High oil pressure

[wonderingAl]

A 1953 super M has a high oil pressure, top number on the gauge. The oil is checked..both "petcocks" (spelling?) have oil coming out when loosened. radiator is good, engine sounds good but why high oil pressure? Temperature gauge is in the cold range also. To the kicker,...driving it slow in 1st gear, cold morning, engine had warmed up...and heard a LOUD "bang" from the engine area, then from an otherwise nice sounding engine...comes a "knock-knock" sound as the engine ran. Quickly put tractor in shed..close by thank goodness. Several hours later turned it over again to confirm...knock still present with some thick black exhaust...turned off fast and plan to let it sit until figure things out. Any ideas on the high oil presure? Any ideas on the "bang" and then the knock-knock noise...the black exhaust?

 

[City-Boy McCoy]

Couple of thoughts. I have a super H that pegs the needle almost all the time. I have never worried about it. In fact, I'm grateful. However, assuming the worst: High oil pressure could be wrong oil (too thick) or, even worse, I've heard of swindlers putting gear oil or STP in a badly worn engine. Could also be that someone rebuilt the engine and used the wrong bearing sizes, meaning the clearances on the rods and/or mains are too tight. Could be you just have a bad oil pressure gauge.
On the bang, if you are very lucky, a piece of carbon came loose from a dirty combustion chamber and is lodged on top of a piston, stuck to the head or partly lodged in a valve seat. You might also have a sticking valve or a broken valve spring, or a bent pushrod. I'd pull the valve cover and see if all 8 valves are moving up and down like they should. mike durhan

 

[High Octane]

If it has live hyd,,, Id be checking the cam gear. They do come loose and can slap the timing cover, bust off a tooth, and sound like a rod knocking. Also, pull the valve cover, and the lifter pan, pull the lifters out, make sure they are good, might have one that has a nick/bad spot, and can make some noise. Could be oil pump gear, could be a piston hitting the head,, say they put a new overhaul kit in it,, from a 450,,, if the SM had the old style head, with the new style pistons,, (from a 400-450) the domes will hit the older heads. The 400-450 domes are wider than the M-SM pistons with the older gas heads,,, Also, could be the little part, that holds the lifters from falling out,,, it could have been bent, or put on backwards and slap the lifters,,, High oil pressure,,, best to check the relifef valve inside the pump,, see if the piston, spring and ball is freely moving, could be sticking and shoot the oil pressure up,,, this can also overwork the pump,, causing the gear to loosen, overstessing the cam in its bearings, and possibly wiggling the cam gear loose,,,, Id pull the head and pan off, and the timing cover and have a closer look. JMHO

 

[Janicholson]

An odd idea easy to check that adds up.
If a screw came out of the choke plate, it might have swallowed it causing it to be embedded in the top of a piston causing the racket, and jambing the carb plate in a way that causes excess fuel (black smoke).
If it has been having black smoke for more than a week, it may be the carbon described earlier.
The carbon could go away with a pretty simple treatment, but it is important to make sure it is carbon before assuming it is. If carbon, running the tractor at 1/2 throttle and spraying a mist of water in the intake of the carb (to the point that it wants to die, but does not, then recovers) until about 12 OZ it sprayed through can loosten it. (No guarantee, and do not use a stream of water that could cause a slug of it to enter. JimN

 

[Janicholson]

Oh yeah, ignore the oil pressure problem, especially if it is not pegged when fully warm and at Idle. JimN

 

[mkirsch]

Ignore the high oil pressure, the bang and the knock? I don't think so...

What may have happened is, an oil galley got blocked, causing the high oil pressure and preventing oil from getting somewhere in the engine. The bang was that unlubricated part breaking.

You're going to have to pull the valve cover and the oil pan, and maybe even the front cover to find the knock.

 

[Andy Martin]

Since the SM has a bypass oil filter, it was very unlikely a plugged oil gallery. I have always found that high oul pressure was from a bad gauge.

The bang and knock is probably unrelated but must be investigated and probably warrants disassembly. It may be as simple as a bent push rod, but you don't know until you look.

By the way, oil should only come out the lower petcock, but too much oil will not have damaged your engine.

 

[poogie]

Read Operator's Manual. Oil should be to the TOP petcock!

 

[Andy Martin]

Yeah, some manuals say to keep it between the petcocks. There is absolutely no reason to "top one off" just because it has used below the top petcock. If it is running out of the top petcock, how do you know you don't ahve a load of water in it? How do you know you don't have two or three quarts too much, which would make the oil foam?

When it won't come out the lower, you add a quart and keep going. I've got one old M that uses some oil, and we work it hard pulling a round baler. I've had to add 3 quarts because I got busy or had a hand using it, but if one does not lose oil pressure you didn't damage the engine.

They are not Swiss watches and don't have to be trated as such to get 60 years service (and counting).

They turn so slow, if you keep oil in them and water in the radiator they are just about bullet proof.