how to degree a cam
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how to degree a cam
ok this is gonna sound stupid, but i don't really care...
i've read many threads about degreeing a cam. i haven't found a good concise answer to how important doing this is. i have done a few ls1 cam swaps now and i have never degreed a cam...simply installed it dot to dot. through these swaps it is noticeable that the timing chain (even some aftermarket) are very loose on the cam gear. i have read people say if its dot to dot it is fine, and some call those people idiots and say it must be degreed to make sure it is setup correctly. if someone could educate me on who is right or wrong i would appreciate it...
i've read many threads about degreeing a cam. i haven't found a good concise answer to how important doing this is. i have done a few ls1 cam swaps now and i have never degreed a cam...simply installed it dot to dot. through these swaps it is noticeable that the timing chain (even some aftermarket) are very loose on the cam gear. i have read people say if its dot to dot it is fine, and some call those people idiots and say it must be degreed to make sure it is setup correctly. if someone could educate me on who is right or wrong i would appreciate it...
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Not a stupid question at all. In fact, one of the best I've seen in a long time.
How important is it? Extremely. No person or shop worth their salt installs a camshaft without using a degree wheel. Don't get me wrong, I'll admit I have done it. It isn't the smartest thing to do by any means. If every manufacturer stuck to the same tolerances and actually held them, you wouldn't need to. Unfortunately that is not the case and never will be.
People around here obsess about every 1-2hp they can make, sometimes spending hundreds of dollars for less than a 5hp gain. Many of those same people just slap in the cam and call it done.
You will never know if it is correct unless you degree it. There is no other way. I've seen several cams installed "dot-to-dot" that were found to be off once they were checked with a degree wheel.
In short "dot-to-dot" will work, but it is a sloppy shadetree way of installing a camshaft. If you're going to do it, do it right.
How important is it? Extremely. No person or shop worth their salt installs a camshaft without using a degree wheel. Don't get me wrong, I'll admit I have done it. It isn't the smartest thing to do by any means. If every manufacturer stuck to the same tolerances and actually held them, you wouldn't need to. Unfortunately that is not the case and never will be.
People around here obsess about every 1-2hp they can make, sometimes spending hundreds of dollars for less than a 5hp gain. Many of those same people just slap in the cam and call it done.
You will never know if it is correct unless you degree it. There is no other way. I've seen several cams installed "dot-to-dot" that were found to be off once they were checked with a degree wheel.
In short "dot-to-dot" will work, but it is a sloppy shadetree way of installing a camshaft. If you're going to do it, do it right.
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my question...
if you install a cam dot to dot...if it were off one link on the chain it is very noticeable...so say you degree a cam, how can the end result be any different than installing dot to dot? with the slack that remains in most timing chains (stock and some aftermarket) if the cam is not installed correctly how can you fix the situation...it doesnt make sense to me.
is degreeing a cam more to see if it installed correctly, or more to see if a cam is indeed the specs that it is ground for...
in the end, if the cam is ground correctly, is installed dot to dot...then how can that be a problem?
if you install a cam dot to dot...if it were off one link on the chain it is very noticeable...so say you degree a cam, how can the end result be any different than installing dot to dot? with the slack that remains in most timing chains (stock and some aftermarket) if the cam is not installed correctly how can you fix the situation...it doesnt make sense to me.
is degreeing a cam more to see if it installed correctly, or more to see if a cam is indeed the specs that it is ground for...
in the end, if the cam is ground correctly, is installed dot to dot...then how can that be a problem?
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I have put many cams in LS1's an even more others.
No ryme or reason, installed dot to dot & have been 1-4 degrees off.
The cam is ground with a purpose to open & close valves at the correct time in crankshaft degrees. This is how it's power band is determained for a particular grind/lobe.
If it is not truely in time (degreed in) how can you expect it to perform exactly as intended?
Once you have the tools to degree one in & see how relatively easy it is even in car, you wont mind doing it.
+ if somethings "off" in your car you know the cams dead on.
No ryme or reason, installed dot to dot & have been 1-4 degrees off.
The cam is ground with a purpose to open & close valves at the correct time in crankshaft degrees. This is how it's power band is determained for a particular grind/lobe.
If it is not truely in time (degreed in) how can you expect it to perform exactly as intended?
Once you have the tools to degree one in & see how relatively easy it is even in car, you wont mind doing it.
+ if somethings "off" in your car you know the cams dead on.
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#8
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As denzSS said, you will not know if it is "correct" unless you degree it in. "Correct" meaning: was the cam ground(ie. valve timing events)to what the cam card states. Most often they are "close", but rarely exactly cut to spec.
In order to degree in your cam on an LS1, you'll need an adjustable timing set. Not everyone does this. Is this "wrong", or "shoddy"?. IMHO....no. In the "olden" days, you really needed to degree in the cam to ensure valve timing events were where they needed to be per a specific application... with today's technology in the tooling/ manufacturing process, it is not unreasonable to install your cam dot to dot, and be relatively confident that it is w/in the window.... given this part of the install was done right..... TDC on #1, 6/12 o'clock.... and valve lash/pre-load is adjusted accordingly.
Sure.... a d2d install, back checked w/a degree wheel will most often always show that further adjustment is necessary to provide maximum efficiency/gains, but from my experience(on an otherwise stock bottom)the gains are negligable. If using a quality non adjustable gear set, unless you're off a tooth... it's gonna be real close.
With all that said, for a simple slip n' slide, d2d will work fine for most, although it's always a good idea to check the cam profle via a cam Dr. to insure it really is(or at least is reasonably "close")to the lift/dur. specs stated on the card to ensure your 232/601 cam isn't really a 248/621(just an example but you get the idea). If you're building a max effort motor, where other "things" have been changed(ie: stroke/dish/cc volume etc...)you should indeed install to the degree wheel to be sure.
In order to degree in your cam on an LS1, you'll need an adjustable timing set. Not everyone does this. Is this "wrong", or "shoddy"?. IMHO....no. In the "olden" days, you really needed to degree in the cam to ensure valve timing events were where they needed to be per a specific application... with today's technology in the tooling/ manufacturing process, it is not unreasonable to install your cam dot to dot, and be relatively confident that it is w/in the window.... given this part of the install was done right..... TDC on #1, 6/12 o'clock.... and valve lash/pre-load is adjusted accordingly.
Sure.... a d2d install, back checked w/a degree wheel will most often always show that further adjustment is necessary to provide maximum efficiency/gains, but from my experience(on an otherwise stock bottom)the gains are negligable. If using a quality non adjustable gear set, unless you're off a tooth... it's gonna be real close.
With all that said, for a simple slip n' slide, d2d will work fine for most, although it's always a good idea to check the cam profle via a cam Dr. to insure it really is(or at least is reasonably "close")to the lift/dur. specs stated on the card to ensure your 232/601 cam isn't really a 248/621(just an example but you get the idea). If you're building a max effort motor, where other "things" have been changed(ie: stroke/dish/cc volume etc...)you should indeed install to the degree wheel to be sure.
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Go to Cranes website and they give you the 2 ways of degreeing a camshaft, Centerline method and Duration method. Duration method is preferred due to the fact that asymetrical lobes can not be degreed in accurately by centerline. With variables like crank key index, timing set phasing, and correct lifter bore angle, you are best to degree the camshaft always.
Chris
Chris
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Originally Posted by Cstraub
Go to Cranes website and they give you the 2 ways of degreeing a camshaft, Centerline method and Duration method. Duration method is preferred due to the fact that asymetrical lobes can not be degreed in accurately by centerline. With variables like crank key index, timing set phasing, and correct lifter bore angle, you are best to degree the camshaft always.
Chris
Chris
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Re: cam doctor, none of the farmers around here have one.
My position is this: if you care about performance, degree the cam. If all you want is a nasty lope to scare ricers, go d2d. Having said that, if you don't have a kit, or have a friend with one, you are going to have to pop for a wheel, indicator, and mag base - about $90 and up - to degree with. I just degreed my new cam. It was off less than a degree, which is more than close enough for casual use. I am impressed with the progress in manufacturing tolerance in the last couple decades.
My position is this: if you care about performance, degree the cam. If all you want is a nasty lope to scare ricers, go d2d. Having said that, if you don't have a kit, or have a friend with one, you are going to have to pop for a wheel, indicator, and mag base - about $90 and up - to degree with. I just degreed my new cam. It was off less than a degree, which is more than close enough for casual use. I am impressed with the progress in manufacturing tolerance in the last couple decades.
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This is one of the most help full threads ive read a week on ls1 tech and ls1.com. The only thing I dont understand is.....if the cam is off just a little in degrees, dosn't the cam position sensor correct and fuel and air readings with the vales opening as they are?
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so it is possible for a cam that is ground correctly to be installed dot to dot and still be installed wrong?
say i have a stock timing chain, cam, and degree wheel...
if the cam is correctly ground, i have it installed dot to dot, and after degreeing it i find something is not right...how do i remedy this problem? i dont see how anything can be adjusted with a stock timing chain...if this occurs is the cam not ground correctly?
say i have a stock timing chain, cam, and degree wheel...
if the cam is correctly ground, i have it installed dot to dot, and after degreeing it i find something is not right...how do i remedy this problem? i dont see how anything can be adjusted with a stock timing chain...if this occurs is the cam not ground correctly?
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Originally Posted by mikemodano9c
so it is possible for a cam that is ground correctly to be installed dot to dot and still be installed wrong?
say i have a stock timing chain, cam, and degree wheel...
if the cam is correctly ground, i have it installed dot to dot, and after degreeing it i find something is not right...how do i remedy this problem? i dont see how anything can be adjusted with a stock timing chain...if this occurs is the cam not ground correctly?
say i have a stock timing chain, cam, and degree wheel...
if the cam is correctly ground, i have it installed dot to dot, and after degreeing it i find something is not right...how do i remedy this problem? i dont see how anything can be adjusted with a stock timing chain...if this occurs is the cam not ground correctly?
#18
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Yes, you can grind the perfect cam and it can be off. Example the lifter bore index is off by 3 degrees + or - so this will throw off phasing.
With the stock sets you can drill out the dowel hole as Carl has stated.. Aftermarket degree bushings for Chevy will also fit the LS1's for a quick fix. Also adjustable aftermarket sets are available to make it easier.
Chris
With the stock sets you can drill out the dowel hole as Carl has stated.. Aftermarket degree bushings for Chevy will also fit the LS1's for a quick fix. Also adjustable aftermarket sets are available to make it easier.
Chris
#19
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This is a good post, just wanted to see it up top. Has anyone actually seen a dyno test or anything to back this? How much horse could potentially be lost? Even if a cam is off a little from dot to dot, it could only be a degree or 2 right? If a cam was more than that I would think that cam would have serious problems.
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I would say in a mild build a few deg can be maybe 15 hp or so . The majority of the change will be just off idle and top end so if You've installed a cam d2d and driven it enough to be used to it , then You deg it n find it was off a few deg and You correct it , You will notice a difference .