12 valve guru needed

Did you replace the engine mount inserts? I have personally ran that cam on a p pumped 24v and it was very smooth minus the full cut delivery valves that caused some loping. I’ve seen loose dampeners cause vibrations as stated. Above 2500 rpm it’s hard to distinguish vibrations since 12vs are not the smoothest motor known to Man kind. I’d also do a once over on your injection lines make sure they didn’t get kinked or bent at some point. What did you set valve lash too? What clutch is in the truck? And what fly wheel? My south bend dual disc had a werid vibration to it that was different then the stocker it replaced
 
Justappumped24v said:
Did you replace the engine mount inserts? I have personally ran that cam on a p pumped 24v and it was very smooth minus the full cut delivery valves that caused some loping. I’ve seen loose dampeners cause vibrations as stated. Above 2500 rpm it’s hard to distinguish vibrations since 12vs are not the smoothest motor known to Man kind. I’d also do a once over on your injection lines make sure they didn’t get kinked or bent at some point. What did you set valve lash too? What clutch is in the truck? And what fly wheel? My south bend dual disc had a werid vibration to it that was different then the stocker it replaced
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I put new oem motor mounts on along with the energy suspension outer pieces. Original mount inserts were torn.

It’s good to know that the cam should idle smooth. Thanks for the reply.

I’m going to look into a new dampener and see if that helps any.

I set valve lash to .01 intake .02 exhaust.

I used a new valair hd single disk with their flywheel.
 
Spurrinit said:
I put new oem motor mounts on along with the energy suspension outer pieces. Original mount inserts were torn.

It’s good to know that the cam should idle smooth. Thanks for the reply.

I’m going to look into a new dampener and see if that helps any.

I set valve lash to .01 intake .02 exhaust.

I used a new valair hd single disk with their flywheel.
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It’s possible you are unfamiliar with the new clutch vibration, I would contact them and see if that is normal before you tear your hair out
 
95cummins5.9 said:
What are the readings with a infrared gun at each cylinder?
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I drove the truck and got it warm then pulled into the shop and checked the exhaust temps at each cylinder on the same spot on the manifold. I took 2 different readings. First is when I pulled in and the second after it idled a while.

Temps

1: 198 : 187
2: 240 : 222
3: 248 : 218
4: 235 : 219
5: 230 : 209
6: 217 : 195
 
Nothing seems wrong there. I'd buy a fluid damper balancer if I was you, seems you have spent money in all the other right spots. I know on my dual disk it has a spray paint line where it was balanced as a assembly. I suppose your flywheel or pressure plate could be out of balance. I wonder if the vibration is the same with the clutch engaged vs disengaged?
 
95cummins5.9 said:
Nothing seems wrong there. I'd buy a fluid damper balancer if I was you, seems you have spent money in all the other right spots. I know on my dual disk it has a spray paint line where it was balanced as a assembly. I suppose your flywheel or pressure plate could be out of balance. I wonder if the vibration is the same with the clutch engaged vs disengaged?
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Thanks for the input. I’m looking at fluid dampers right now.

I checked that today. Engaging and disengaging the clutch doesn’t seem to change the vibration at all.
 
Take a close look at the OEM damper. There is an indexing mark on the outer housing and the hub. Those marks should align. Cummins says if they're offset either direction, the damper needs to be replaced. Without referring to my Cummins manual, I don't remember the value they specified, it may only be 1/16"-1/8".

Also check the rubber isolator between the hub and outer housing for cracking or missing pieces which can also warrant a replacement.

I'm not sure if either of the above could cause enough of a vibration to be noticeable but it's worth looking into.
 
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