NAA engine knocking

[Rob J]

Hello again! thought i'd create a new post for my knocking noise. (now that i know its a NAA instead of a 600, thanks to you guys) Now the guy that sold me this tractor said the loader was too big for the little tracker so the fan was banging on the shroud. But also I have no oil pressure on the gauge. Maybe the gauge doesnt work? my temp. gauge is the only gauge that works, everything else doesn't. So i was thinking I would have low oil pressure if i had a rod bearing out, but it still would register low oil pressure and not 0, correct? maybe oil pump is out? or maybe its as simple as the fan banging on the shroud and my oil pressure gauge is just broke?.. I know it's extremely hard for you guys to diagnose an engine knock noise problem on paper. It's a steady knocking noise, doesn't matter if the rpms are low or high. its not perticularly loud, you just know its there. Was wondering if the fan banging on the shroud makes a similar knocking noise caused by a bad bearing. Thanks, Rob J

 

[old]

Well you can try this to see whats up. Take the oil pressure line loose where it goes into the side of the engine and spin the engine over. Don't turn on the key, starter will if wired right still turn the engine over. You should get a good flow of oil if you do that. If you don't then you may have big problems. You can also loosen up the fan belt and start the engine and if the noise goes away you know its up front and may well be the fan but not likely
Hobby farm

 

[Rob J]

I can just use a screwdriver (or a piece of 0 gauge wire) to connect the terminals to turn the starter over correct? used to work well with my old mustang.

 

[GlenIdaho]

Rob;

If the fan is hitting the shroud it is probably because the front axle center pin is worn out. The center pin bears a lot of stress due to the loader. The noise from a rod and the noise from the fan hitting the shroud are going to be somewhat different. Loosen the fan belt and turn the fan blade by hand and you'll find where it is hitting, if it is. To check the center pin you can jack the front of the tractor up so the front axle is free to move. With some help you can try moving the axle side to side, back and forth etc to see what kind of play tou have. There should be none. You might take the front wheels off to lighten the front end up. Be sure to use jack stands to stablize the tractor and use the apropriate safety precautions.

Go with what Old told you first, because as he says, if you have no oil pressure you have some potentially big problems.

 

[old]

Well if its wired as it should be the starter will work with or with out the ignition switch on or off. Ford used a grounding system start on there older tractors and as I said if wired right that push buoon on top of the tranny will spin the engine no matter what you do to the key.
Hobby farm

 

[Rob J]

Theres an inlet hole on the side of the push button, is something suppose to lead into there? or is it a breather hole? nothin happens when i push the button. Also i don't know if there was an aftermarket ignition key installed on this tractor, its a turn key start type, no button start like the select-o-speeds im used to.

 

[Dan]

You say "...It's a steady knocking noise, doesn't matter if the rpms are low or high. its not perticularly loud, you just know its there...".

Are you saying that the noise does not speed up or slow down by varying the RPMs - or that the noise does not increase in loudness with the varying RPMs? If it does not speed up when you increase RPMs - then it has nothing to do with the fan or the engine internals, as they both speed up with increasing RPMs. If it just does not get any louder as it speeds ip in frequency - then it could be quite a few things. Using a mechanics stethascope (or a long screwdriver, wire, piece of tubing, etc.) can really help you isolate and locate the source. If you do hear that it is coming from the engine, pull ONE spark plug at a time and see if the noise goes away or greatly reduces to isolate the rod that may be knocking.

Before doing anything of course, make sure you have oil pressure and don't run the engine until you do.

Good luck,
Dan

 

[old]

Its been rewired then. So the easy way to check the oil flow would be to pull the coil wire off and then trun the key. That way it can't start up on you and if it has oil pressure spray oil all over the place

 

[Rob J]

I tracked the oil pressure line. And i am unable to take it out because the hydraulic pump is in the way, the line leads in back of it. too tight to even get my fingers in...also i tracked the knock to one of my cylinders by process of elimination. when i remove the plug from the knocking cylinder the knocking reduces greatly, I hope its the bearing and nothing more.... :-/

 

[Charlie C.]

Guys how about a wrist pin knock but that should change with the rpm?

 

[john_Bud]

Not to sound like a real AH, but drop the pan and check the rod bearings! If you keep running it you may find out that it was worse than you imagined. You can find the bearing size needed and replace easily.

I had a buddy long ago that was "proud" of his engine knock. See it knocks! And would rev it up. He claimed it didn't harm the engine at all. I was not there when the rod parted company with the block.... The replacement engine didn't knock.

jb

 

[john in la]

Wait a minunte.
Why not look at the fan. If it is hitting the axle or the shroud you should be able to see where it is hitting. You could even take the fan belt loose and start it up and see if you still have the knock.

That sure seems like a lot easier than dropping the pan and checking bearings or gussing what the oil pressure is.
Also; if you had "ZERO" oil pressure the motor would be locked up.

I will reserve my right to post a answer to your question in the other thread of did you pay to much after you find out what all is wrong with this tractor.
The cracked hyd housing has me worried the most. Sure sounds like this LOADER tractor has seen better days.