03 hemi cam

[Tsnyder527]

I have a 2003 ram 1500 with the 5.7 hemi and I'm looking for some help with a few issues. I recently bent a connecting rod so I have my motor rebuilt (only has 100,000 mi). While the motor was out I had the comp cam 260 installed and am now having some issues that I am not sure if they are related to the cam or other internal components. My 1/4 mi time went down 2 1/2 seconds and 0-60 is almost 12 seconds. I am getting misfires, have no power, my oil pressure drops to 0 when stopping, and at steady rpm my truck shakes. Any suggestions are greatly appreciated!

 

[ST-8]

That's the cam needing more fuel at idle. When mine comes to a stop allt of times my afr goes past 17 an the truck starts to sputter an buck, then after a few seconds usually the computer adjusts an it Idles fine. You throwing a p0300?

 

[Tsnyder527]

Mine idles ok, I mean the rpms bounce around a little bit but it doesn't stall out or anything. And yeah I had a cylinder 4 misfire, put new plugs and wires in, cleared code, it was still there, swapped coil packs with cylinder 2, clears codes, to see if it jumped to there but it stayed at 4. Then when driving down the road if I get into the gas my light starts blinking and throws the p0300

 

[HemiLonestar]

Ok, stupid question (sorry gotta ask), but you did put some kind of tuning in to compliment the cam, right?

 

[Tsnyder527]

I have not yet, that was my next step was to try my old superchips 91 tune on it. I plan on getting the Diablosport with a tune from hemi fever but I will probably swap out to an 05 computer and harness first. Will it make that much of a difference without a tune? I've read where some guys have ran this cam without a tune and some have just used a canned tune...I don't know much computer wise

 

[ST-8]

I'm running a canned sc tune with my 260.

 

[HemiLonestar]

I have not yet, that was my next step was to try my old superchips 91 tune on it. I plan on getting the Diablosport with a tune from hemi fever but I will probably swap out to an 05 computer and harness first. Will it make that much of a difference without a tune? I've read where some guys have ran this cam without a tune and some have just used a canned tune...I don't know much computer wise

That's why it's running like ****, you're confusing the poor computer lol. If you do the swap, you'll be able to get it tuned MUCH better to compliment that cam.

I'm running a canned sc tune with my 260.

Gotta at least have this.

 

[Tsnyder527]

Installed the sc performance 91 tune and nothing changed, 1st gear isn't terrible but it just doesn't have the power that it did before the rebuild/cam swap and when it hits second it falls on its face

 

[Blackram]

If the problem is in cylinder 4 still after swapping coils and changing plugs and wires then you probably have a mechanical issue. What do you use for valve springs and push rods? Did you get the timing marks lined up? It's not a tuning problem, I ran my sidewinder with no tune for a day or two after I installed it without issue.

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[Tsnyder527]

Springs and pushrods are both stock, everything I've read and the mechanic both told me the 260 was small enough I didn't need the spring and pushrods upgrade...I realize I should have to be on the safe side and if we tear apart the top end again I will do so. We are going to pull the front off today to double check the timing but he says he has never mis timed a motor...the symptoms have lead me to believe the timing may be off a tooth tho

 

[HemiLonestar]

No, should have...260 may be a mildish cam, but is still based on a 6.1 cam base circle.

 

[Blackram]

Springs and pushrods are both stock, everything I've read and the mechanic both told me the 260 was small enough I didn't need the spring and pushrods upgrade...I realize I should have to be on the safe side and if we tear apart the top end again I will do so. We are going to pull the front off today to double check the timing but he says he has never mis timed a motor...the symptoms have lead me to believe the timing may be off a tooth tho

So you didn't use 6.1 springs and push rods when you swapped the cam?

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[ST-8]

**** having a 03/04 HEMI I'd wanna get the stock springs out of there asap. To many horror stories on the forums about them just breaking

 

[Blackram]

Bigger problem is the smaller base circle of a 6.1 based cam (which the 260 is) requires longer push rods. Sounds like he reused his stockers, not good.

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[Tsnyder527]

Tore the front off, retimed it again just to be sure it's right and it still runs the same. The only difference is it is now throwing a fuel to rich code, and hasn't thrown another misfire code yet. (Before it threw the cylinder 4 misfire almost right away and the multiple cylinder misfire when I got into the gas) Check engine light still flashed when I get into the gas

 

[Tsnyder527]

Just saw the replies, and the stock pushrods were reused from the 5.7...so I need the longer pushrods then? Whether it's aftermarket or from the 6.1

 

[Blackram]

If you used the 5.7 push rods they are too short for a cam based on a 6.1 base circle.

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[Tsnyder527]

Ok, thank you for all the help! Will get the new pushrods and springs ordered and see if that helps with any of my issues...it does explain why it would be running rich.

 

[Tsnyder527]

Ok guys I'm lost again, so the stock 5.7 lengths are Intake 6.600 and exhaust 7.825, the stock 6.1 are intake 6.650 and exhaust 7.850, and the 260 suggested pushrods are 6.600 intake and 7.850 exhaust from what I can find. What is my best bet here, 6.1 or the comps?

 

[ST-8]

I've been running the 260 with 6.1 springs an pushrods for over 3yrs, 25k miles, 2 transmissions, an countless wot shifts at 6300+ rpm with no problems lol