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What are the best steps to rule out either an exhaust leak or possible failed injector? My 4840 recently started ticking/knocking towards what appears to be the top of the engine. It's very faint when at idle and gradually louder when throttling up, but the moment its got a load on it the noise can be heard from within the cab. I'm assuming its piston slap or a wrist pin but trying to diagnose everything before tearing it apart. Any pointers would be appreciated.
Thanks!
 

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The tractor seems to run great. It has a minimal amount of blow by. I just dont want to dig into the engine only to find the issue elsewhere. Did your tractor have the same symptoms where it still ran great just had the same tick noise?
 

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I bought a nice second hand 4630 from the local dealer in the 80’s. When spring came I found out two different sounds could be induced with the throttle. The first one was a high pitched sqealing sound that turned out to be the lower radiator hose collapsing at high rpm. The other noise always began as a faint tapping that would grow louder. Eventually I dropped the pan to remove the rod caps and inspect the bearings. It had one loose rod bolt that you could turn with your fingers. On some jobs the harmonics would cause it to snug up and quit flexing the cap causing the tapping and in other situations the sound would scare you into idling it down and the bolt would rotate inward and stop the noise, sometimes for hours. This is an unlikely scenario but possible.
 

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The tractor seems to run great. It has a minimal amount of blow by. I just dont want to dig into the engine only to find the issue elsewhere. Did your tractor have the same symptoms where it still ran great just had the same tick noise?
didn't really effect unit even not really a detectable miss, when running loosen the injector lines individually and see if it changes, thats how I found mine , I changed injector and it didn't change. If you find the effected cylinder. remove injector line and unscrew the cartridge in to of pump, there is a copper sealing washer in plain view ,it could be cracked
 

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Neighbour's 8210 with 8.1L engine had a similar sound that turned out to be an exhaust gasket. As white owl mentioned the best way to find the affected cylinder is to crack the injector lines and listen for a change or no change. In the case of an exhaust gasket we used a good light and an inspection mirror to look for black soot. Also found a broken exhaust manifold stud on another cylinder when we started to take it apart. that one hadn't started to leak......yet.
 

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Take an oil sample and send it in. Know if it is serious and needs torn down before major damage occurs. For a quick check for metal, cut the oil filter open, cut out a few pleats of filter material. Put those pleats in a rag or two and squeeze the oil out with a vise. Simply look for metal or something bad in the filter. Then, injector line cracking is good. Can probe around with a mechanic stethoscope. A stethoscope with a metal rod on the end.
 

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I bought a nice second hand 4630 from the local dealer in the 80’s. When spring came I found out two different sounds could be induced with the throttle. The first one was a high pitched sqealing sound that turned out to be the lower radiator hose collapsing at high rpm. The other noise always began as a faint tapping that would grow louder. Eventually I dropped the pan to remove the rod caps and inspect the bearings. It had one loose rod bolt that you could turn with your fingers. On some jobs the harmonics would cause it to snug up and quit flexing the cap causing the tapping and in other situations the sound would scare you into idling it down and the bolt would rotate inward and stop the noise, sometimes for hours. This is an unlikely scenario but possible.
Wow. Can’t say I’ve heard that one before. Did you buy a lotto ticket after finding that loose rod bolt?
 

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Wow. Can’t say I’ve heard that one before. Did you buy a lotto ticket after finding that loose rod bolt?

No. I bought an OEM piston, sleeve and the rod assembly because the piston had an either crack in the crown and then hooked it to my dad’s new Hesston 60A stacker and let it howl, until I traded the silly thing for an 8640 so I wouldn’t have to steer with the brakes or get shaken baby syndrome.
 

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However, climbing out of creeks blowing hay making smoke and power shifting with the front wheels in the air while watching free TV is still a lasting memory of the venerable 46.
 

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What are the best steps to rule out either an exhaust leak or possible failed injector? My 4840 recently started ticking/knocking towards what appears to be the top of the engine. It's very faint when at idle and gradually louder when throttling up, but the moment its got a load on it the noise can be heard from within the cab. I'm assuming its piston slap or a wrist pin but trying to diagnose everything before tearing it apart. Any pointers would be appreciated.
Thanks!
Often a ticking sound that gets louder with increased power can be traced to a leaking exhaust manifold.
 

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Often a ticking sound that gets louder with increased power can be traced to a leaking exhaust manifold.
Had that scenario on my cat 855. Thought it was an injector gone out but as rpm increased it went away antil under heavy load. Fuel pressure dropped and turbo pressure dropped looked by the manifold and could see soot staining. Gaskets were cheap but I drove it too long before fixing and it fried the manifold too.
 
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