HDJ80 undiagnosed "knock" (3 Viewers)

[67azcruizr]

1990 LHD HDJ80 has a knock that I've been unable to clear despite long list of corrected possibilities.

Recent work by myself includes; BEB's, injectors, IP timing, Turbo, rebuilt entire exhaust manifold/replaced all exhaust gaskets, cleaned both tanks, flushed fuel lines and replaced soft fuel lines, new filter/Sedimenter, timing belt and tensioner, full valve adjustment, compression test, added mechanical oil pressure gauge, water pump, radiator and fan clutch.

Result, continued knock. I'm beginning to think the knock is just resonating through the engine, starting in between the engine and tranny somewhere!! Any help is greatly appreciated, I'm at my wits end. The video isn't great but hopefully it clicks with someone out there

Thanks for listening, please watch to the end as I go under the truck to the bellhousing.

 

[67azcruizr]

added video

 

[veiloctane]

If you put your hand on the bell housing can you feel the knocking with your hand?

 

[Malahki]

It doesnt sound good!! Did you see my thread and video? Sounds similiar
Need advise on 1HDT tick/knock and recomendation on Calgary / southern AB diesel shop
I need to update the thread but it ended up needing a complete rebuild. I'd say pull the head and have a look

 

[67azcruizr]

If you put your hand on the bell housing can you feel the knocking with your hand?

its not pronounced enough to say yes. the knock is definitely resonating through the entire engine bay, but it is loudest by far directly around the small inspection plate on the bottom of the bellhousing. there was minimal debris at the bottom of the bellhousing, and all the torque converter bolts checked out.

 

[whitey45]

Sean, did you measure the rod bearings,or just replaced with standard size? Does it knock when revved? Sounds like a rod knock , an old trick on a gasser was to remove the spark plug wire from each cylinder until the knock went away or changed sound( your taking the load off of the cylinder thus reducing the knocking sound) Never done it on a diesel, but you could crack each injector line one at a time and see if the knock goes away. Just from past experience, a rod knock will resonate everywhere and is very hard to pin point. Nothing more frustrating. Did it knock before beb swap?

 

[67azcruizr]

Sean, did you measure the rod bearings,or just replaced with standard size? Does it knock when revved? Sounds like a rod knock , an old trick on a gasser was to remove the spark plug wire from each cylinder until the knock went away or changed sound( your taking the load off of the cylinder thus reducing the knocking sound) Never done it on a diesel, but you could crack each injector line one at a time and see if the knock goes away. Just from past experience, a rod knock will resonate everywhere and is very hard to pin point. Nothing more frustrating. Did it knock before beb swap?

It did knock before replacing the BEB's. I decided early on to go over the engine with a fine toothed comb before putting any miles on it. When I dropped the pan to do the BEB's, the piston skirts looked good, there wasn't any unusual discoloration anywhere, the wrist pins seemed fine, actually the original BEB's where in very good condition and very little wear.

Digging through maintenance records on the truck, a complete transmission rebuild was performed less than 25,000 km's ago but than within 10,000 km's there was another rebuild on the transmission, torque converter replaced and the valve body was "welded and machined"! It is the early hydraulic A442F tranny so I'm guessing they could not locate another valve body, but that does not sound good...............,

 

[whitey45]

Unbolt the torque converter to eliminate the transmission from the equation.

 

[mudgudgeon]

Definitely sounds sinister.
Sounds like a hydraulic rock hammer on an excavator. Some thing is getting hammered.

Try using a long screw driver or metal bar as a stethoscope to isolate the knock.
Hold a closed fist around one end and put your ear to your fist, touch the other end against different parts of the block /engine to try and pin point it

 

[67azcruizr]

Definitely sounds sinister.
Sounds like a hydraulic rock hammer on an excavator. Some thing is getting hammered.

Try using a long screw driver or metal bar as a stethoscope to isolate the knock.
Hold a closed fist around one end and put your ear to your fist, touch the other end against different parts of the block /engine to try and pin point it

I've done just this and it's definitely loudest at the bellhousing .......... ?

also found out there were 2 extra quarts of tranny fluid in the A442F today

 

[whitey45]

Screw driver works sometimes, but lower end issues are hard to detect. Almost guarantee its a crank, rod, piston issue, trans will not make that noise at idle..does it knock off idle? Under load?

 

[67azcruizr]

Screw driver works sometimes, but lower end issues are hard to detect. Almost guarantee its a crank, rod, piston issue, trans will not make that noise at idle..does it knock off idle? Under load?

RPM's don't change the magnitude, nor does putting it in gear and holding brake while raising the RPM's.

Raising the RPM's simply increase the speed of the knock.......,?

 

[handcannon]

First, I'm not a mechanic, so take this with a grain of salt. I had a similar knock in my pickup with the 6.5 TD. The knock was engine crank speed dependent, and the volume of knock increased with the speed of the motor. When I finally had a chance to tear the motor down I found a loose wrist pin, and of course several pistons and cylinders showed some real bad scoring.

Don

 

[Greg_B]

Any update on diagnosis: Any TC wobble when running, unbolting the TC and seeing if it changes, loosening each injector line into the injector one at time and see if it changes at each cylinder?

gb

 

[Brutus da 80]

Did you ever get to the bottom of this problem, mine does the same thing

 

[67azcruizr]

Not yet
Swapped transmission to a manual last year and nothing changed.
It doesn’t “knock” immediately, a few seconds into running it starts. It is also blowing a lot of white (unburnt fuel) smoke now.
I’m leaning towards a bad IP, possibly bad delivery(s) valves.
I have no blow by and my compression numbers are very good. When I do the BEB’s I checked the piston skirts and what I could see if the cylinders and they all looked good.
Unless there is a crack in one of the rods, the wrist pins all seemed fine too!!!
Total mystery at this point.
Very troubling.

 

[Brutus da 80]

Not yet
Swapped transmission to a manual last year and nothing changed.
It doesn’t “knock” immediately, a few seconds into running it starts. It is also blowing a lot of white (unburnt fuel) smoke now.
I’m leaning towards a bad IP, possibly bad delivery(s) valves.
I have no blow by and my compression numbers are very good. When I do the BEB’s I checked the piston skirts and what I could see if the cylinders and they all looked good.
Unless there is a crack in one of the rods, the wrist pins all seemed fine too!!!
Total mystery at this point.
Very troubling.

Mine is worse when it's cold,
Yet when it's been working hard an nice an hot , not in over temp but after a good run it's not overly noticeable,
Done injectors, an pump, about go check beb now

 

[Brutus da 80]

Just had transmission out an overhauled, torque converter serviced not 3 weeks ago ,
An still the same...

 

[Brutus da 80]

Have you checked for exhaust manifold leaks?

 

[Andy16]

Mine has the exact same noise. 92 auto 1HDT.

Happens a couple seconds after startup.
Goes away with increased RPM
Quieter when in neutral or park
Sound is coming from inspection hole at bellhousing.
Not sure if someone mentioned this but very rarely the sound will completely disappear, but will quickly come back the next time I drive it.


I'm not sure if it was there before or after my full engine rebuild (7000kms old) but it is driving me nuts and I'm questioning whether the mechanic has stuffed up at some point.

If anyone has any information on this I'd be very grateful!