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2G Camshaft degreeing help

DSM_Kola

Probationary Member
11
1
Jun 28, 2019
Franklin, Wisconsin
Hello everyone, I have Kelford 272's with some aem adjustable cam gears and I was wondering if others would look over all my measurements, there are a few things that I'm a little unsure about.


All of my Measurements
Intake Timing
When Cam gears are at 0 degrees
Open 5
Centerline 107
Close 45

When Cam gears are at 2 degrees retarded
Opens 3
Centerline 109
Closes 42

Exhaust Timing
When Cam gears are at 2 degrees Retarded
Opens 45 or 47?
Centerline 112
Closes at 1

Intake Valve clearances
When Cam gears are at 2 degrees retarded
20 .386
15 .325
10 .281
5 .247
0 .226
5 .215
10 .220
15 .235
20 .271

When Cam gears are at 0 degrees
20 .391
15 .334
10 .282
5 .247
0 .222
5 .213
10 .216
15 .231
20 .259

Exhaust Valve clearance
When Cam gears are at 2 degrees retarded
20 .312
15 .290
10 .275
5 .272
0 .282
5 .303

So the first thing that I was unsure about was that for the intake time it seemed odd that it was very close at the opening and centerline, but the closing event was 5 degrees off. The next thing was that when I was doing the exhaust timing I found that when I was doing the opening event and I waited some how it would slightly open like it was. For example I would find the opening at 0.040" at 45 degrees and I would wait a few minutes and it would be 0.047" and it would still be at 45 degrees. Should I take the initial measurement or account for the movement? Another thing is it normal to have that much valve clearance and should I just keep the cams set at Kelford specifications?

Would any of these things be caused by human error, like have I done anything wrong to cause these mishaps, being this is my first time degreeing anything. All advice helps
 

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kanusky1990

Proven Member
95
8
Sep 14, 2011
Easton, Pennsylvania
Are you using solid lifters while taking the measurements?
If you are using the normal hydraulic lifters, they will bleed down over time from the spring pressure and give you an inaccurate measurement. It sounds like that is what is happening when it changed from 0.040" to 0.047" while maintaining 45 degrees.

Great Jafro video for information:
You must be logged in to view this image or video.
He shows how he made solid lifters around 9 mins in
 

jakelandry

Proven Member
936
128
Oct 13, 2009
Minden, Louisiana
I have degreed a handful of cams and had similar scenarios where non-linearity occurs. Because of this, I always just focus on one event. You can’t get an indicator dead inline with the valves, you have some room for error with the solid lifters, the human eye is only so accurate with a homemade stick and wheel combo. It always made the most sense to me to pick one valve event and hit it. Why follow the cam through it’s entire cycle and compare the opening and closing events when there are so many variables to take into account? The opening and closing events are fixed by the cam and you’re not going to change them in relation to one another, so just pick one, set it, and forget it. At the end of the day, the valves do some pretty crazy stuff even when the cams aren’t influencing them and you can’t remove many of the variables the car sees in a running condition. I’m not saying degreeing them is a waste of time, in fact I always degree my cams, but it’s not something I would obsess over.
 

DSM_Kola

Probationary Member
11
1
Jun 28, 2019
Franklin, Wisconsin
I have degreed a handful of cams and had similar scenarios where non-linearity occurs. Because of this, I always just focus on one event. You can’t get an indicator dead inline with the valves, you have some room for error with the solid lifters, the human eye is only so accurate with a homemade stick and wheel combo. It always made the most sense to me to pick one valve event and hit it. Why follow the cam through it’s entire cycle and compare the opening and closing events when there are so many variables to take into account? The opening and closing events are fixed by the cam and you’re not going to change them in relation to one another, so just pick one, set it, and forget it. At the end of the day, the valves do some pretty crazy stuff even when the cams aren’t influencing them and you can’t remove many of the variables the car sees in a running condition. I’m not saying degreeing them is a waste of time, in fact I always degree my cams, but it’s not something I would obsess over.

Thanks for the information this at least puts me at ease a little bit being that this has happened to others. I kind of knew the main thing to worry about would be valve clearance because you don't want to bend a valve. One thing though, do you think I should leave the cams where they are at or should I make the timing events more aggressive because isn't the point of degree your cams to also get the most out of them?
 

DSMPT

DSM Wiseman
1,434
977
Jun 12, 2014
Japan / Mexico, Arizona
Hello everyone, I have Kelford 272's with some aem adjustable cam gears and I was wondering if others would look over all my measurements, there are a few things that I'm a little unsure about.


All of my Measurements
Intake Timing
When Cam gears are at 0 degrees
Open 5
Centerline 107
Close 45

When Cam gears are at 2 degrees retarded
Opens 3
Centerline 109
Closes 42

Exhaust Timing
When Cam gears are at 2 degrees Retarded
Opens 45 or 47?
Centerline 112
Closes at 1

Intake Valve clearances
When Cam gears are at 2 degrees retarded
20 .386
15 .325
10 .281
5 .247
0 .226
5 .215
10 .220
15 .235
20 .271

When Cam gears are at 0 degrees
20 .391
15 .334
10 .282
5 .247
0 .222
5 .213
10 .216
15 .231
20 .259

Exhaust Valve clearance
When Cam gears are at 2 degrees retarded
20 .312
15 .290
10 .275
5 .272
0 .282
5 .303

So the first thing that I was unsure about was that for the intake time it seemed odd that it was very close at the opening and centerline, but the closing event was 5 degrees off. The next thing was that when I was doing the exhaust timing I found that when I was doing the opening event and I waited some how it would slightly open like it was. For example I would find the opening at 0.040" at 45 degrees and I would wait a few minutes and it would be 0.047" and it would still be at 45 degrees. Should I take the initial measurement or account for the movement? Another thing is it normal to have that much valve clearance and should I just keep the cams set at Kelford specifications?

Would any of these things be caused by human error, like have I done anything wrong to cause these mishaps, being this is my first time degreeing anything. All advice helps
This mostly happens when you don't set the dial gauge properly. While the cam is compressing the spring it reads fine but when the spring returns, that pushes and changes the dial gauge tip position a bit. Set the gauge the same angle/inline as valve and use a "L" shape tip and put it on a flat part of retainer, there is a tiny flat space on retainer under rocker arm where the valve keepers are. Normally I use that spot to set the gauge tip.

As for the piston to valve clearance, that would depend on the shape of piston top, gasket thickness etc, too. Set the indicator properly and check again. The numbers would probably be more or less like those, so those numbers seem to be right to me.
 

DSM_Kola

Probationary Member
11
1
Jun 28, 2019
Franklin, Wisconsin
This mostly happens when you don't set the dial gauge properly. While the cam is compressing the spring it reads fine but when the spring returns, that pushes and changes the dial gauge tip position a bit. Set the gauge the same angle/inline as valve and use a "L" shape tip and put it on a flat part of retainer, there is a tiny flat space on retainer under rocker arm where the valve keepers are. Normally I use that spot to set the gauge tip.

As for the piston to valve clearance, that would depend on the shape of piston top, gasket thickness etc, too. Set the indicator properly and check again. The numbers would probably be more or less like those, so those numbers seem to be right to me.
I see what you are saying, I will give this a try and see what kind of results I get and I will double check the valve clearances. Also thanks for the advice
 

jed344

Supporting VIP
1,084
209
Jan 10, 2008
Waterville, Iowa
I always respond to this type of stuff wit what GSC told me directly. Degreeing a 4g63 is easily done wrong. They told me find my max adjustment either way then install straight up and adjust them on the dyno. I find more cams make most power when they are adjusted for max vacuum at idle. So least amount of overlap. That being said i have played with adding overlap to help bring the boost in sooner and harder, example on say a auto car it can help spool it. I hope ya get it figure out but i do not even bother with degreeing anymore. Just check my piston to valve, and max adjustment. Toss them in and play with them.
 
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