Engine REALLY loud, timing troubles

[jcomp]

My new engine is nearly deafening until the HPCA turns off, then it's just real loud. I checked my timing (pulse adapter, engine warm) and it was somewhere around 18 degrees before TDC (off the scale). This was with the the IP mark lined up with the mark on the timing cover. I adjusted the IP so that the timing was down to 12 degrees BTDC and the truck ran very poorly, so I put it at 16. The truck was much harder to start and had less power but quieter. I put it back to 18 and now the truck runs and starts great but is loud. So...

My harmonic balancer, timing gears and pretty much the entire engine are new. Why am I getting such an advanced reading? If these readings are accurate, will too much advance hurt my engine? Is there even such a thing as too much advance in a compression ignition engine?

The timing appears to be set to where the engine runs, starts and idles the best. Listening to it though, it sounds way advanced at idle. I swear it's louder than a cummins dodge. It doesn't help much that I took out all the carpet in my truck :cool:

[Dieselboy]

Wow! 18 degrees is a lot of advance. I have seen as high as 10 degrees at idle, but that quickly falls to between 3 and 5 degrees0 as you approach 1500 rpms.

That much advance can cause cylinder pressures to exceed the limit of the cylinder head clamping force. If there is to be a failure, it will most likely come in the form of a blown head gasket. Remember, we have only five bolts per cylinder holding the heads to the block (the 5.9L Cummins has six).

Double check to make sure you have the correct offset on the meter and that the probe is in the correct glowplug hole - 99.5* and #3 respectively.

Assuming the reading is correct, and that the internal timing of the pump is accurate, it would be smart to back the pump down to a more reasonable timing spec.

A nominal 3* BTDC @ 1300-1500 is a good place to start.

[grape]

sounds like the pump gear may be a tooth off.

[Old6.2]

I'm thinking along the same lines as grape. If those Phazer gears are new they could be off one tooth.

[jcomp]

The phazer set and the 4911 are both new.

It is possible that one of the gears is a tooth off, but I gave that a lot of attention when I assembled the engine. I'm certain the cam gear is correct, I checked it several times on several different days while I had the engine on the stand. If the IP gear is a tooth off (I only checked it twice smile.gif ), wouldn't the engine run better as I reduced the advance? I went from 18 (ish) to 12 BTDC and the engine would barely run, very rough idle and lots of smoke. As it is now, the entine runs very well.

How likely is it that my new GM harmonic balancer is bad? Is there any way I can check it while it's still on the engine?

I just went out and rechecked my readings. With the HPCA disconnected, my timing is 20 degrees BTDC at idle and 14 degrees if I rev it up around 1500 rpm.

Maybe it's my measurement techinque? I'm using a Ferret 765, clamped to the #1 injection line. Before I replaced my engine, the timing (using this equipment) was around 8 degrees.

Thanks for all the help.

[Old6.2]

I suspected the phazers from my own experience. While installing mine three years ago I noticed that the marks did not align with the crank/cam centerline. I called their tech and was told this was due to an advance built into the gears. The quickest and easiest way to find out if your cam is timed correctly is by doing a compression test. High cylinder pressure = advanced ; low cylinder pressure = retarded. Normal cylinder pressure = look elsewhere. Now that I think about it I'm not sure you could be off a tooth without valve to piston contact!

Mine runs well with the pump advanced the width of the line and I have never had it timed. It is very loud when cold so I disconnected the cold start advance a year ago with no regrets.

I have heard the 4911 develops pressure at a faster rate and would make the combustion process louder. Wish I could be of more help!