Engine knock N14 Celect

Hey everyone. Here is my dilemma. I had to replace my N14 because the driver ran it low on oil. Burned 4, 5 and 6 road bearings and a couple of mains. Found a used engine from a respectable truck parts dealer with 800k on the engine. Installed the new engine, and rolled new bearings and new clutch.

Fired the truck up, and runs fine. did have a short in the number 5 injector harness, but repaired it. Truck has good oil pressure. At a stand still the engine really runs good. Take it out to drive it, and it runs good until 1200 RPM, than develops a knock. unplugged each injector at idle and all seem to work. The truck does have more white smoke than it should when you start it. Going to drive it this morning with each injector unplugged and see if it is a bad injector. I have heard bad injectors in the N14 can make them knock, and I know N14 are known for injector issues. Also checked and set the overhead while the engine was out. Only a couple of the valves needed to be reset.

I really have a hard time believing this is a mechanical issue as it gets a little better at about 1500 RPM.
Any ideas would be greatly appreciated. Also the truck started a new symptom and dies at an idle after about a minute and half. Thanks in advance for any help.

 

Stroll,
Turned out to be the number 5 injector. I just replaced it with a brand new one bought from Cummins. Unplug it and the knock goes away. Thanks for the reply. I replaced before the knock I meant. SO bad injector.....grrrr

 

Stroll,
Going to swap 5 and 6 injectors tomorrow and see if the problem follows. Also Cummins Quik Serve said to seat the injectors 4 times to make sure the fuel is out of the injector, and than once bottomed back out 2 flats or 120 degrees. I am going to bottom number six before I take it out and count the turns it takes to bottom, and set them both the same.

 

Doug,
Thanks for he offer, but we do almost all of our own engine work and rebuilds. Wee have extra heads for them, oil coolers and pumps etc.

Only reason we lost this one completely is due to the driver running the oil low and wiping the crank. Found a rally nice 500 N14 for a great price with only 800k on it. We rolled new bearings into it, swapped number three jake head as the one we got had bad solenoid and didn't want to wait for parts, so just marked what it needed and stored it with rest if parts, We mark everything so if we need a part of want a spare we know what it needs to be fixed.The driver was fired once we knew the cause, and sent him on his way. Truck had a miss when we fired it, and unplugged number 5 injector. Other than that it purred. Took it out on a test drive and it knocked at about 1200 rpm and got better about 15 but still knocked. Did injector cut out old fashioned way, and was the new one we put in. Gong to swap 5 and 6 on Monday, to see if the problem follows. I highly doubt it is mechanical. Every thing looked great inside, plus i have always had mechanical issues follow the truck rpm through the whole range. Called Cummins about bad injector and thy said they very very seldom have bad re-manufactured injectors. Funny thing is I went on the web, and everyone complains about them. I will count my flats and bottom number 6 out before I remove it, and count the turns. Quik Serve says to tighten 3 or 4 times to empty any fuel, than back off 120 degrees ( 2 flats according to manual). I didn't crush, but want to make sure i didn't start to tight when I backed it out.

I posted thid thread so long so others can learn. These engines are very very easy to work on people do do not be afraid of them. Forgot to mention Ran the overhead and jakes with the engine on the stand. Much easier to do than in the truck. Only found a couple of valves out of adjustment by just a little. Side note is I bought through a reputable yard with a 30 day warranty. Th engine came with a stand built out of a pallet. This pallet will work for all engines between 12 and 16 liters. I would save, very handy. Can perform all work on stand except crank bearings.

Will post Monday what I find, but 95 percipient sure bad injector or about 5 % I over tightened it.