Sharp tick & knock that started quickly

[jhenegh]

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1994 IDIT that just developed a harsh tick. It’s the truck I’ve had for 9 years now and admittedly had apart a few times, but has been solid for 4 years now.

A month ago, 1/8 mile from home, something let loose and I heard an immediate knock. Got in the driveway and let it idle and it just sounded like a valve train something. I started it the next morning and it sounded worse and was missing & the sound was transferring out of the exhaust too. Haven’t run it since.

Opened it up this morning to look at rockers & valves and they appear fine. Loosening each injector line has the same effect on the engine and doesn’t help or hurt the tick.

Glow plugs all seem to work fine so I don’t think one spontaneously broke off while cruising home.

Any thoughts? It’s not really in my plans to pull an engine in the near future.

 

[Big Bart]

Couple of thoughts

1) Many develop injector knock (Tick) which sounds bad. You may have more than one injector knocking. So usually as you did, undoing the injector line helps find the knock. Again maybe you have more than one, so it does not go away.
2) A compression test would be a good idea, see if something in the engine is hurt. The Harbor Freight unit is cheap, the OTC one on Amazon is nicer. Some members who bought the HF one said they had to cut off some of the tip off the glow plug adaptor to make it fit. They cut the side that sticks into the engine. I see a lot of blow by so a compression test is in order. Blow by is ok if your compression is healthy. (Multiple cylinders contributing some to the overall blow by vs one cylinder creating most of it.)
3) Videos don’t do noises much justice, between the valve clatter, diesel clatter, and belts all I heard was what sounded like an exhaust leak. Perhaps a nocking injector. Did you check for exhaust leaks? A long vaccum line can help. Put one end up to your ear but not down in it. Then use the other end to inspect for a leak. You will hear it if you find one. Also listen to your vacuum pump they can get noisy too and start ticking.

When you put the valve covers back on be sure to do another video for us. It might be easier to hear what you are hearing as different.

Rod knocking is usually quite loud and often gets louder as you rev the engine, I did not hear that in the video.