4430 with knock advise

I know diagnosing a knock without being there is near impossible but.....

My 4430 has a knock starting when it gets to about 1200rpm and gets worse from there. It comes from the center of the engine, in the upper part like in the cylinder area. Between cyls 3 and 4. I'm not sure but from the sound it could be piston slap, a bad piston pin bushing. It might be but I don't think it's the piston hitting the head.

The engine has good oil pressure. I set the engine speed so it just barely knock and loosened the injector lines and there was no change in the level of the knock.

No it's not the pump coupler. That's the first thing I tried.

Anything else to try or look for before tearing into it?
Anything to look for while tearing into it?

Any helpful advise is appreciated.

Water pump ? check bearings for any play at all with engine shut off of course.

How many hours? Cousin had two 4630's that the rings liked the top of the piston more than the sides, unknown hours. I had a small flexible light that I could put down the injector hole to see. But then I could tell which hole by cracking the injectors. chris

The hours are unknown. I should have added this is a combine engine I put in two years ago.

Drain the engine oil into a clean 5 gallon bucket. Then pour it through some paint strainers to see if you catch some bearing material. If the rod bearing spins that allows enough space for the piston to hit the head and the valves. I usually catch the first few quarts out first, that's where you catch most of the metal if it is a bearing

Loosen the injector line on each cylinder, run and see if knock goes away, do not get squirted with high pressure fuel.

Yea I did that as stated.

Sorry, missed that.

The noise should change if it is a rod or piston issue.

Did you check your valve clearances, I have heard them pop back though the intake if the exhaust does not open.

That's my next step. I haven't opened it up yet. Wanted to gather advise first. The knock sure sounds mechanical and solid like a piston knock.

I have one doing the same thing, also with a combine engine. Between cyls 3 and 4. I am getting ready to tear it down.

Neighbor's 4230 did that three years ago, knock above 1400, quiet at idle. Disconnected all front drive accessories, and hydraulic pump, noise still there. Dropped the pan, found # 1 had a rod bolt laying in the pan. Mechanic asked me what I'd do, told him I'd be afraid that rod is due to break. Tightwad owner had the mechanic just put the bolt back, and recheck the rest. Still running fine now, but I'm sure my luck would not have been so good..

I do not have that kind of luck either.

WOW I'd want to look at the rod bore and make sure it's ok and not worn from the bearing shucking. Then if all looked ok I'd put a new bearing in that rod. Would still be afraid the bolt would come loose again.

My first guess is a burnt piston..open it up and look before it gets worse,,and it will...

Sounds like a broken rod bolt

I have seen this a few time the past 5 months, and it was the burnt piston all but once...

hello, just another opinion as i've been here a number of times in the last 40 years. IF the knock is up top there is a good possibility the piston is hitting the head, SOO that means the piston is traveling tooo high,,which means a loose rod bolt or a spun bearing. IF!!! this is the case,, i have some useful experience to share if you want it. the original rods had NO HOLLOW DOWELS in the bolt together area of the rod & cap, soo,, that means they were originally torqued to spec. and left to be good. i believe the ''40'' series tractors' certainly the ''50'' series had the newer rods with the hollow dowels. what i'm getting at is this,, IF you want to fix it 'RIGHT'' YOU NEED to put it together with EITHER THE NEWER RODS or,,TORQUE TURN NEW ROD BOLTS in your good used rods & send them to the machine shop to be trued up in the bottom end, as the old style rods get crushed out of round with this torque turn procedure. get new rod bolts as they are the TORQUE TURN TYPE,,the old bolts are NOT designed to be stretched, either way you NEED to torque turn the rods as this prevents rod bolts from coming loose. if,,you have the newer rods,to be safe, torque turn new bolts in them and have the machine shop check them. ''TORQUE TURN'' means, torque the new bolts '55' ft. pounds, mark the head of the bolt & turn an additional '90' degrees,, or 1/4 turn.. oil the bolt under the head & threads. i've been there at this repair procedure a number of times. HOPE you find a smaller problem than this..

Around 3000 hours the injector pump rack gets worn and letting the cyls. get more fuel as well as out of time , Can cause pistons to burn as well. Yeah I know you have a tractor that has 15000 hrs. and its ok, just saying been there done that . I went to BOSCH PUMP school 1978 and worked on them for 10 years . I learned first hand how they wear .Also the tip can blow off of an injector and cause that knock .

It was common on those engines for a rod bolt to loosen.
The knock is from the piston bumping the head starting at higher rpm.
The other bolt will eventually break where you can see the rod sticking
out the side of the block.
Do not try just replacing bolts as many times the tongue groove on the
rod or cap is cracked. This will cause you to spin the bearing and ruining
the crank.

I got the head off today. Nothing obvious yet. The pistons seem a bit sloppy. None of the liners are scored, well worn though. The head doesn't look like the piston has been hitting it. Tomorrow the pan comes off.

That's when I attended Bosch school too.. Maybe we were in the same class! LOL