situation with a 1979 international harvester( 345 cid engine)?

A mechanic's stethoscope will help find where the knock is. I would listen closely around the cylinder that is misfiring, and around the oil pan. You may need to remove the valve cover and check the clearance. They are not adjustable. If you think it is a stuck lifter, I would add Marvel Mystery oil to the engine oil and run it. Many times it will free them up.

You didn't say how the oil pressure was.

International 345 Engine

A rod knock is a pretty distinctive noise. Without being able to listen to it, there's not much of a chance of diagnosing through Yahoo! Answers but a rod knock:

1) gets worse under load

2) pretty much never goes away

3) sounds like someone hitting the engine block with a hammer

The other answer mentions lifters. I agree that's a good thing to check. If a hydraulic lifter is bad, that causes the cylinder it's on to not fire very well also. And sitting for a long period of time is a good way to have a bad (stuck) lifter.

You can try chemicals on hydraulic lifters and it might help. One time, my dad had me remove the hood from our family car -- getting ready to tear the engine down because of a terrible noise and the engine running really bad (my fault for driving it like a maniac). I worked at a gas station and decided to try dumping almost every chemical they had in the engine just to see if it worked. Son of a gun, in about 10 minutes, the lifters (more than one) freed up! The car ran great from then on. I got to put the hood back on and we were done.

After reading the additional information you provided, my guess would still be lifters. A collapsed hydraulic lifter makes a really bad noise and causes that cylinder to run weak, or misfire.

Any bearing issues will eventually get worse. You won't have trouble diagnosing things then :-) If he made any mistakes in reassembling the engine like rod caps swapped, pistons in the wrong cylinder, etc. that could account for the noise. If he's good at rebuilds, my apologies, I'm just listing some possibilities.

This Site Might Help You.

RE:

situation with a 1979 international harvester( 345 cid engine)?

just got the truck running last month for the first time on, well since i have known the owner ( 9-10 years). now it has a miss ans what sounds like a rod knock. he replaced the connecting rod bearings and main bearings twice, plasi-guaged them in between to confirm tolerances. we have replaced...

You could have the timing 180 out?

when you are setting the engine timing, hook up timing light lead to NUMBER 8 CYLINDER the timing should be TDC,

Bad gas ?

index the plugs?

Coil ?

baluster?

If its Hei it could be an ignition module. or the internal connections from the the coil.

Knocking could be timing detonating

Check for message boards about IH maybe someone else has had the same problem.

good luck hope it is something little and stupid.

Use the old poor mans stethoscope an extra long screw driver to the ear trick for listening to your engine. Put the handle up against your ear and the tip on the running engine. Not as good as a stethoscope as mentioned below but it works pretty good.

Good question and sounds like you know what your doing. Hmmm.... am i interrupting this right? the truck hasn't ran in 9-10 yrs?. Sure it ain't stuck lifter? tat, tat tat? or rod bang bang bang? Sorry buddy sounds like a spun Main Bearing. With truck running pull a plug wire at time and see if it isolates the noise if it does Aint a main. it's a wrist pin keeper. International design. this may sound stupid but when you put the bearing in did you coat them with anything and are they seated in correctly.. Hmmm another stupid idea: Auto Tranny? are your torque converter bolts to long banging on the side of the flywheel.(Believe it or not I once did it) Hmm. My friend you got me stumped. Hmmm... now you said HE.. replaced the bearing not you. Pull pan and see if one of the bearing are not sitting correctly in its bridge port (the little slot that holds the bearing correctly) and check to see if one of your wrist pins retainer (between rod and piston didn't fall off or is gone. remember it's an International. slightly different design internally. Good luck and sorry i can't help you, By the way nice GTO 400 4 spd heh

Did you check the tolerances in the valvetrain ?

Replaced the lifters ?

What about the cam, cam bearings ?

I mean jeez, it is a 30 year old motor after all........

oddly, this was not my q but i get emails about it.