Farmall bn rebuilt engine sound

[farmboy1215]

I just rebuilt the engine on my bn. New sleeves, pistons, rod and main bearings. Old bearings were not wore out, so went with the same size bearings. Engine starts up great, and has good oil pressure. It sounds like it has a knock in it towards the back of the engine. Nothing scary sounding, but a consistent knock nonetheless. We dropped the pan, and cannot see anything loose. The engine was tore down because it had a tick that became a knock. Ended up being a screw from the carb that got sucked into a cylinder. Any ideas to what we're missing? Thanks for the input.

 

[Dieseltech]

I just rebuilt the engine on my bn. New sleeves, pistons, rod and main bearings. Old bearings were not wore out, so went with the same size bearings. Engine starts up great, and has good oil pressure. It sounds like it has a knock in it towards the back of the engine. Nothing scary sounding, but a consistent knock nonetheless. We dropped the pan, and cannot see anything loose. The engine was tore down because it had a tick that became a knock. Ended up being a screw from the carb that got sucked into a cylinder. Any ideas to what we're missing? Thanks for the input.

Did you have the rod wrist pin bushings replaced and resized to the new pins, or reuse the old bushings? If fit is loose that will cause noises.

 

[farmboy1215]

Did you have the rod wrist pin bushings replaced and resized to the new pins, or reuse the old bushings? If fit is loose that will cause noises.

I did not. Just used the new wrist pins.

 

[Sprint 6]

Squatch 253 on YouTube recently experienced this on a fresh H engine. He found the aftermarket headgasket he installed had a bore area that was a touch too big, leaving the sleeve edge exposed. So after a heat cycle, one of the sleeves was able to travel up and down slightly, allowing contact with the head.

 

[Dave BN]

Use a long blade screw driver or a long wooden dowel as you would a stethoscope. With one end in your ear press the other end quite firmly on different areas of the engine. It will help you pinpoint the problem.
Dave

 

[Janicholson]

Wrist pin sound is a bit higher in the block and changes (sometimes disappears) at different engine speeds and loads. that fact can define it. a rod that has had some abuse can be the source. Jim

 

[37 chief]

I just rebuilt the engine on my bn. New sleeves, pistons, rod and main bearings. Old bearings were not wore out, so went with the same size bearings. Engine starts up great, and has good oil pressure. It sounds like it has a knock in it towards the back of the engine. Nothing scary sounding, but a consistent knock nonetheless. We dropped the pan, and cannot see anything loose. The engine was tore down because it had a tick that became a knock. Ended up being a screw from the carb that got sucked into a cylinder. Any ideas to what we're missing? Thanks for the input.

What does the sound do, if you push in the clutch? Stab

 

[used red MN]

I did not. Just used the new wrist pins.

How hard did the screw hit the old piston. I also suppose you didn’t have the rods checked for being straight. The one that was in the hole the screw went in may be bent slightly and could cause this noise.

 

[560Dennis]

What was done to the oil pump in this rebuild ?

 

[farmboy1215]

What does the sound do, if you push in the clutch? Stab

Sound does not change

 

[farmboy1215]

What was done to the oil pump in this rebuild ?

Oil pump was not touched. Pressure runs in the middle of the gauge

 

[560Dennis]

Oil pump was not touched. Pressure runs in the middle of the gauge

Case IH FARMALL BN - TRACTOR(01/40 - 12/47) Parts Diagrams

Case IH Parts Catalog Lookup. Buy Case IH Parts Online & Save!

www.messicks.com

Is the some noise coming from the oil filter area?

 

[farmboy1215]

Case IH FARMALL BN - TRACTOR(01/40 - 12/47) Parts Diagrams

Case IH Parts Catalog Lookup. Buy Case IH Parts Online & Save!

www.messicks.com

Is the some noise coming from the oil filter area?

I don't think we listened to that specific spot. Just noticed we heard it best at the back of the block, and below the fuel tank.

 

[olddog]

Loose flywheel?

 

[farmboy1215]

I just rebuilt the engine on my bn. New sleeves, pistons, rod and main bearings. Old bearings were not wore out, so went with the same size bearings. Engine starts up great, and has good oil pressure. It sounds like it has a knock in it towards the back of the engine. Nothing scary sounding, but a consistent knock nonetheless. We dropped the pan, and cannot see anything loose. The engine was tore down because it had a tick that became a knock. Ended up being a screw from the carb that got sucked into a cylinder. Any ideas to what we're missing? Thanks for

Wanted to give an update. Pulled the head today. Cylinders 3 and 4 are hitting the head on the side of the fire craters, not on the top. Thinking about just reaming that lip on the head down and eliminating the issue.

 

[used red MN]

Cylinders 3 and 4 are hitting the head on the side of the fire craters, not on the top.

I doubt you have NOS IH “Fire Crater” pistons. They wouldn’t hit the head unless it was milled a bunch. You have aftermarket “step head” or pop-up pistons. Just wanting to be there for the IH purist. Too bad you had to tear it back apart.

 

[farmboy1215]

I doubt you have NOS IH “Fire Crater” pistons. They wouldn’t hit the head unless it was milled a bunch. You have aftermarket “step head” or pop-up pistons. Just wanting to be there for the IH purist. Too bad you had to tear it back apart.

Correct, they are aftermarket pistons. I think I will put a burr wheel on a die grinder and ream the head back a little where it is hitting.

 

[RedRamGT]

Wanted to give an update. Pulled the head today. Cylinders 3 and 4 are hitting the head on the side of the fire craters, not on the top. Thinking about just reaming that lip on the head down and eliminating the issue.

I had that problem with the domed pistons on a Farmall A that I rebuilt a few years ago. I just took a little off each piston dome, on the side that was hitting the cylinder head. Problem solved.

 

[Dennis K (WA)]

I had that problem with the domed pistons on a Farmall A that I rebuilt a few years ago. I just took a little off each piston dome, on the side that was hitting the cylinder head. Problem solved.

That is what I would do also. Why take a chance of damaging the head when the pistons are the problem.

 

[rustred]

curious as to what sort of glue u used on that head gasket to tear it apart like that. that gasket should have been good yet if it is a fresh rebuild. its only a gas engine. i use permatex high tack sealer and easy removable.