Ideas? Extra clack in engine at idle. 1993

[WarWagon]

Ideas? Extra clack in engine at idle. You can hear the loud clack above the diesel clatter. Is this normal for new injectors?

This is the engine I recently overhauled with new pistons, new injectors, gapless rings, new timing chain, and used 6.5 heads. (It FINALLY starts cold after sitting overnight without 30 seconds of cranking after the injectors...)

The only thing I noticed that was odd when I changed the injectors is the intake valve on #1 has 1/4" of a bronze guide viable below where a non repaired head valve guide would be. I don't know that much about them or if it was a bad job. Attempts to pry it up appear that the guide is solid with valve closed. The noise appears to be stronger in this area, driver's side head front of engine.

Otherwise I am suspecting a lifter going flat.

[video=youtube;cS2q5u5RKT8]http://www.youtube.com/watch?v=cS2q5u5RKT8[/video]

 

[NVW]

I had a rocker on a 350 gas job split in 1/2, it would be similar to a bad lifter. It made a sound similar to that.

 

[bk95td]

Freshly rebuilt injectors are slightly louder for a while. With roller lifters it's rather hard for the lifter to go flat but it can happen.

 

[Acesneights1]

have you tried loosening inj lines one at a time to see if any change ? Also if you don't have one, A mechanics stethoscope is invaluable for chasing stuff like this.
x2 on new injs being noisy.

 

[WarWagon]

The stethoscope has the noise on the driver's side #1. RPM off idle clears up the noise.

 

[Acesneights1]

I doubt it's a lifter. Probably the inj. Does it clear up if you loosen the line ?

 

[buddy]

Its not supposed to sound like that? Mine is probably louder. I doubt the injector would sound like that, pure guess would be valvetrain, valve seating or lash which either could be rocker related.

Sound may change either way if unscrew injector, just due to lack of combustion, although its easiest thing to check and try.

 

[great white]

Have you tried disconnecting the accesory drive belt?

I had a tensioner pulley on it's way out that made a random clacking noise (besides the diesel noise that is) similar to what you've got there.

Probably not what you have going on, but it's a simple 5 minute check to perform and eliminates a whole bunch of components as a source all at once.....