Duramax adjustable cam gear

juddski88

Freedom Diesel
Jul 1, 2008
4,657
120
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Chesterfield, Mass.
How much have you guys seen people degree the current after marker cams? I know mines just set up degree mark to degree mark. Just curious

Some cam designers/sellers have already done the R&D to know where to cut the key way. I guess a little testing and tuning ability is always nice to have, but in my opinion, if I am buying the proper cam that is being sold to me as being right for my application, that designer/ seller should have already tested it and degreed it himself.
 

Stingpuller

The Pusher Man
Jan 11, 2007
2,019
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I have to agree Tim. If you need to change the cam more than a few degrees you have the wrong cam. When you Advance or retard the cam you are changing both intake and exhaust the same amount! It's a good thing to HELP dial in the cam but if anyone thinks there is magic there they may want to save there money.
 

Yellow Jacket

WannaBe Sled Puller
Feb 11, 2009
917
0
16
Waterloo, IA
Some cam designers/sellers have already done the R&D to know where to cut the key way. I guess a little testing and tuning ability is always nice to have, but in my opinion, if I am buying the proper cam that is being sold to me as being right for my application, that designer/ seller should have already tested it and degreed it himself.

I have to agree Tim. If you need to change the cam more than a few degrees you have the wrong cam. When you Advance or retard the cam you are changing both intake and exhaust the same amount! It's a good thing to HELP dial in the cam but if anyone thinks there is magic there they may want to save there money.

Have you guys ever degreed any of the cams you have ever purchased? I have 5 cams from 4 different companies, ALL very reputable shops and 4 were billets, none of them degree in where the manufacturer wants them, I've seen off by as much as 8 degrees from where they want them for a pulling application... 3 were pretty big duration for a 4 valve diesel, and 2 of same cam were small street with no valve reliefs... Every custom billet aftermarket cam for BBC's I've ever seen had to be degreed in also, and on a stock BBC block I've seen 1.5* difference from one bank to the other...

Your right though, no magic, just piece of mind.

And the three that were 6* or more off 2 were regrinds and you are limited to where they can get material from... And the billet was 8*, but on a street application or if enough valve relief permitted it would be fine straight up and make more top end HP or shift power curve up 2-300 rpm, but with pulling 6-10* can be the difference of spooling a big charger or not...
 

S Phinney

Active member
Aug 15, 2008
4,008
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Quncy, Fl
There is more to the overall dynamics than just the camshaft. The gears may not be indexed properly as well and that throws off valve timing in respect to when they are suppose to open and close in reference to the grind itself. a lot of the cams are off when you degree them. When you degree them you can move the power curve up or down via retarding and advancing the cam per your specific needs. I am sure the cost of this gear is more than it is worth in all reality but so are most of the parts for a diesel engine. Maybe one day enough companies will make these parts and the prices become competitive but it probably won't happen in my lifetime.:hug:
 

juddski88

Freedom Diesel
Jul 1, 2008
4,657
120
63
Chesterfield, Mass.
Have you guys ever degreed any of the cams you have ever purchased? I have 5 cams from 4 different companies, ALL very reputable shops and 4 were billets, none of them degree in where the manufacturer wants them, I've seen off by as much as 8 degrees from where they want them for a pulling application... 3 were pretty big duration for a 4 valve diesel, and 2 of same cam were small street with no valve reliefs... Every custom billet aftermarket cam for BBC's I've ever seen had to be degreed in also, and on a stock BBC block I've seen 1.5* difference from one bank to the other...

Your right though, no magic, just piece of mind.

And the three that were 6* or more off 2 were regrinds and you are limited to where they can get material from... And the billet was 8*, but on a street application or if enough valve relief permitted it would be fine straight up and make more top end HP or shift power curve up 2-300 rpm, but with pulling 6-10* can be the difference of spooling a big charger or not...

Matt, I'm willing to try anything once, just like you. I won't disagree that I could probably advance the cam with an adjustable gear and spool a little faster (however it is already advanced 3* ), but what if I give up torque where I have it now which is where I want it? Then I just spent entirely too much money and time proving my designer/seller right.
 

Stingpuller

The Pusher Man
Jan 11, 2007
2,019
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central Ohio
Cams

I have degreed a cam or two over my lifetime. I just don't try and sell stuff and pimp my service! If its a spade I call it a spade. I'm not a talker (salesman) and never will be. I do sleep pretty good at night.
 

Stingpuller

The Pusher Man
Jan 11, 2007
2,019
35
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central Ohio
Degree

Also for all you guts that are looking for black magic can do it for few dollars with a offset keyway. Damn maybe I should be a salesman.
 

Yellow Jacket

WannaBe Sled Puller
Feb 11, 2009
917
0
16
Waterloo, IA
Matt, I'm willing to try anything once, just like you. I won't disagree that I could probably advance the cam with an adjustable gear and spool a little faster (however it is already advanced 3* ), but what if I give up torque where I have it now which is where I want it? Then I just spent entirely too much money and time proving my designer/seller right.

I agree, this is only functional to 2-5% of customers, I just didn't want people to read what you said and think every cam is ground exactly where it needs to be. :thumb:

I have degreed a cam or two over my lifetime. I just don't try and sell stuff and pimp my service! If its a spade I call it a spade. I'm not a talker (salesman) and never will be. I do sleep pretty good at night.

I'm not pimping anything or a salesman either, most guys probably pay someone to put it together, and offset keyways are FAR cheaper and is what I have used in past. This with a modified cover would be best suited for a puller who wants to go to the dyno and see where the power curve of his turbo and cam can be at... And Staab builds and designs stuff for tractor pullers.

Just to clarify this gear isn't going to gain anyone a magic 30+ hp, and is not gonna magically correct a poor setup... And I never see this being used in a street application
 

Fahlin Racing

New member
Aug 22, 2012
330
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0
NE Ohio
There is more to the overall dynamics than just the camshaft.

Indeed! EACH person needs to absorb the engine as a whole from induction to exhaust and comprehend how a change in camshaft timing can tune the engine differently at different levels of performance. Perhaps showing dyno sheets with same overall parameters showing effects of different IVO and EVC (two most important points in the 7 cycles we are dealing with) :popcorn: