Mini engine parts broke this time

JimP2014 said:
So a few nights ago I was merely cutting the lawn and then all of a sudden the engine just quit. So I decided to take off the valve cover, and pretty much found all this stuff. Not positive I think the rest of the engine's okay. I have bent push rods before this is the first time ever broke the rocker arm stud. The only thing I found that I thought was unusual is the stud for the rocker arm It requires a 10 mm deep socket and I think the torque is around 10 ft lb I was under the impression it was a 3/8 in deep socket but that socket was too small. I couldn't find where the size is printed but it seems it would have to be a 7/16 in deep socket that would work.

Does anyone know if this is 10 mm for the actual hex nut?

Thanks,
Jim
Click to expand...
Try it and see!!!
 
Gord Baker said:
Try it and see!!!
Click to expand...
Thanks so much for the answer if it wasn't indicated here maybe in the previous post would that be the specification directly from Briggs& Stratton. As opposed to 3/8 in which does not work. And thanks in advance for your answer.

Jim
 
JimP2014 said:
So a few nights ago I was merely cutting the lawn and then all of a sudden the engine just quit. So I decided to take off the valve cover, and pretty much found all this stuff. Not positive I think the rest of the engine's okay. I have bent push rods before this is the first time ever broke the rocker arm stud. The only thing I found that I thought was unusual is the stud for the rocker arm It requires a 10 mm deep socket and I think the torque is around 10 ft lb I was under the impression it was a 3/8 in deep socket but that socket was too small. I couldn't find where the size is printed but it seems it would have to be a 7/16 in deep socket that would work.

Does anyone know if this is 10 mm for the actual hex nut?

Thanks,
Jim
Click to expand...
7/16 is 11mm.
 
JimP2014 said:
So a few nights ago I was merely cutting the lawn and then all of a sudden the engine just quit. So I decided to take off the valve cover, and pretty much found all this stuff. Not positive I think the rest of the engine's okay. I have bent push rods before this is the first time ever broke the rocker arm stud. The only thing I found that I thought was unusual is the stud for the rocker arm It requires a 10 mm deep socket and I think the torque is around 10 ft lb I was under the impression it was a 3/8 in deep socket but that socket was too small. I couldn't find where the size is printed but it seems it would have to be a 7/16 in deep socket that would work.

Does anyone know if this is 10 mm for the actual hex nut?

Thanks,
Jim
Click to expand...
A 10mm hex may not be a 10mm stud. And torque into aluminum will be far less....
 
RevB said:
7/16 is 11mm.
Click to expand...
Okay this is actually the question does Briggs& Stratton mix and match SAE and Metric when designing an engine for lawn equipment or anything really?

I was under the impression they use SAE throughout everything but that's just a guess and I was hoping someone knew the answer maybe even an engineer from Briggs and Stratton could answer?

Thanks,
Jim
 
JimP2014 said:
Yeah I don't know why it says Mini okay thanks for your info you know that black plastic you can't just buy it you have to buy the guide plate but it's only like $7 or $8 so I have that and then the rocker arm stud and then it comes with that barrel hex nut plus that little torx screw I've had this thing apart maybe a hundred times I just never ordered any of that stuff before but But the push rods actually have brand new including the aluminum one for the intake I don't know since you did respond like why would it just break after 30 minutes of use like I can put everything back together and then it breaks again the engine's probably 15 years old I wonder if that rocker arm stud broke because it's just old and I'm hoping when I install a new one and go through all the hassle putting everything together it doesn't break again after 30 minutes I don't know why it broke that's the problem but thanks for your help I just don't understand why Briggs& Stratton and it seems like they mix SAE and then metric.

Jim
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Could be the stud was backing out and the repeated side load snapped in the threads, the weakest point. Look carefully at the broken end....shiny is new fractured dull is old existing fracture...usually.
 
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RevB said:
Could be the stud was backing out and the repeated side load snapped in the threads, the weakest point. Look carefully at the broken end....honey is new fractured dull is old existing fracture...usually.
Click to expand...
Okay thanks for your answer everything is actually put back together and the engine's running fine but I was trying to account for what was going on inside the engine well according to a few other folks they were telling me to look at the valve guide and then the valve guide actually just fell right out of the cylinder head so then that caused the push rod to bend and then I'm now guessing until someone says otherwise that stud that holds the rocker arm started out as 3/8 in and then the extreme heat somehow changed it to basically 10 mm that's the only thing I can think of unless someone says yes Briggs and Stratton uses 10 mm for that specific bolt which is part of the rocker arm with the rocker arm sits on.

Jim
 
JimP2014 said:
Okay this is actually the question does Briggs& Stratton mix and match SAE and Metric when designing an engine for lawn equipment or anything really?

I was under the impression they use SAE throughout everything but that's just a guess and I was hoping someone knew the answer maybe even an engineer from Briggs and Stratton could answer?

Thanks,
Jim
Click to expand...
No it seems that way but uses Metric it is all Metric and If it uses SAE it is all SAE at the current time. Now threading and actual screw size is usually always different different between SAE and Metric.

It just some hex sizes [tool sizes] are inter-changeable like

5/16 > 8mm
7/16 > 11mm
1/2 > 13mm
5/8 > 16mm
3/4 > 19mm
7/8 > 22mm
15/16 > 24mm

and 3/8 is smaller than 10mm not the other way around so if the size change then the 3/8 would a loose fit in a 10mm hole.
 
JimP2014 said:
Okay thanks for your answer everything is actually put back together and the engine's running fine but I was trying to account for what was going on inside the engine well according to a few other folks they were telling me to look at the valve guide and then the valve guide actually just fell right out of the cylinder head so then that caused the push rod to bend and then I'm now guessing until someone says otherwise that stud that holds the rocker arm started out as 3/8 in and then the extreme heat somehow changed it to basically 10 mm that's the only thing I can think of unless someone says yes Briggs and Stratton uses 10 mm for that specific bolt which is part of the rocker arm with the rocker arm sits on.

Jim
Click to expand...
Do you have that valve guide in your hand?

And no...hex sizes don't change magically.
 
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