Little extra rattle in 7.3

[91flatbed]

I finally got the motor in and started it up. While i was letting the truck run for a few minutes, to check for any leaks,i started getting this little clicking noise. The longer the truck ran the louder the noise got. Now the clicking sound has gone from a click, to what sounds like a full blown knock. When it first started, i thought it was a valve that had just not seated good, so i revved the motor just a little. This is when the knock came about. It kinda sounded like a bent pushrod in a gas engine, so i took off the valve covers and checked the rocker arms,and the push rods, they were all fine. Just put in bearings and checked the torque on all right before i put on the oil pan Really got me puzzled, i don`t know what else to look for. any of you guys run in to this before ? Thanks for any help

 

[DaytonaBill]

Um, injector knock, or bad rod bearing... maybe a bad clutch or transmission?

Did all of the bearings get checked for clearance?

 

[93f250idi]

Is it a 5 speed? Maybe a bad dmf. Maybe an injector stuck open? Crack each line individually and if the knock quiets down with one of them cracked then that's the bad injector.

 

[dmaxjoe]

If and when you find it Please let us know. I have a 6.9 in my 84 that developed a knock over a period of about 3 days. That was over 3 yrs. ago. I have checked and changed everything except the injector pump. My thinking is it is in the pump. I have put close to 20,000 mi. on it since it started knocking.

 

[91flatbed]

I changed the flywheel from a dmf to a solid before i put the engine back in the truck. I don`t think the flywheel would cause this kind of knock. The engine came out of another truck that the automatic transmission went out in. It was overhauled not to long before i purchased it. I heard the engine run before i bought it, and there was not knock or noise at all. After i got the engine, it has taken me about six months to get around to putting it in the truck. Before it was put in the truck, i freshened up the gaskets, changed the glow plugs, but didn`t change the injectors. The knock sounds like it has had a shot of starting fluid sprayed in it, would be the best way to describe it. Would a bad injector cause this ? What would cause the injector to go bad, would the engine sitting for a period of time cause it to go bad ? As for a rod knocking, this just doesnt sound like a rod. I drained the new oil out and strained it as it came out of the engine, and there was no metal what so ever in it, so i dont think it would be a bearing shot. I dont know, i`m at my wits end with this thing

 

[DaytonaBill]

It's gotta be your injectors... Do what is described in post #3, but be sure you keep a rag over and around the injector you are testing, fuel can shoot out in a fine stream that is capable of penetrating your skin and causing blood poisoning which is not good. People loose limbs from that...

Maybe you can make you a homemade tester so you can record the psi and flow pattern of the injector.

http://www.oilburners.net/forums/showthread.php?t=43126&highlight=tester
http://www.oilburners.net/forums/showthread.php?t=13946&highlight=tester

 

[91flatbed]

Would it be possible that a glow plug could cause the knock ? I checked all the injectors none seemed to have an effect on the engine. But in the process of checking out the injectors, i found a glow plug that looked like it had been damaged somehow. Would it be possible that the injectors were working fine and pumping that cylinder full of fuel and not burning it, causing the knocking ?

 

[hagmo92]

I have the same knock that you may have! does it get louder while cruising at about 2500 rpm? I tried injectors and injector pump, with no results. the noise is loud and people stare at me at the lights.I have had one good diagnose come from a friend who doesn't have a whole lot of knowledge about diesels but it made the most sense of the 5 or so that looked at it. He thought a or multiple
cylinders have lost ring compression.,when i add 20% lucas additive the noise quiets some, not all and then when the oil is hot it can be loud again.and then sometimes quieter. Wierd is how i can explain it. I wonder if dirty fuel caused the problem?

 

[BioFarmer93]

...Did you remember to put the oil back in it?

 

[MidnightBlade]

If you open the hood and stand by the intake can you hear a kind of "Chuffing" sound? http://www.youtube.com/user/blackhawk8427#p/u/32/7PYywh_mOR0

 

[hairyboxnoogle]

I have the same knock that you may have! does it get louder while cruising at about 2500 rpm? I tried injectors and injector pump, with no results. the noise is loud and people stare at me at the lights.I have had one good diagnose come from a friend who doesn't have a whole lot of knowledge about diesels but it made the most sense of the 5 or so that looked at it. He thought a or multiple
cylinders have lost ring compression.,when i add 20% lucas additive the noise quiets some, not all and then when the oil is hot it can be loud again.and then sometimes quieter. Wierd is how i can explain it. I wonder if dirty fuel caused the problem?

Id say this sounds like a bad bearing, especially if adding lucas makes it quieter. If its kinda light like a really bad lifter tick, it could be a wrist pin/injector. If its really heavy and low, id say rod/main/injector. If the knock gets worse under heavy accel, good bet its an injector. If it never goes away sounds more like a wrist pin.

Cracking an injector will also stop a rod knocking if its that cylinder. If crackin them doesnt change anything, its likely a main bearing.

Mine has what im 98% sure is a bad wrist pin. Doesnt go away no matter what, fairly light as far as knocks go in a diesel, but too heavy to be a lifter.

 

[hagmo92]

I am new to the forum and want to thank you all!;
I bought the truck with the knocking and have never worked on diesels before.
so going on leads from different suggestions i bought new injectors and i.p.,
from pensecola fuel injection (they are great and reasonable). I still had that wierd almost hollow knocking sound the funny thing is that when you floor it the sound darn near dissapears, but upon letting up it's right back. I have driven the truck for 1.5 years this way and it has not gotten worse. I have listened to newer( not real new) powerstrokes in parking lots,co- workers, and have found that same knock but only "lighter" I think it almost sounds like it is originating from the cylinder. Which lead me to think "rings". Again thank you all for the help .

 

[hairyboxnoogle]

Well you may know something i dont, but i dont see how rings could possibly knock. If it goes away when floored or when you completely let up, my bet is its a rod/main, crack the injectors one at a time, if it goes away on one, thats the cyl with the bad rod bearing, if it doesnt go away its a main.

 

[icanfixall]

Rings wont knock. A loose piston in the cylinders will cause a slapping sound. Who and how was the timing done when you changed the injection pump.

 

[hagmo92]

i,m not absolutely sure about the rings, the rod knock could very well be the issue. the noise is very hollow, like a dang,dang,dang but not a loose external,definitely internal noise. that 89 F250 did not work out,that motor come to find out was blowing white smoke when it was parked.So i'm looking for other
options . I really like the truck and am not sure if re-build is the answer,i have no experiance with diesels. can the 7.3 be rebuilt or is a crate a better choice?