Hey guys.

Have a question about my truck wondering if you can shed some light.  I bought this truck a couple years ago and have been slowly restoring it. I hear a loud knock/clank I believe to be coming from cyl 5 or 6. I say this because I originally thought the TC bolts were loose. I checked them. Removed,  locktite, retourqued. I cracked fuel injector lines one by one to try to isolate noise, etc. Each line I cracked,  I heard a noicable miss but the noise never stopped. Today I took my valve cover off to look for anything obvious. I found a few things! I see all my rockers getting evenly oiled, no visibly bent pushrods, no dropped valves/carbon buildup anywhere.  I did notice however that my oil has a rainbow/tie die effect when I hit it with the flash light. Also when I stuck my finger into the coolant plugs cups, most seem to be weeping because I see, although very minor, some grey milky substance on my finger. I know this is a multipart question but what direction would you guys think I should go next? Why did noise never stop no matter which injector was killed? I ran the truck with cover off to see that each rocker will collect bubbles above it. Is this normal from vibration from being pumped? I'm pretty sure in the near future the head will need to come off to replace coolant plugs? I'm going to include some stuff here..

 

Oil pressure cold start 70-80psi then slowly drop to 28-30 psi fully warmed. 

Valve lash has been done 

Never loose oil pressure

WOT feel no misfire

No extended crack times

No noticeable smoke whatsoever

Truck has minor mods 4" exhaust, air dog lift pump, gauges, intake horn, and cold air intake.

 

Thank you so much!

I

12 minutes ago, Bduhigg86 said:

Oil pressure cold start 70-80psi then slowly drop to 28-30 psi fully warmed. 

 

Minimum limits on oil pressure: 10 PSI at idle and 30 PSI at 2,000 RPM. 

14 minutes ago, Bduhigg86 said:

I hear a loud knock/clank I believe to be coming from cyl 5 or 6.

 

Most likely bearing issue or piston issues. I was helping a guy with the same problem I can tell you that we went as far as pulling the transmission and starting with just a flywheel. After that we knew that its internal to the engine. Sorry to say I've never seen the out come of that particular case but I'm sure its bearings or piston issues. 

 

 

Ok thank you for the reply man! I was really hoping you weren't going to say that hehe I thought beings I had good oil pressure I could maybe rule out a bearing? I will possibly just pull my injectors anyway to see if it's they are cracked or something. Any secret methods for checking crank bearings and other bottom end components without pulling motor?

 

Also I should have specified im sorry.  My oil pressure fully warm, at idle is 30 psi and I'll have to double check but I believe between 40 -50 at 2000 rpm. Is that good or too high? Is it possible that my I'm just not used to how loud these trucks are? I know this sounds crazy but I don't think I've ever heard a 100% running properly vp44 5.9l. With my head under the truck anyway. 

Edited March 29, 20187 yr by Bduhigg86

How many mileson truck/injectors , try adding 2 cycle oil to fuel 1oz to gallon ashless 

261k on truck. I bought it with 256k on it. Injectors very well may be original. How could I tell if I pull them? What exactly should I do with the oil? 2 stroke oil you mean?

1 minute ago, Bduhigg86 said:

How could I tell if I pull them?

 

Send them in to be pop tested. Most likely if the injectors are stock OEM they are popping low pressure and early. Suppose to be 310 bar for fresh injectors. My OEM stock injectors have 150k miles on them and my lowest was 240 bar. So for spec it should be 293 to 327 bar to be within spec.

 

 

5 minutes ago, Bduhigg86 said:

What exactly should I do with the oil? 2 stroke oil you mean?

 

Mix it in the fuel.

 

If you take injectors out and they are in fact original  (at least it will say Bosch on them) send them to DAP and have them look at them, if they confirm that they are original then trade them in as a core and get a set of rv275 or 60hp they have a sale I believe going on now. You can always call them and talk to them, say this forum send you there and they will treat you good, if in fact if they have a deal going now you can at least get locked in it. 

I have a filling you may have bigger injectors then stock considering 4" exhaust air dog etc, so before you just get random injectors verify what you have, if you already have let's say 75hp DAP can rework them much cheaper then getting a new set. 

How is your egts now 

Edited March 29, 20187 yr by Dieselfuture
Spelling

Still doesn't resolve the knocking though. That's my biggest worry. The only thing I can think of is pull the injectors out and stuff a borescope in the cylinder and look and see if there are any marks on the cylinder walls. 

Yeah I'm hoping it's injector related, but your right if they are out it would worth seeing inside and be nice to do compression test. 

Also when you get injectors out make sure all copper washers stay on injectors and not in a hole, and make sure to get new orings for cross over tubes, injectors will come with new washers and orings. 

Read a lot on how to do the job if haven't done it before so you don't make simple costly mistakes, like trying to pull injectors out before removing cross over tubes etc. Ask here will walk you through it. Good luck. 

1 minute ago, Dieselfuture said:

be nice to do compression test. 

 

Yeah, that might give clues too. 

 

The knock can only be a few things...

• Piston/cylinder damage
• Connection rod bearing
• Rist pin

3 minutes ago, Dieselfuture said:

Yeah I'm hoping it's injector related,

 

Worth a try... If it's injector related then if you move the 5 and 6 injectors to 1 and 2 and the noise moves forward that would be the smoking gun of bad injectors.