Cams, Cams, Cams, What do you think
09-13-2008, 11:20 PM
#1
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Cams, Cams, Cams, What do you think
I'm looking to get a cam soon, and was wanting to know what some of you would or wouldn't run, i know setup plays in. With everything in my Sig, would I need to go deeper in the power plant, with like a H2. My consern is taking a chance on beating a piston up, with a heavy lift cam?
Also, what can i expect out of a cam? With all the choices out there, i'm still leaning towards the F1 line, Don is great with injectors, so I would think this would be a great choice.
Also, what can i expect out of a cam? With all the choices out there, i'm still leaning towards the F1 line, Don is great with injectors, so I would think this would be a great choice.
.
09-14-2008, 01:25 PM
#4
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Hello,
I am clueless about diesel cams. In the gasser world there are an unbelievable number of cams available. Actually custom cams are everywhere. I can only guess there is 1 manufacturer of cummins blanks. Is this correct? If blanks can be had, numerous cam companies can grind whatever will fit on the cam. Stockers can be reground also. So i guess i am asking why isn't there more choices for the diesels. Does it come down to people do not know this in the diesel world, afraid to do something out of the box or is it a pricing issue? Maybe it's a head limitation or they don't want to fly cut pistons. Seems like we are barely scratching the surface in the diesel market. I'm confused.
Damon
I am clueless about diesel cams. In the gasser world there are an unbelievable number of cams available. Actually custom cams are everywhere. I can only guess there is 1 manufacturer of cummins blanks. Is this correct? If blanks can be had, numerous cam companies can grind whatever will fit on the cam. Stockers can be reground also. So i guess i am asking why isn't there more choices for the diesels. Does it come down to people do not know this in the diesel world, afraid to do something out of the box or is it a pricing issue? Maybe it's a head limitation or they don't want to fly cut pistons. Seems like we are barely scratching the surface in the diesel market. I'm confused.
Damon
09-14-2008, 02:05 PM
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Their are several aspects to consider in a cam for a Diesel application. If valve to piston clearance is not an issue, then it opens the door to new possibilities.
There is not alot of room for much lift at TDC during overlap, 0.030-0.040" is about all that is available. To promote better spooling, we need as much as we can get without running the valves into the pistons, and still maintain some needed clearance. To accomplish this, the cam geometry gets compromised to make it all fit. The idea is to get the valve open quickly, hold it open as long as possible then close it quickly.
Since we have already dictated available lift at overlap, we must determine seat to seat events. Opening and closing events for the intake and exhaust valves, must allow for all the overlap we can stuff into the engine. This helps during low or no boost situations, after all until boost is present we have an N/A engine. Next in consideration is when the intake and exhaust valves open and close. If you keep the intake valve open well beyond BDC, you can lose some intake charge through reversion. When the exhaust opens, it must overcome the positive pressure already in the manifold. Obviously as the engine speed and load changes the dynamics change as well.
Custom cam development is here now. There are several options for cores, regrinds will not get you very far.
The most popular cam available has been around awhile, I think as choices have been very limited most go by what is available. The best cams are yet to come.
There is not alot of room for much lift at TDC during overlap, 0.030-0.040" is about all that is available. To promote better spooling, we need as much as we can get without running the valves into the pistons, and still maintain some needed clearance. To accomplish this, the cam geometry gets compromised to make it all fit. The idea is to get the valve open quickly, hold it open as long as possible then close it quickly.
Since we have already dictated available lift at overlap, we must determine seat to seat events. Opening and closing events for the intake and exhaust valves, must allow for all the overlap we can stuff into the engine. This helps during low or no boost situations, after all until boost is present we have an N/A engine. Next in consideration is when the intake and exhaust valves open and close. If you keep the intake valve open well beyond BDC, you can lose some intake charge through reversion. When the exhaust opens, it must overcome the positive pressure already in the manifold. Obviously as the engine speed and load changes the dynamics change as well.
Custom cam development is here now. There are several options for cores, regrinds will not get you very far.
The most popular cam available has been around awhile, I think as choices have been very limited most go by what is available. The best cams are yet to come.
09-14-2008, 03:35 PM
#7
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There is a small window on performance grinds that will work well without killing the bottom end power or taking away too much from the top.
We tried so many grinds. So many combinations of grinds. So many lobe seperations, lifts, durations, opening points, etc. it would make you dizzy.
Most Diesel cam companies over time have figured out a couple of things after years: bolt the cam gear on the cam and dont go radical with grinds.
I cant tell you how many intake runners have been filled with carbon and soot or how many times gears have popped off the end of the cams without a good bolt on system. When many of the others were telling people to weld the gear on or a bolt on system is not needed, etc now they all are going that route.
The latest mis-info going around is that you cant run a cam core with a fuel pump lobe and use the wider CR tappet. Nothing could be further from the truth with a Helix cam.
We tried so many grinds. So many combinations of grinds. So many lobe seperations, lifts, durations, opening points, etc. it would make you dizzy.
Most Diesel cam companies over time have figured out a couple of things after years: bolt the cam gear on the cam and dont go radical with grinds.
I cant tell you how many intake runners have been filled with carbon and soot or how many times gears have popped off the end of the cams without a good bolt on system. When many of the others were telling people to weld the gear on or a bolt on system is not needed, etc now they all are going that route.
The latest mis-info going around is that you cant run a cam core with a fuel pump lobe and use the wider CR tappet. Nothing could be further from the truth with a Helix cam.
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09-15-2008, 08:01 PM
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I was hoping the git the benifits of these differant cams. I get that you guys love these cams but why do you love these cams. Are you in love with them because there in YOUR trucks or is it because it is the better fit for your truck, Why? Why is it the better fit? I dont want to hear you love it and not explane Why? Or do you even know why!!!
09-15-2008, 09:10 PM
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Corey i don't know what egts you see down the track but I bet a cam would drop you egts alot. I'm sure you know I run the scheid cam and a few other trucks do. I went with a Scheid cam because I was gonna go with scheid injectors instead of Don but then Scheid ended up being more expensive on injectors and went with Don M injectors and springs and scheid cam. I know my 66 lites on the street with no problems I wouldn't see a problem with pulling 10-15,000lbs behind my truck with no problems. Personally I don't think you can go wrong with any cam out there, whether it be Scheid, Don, Or Maxspool. Has anybody ever tested each cam like back to back alot of work just to find out?
