Hmmm...poing-poing-poing?

[steved]

Well, I got a new noise...



If I didn't know better, I swear it was a slight rod knock... louder when you listen through the radiator, not as loud when over top the engine. It is very regular, almost wondering if it is the IP (gear slap)... but I thought you either had it or you didn't, it just didn't appear? Although this does sound like it might be coming from the timing gear case...



Truck runs like a top... just noticed this the other day.



Any ideas?

 

[rbattelle]

First, check the harmonic balancer (my current paranoia).

Then check the idler pulley (tensioner), and check the fan drive.

You might also consider removing the belt and starting it up briefly to see if the noise is coming from an accessory.

Could be out-of-adjustment valves. I doubt it's rod knock.

Ryan

 

[steved]

I read that about the balancer... it was off at around 33k for a new seal... . currently at 148k...



The fan was the first thing I thought about... I tried to wiggle things, it seems tight.



The idler is a good possibility...



The valves were run around 100k, and rechecked at 143k when the injectors were replaced...



I'll check all that stuff tomorrow or this weekend...

 

[steved]

Oh, and the noise *sounds* similar to a rod knock or bad lifter in a gasser... that was just my descriptor!

 

[rbattelle]

Oh, and the noise *sounds* similar to a rod knock or bad lifter in a gasser... that was just my descriptor!

How quiet is your engine normally? I couldn't possibly identify a knock like this over all the other myriad noises my engine makes!



Could be the infamous 3rd gen "tick". Link.

 

[steved]

I just had the injectors replaced, and I know they tick; this is a hollow rapping, like a rod knock.

 

[steved]

Well... decided to see if maybe babying it was causing this...



I ran the better part of my 50 miles commute at 75mph or greater (yes, I can safely do that around here without being out of "normal"... just need to step into the left lane with the rest of traffic!)... that netted me continuous EGTs right about 1000*, rail pressures greater than 20k psi, coolant temps around 208*F, and boost between 25 and 38 psi...



It was there this AM when it was cold (24*F), I visually inspected the damper, fan, and tensioner for abnormal movements. Nothing appeared out of the ordinary. Oil level is normal, and the oil looks good.



But the noise was there once I got to work. I'm leaning toward injector, although this is unlike the noises my old injectors were making... it is most likely #1 cylinder.



I'll dive into it deeper this weekend with my screwdriver.

 

[Bob4x4]

Well... decided to see if maybe babying it was causing this...



I ran the better part of my 50 miles commute at 75mph or greater (yes, I can safely do that around here without being out of "normal"... just need to step into the left lane with the rest of traffic!)... that netted me continuous EGTs right about 1000*, rail pressures greater than 20k psi, coolant temps around 208*F, and boost between 25 and 38 psi...

.

Your truck runs 1000 degrees and 25-38psi at 75mph+ CRUISE or is that playing up and down?



Bob

 

[steved]

Yep... 4. 10s limit me to WOT at only 96mph... it runs hot... flat level ground is 25psi boost/1000*F.



And that is based on a Granatelli/Outlook monitor...



steved

 

[THorn]

Wow, does that seem really high to anyone else? I assume this was done "empty"?

 

[steved]

Under WOT, I can easily hit 1500-1600*F... that's empty, in 6th (not lugging).



From what I've read, I see normal temps for a 3rd gen truck.



steved

 

[steved]

You also got to understand I'm turning over 2500RPM at 75mph... I'm pushing 2700 at 80mph and 3200 at 96mph.

 

[Cattletrkr]

Water pump? Mine made a ticking sound the last time it went out. By then it ws already leaking a little though.

 

[rbattelle]

Check the hold-down clamps for the injector lines too.

Ryan

 

[leaky gasket]

A bad injector will sound just like rod knock.

 

[steved]

I got to put a screwdriver to things tonight...



The "knock" seems to be loudest from #3 cylinder... based on the noises coming from the injector supply lines. However, it does seem to be coming from the block.



However, that noise sounds like the typical rapping of a Cummins (you will understand this if you ever placed a screwdriver on one before). If you get in front of the rad, it is louder... and you can hear it from underneath.



What I don't understand is that it is quiet when cold (thick oil acting as a cushion or cold fuel not having the energy it normally does?)??



And unless DonM's injector rebuilding isn't up to par, they have less than 5k miles on them.

 

[steved]

Check the hold-down clamps for the injector lines too.



Ryan

Hmmm, I'll check this tomorrow... since they were off recently.

 

[Bob4x4]

Loose connector tube nuts or leaking/deformed tubes will give you rough running or an actual miss depending on severity.

Your egts are much higher than mine. Mine will hit 120 @ 3000rpm with 4. 10s I guess I have the proper size tires :-laf,the boost is also lower. My 05 has never seen over 1350 and has no trouble staying up front in any of the convoys we have to events. I go for the airflow over max power along with a good handling truck. It makes a much more user friendly rig. No need to watch gauges all the time.



Bob

 

[Bob4x4]

I got to put a screwdriver to things tonight...



However, that noise sounds like the typical rapping of a Cummins (you will understand this if you ever placed a screwdriver on one before). If you get in front of the rad, it is louder... and you can hear it from underneath.



What I don't understand is that it is quiet when cold (thick oil acting as a cushion or cold fuel not having the energy it normally does?)??



.

Remember we have straight cut spur gears up front. Pull the access cover for the injection pump nut and you will be able to tell how loud they are with out the benefit of the insulation the cover does.



Bob

 

[steved]

Considering this truck is more/less stock, it is normal temps/speeds/max's.

I'm not going to worry about it... there is nothing I can do about it.

I'm going to pull a oil sample and have it analyzed...