of the cam with the cam card.
You have to degree it by using the opening/closing points. I suggest just aligning the @ .050 IVC point of the cam with the cam card.
And glad to hear that Bullet/Ultradyne is doing better at getting things lined up than Comp did.
I suppose the alternate instructions would be
1) Hand cam and cam card to machinist / engine assembler
2) Pay $75
10-17-2008, 08:32 AM
#18
Typically if one were to have a motor that does not run like it should, by knowing they did degree the cam and it came out right, that is one major possibility that can be eliminated so one can move on to the simpler things. A cam that is ground wrong will make the engine run like ****.
My last cam was off by 2 degrees. My current cam is dead nuts on. It took 15 minutes to do BTW.
My last cam was off by 2 degrees. My current cam is dead nuts on. It took 15 minutes to do BTW.
10-17-2008, 01:58 PM
#19
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so did i miss how to do it?? cuz my cam is out right now...geting the cam pin swapped out..
and i have no idea how to get it back in the right spot. (for timing)
it is a bullet solid roller....
can u help me?? lol
and i have no idea how to get it back in the right spot. (for timing)
it is a bullet solid roller....
can u help me?? lol
10-17-2008, 03:19 PM
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Mine too! after I spent 35-40 minutes freaking out wondering how my cam could be that far off and then noticing I was using exhaust lobe
in my defense it was just the shortblock on an engine stand without the heads.
I agree with Lloyd in that it doesn't hurt and your ensuring everything is CORRECT
Its ironic how many folks can't find the time to do things right but they always find time to do it OVER.
Mike
in my defense it was just the shortblock on an engine stand without the heads.
I agree with Lloyd in that it doesn't hurt and your ensuring everything is CORRECT
Its ironic how many folks can't find the time to do things right but they always find time to do it OVER.
Mike
