degree in camshaft
10-16-2009, 03:54 PM
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degree in camshaft i purchase this camshaft and i am in the process of checking it with a degree wheel every time i check it i come up with a 107.5 centerline and its calling for a 109 so it throws everything a few degree's off should i buy the adustable set or is it ok
10-16-2009, 07:07 PM
#4
Considering that the cam card shows there are already 5 degrees ground in (109 ICL, 114LSA) you don't need any addtional advance on top of that. Are you using an adjustable timing set? Are you certain you are using the correct keyway and markings on the crank gear?
If you are truly getting a 107.5 Intake Centerline, IVC at 41.5 ABDC and IVO at 4.5 BTDC , then you are advanced an additional 1.5 degrees. When you say "they are off by 5" are you actually getting an IVC of 38? That is advanced a lot more than your original post suggests. If you want good answers, you might want to provide more data.
If you are truly getting a 107.5 Intake Centerline, IVC at 41.5 ABDC and IVO at 4.5 BTDC , then you are advanced an additional 1.5 degrees. When you say "they are off by 5" are you actually getting an IVC of 38? That is advanced a lot more than your original post suggests. If you want good answers, you might want to provide more data.
10-16-2009, 08:06 PM
#5
Cam timing The cam card says the cam has a 114 degree lobe spread but it actually has a 113 lobe spread. The intake spec should read: 3 BTDC 43 ABDC not 43 ATDC. 3 + 43 + 180 = 226/2 = 113 which is your intake centerline. The exhaust: 54 + 2 + 180 = 226/2 = 113 which is your exhaust centerline. Since both are 113 degrees the cam has a 113 degree lobe spread.
Most chains will stretch 2 degrees after a very short time. So if you doing things correctly, after chain stretch you will be at 109.5 or 3.5 degrees advanced.
Always check the point of peak lift on the intake and exhaust lifter. Checking at the valve opens a can of worms since the valve action is dependent on the valve train geometry and can vary greatly depending on pushrod length, true rocker arm ratio and fulcrum height.
Steve
Most chains will stretch 2 degrees after a very short time. So if you doing things correctly, after chain stretch you will be at 109.5 or 3.5 degrees advanced.
Always check the point of peak lift on the intake and exhaust lifter. Checking at the valve opens a can of worms since the valve action is dependent on the valve train geometry and can vary greatly depending on pushrod length, true rocker arm ratio and fulcrum height.
Steve
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Steve Demirjian
Race Engine Development
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Steve Demirjian
Race Engine Development
Oceanside, Ca.
760-630-0450
web: www.raceenginedevelopment.com/
e-mail: race-engine-development@***.net
10-16-2009, 08:49 PM
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ok i don't know alot cams and the degreeing of it i started from scratch several times come up with the same thing every time 153 deg & 62 deg added then divided got 107.5 that was checking at the lip of the lifter at .50 i only checked were valves were 1 time since the other was off i stopped if i remember intake was 8 & 48 didn't check exhaust i come inside i went ahead and ordered an adjustable timing set the one i have is a stock fixed one from gm also does that cam look to put out decent numbers it came from patriot
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10-17-2009, 09:50 AM
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i am checking at .50 i will recheck in a while and post all results i am using a standard ls7 lifter but i am putting the dial indicator on the edge not in the cup i did it from scratch 3 times find tdc the find peak lift then go .50 before and after add together then divide by 2 but i will do it all over again and record valve opening and all i will post it up tonight and maybe someone will help i am using a standard chain and gear set so i have no adjustment in it i ordered a trickflow double adjustable chain from summit
10-17-2009, 10:43 AM
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ok i did it again from scratch here is what i came up with 153.5 + 61.5=215/2= 107.5 centerline ok then i checked both intake and exhaust open closed
int 8 deg 37 deg
exh 59 deg 9 deg
i was checking it on the edge of the lifter if anyone knows why its off or exactly how to fix it or just a suggestion let me know
10-17-2009, 11:11 AM
#12
I always find max lift first, then I roll the engines counter clockwise .100" off of max lift. So I start finding my first .050" mark turning the engineclock wise, so the timing chain slack has been taken up.
So I hit my first .050" mark, then past max lift, and then hit my 2nd .050" all while rotating the crank the same direction. Seems to be more repeatable.
So I hit my first .050" mark, then past max lift, and then hit my 2nd .050" all while rotating the crank the same direction. Seems to be more repeatable.
10-17-2009, 09:22 PM
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ok i checked the degree on my cam again here is what i came up with 153.5 + 61.5=215/2= 107.5 centerline so its off 1.5 deg then i checked both intake and exhaust
open closed
int 8 deg 37 deg
exh 59 deg 9 deg
anyone else have this problem or any more comments thanks i rotated engine clockwise on every measurement to make sure i had all slack out of chain
open closed
int 8 deg 37 deg
exh 59 deg 9 deg
anyone else have this problem or any more comments thanks i rotated engine clockwise on every measurement to make sure i had all slack out of chain
10-18-2009, 07:05 AM
#14
I think you will NEVER notice a 1.5 degree change in ICL. This is one of those things that sometimes you have a lot of information and it makes you worry about something that not a real issue.
ICL isnt static either, when the engine is running the camshaft moves independatly of the crankshaft slightly, and you cant control that.
Youve done the extra work to to make sure the cam is in correct and safe. Check piston to vavle clearance and move on...
If your buying and adjustable chain, just retard it a degree or two if it will really make you feel better.
ICL isnt static either, when the engine is running the camshaft moves independatly of the crankshaft slightly, and you cant control that.
Youve done the extra work to to make sure the cam is in correct and safe. Check piston to vavle clearance and move on...
If your buying and adjustable chain, just retard it a degree or two if it will really make you feel better.
10-18-2009, 01:49 PM
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ok i checked the degree on my cam again here is what i came up with 153.5 + 61.5=215/2= 107.5 centerline so its off 1.5 deg then i checked both intake and exhaust
open closed
int 8 deg 37 deg
exh 59 deg 9 deg
anyone else have this problem or any more comments thanks i rotated engine clockwise on every measurement to make sure i had all slack out of chain
open closed
int 8 deg 37 deg
exh 59 deg 9 deg
anyone else have this problem or any more comments thanks i rotated engine clockwise on every measurement to make sure i had all slack out of chain
10-18-2009, 05:35 PM
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yep patriot performance i'm waiting on a adjustable timing set from summit gonna try to retard it some looks to far advanced by the numbers and all looks like it should be a decent all around camshaft for an everyday driver i hope so anyway
10-19-2009, 12:27 PM
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Send it back a pick a better Vendor over to the right and get a better cam.
10-19-2009, 01:48 PM
#19
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If you want my HONEST IMO man, pull that thing out and send it back. Any "real" cam companys cams are not that far off. I used and sold Crane for years, and if any of my LSX cams were more then 4* off, I sent them back and they ground me a new one. Your having to buy a new T/C set because of a improper ground cam is BS imo. There heads work about as good as there cams=JUNK! Send it back a pick a better Vendor over to the right and get a better cam.
Send it back a pick a better Vendor over to the right and get a better cam.