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Old 05-19-2013, 01:46 PM
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Having trouble degreeing cam

I've got an oldsmobile 403 and i'm having some trouble installing the new comp cams cam kit.

I bought the comp cams cam degree kit (heads on) and watched the instructional DVD a few times, also found a comp cams video online that i'm using as a reference as well.

Now here's the first problem, i keep coming up with my cam being in the motor at 115 degrees intake center line, it's supposed to be at 102 degrees, what do i do???

second when i push forward and try to locate true TDC using the degree wheel and a piston stop, i keep coming up with WAY off results, following the procedure in the second video my TDC point ends up being with the piston down in the bore, why is this happening?

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Old 05-19-2013, 02:23 PM
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OK, let's begin from scratch. You have the heads installed on the motor, is that correct?

If that's correct, then you will need this tool. Do you have this tool?
Competition Cams 4795 Top Dead Center Stop, 14mm Bolt-Style : Amazon.com : Automotive Competition Cams 4795 Top Dead Center Stop, 14mm Bolt-Style : Amazon.com : Automotive
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Old 05-19-2013, 02:40 PM
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Yes heads are on installed on the motor, Torqued to spec.

Yes i have that tool ,it came with my cam degree kit.
http://www.summitracing.com/parts/cca-4796

Additionally i also purchased a solid lifter to use while degreeing the cam.
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Old 05-19-2013, 03:05 PM
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Quote:
Originally Posted by camaroadam73 View Post
Yes heads are on installed on the motor, Torqued to spec.
Yes i have that tool ,it came with my cam degree kit.
http://www.summitracing.com/parts/cca-4796
Additionally i also purchased a solid lifter to use while degreeing the cam.
OK, first thing is to find TDC on #1 cylinder.
A solid lifter isn't the best tool to use in degreeing in the cam, but it's what you have, so lets try to make it work. Remove the snap ring and turn the pushrod socket plate over, replace the snap ring, so that you have a flat surface on the pushrod socket plate for the dial indicator stem to register on. Trying to use the half-round indentation on the plate as a register base for the dial indicator stem will make you pull your hair out, as you have discovered.
Read through and follow this wiki tutorial. Let us know where you are having trouble as you wade through it.....When you set up the dial indicator, view the dial indicator stem from the front of the motor and from the side of the motor and get the indicator stem as close to square as you can on both planes.....
http://www.crankshaftcoalition.com/w...op_dead_center

What means do you have to change the cam timing? Offset dowels, offset crank key, or what?

Also, pay attention to whether you are on an intake lobe or an exhaust lobe. Not sure about an Olds, but on a SBC, the very first cam lobe at the front is the exhaust lobe for #1 cylinder. Make sure you know where you are.

Last edited by techinspector1; 05-19-2013 at 03:15 PM.
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Old 05-19-2013, 03:21 PM
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Ok i flipped the pushrod socket plate in the solid lifter so that i have a flat surface to work with. I need to mention that I've been using the dial indicator at the top of the valve spring retainer, so i'll need to get a dial indicator stem extension tomorrow to carry on.

Yes i am definitively on cylinder one intake, i double checked that when i first hit snags.

As for adjusting the timing, right now i don't have any means to do so. What do you recommend? I do have a comp cams supplied timing chain set, and the crankshaft sprocket has multiple keyways, right now i'm using the 0 degree keyway and timing mark, my sprocket has a keyway for +/- 4 degrees.
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Old 05-19-2013, 03:57 PM
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Quote:
Originally Posted by camaroadam73 View Post
Ok i flipped the pushrod socket plate in the solid lifter so that i have a flat surface to work with. I need to mention that I've been using the dial indicator at the top of the valve spring retainer, so i'll need to get a dial indicator stem extension tomorrow to carry on.
What you need is a magnetic base, so that you can get the indicator down into the valley and registered right on the lifter. Since there is little weight to a lifter, I suggest having a friend there pushing down on the lifter edge with a wooden stir stick or other material that will not scratch the lifter while you're turning the motor over. If the lifter does not exactly follow the cam lobe profile at all times, then you are just wasting your time.

Quote:
Originally Posted by camaroadam73 View Post
As for adjusting the timing, right now i don't have any means to do so. What do you recommend? I do have a comp cams supplied timing chain set, and the crankshaft sprocket has multiple keyways, right now i'm using the 0 degree keyway and timing mark, my sprocket has a keyway for +/- 4 degrees.
I like to drill the cam sprocket register hole to 1/2" so I can use offset dowels, but don't do anything until you see where the cam dials in.
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Old 05-19-2013, 04:28 PM
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Ok doing what you just said, and following the method on the page you directed me too, and using the comp cams guide i think I've made some lead way.

I located TDC on compression stroke. from there i went on to locate my intake center line to TDC. I used a pushrod as an extension so i do not trust this, but repeating the process 3 times yielded the exact same results. Tomorrow i will repeat the process again with the correct tools as you mentioned.

Using my solid lifter and a pushrod as an extension, i had my friend apply pressure to the lifter with a pop-sickle stick as i went through the procedure. I located the maximum point of lift on the intake lobe, and dialed my indicator to 0, than rotated the motor counter clockwise past 0.050 thousands, then clockwise back to 0.050 thousands (The video said to follow this procedure to take up for slack in the timing chain). Marked degree wheel, 57. From here i continued to rotate the motor clockwise to maximum lift and back down again to .050 thousands. Marked degree wheel, 150.

Adding the two numbers i got 207 / 2 = 103.5 which isn't far off, my cam card calls for 102 degrees. How am i doing so far? this is my first time degreeing in a camshaft so i'm a little nervous.

as for the magnetic base, i don't think that will help because my dial indicator just won't fit parallel to lifter travel with the heads on. The only way i see is to use an extension and travel down through the push-rod opening in the head.
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Old 05-19-2013, 04:58 PM
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Quote:
Originally Posted by camaroadam73 View Post
Ok doing what you just said, and following the method on the page you directed me too, and using the comp cams guide i think I've made some lead way.

I located TDC on compression stroke. from there i went on to locate my intake center line to TDC. I used a pushrod as an extension so i do not trust this, but repeating the process 3 times yielded the exact same results. Tomorrow i will repeat the process again with the correct tools as you mentioned.

Using my solid lifter and a pushrod as an extension, i had my friend apply pressure to the lifter with a pop-sickle stick as i went through the procedure. I located the maximum point of lift on the intake lobe, and dialed my indicator to 0, than rotated the motor counter clockwise past 0.050 thousands, then clockwise back to 0.050 thousands (The video said to follow this procedure to take up for slack in the timing chain). Marked degree wheel, 57. From here i continued to rotate the motor clockwise to maximum lift and back down again to .050 thousands. Marked degree wheel, 150.

Adding the two numbers i got 207 / 2 = 103.5 which isn't far off, my cam card calls for 102 degrees. How am i doing so far? this is my first time degreeing in a camshaft so i'm a little nervous.

as for the magnetic base, i don't think that will help because my dial indicator just won't fit parallel to lifter travel with the heads on. The only way i see is to use an extension and travel down through the push-rod opening in the head.
If you pre-load the stem on a dial indicator, there is room to position it directly above the lifter. This tool has a 1.000" travel, so pushing the stem up into the tool a half inch and installing the indicator there will still leave a half inch of travel on the stem, enough to check out a cam with 0.750" valve lift, using 1.5 rockers. Here's a 403 lifter valley and you can see that there is plenty of room to mount an indicator with a magnetic base, if you push the stem up a little and zero the dial from there.
https://www.google.com/search?hl=en&...%3B1809%3B1357

What are the 0.050" tappet lift intake open, intake close, exhaust open and exhaust close numbers from the timing card? Finding the cam timing numbers within 1 1/2 degrees is pretty close. I just want to see where the intake and exhaust open and close at 0.050" tappet lift.

Last edited by techinspector1; 05-19-2013 at 05:06 PM.
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Old 05-19-2013, 05:45 PM
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Yeah your right i can make it fit if i pre-load it, i'll pickup a magnetic base tomorrow. Oh and i'm using 1.6 ratio rocker arms, dont know if that makes a difference right now or not.


Here's a link to my cam card, it's a little easier than me typing it all out
42-600-5 - Hydraulic Flat Tappet Camshafts
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Old 05-20-2013, 02:10 AM
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Installed straight up, here are the opening and closing points @0.050" tappet lift.
Intake opens (11) BTDC
Intake closes (35) ABDC
Exhaust opens (52.5) BBDC
Exhaust closes (8.5) ATDC
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Old 05-20-2013, 09:16 AM
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Quote:
Originally Posted by techinspector1 View Post
Installed straight up, here are the opening and closing points @0.050" tappet lift.
Intake opens (11) BTDC
Intake closes (35) ABDC
Exhaust opens (52.5) BBDC
Exhaust closes (8.5) ATDC
Tech, I don't think you guys are on the same page. You're saying to measure off the lifter, he's measuring off the rocker, well spring retainer. He isn't going to get the correct readings till he pulls the intake and gets set up in the valley to directly read the lifter, does away with push rods and popsicle sticks and whatever else that's getting between the dial indicator stem and the tappet. And he really needs a friend with an easy way of turning the motor while he reads dimensions and degrees.

Also before reading the cam timing events, he's got to identify true TDC, not come off the timing tab unless that has been validated by the typical process of getting to true TDC.

Bogie
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Old 05-20-2013, 03:33 PM
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Intake is off the motor, haven't put it on yet. At first i tried reading from the rocker ( spring retainer) but ditched that effort as i kept getting really off results, i am now reading directly from the lifter.

Yes i have located true TDC using a piston stop, i was having trouble at first because i kept doing my math wrong.

It's not that hard to rotate the motor myself, i've got a nice breaker bar as leverage and if i pull with one hand and push with the other i can actually get the dial indicator to creep to position.

I just got off work, getting cleaned up ( i work with fiberglass, itch) then heading over to the garage and giving this another go.
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Old 05-22-2013, 03:41 PM
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Quote:
Originally Posted by camaroadam73 View Post
Ok doing what you just said, and following the method on the page you directed me too, and using the comp cams guide i think I've made some lead way.

I located TDC on compression stroke. from there i went on to locate my intake center line to TDC. I used a pushrod as an extension so i do not trust this, but repeating the process 3 times yielded the exact same results. Tomorrow i will repeat the process again with the correct tools as you mentioned.

Using my solid lifter and a pushrod as an extension, i had my friend apply pressure to the lifter with a pop-sickle stick as i went through the procedure. I located the maximum point of lift on the intake lobe, and dialed my indicator to 0, than rotated the motor counter clockwise past 0.050 thousands, then clockwise back to 0.050 thousands (The video said to follow this procedure to take up for slack in the timing chain). Marked degree wheel, 57. From here i continued to rotate the motor clockwise to maximum lift and back down again to .050 thousands. Marked degree wheel, 150.

Adding the two numbers i got 207 / 2 = 103.5 which isn't far off, my cam card calls for 102 degrees. How am i doing so far? this is my first time degreeing in a camshaft so i'm a little nervous.

as for the magnetic base, i don't think that will help because my dial indicator just won't fit parallel to lifter travel with the heads on. The only way i see is to use an extension and travel down through the push-rod opening in the head.
No problem here, your right on your method.

The on the pushrod tip is the same method I always use, and it works just fine, really no different than a long extension tip on the indicator.

You are doing great, the 1.5° you are coming up different from Comp's specs is well within the production variance of the cam, timing set, and where GM cut the crank keyway. All three might be off .5° from blueprint spec.... in the same direction. This is known as "tolerance stack-up" in the manufacturing world.

You can stay at the 1.5° retarded intake centerline, ot use your timing sets available +4° setting to come out 2.5° advanced intake centerline. I tend to go this way, figuring timing chain stretch and running load on parts will retard the cam a degree or so.
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Old 05-25-2013, 05:32 PM
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Alright so i picked up an extension set for my indicator and re-checked my intake center line to TDC just to be safe, and came up with 103°. I gave comp cams a call and they said just to button it up lol.

I've got the front of the motor assembled now but i'll keep that in mind next time ericnova72.


Thanks for all the help guys, its much appreciated.
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