Excessive engine noise?

[m880cummins]

Hi Guys,

I have been driving my Dodge since May of last year and have been battling the decibels ever since. I have an inch of noise/heat suppressant on the floors and behind the seat and foil insulation on the firewall. I have a lot of mechanical noise that sounds like a mixture of valve train and timing gears. Just a lot of racket. Valves have been adjusted twice, oil is changed and fine, no metal in pan and everything is up to date on the engine. In comparison to dad's cummins (M880 with NON IC engine) his is so much quieter and has not nearly as much noise suppressant. All you hear on his is the exhaust, the engine makes no noise at all. Even my buddies 1st gen with a gutted cab is quieter.... Mine just seems in excess. I'm starting to think more about the engine now. Could I have a junky tappet? Maybe the dowel pin messed up the timing gears?

Need some opinions. Ear drums are getting tired of it. I love the exhaust notes but not the engine racket. I know my injectors need rebuilt too..... Does advanced timing make it louder?

Thanks

Charlie

[Tacoclaw]

What about your engine and cab mounts?

[m880cummins]

All new!

[142autox]

Too much timing advance?

[PToombs]

If the timing is advanced too far it will clatter like a SOB.

[m880cummins]

I haven't checked if the timing is lined up at the teeth but, does an 1/8" change the noise level? I may just back it off to maybe a 1/16 past stock and see how it is. Anyone out there have the timing advanced and noticed a noise difference?

Charlie

[Alec]

I have been thinking about this recently, as my new truck is much quieter than my old truck.

When I got my old truck, the timing was set at 1.3 mm, everything was adjusted, etc., but the interior was shaken to pieces at 208k miles. I cleaned, and tightened, and glued, and etc. to make things more bearable, but it was always pretty rough. A few years ago I advanced the timing to the point that the KSB slows the idle instead of increasing it. This increased the injector noise (or "rap"), but did NOT change the overall cab noise and vibration. Currently I am thinking that the clutch damper repair was never done to my old truck, and that a bad/noisy clutch center may be a contributor to the overall noise and vibration. I have also been meaning to check for a "bound" motor mount. Other than that, I have found no contact points, valve train problems, etc. that would explain why my truck is worse than average.

[m880cummins]

Thanks for the input.

I have all new engine/trans mounts and did check the torque pads on the motor mounts and any contact points. All clear. Clutch is new and trans input and the bearing retainer on the front were cleaned and polished for smooth operation.

On the KSB, if it is on all the time does that make excessive noise? The KSB advances the timing when cold right? Could it be stuck because i have unhooked the wire and noticed no change...

Charlie

[Alec]

The KSB only gives limited advance at low engine speeds. If you have the original '89 KSB it uses a wax motor to operate, and it takes a while for the wax to heat up & cool off . . . and power to the wax motor is KSB off.

As for the vibration

[m880cummins]

Thanks for the KSB info.

My truck doesn't vibrate bad at all. It cruises really smooth and cab barely shakes at idle. Really smooth for a Cummins 1st gen.

[Tacoclaw]

My truck's engine noise is noticeably louder when my KSB wire falls off. Annoyingly loud for that matter, so your timing may have something to do with it.

[m880cummins]

It was indeed the timing. I set it back to stock using my "custom" s bend 13mm wrench and it has no clatter at all now just the straight pipe exhaust drone which is kinda nice. I actually gained about 1-2 PSI of boost by backing the timing back to stock. I think I will buy a dynamic timing advance for it. Gained a lot more low end torque (towing a trailer today was fricken' awesome!)

Along with that today, I eliminated all of the factory throttle linkage and brackets and installed a shortened lokar throttle cable and it looks so much better and refined and along with that, the pedal is very responsive and I get full injector lever travel.

[Alec]

eliminated all of the factory throttle linkage and brackets

I have been wanting to do this since I got my truck ten years ago . . . I figured the trick would be to find a cable from a different engine application, but I'd love to see pics of what you did & more detail on how to get the cable you used.

Thanks,

Alec

[m880cummins]

Check out my post in good stuff. I used a lokar cable and shortened it and then used a jam nut provided to squeeze the factory firewall grommet. Really easy only took 20 mins.

Charlie