560 gas motor knock

Brad Vaughn · Sep 28, 2014

Bought a 560 gas that had been sitting outside for a few years. Motor was not stuck, so after rebuilding the carb the tractor ran. There is a slight knock in the motor. At first I thought it was valve adjustment, but that didn't fix the problem after adjusting them. To me it sounds like a ball bearing that is bad knocking together. It's not a constant knock and sometimes it is more noticeable than others. Looking for some opinions on what it might be. Didn't know which end to take apart first. Head or pan. Thanks

notjustair · Sep 28, 2014

So when is this knock? It matters. Some mean main bearings, some rod bearings, some are tappet slap against the cam (depending on the engine). It's when it does it that determines the problem.

Brad Vaughn · Sep 28, 2014

The knock is more noticeable at low idle. When driving down a slight hill the knock stops, but as soon as the motor gets a little load I can hear the knock again. All this is at an idle. At high rpm I can't hear it over the motor. I dumped some sea foam in the oil because it said it would quiet lifters and that did seem to help a little bit but not enough to satisfy me.

Janicholson · Sep 28, 2014

If you are using 10-30 oil, change to 15-40 Diesel grade. If your oil pressure is good, and the thicker oil mellows it some, run it. Jim

CDN 400 · Sep 28, 2014

If you are running low octane gas either drain it and dump high octane it or go buy some octane boost and dump in it and see what that does.I've heard some awful noise with low octane gas in six cylinder tractors.

Hugh McKinney · Sep 28, 2014

My 460 had a slight knock, turned out to be spun rod bearings on several cylinders. Almost ruined the crank before I pulled the head and found that several of the affected cylinders were about a .050 inch lower in the cylinders than they should have been. Caught it in time before major crank damage, but just barely. Just sayin', Hugh

notjustair · Sep 28, 2014

Get it hot so the oil thins a little then listen to it. If it knocks when you load it up or when you throttle it up quick it is a rod bearing. At least in my experience. I had one that I didn't notice when using but after it was hot (like when you were parking it) it knocked like Thor's hammer at idle (lower oil psi) and really bad when you throttled it up, too. The crank was totally toast on that one not just the bearings. Have it pull a hill and it will knock as well. Main bears are deeper down - more of a rumble. Rod knock makes it sound like a diesel if it is all of the rod bearings worn out like mine was.

Do something about it before you have a rod make an escape attempt or the crank is too abused to reuse. If it is knocking the crank will need ground.

d282 · Sep 28, 2014

I believe you have a broken piston skirt. I had the same thing on my 460. The pan is easy to take off, and it doesn't hurt to look things over either. Good Luck.

John A · Sep 28, 2014

Brad, Drop the Pan and Inspect the bottom side!!
15 minutes, Drain the oil, A 3/8 air ratchet /w a 9/16 socket, a rubber hammer to tap right smartly on the oil pan and it is off and you can put a visual inspection on that 263 IH gas motor! If a piston skirt or any thing else has broken off it will be in the bottom of the pan .
Wash out the pan with Gas, also drop oil pump and wash out the screen, dump out the mixture of gas, oil, sludge, and other nastiness but the last part look for metal filings in the bottom of the pan that would be a tell-tale sign of problems. Do not run it more than you have to, If a piston skirt has broken off! A good honing might correct the cylinder so only a new piston is needed! Hope this helps!
Later,
John A.

560 gas motor knock

Brad Vaughn

Member

notjustair

Well-known Member

Brad Vaughn

Member

Janicholson

Well-known Member

CDN 400

Member

Hugh McKinney

Member

notjustair

Well-known Member

d282

Member

John A

Member

Similar threads