Helix cams

[R-N-R]

Wondering how a 24v acts with a mech. LP. I would like to get away from the elec. one. Is it as simple as unplugging the elec. LP and replacing with a mech. and taking off with no problems. Maybe a silly question but the only dumb question is the one not asked, lol.

You would need a cam with the fuel pump lobe such as the Helix, or a Rasp system.

 

[Matt400]

Well then. . suddenly springs along with the #2 grind is looking better.

Whew! that was until I saw the price of springs. So the #1 doesn't need springs but the #2 does which doubles the cost.



I am mostly interested in advancing the cam timing for better response/spool up, mpg and lower EGT's towing. Hardly ever run above 2500 RPM and spend a ton of time 1400-1800.



The question is- Is the #2 cam better than the #1 cam @ 1400-1800 RPM?

I don't mind spending more to get more but if that "more" is 2000-3000 then I would be buying into an area I hardly ever see.

 

[Fishin Guide]

I've wanted a cam forever but I don't have the tools or facilities to accomplish this job. A little over $1,000 is the cheapest I've found to have it installed by a shop. Anyone have a better bid ?

I did it myself and the number of special tools are limited. This is a job for the mechanically inclined however.



Dave

 

[Fishin Guide]

Don't you have to strip the motor down to the block to swap the cam? Something about the lifters being a pita to keep from dropping into the pan?

Not exactly. The motor gets very little removed. Everyhting in front of the cam comes out. CAC, Radiator, I pulled the bumper, but not a requirement, pull the coolers out of the way, fan shroud, fan, fan hub, and gear cover, but not the case. On the top end, I pulled the entire valve train, pushrods, ect.



You do need a special tool that can easily be fabricated or purchased to catch and hold the tappets in place when the cam is out. Also, a line and plug to pull the tappets back into the bores if they were removed and some wooden dowels and rubber bands to hold the tappets in place.



Hardest part of the entire job for me was pressing off the cam gear and getting the gear on the new cam. When that was done, it was all gravy and install is the reverse of removal.



Dave

 

[Fishin Guide]

Wondering how a 24v acts with a mech. LP. I would like to get away from the elec. one. Is it as simple as unplugging the elec. LP and replacing with a mech. and taking off with no problems. Maybe a silly question but the only dumb question is the one not asked, lol.

It acts great! I have full fuel pressure before the thing actually lights. Meaning that pressure is built during cranking. And it fires just as fast as before! The lift pump is unplugged and does throw a code. This does not turn on the CEL and does not have negative effects on the computer. With a small light bulb or a resisitor plugged into the harness, this code is not present.



Dave

 

[Fishin Guide]

Is the 12 valve lift pump and option on a common rail?

No. At least I do not believe so. There is no hole in the block for the pump to mount. At least that is what I have heard.



Dave

 

[Fishin Guide]

Whew! that was until I saw the price of springs. So the #1 doesn't need springs but the #2 does which doubles the cost.



I am mostly interested in advancing the cam timing for better response/spool up, mpg and lower EGT's towing. Hardly ever run above 2500 RPM and spend a ton of time 1400-1800.



The question is- Is the #2 cam better than the #1 cam @ 1400-1800 RPM?

I don't mind spending more to get more but if that "more" is 2000-3000 then I would be buying into an area I hardly ever see.

I do not know the answer to this one. Doug would probably be your best lead here.



I have not tried the Helix 1, but I am sure happy I have the Helix 2!! just the ability to rev further and harder with the same fueling is awesome! If I plant my foot to the floor, I can't watch the boost gauge from 7-8 psi on. And the truck accerates so much smoother, with no "hit" like before. Just electric. Also, the engine is a little quieter. I can actually hear the valve train instead of clatter.



I run my truck at the RPMs you are talking about. With a lot of freeway cruising and that tops at around 2K in overdrive. I have no complaints. And the faster turbo spool for passing is a welcome addition. Especially with the reduced smoke. And the ability to have the truck rev out to redline and beyond without nosing over was worth every penny to me.



Dave

 

[Matt400]

Thanks Dave for sharing the changes you see with the Helix 2.

 

[Fishin Guide]

Thanks Dave for sharing the changes you see with the Helix 2.

My pleasure. After all the lift pump failures, I am happy to talk about something that works as advertised!!



Dave

 

[tshort]

What all would be required to go with a stage 3. I have an HX-40 turbo, 370's, 191 DV's, 60# valve springs, 0 plate, and 4K GSK. Will eventually go to twins and different inj. Would I need to have pistons fly cut.

Ryan

 

[Fishin Guide]

What all would be required to go with a stage 3. I have an HX-40 turbo, 370's, 191 DV's, 60# valve springs, 0 plate, and 4K GSK. Will eventually go to twins and different inj. Would I need to have pistons fly cut.

Ryan

I think the answer is no.



You have to keep in mind, that when you start with a raw blank, you can control the valve timing. Meaning, you are not trying to "make do" with a reground. With commonly requires changing the valve timing as well as the vale train geometry somewhat.



There really should not be many applications that the valve should occupy the same space as the piston unless you are sled pulling and turning crazy RPM. Even then, there is a ton of pumping loss in order to maximize rpm. The Helix 3 is an all out cam. High RPM power builder! That I do know. And I would expect Don has the ability to do some custom grinds if the price is right.



Dave

 

[nickleinonen]

ooh, now i am dreaming of a #2 helix for my truck... if the engine ever comes out of the truck for any reason, it will be getting a new camshaft

 

[Matt400]

I did it myself and the number of special tools are limited.

Hi Dave,

Did you use the Cummins or Miller Dowels. . or make your own?

From what I have dug up is that they are simply 1/2" wooden dowels with a slit in the end so they compress some.



Also, did you cut the cross member or lift the engine for access?

 

[SRadke]

You're right on with the dowels Matt and the cross member is only and issue on the third gens.



-Scott

 

[Fishin Guide]

Hi Dave,

Did you use the Cummins or Miller Dowels. . or make your own?

From what I have dug up is that they are simply 1/2" wooden dowels with a slit in the end so they compress some.



Also, did you cut the cross member or lift the engine for access?

Matt, the dowels were home made with a slit cut into one end. This needs to be thin so that the dowel can collapse to bottom on itself. That way, when you shove the dowel in, it stays real tight. I think the dowles were 7/16" but I would have to go grab one of my spares to be sure. Also, you need to chamfer the end with the slit to help guide the dowel in. Just a quick trip with the sand paper and it's done. I have heard of guys using one of the old time humungo pencil sharpeners to turn it down as well.



On the 2nd gen, there is no cutting or lifting. I have heard that you have to do one or the other on the 3rd gen and it looks like lifting the engine is the best solution. Although, I think you only have to lift one side. Doug would know this one!



Dave

 

[Fishin Guide]

And the other special tools are available through Cummins. But, a piece of 2" tube capped on one end and then cut in half lengthwise, a long dowel with a cup hook in the end and a piece of braided string with a rubber plug that will fit into the tappet. The string runs through the plug and use a small washer as a stopper. This way, the plug or string does not come out while dangling.



Another note, my tappets looked like new after 70+ thousand miles. I had new tappets, so I installed them, but it clearly was not required. And the job would have been done in much less time if I had not swapped them out.



Dave

 

[rubberneck]

Another note, my tappets looked like new after 70+ thousand miles. I had new tappets, so I installed them, but it clearly was not required. And the job would have been done in much less time if I had not swapped them out.



Dave

I think if i spend the money and time to put in the cam, i'm going to do the lifters. I have always been told that the cam and lifters work harden together during break in and that you should never use a new cam with old lifters, and vice versa. Once joined, they are married for life. I usually mark the lifters as to which lobe they came off of that way if i ever reuse the cam, they go back in the same spot they came out of. What do you guys think. Jetpilot, sounds like you have put in a few of these, what do you think?? Did don design the metalurgy of the new cam to work with the old lifters. How much is a new set of lifters from cummins??

 

[Fishin Guide]

I think if i spend the money and time to put in the cam, i'm going to do the lifters. I have always been told that the cam and lifters work harden together during break in and that you should never use a new cam with old lifters, and vice versa. Once joined, they are married for life. I usually mark the lifters as to which lobe they came off of that way if i ever reuse the cam, they go back in the same spot they came out of. What do you guys think. Jetpilot, sounds like you have put in a few of these, what do you think?? Did don design the metalurgy of the new cam to work with the old lifters. How much is a new set of lifters from cummins??

I know you asked Jetpilot for his response, but here's mine. The tappets of our engines are far different than our smaller ancestors, the gas motor. On those engines, the cam and lifter do wear into one another. Especially with hydralic lifters. Solid lifters are not nearly as bad and I have reground them in the past.



Bottom line is this, the metal used in the tappets of the Cummins motors is hard enough that the cam lobe will most likely wear before the tappet. I have seen many cam swaps that never had the tappets touched in applications including buses and emergency vehicles. There simply is no to very little wear on the tappets.



I have my stockers in a box, but they literally look brand new. Hardly polished. The curvature is still there and they would have worked fine with a new cam. Also, unless the lobe shows sign of wear, they are fine.



One note, if the cam must be replaced due to worn lobes, the tappets must be replaced, per the factory manual. And there is a minimum service diameter for the tappet stem. This is a more precise way to determine if they should be replaced, although, the tappets must be out to measure them.



Again, with all the miles I had on my truck, putting a new in the box tappet next to any any out of my motor showed no indications of differences other than the coating being worm off the bottom of the tappet and along it's stem.



These things are not gassers!!



Dave

 

[rubberneck]

FG, how much were the tappets? Like you said, they have to be out to measure them. so i probably will just replace them. I hear you that its probably not necessary, but oh well, guess im just to neurotic not to do it. I now have 100k of hard miles on the truck (been over 425 HP since 1800 miles), and i use all of them ponies every single day. Not to mention it sees redline at least once or twice a day. or more, or a lot more. I guess I figure any oem part still on the thing has done its job and deserves to be relieved of duty if im in there anyway. I dont know, Ill think about it. gonna be a couple of months before i have the time to get the cam anyway, so i will take some prozac and tell myself it's ok. LOL

 

[Fishin Guide]

FG, how much were the tappets? Like you said, they have to be out to measure them. so i probably will just replace them. I hear you that its probably not necessary, but oh well, guess im just to neurotic not to do it. I now have 100k of hard miles on the truck (been over 425 HP since 1800 miles), and i use all of them ponies every single day. Not to mention it sees redline at least once or twice a day. or more, or a lot more. I guess I figure any oem part still on the thing has done its job and deserves to be relieved of duty if im in there anyway. I dont know, Ill think about it. gonna be a couple of months before i have the time to get the cam anyway, so i will take some prozac and tell myself it's ok. LOL

LOL so you sound just like me! I think I about gave Don a coronary when he heard that I was gonna change them. It didn't matter what they looked like.



Honestly, I do not remember the cost, but they were relatively cheap. Also, I recommend not using moly on the tappets or cam. Use assembly lube. It breaks done much better into the oil and does not give you tolerance issues.



Getting the tappets back in the bores can be a major challenge. Lots of shaking the tray to get them in. Also, the string does not just fall straight through to the cam bore. I used a "special tool" made of a piece of coat hanger with one end slightly flatened courtesey of a 32oz ballpeen and I put a curl in the other end to hang onto it. Just pust the rod into the rubber plug, insert the plug through the tappet bore and put the plug against the side and pull out the wire. Then it's easy to fish the plug out with the dowel with the cup hook.



Dave