Advance CAM Timing (who's done it?)
08-08-2006, 11:38 AM
#16
Drifting
Ken's tool is great... my cams were way out of whack (how, I don't know), but one was retarded 5 degrees and the other was advanced 2 degrees. I adjusted them both to 3 degrees retard for a race car.
08-08-2006, 12:47 PM
#17
Three Wheelin'
Originally Posted by Darien Nunn
Hi Andrew,
If everything goes right, Tony will stop by Thur and we'll give the porken tool a try
If everything goes right, Tony will stop by Thur and we'll give the porken tool a try
Am I missing something? Until you are assured the cams are set to some known reference, even if you know how much you change them, you still don't know where you are. I've never checked cam timing on a 928 and found it to be correct. One side advanced, the other side retarded, or could be anything. Educate me. Is there an easier way to know for sure what the crank/cam timing relationship is than to grind through the WSM procedure?
08-08-2006, 01:02 PM
#18
Inventor
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As much as I've heard back, and personally observed, after setting the cams with a dial indicator according to the WSM, the center of the parallel key keyway (which my tool indicates) is within a cam degree.
GT's appear to be advanced (1) degree to the keyway.
At different engine speeds, the timing is changing all the time with the different tolerances, engine temp, etc. It's not science, just valve timing.
GT's appear to be advanced (1) degree to the keyway.
At different engine speeds, the timing is changing all the time with the different tolerances, engine temp, etc. It's not science, just valve timing.
08-08-2006, 01:13 PM
#19
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Thread Starter
Louie,
Without having the CAM position "templates", I hope to get a good read with ken's tool. It should give me an idea if I'm way off or not..
Without having the CAM position "templates", I hope to get a good read with ken's tool. It should give me an idea if I'm way off or not..
Originally Posted by Louie928
Maybe someone can 'splain this to me better than I can figure it out. Ken's tool is great, but seems to me to make no sense to use it with unknown initial cam/crank timing relationship. Once the cams are set to factory specs, using the WSM procedure, then of course change timing with Ken's tool as you wish without further having to take off the cam covers and go through the long WSM procedure.
Am I missing something? Until you are assured the cams are set to some known reference, even if you know how much you change them, you still don't know where you are. I've never checked cam timing on a 928 and found it to be correct. One side advanced, the other side retarded, or could be anything. Educate me. Is there an easier way to know for sure what the crank/cam timing relationship is than to grind through the WSM procedure?
Am I missing something? Until you are assured the cams are set to some known reference, even if you know how much you change them, you still don't know where you are. I've never checked cam timing on a 928 and found it to be correct. One side advanced, the other side retarded, or could be anything. Educate me. Is there an easier way to know for sure what the crank/cam timing relationship is than to grind through the WSM procedure?
08-08-2006, 01:44 PM
#20
Three Wheelin'
Originally Posted by PorKen
As much as I've heard back, and personally observed, after setting the cams with a dial indicator according to the WSM, the center of the parallel key keyway (which my tool indicates) is within a cam degree.
GT's appear to be advanced (1) degree to the keyway.
At different engine speeds, the timing is changing all the time with the different tolerances, engine temp, etc. It's not science, just valve timing.
GT's appear to be advanced (1) degree to the keyway.
At different engine speeds, the timing is changing all the time with the different tolerances, engine temp, etc. It's not science, just valve timing.
08-08-2006, 02:22 PM
#22
Supercharged
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And if Tony is interested in using the cam timing tool, feel free to send it over to him. I've got his G-tech, so I can hold it randsome! 
08-08-2006, 05:59 PM
#23
Chronic Tool Dropper
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Louis-
I had this same discussion offline with Keith and some others here in the SoCal area. My take is that it all depends on how well the camshaft factory did when they ground the cams from blanks. My concern I guess is that if the cams were so darn good and consistent from the grinder (+/- a degree or so) why do we have those big adjusting slots in the gears? Of course, the next question would go to whether the factory did any fine-tuning on a per-engine basis before the cars were delivered.
Just a heads-up to those doing the adjustments at home-- Keeping track of whether you are advancing or retarding the cams is very important. I've watched more than a few 'experts' move the gears clockwise, thinking they were moving the cams in the right direction. Moving the gears is the opposite of moving the cams, of course.
I had this same discussion offline with Keith and some others here in the SoCal area. My take is that it all depends on how well the camshaft factory did when they ground the cams from blanks. My concern I guess is that if the cams were so darn good and consistent from the grinder (+/- a degree or so) why do we have those big adjusting slots in the gears? Of course, the next question would go to whether the factory did any fine-tuning on a per-engine basis before the cars were delivered.
Just a heads-up to those doing the adjustments at home-- Keeping track of whether you are advancing or retarding the cams is very important. I've watched more than a few 'experts' move the gears clockwise, thinking they were moving the cams in the right direction. Moving the gears is the opposite of moving the cams, of course.
08-08-2006, 08:31 PM
#24
Three Wheelin'
Originally Posted by dr bob
Louis-
I had this same discussion offline with Keith and some others here in the SoCal area. My take is that it all depends on how well the camshaft factory did when they ground the cams from blanks. My concern I guess is that if the cams were so darn good and consistent from the grinder (+/- a degree or so) why do we have those big adjusting slots in the gears? Of course, the next question would go to whether the factory did any fine-tuning on a per-engine basis before the cars were delivered.
Just a heads-up to those doing the adjustments at home-- Keeping track of whether you are advancing or retarding the cams is very important. I've watched more than a few 'experts' move the gears clockwise, thinking they were moving the cams in the right direction. Moving the gears is the opposite of moving the cams, of course.
I had this same discussion offline with Keith and some others here in the SoCal area. My take is that it all depends on how well the camshaft factory did when they ground the cams from blanks. My concern I guess is that if the cams were so darn good and consistent from the grinder (+/- a degree or so) why do we have those big adjusting slots in the gears? Of course, the next question would go to whether the factory did any fine-tuning on a per-engine basis before the cars were delivered.
Just a heads-up to those doing the adjustments at home-- Keeping track of whether you are advancing or retarding the cams is very important. I've watched more than a few 'experts' move the gears clockwise, thinking they were moving the cams in the right direction. Moving the gears is the opposite of moving the cams, of course.
08-08-2006, 11:57 PM
#25
Originally Posted by Darien Nunn
Louie,
Without having the CAM position "templates", I hope to get a good read with ken's tool. It should give me an idea if I'm way off or not..
Without having the CAM position "templates", I hope to get a good read with ken's tool. It should give me an idea if I'm way off or not..
Might I suggest that you fine tune your cams first per the WSM, and find out exactly where they are set at before playing with the timing. I just did this to the Koenig motor last week (set the factory setting). It's kinda a PITA, but I've got the procedure fresh in my mind. The WSM's procedure seems a little confusing at first, but Big Dave's write-up made it very clear. (THANKS!)
I've got a dial indicator and stand you can borrow if you want. I have to redo mine still since I didn't have that bent indicator extension.
Let me know
08-09-2006, 12:04 AM
#26
Originally Posted by Louie928
I'm guessing the sprocket slots are mostly to account for differences in belt lengths. You always set timing with a used belt since it's different with a new one. I don't trust much of anything and would still want to check the actual valve lift vs. crank position.
Darien,
Also, I forgot, you really don't need the cam templets. They're nice to have and will get you in the neighborhood, but the exact cam timing is done with the dial indicator.
08-09-2006, 01:06 AM
#27
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Absolutely, might as well put it back together knowing everything is to spec.
Originally Posted by Koenig928
Darien,
Might I suggest that you fine tune your cams first per the WSM, and find out exactly where they are set at before playing with the timing. I just did this to the Koenig motor last week (set the factory setting). It's kinda a PITA, but I've got the procedure fresh in my mind. The WSM's procedure seems a little confusing at first, but Big Dave's write-up made it very clear. (THANKS!)
I've got a dial indicator and stand you can borrow if you want. I have to redo mine still since I didn't have that bent indicator extension.
Let me know
Might I suggest that you fine tune your cams first per the WSM, and find out exactly where they are set at before playing with the timing. I just did this to the Koenig motor last week (set the factory setting). It's kinda a PITA, but I've got the procedure fresh in my mind. The WSM's procedure seems a little confusing at first, but Big Dave's write-up made it very clear. (THANKS!)
I've got a dial indicator and stand you can borrow if you want. I have to redo mine still since I didn't have that bent indicator extension.
Let me know
08-09-2006, 03:25 AM
#28
Race Car
Originally Posted by Koenig928
The WSM's procedure seems a little confusing at first, but Big Dave's write-up made it very clear. (THANKS!)
Link for that?
08-10-2006, 01:36 AM
#29
Rennlist Member
i went the stock specs and the car ran poorly. matched both sides at a higher than specified , 2mm per side. it changed the exhaust note and I picked up some power. stock spec was 1.6 to 1.8mm on the setting side. Interesting the stock spec for the GT cams is more advanced and further advanced for the GTS, while the GT has the most desirable cam profile. (actually very close to the 85 cam, with a very subtle difference in lobe positions)
MK
MK
08-10-2006, 09:54 AM
#30
Rennlist Member
Thread Starter
Mark,
Did you use the porken tool?? Not sure what 2mm, does that equate to deg?
Did you use the porken tool?? Not sure what 2mm, does that equate to deg?
Originally Posted by mark kibort
i went the stock specs and the car ran poorly. matched both sides at a higher than specified , 2mm per side. it changed the exhaust note and I picked up some power. stock spec was 1.6 to 1.8mm on the setting side. Interesting the stock spec for the GT cams is more advanced and further advanced for the GTS, while the GT has the most desirable cam profile. (actually very close to the 85 cam, with a very subtle difference in lobe positions)
MK
MK