Briggs Z 1942 Out Put Shaft "Gets HOT"

Handiman

Subscriber
Hello All
I have a 42 Briggs Z with the oil pump (no slinger,dipper). The output shaft gets hot after 30 minutes of running with no load. I don't think that's normal .
The housing and bearing the shaft goes through is only warm as the rest of the engine.
Any Ideas?

Ted
I'll post pics later!
 

Kevin O. Pulver

Email NOT Working
My initial thought is that it's not normal. But I don;t know that for sure, and there might be enough friction on the rod bearing that it heats up the crank and transfers the heat to the output end of the shaft.
If the case is aluminum, it may dissipate the heat from oil, etc... quicker than the crank can.
If this was caused by something AB-normal, I would suspect that it would be making noise or acting like it was laboring/pulling down.
I'm sure someone here with actual experience will chime in soon.
Kevin

---------- Post added at 08:23 PM ---------- Previous post was at 08:21 PM ----------

I suppose I should know that a 42 has a cast iron crankcase, but I'm not even SURE about that!
 

Road Torpedo

New member
What is your definition of hot?

Hot as in: cant touch it, burning kind of hot? or Warm hot were could not comfertably hold the shaft for a lengthly period of time?

Keep in mind, these things were cast iron and steel. These metals do not disapait heat as quick as the new engines.

A crank shaft is gonna get fairly hot. Even when idling long enough.

If it gets hot quick though, no, that would not be normal.

Other than heat, what is your other concern's?

Is the engine "pulling down" such as, loosing power? Does the crank feel as if it has a parasidic load on it when you go to start the engine? Do you hear any squeeking or gulding noises coming from the bearing?
 

Andrew Mackey

Moderator
What weight oil are you using? i believe the ones with the pump needed SAE 20 oil. Are you sure the pump is working? I would pull the base, and checl the pump. Have a look at the bearings, and make sure all oil passages are clear. Do you have enough end play in the crank? If there is no endplay, cold, then the crank could be binding, as the engine warms, and the crank expands. The gasket behind the mag mount plate, sets endplay. they come in various thicknesses, or you could double them up to set endplay.Proper oil level? Too much, the pump will not work correctly. Dirt in intake screen? Too low oil level? Like othes have said, warm is one thing, too hot to touch is another.
Andrew
 
Since its a Briggs model "Z" they are made of cast iron. At least Im gonna suspect it is. Coz Im looking at a Briggs model "ZZ" and its all cast. Crankshafts have alot of load on them, and normally DO get hot. I dont know how hot the OUTPUT is sposed to get upon idling, OR even running on no load for that matter. SOOO my best guess is it MAY be ok, or it may not be. I dont know for sure. I know on vehicles they DO get too hot to touch. I also would THINK that the bearing end spacing is set by multiple thin sheets of gasket material. I KNOW thats how the tapered bearing preload is set on my Wisconsin AHH. But thats a Wisconsin, not a Briggs. Plus ive never torn apart a Briggs model Z or model ZZ. Part of the reason I want this one model ZZ im looking at. All things in time tho. I need a job first, and to reassemble the AHH wisconsin seeing as the painting is compleate.
 

Handiman

Subscriber
Well,
Thanks Good Information! The shaft gets very warm I can hold on to it but you know something is not correct. Shaft end play is around .004" (.002 to .008" is okay ?) The oil is 10W30 , its right up to the top of the filler neck. I have pulled the base and the screen was clean, pump discharge pointed at the bottom of the piston. I figured if the pump wasn't working good it would be making a bad noises or binding by now. I'm wondering if I should
pull the output flange and check it out don't know anything else to do.
Any further thoughts?

Ted
No pics yet can't get the computer to corporate!
 

Road Torpedo

New member
How long does it take for the shaft to get hot?

If your not experiencing any strange noises or the engine doesnt seem to "pull down"; I'd say your perfectly fine.

Like I and others have said, these engines were cast iron and steel. Those metals do not disperce heat quickly and it's normal for a crank shaft to get hot within engine operating temp.
 
L

Lead Head

Guest
If you can hold the shaft more more than half a second or so, then it is not any hotter than 130-140*F.

Air cooled engines under load can run up to 300-400*F on the cylinder and cylinder head, and it is typical for them to run oil temperatures of 250-275*F if not higher.

Combustion temperatures can easily exceed the melting point of aluminum. The only thing that stops air cooled engines (and any engine really) from melting down is oil splashing all over the place.

You have an oil pump that is squirting oil directly at the bottom of the piston to cool and lubricate it, which is taking a ton of heat from combustion. That will heat the oil up much faster, which in turn will heat the crankshaft and everything else up.

In the grand scheme of air cooled engine things, 140*F is pretty much stone cold. I wouldn't worry about it at all unless the engine sounds labored or starts making undesirable mechanical noises.
 

fordiesel69

New member
One wind of black electrical tape - single thickness. Do not wrap it a few times, just once. Then aim a infared thermometer and take the reading. I bet the reading is normal. I had a honda power washer that got hot on the shaft but somthing in the engine was getting tight at the same time. I pulled the pump to rule that out and the engine still got tight as it got hotter.
 

Handiman

Subscriber
I checked temperatures, shaft was about 125°, head 200°, exhaust nipple 300°. I pulled the output flange and check the seal, bearing and oil drain hole. Everything looked and felt good (cleaned the shaft under the seal, lubed everything with Lucas ). With the black tape on I'll run for 30 minutes check temperatures and check again at 1 hour. I'm working late today let you know what I find out tomorrow.

Ted
 
L

Lead Head

Guest
125*F is nothing to worry about at all. Think about, the head with fins and constant air cooling is sitting at 200*F, while the only cooling the piston has is the oil shooting at it, and a brief period during the intake stroke. All that heat from the piston is going right into the oil which heats the rest of the engine up.
 

Handiman

Subscriber
Thanks Everyone!
Ran today output shaft temperature observed before starting 82.5° , 30 minutes 132°, 1 hour 142°.The flywheel end after 1hour 100° ( was gonna check after 1 1/2 hours but it ran out of gas) . I guess there is not too much to worry about with those temperatures. Its going on a non working tractor anyway.

Ted
 
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