6.2 gets extremly loud after load

[Mohawk Dave]

Hey SS,

My 6.2 starts up and humms a good song, but sometimes when I put it under load, it starts being REAL LOUD. it sounds like a dang Peterbuilt idling. CLACK-CLACK-CLACK-CLACK-CLACK

It's not as if a piston is flying around or anything, but, idk, timing???

I can shut her down and restart and sometimes it will go away, sometimes it wont. Sometimes it does it on the road, and sometimes it doesn't.

Fresh diesel fuel, no water in it, new fuel filter. Ideas???

I will videotape it and post if needed.

Thanks,

Dave

 

[Mohawk Dave]

Found this on another forum.

"A bad injector could be the problem,dumping too much fuel into a cylinder."

Thoughts?

Thanks, Dave

 

[Mohawk Dave]

Found this at Dieselplace.com also

"could be a stuck injector too, that sounds the same like you lost a bearing.

crack the fuellines one by one with the mill idling, if the banging disappears then that's the critter causing it."

Will do this tomorrow. Ideas/thoughts?

Thanks-Dave

 

[Recovry4x4]

Wonder if there is something going amuck with the cold advance in the IP or the wires that feed it. I can certainly tell a difference on my Oh-8 when the cold advance shuts down, gets real quiet. As I understand it, there is a temp switch in the pass cylider head that controls this function. I don't know if the switch goes open or closed when the engine reacehes the correct temperature.

 

[Warthog]

The switch opens when hot, cutting the power to the solenoid.

Normally closed when cold.

 

[BIG_RED]

Maybe a clogged return line? (I know IP housing pressure changes the timing.. I don't remember which direction though)

 

[Mohawk Dave]

ok, so I went to Diesel Injection Services in San Bernardino today, and Lou, a very wise, long in the tooth and experienced diesel guru heard it and immediately said "Your timing is advanced." I shut it down and he told me to look at the set marks on the IP versus the block. He stated the IP would be to the right, which we could plainly see also. So I climbed in the bay and the IP was about 5/64 inch to the right.

I did as he said and loosened the 3 15mm bolt/nuts WITH THE ENGINE OFF-(He said you could seize it while doing it running, not like a gasser), set the marks up with eachother and now I'm golden.

I asked him why the Navy would have advanced the timing, and he said it is a common misconception that more advance=more power, but obviously this was too much, and with it advanced it sounds extremly DIESEL-y.

He also stated that as the timing chain wears out and stretches, you can turn the IP to the right (advance) to counter this. (Only for so long obviously)

Anyways, thought I'd share this in case anyone needs to know.

Here's the shops place page from google. Diesel Injection Services

Best wishes,

Dave

 

[PropDr]

Did you get alternator sorted out?

 

[Mohawk Dave]

Did you get alternator sorted out?

I did. I rebuilt both as you know and oddly enough, after a few miles they started working as they should. The only thing we can come up with is the brushes had to make better contact. Maybe there was some kind of coating on them? This is still an unsolved mystery. To err on the side of caution, I rechecked ALL my ground and positives, took them apart, resanded, new star washers, dialectic grease and re-installed. No problems. I've been DD'ing it since, with correct amps all day long.

-Dave

 

[PropDr]

Wow that is weird, but I'm glad to hear that they are working. Was their grease on the slip rings where the brushes ride?

I'm curious about how much your fuel economy will change since you backed the timing down. I have a feeling it will go down slightly.

 

[Mohawk Dave]

Grease, no, I was not using any when rebuilding, and I had clean hands, tools, and AO.

As far as MPGs go, time will tell.

-Dave

 

[PropDr]

an after thought...............

A trick that a old timer taught me to seat brushes on generators and starters.. After installing the new brushes in the brush holder use double sided tape to stick a strip of sand paper to the slip rings. Then install the rotor into just the back housing and remove the temporary brush retainer pin. Rotate rotor until brushes are fully arced to match slip rings. disassemble, remove sand paper clean slip rings with acetone blow out housing and continue rebuild as normal.

 

[Mohawk Dave]

PropDr,

Makes sense. I think this is more or less what it did by itself, because there is no other explanation. The trucks electrical is very good and as you know I have PM'd the whole dang thing. Thanks for the input and thanks for the help the other day. If I can ever return the favor, don't hesitate to ask.

Dave