Video: Diesel engine knocking noise

[billyonemate]

Hi All,

Am trying to work out the source of the heavy knocking noise on this Jeep Diesel engine (see video link below). The oil cooler failed and it did overheat as there was contamination of the coolant with oil. Oil cooler now replaced and coolant flushed. Now coolant is good with no contamination, but there is this metallic knocking noise, any thoughts what it might be?

http://youtu.be/Ux9mR-hmguU

thanks

 

[billyonemate]

Thanks for your helpful suggestions, really appreciated and has kept me really well informed.
I am still waiting for a full diagnosis. But I had a guy come round this morning and have a quick look, its common rail and he loosened off the fuel intake on the middle cylindar and reckoned it wasn't that, loosened the second one and it looked like the noise died a little. It started fine cranking over and ticking over ok so he thought the compression was fine. The follower seems to be fav at he mo. He gave me the number of an engine guy who said he would take a look when he is next down my way which should hopefully be this week.

i will keep you posted, the cranking issue is not a problem now at all (that was because i had to disconnect the fuel lines to get the oil cooler off when i was replacing that)

thanks again

 

[patprimmer]

Isaac

If you fail to undo a bolt or two at one end of the head and use a really long breaker bar lifting at the other end, you might remove most of the head. ;-)

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[BigClive]

Thank you Billy - let us know what happens - it is an interesting problem.

 

[billyonemate]

UPDATE: the jeep has been off the road for 2 months now as getting parts at a resonable price here is not easy. But have eventually got some new injectors (at suggestion of local diesel engine specialist) imported, they have been put in, but the knocking noise is stil there - dissapointed - where next?

BigClive seems the most likely "Probably just a very wide rocker clearance (like 1/8 of an inch) caused by a dead hydraulic lifter or bent pushrod"

 

[dicer]

Not much knocking when its cranked? An exhaust leak can sometimes sound like a knock. Why haven't you removed the valve cover and examined it? Run it with the valve cover off.
It does act like a low cylinder when cranking.

 

[winfieldblue]

I will bet my left foot that you have at least spun a big end bearing.......That sounds just like my toyota diesel when I spun a bearing....There is definitely low compression in at least one cylinder as mentioned earlier....you need to take it apart, trying to fix it with bolt-ons is going to get too costly!

 

[billyonemate]

finally got the valve cover of ... not so simple as required either dropping the engine or drilling some holes in the bulkhead to get the injectors out ... went for drilling the holes in the end.

anyway here's a video of it cranking with the valve cover off, notice it cuts near the end after we take one of the cams off, i'm still confused as to what is causing the noise though - any thoughts ?

http://youtu.be/zF14UVlkJsw

 

[BigClive]

How do you make that video work?

 

[billyonemate]

does this link work?

[URL unfurl="true"]http://youtu.be/zF14UVlkJsw[/url]

 

[billyonemate]

or this one?

[URL unfurl="true"]http://www.youtube.com/watch?v=zF14UVlkJsw[/url]

 

[BigClive]

No - neither of the two new links work for me.

 

[billyonemate]

what about this one?

[URL unfurl="true"]http://www.youtube.com/watch?v=zF14UVlkJsw&feature=youtu.be[/url]

 

[billyonemate]

THIS ONE WILL DO II - sorry, the editor does not like it if you put http:// at the front of a URL!

got there in the end!


www.youtube.com/watch?v=zF14UVlkJsw&feature=youtu.be

 

[BigClive]

Billy - thanks for the video.
A twin-cam, four-valve diesel? So much for theories about bent pushrods and damaged lifters etc.

 

[dicer]

Any news on this one? Did you find the problem?

 

[billyonemate]

well, four months on and we have finally got the head off and got to the bottom of it - did anyone go for piston ring?

[link youtu.be/4m0dLbrenws]youtu.be/4m0dLbrenws[/url]

 

[patprimmer]

Mike Halloran did.

Several others suggested compression checks which at least hinted toward piston.

That twin rail thingy all jammed up with scuffed off piston bits is an oil control ring.

You still need to ensure you rectify the cause for the piston to scuff up like that. It very nearly seized. It is probably a result of overheating, but also possibly poor timing. Basically the piston got to hot and grew to much for the bore.

The bore might also now be out of shape.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules

 

[winfieldblue]

That first piston looks to have a discolored upper big end bearing,take a closer look at it, my left foot is at stake here!

 

[billyonemate]

yes, well done mike, and thanks everyone for the help over the last four painful months, hopefully it's a rebore, new rings, skim and put back together job now - hopefully...

 

[patprimmer]

If the bore is still relatively straight and round and within spec on dia, a simple hone and one new (or even second hand) piston and new rings might suffice if on a tight budget.

I would at least check all the bearings as the load from that damage being caused may have harmed them. Also the metal contamination may have found its way to the galleries and bearings and oil pomp.

Regards
Pat
See FAQ731-376 for tips on use of eng-tips by professional engineers &

http://eng-tips.com/market.cfm

for site rules