Cylinder head question

[Crunchie58]

Thanks for having me on this forum. Not sure if this forum is for lawn mowers only but let me know if it is. I'm having issues with push rod on the exhaust side of my snowblower, engine is a BS 1350 snow series. Long story short (I hope), suspect motor overheated (bought used), bent push rods probably due to valve guides moving and rocker arm retainer washer butting up against valve seal. My question, please see attached picture and notice the exhaust side (spring and retainer washer removed), there's a lip about 1/4 of an inch around the valve guide, the intake doesn't have this lip. Anyone know what it's purpose is, the rocker arm retaining washer is butting up against the seal when the valve tries to open. If that lip wasn't there, I could drop the valve guide down and slip the seal on and it probably wouldn't hit it.
I should point out that the valve stem is not where it should be, it's because it's sitting on the bench, no problem with the valve.
Hope this is clear and tks to anyone that can help.

 

[StarTech]

No seal is used on the exhaust valve side, only use on the intake side

 

[Crunchie58]

OMG, I was thinking the same thing last night, you're a lifesaver man. ty ty ty.
Merry Xmas and Happy New year,

 

[Crunchie58]

No seal is used on the exhaust valve side, only use on the intake side

Well got her going, thanks again.

 

[bertsmobile1]

Intakes suck so they drag crankcase fume into the engine thus altering the air : fuel ratio .
This was not a problem till idiot emission laws came in forcing the air : fuel ratio to become too lean for an air cooled engine.
Adding to that modern oils do not fully burn so you also end up with unburned hydrocarbons in the exhaust which also is against EPA regulations.

Exhaust blow so any gasses that go down the side of the valve guide will just enter the crankcase then get recycled through the carb.

 

[Gumby83]

I see this thread is a few weeks old, but it doesn’t look like anyone answered the question about that lip being there.

I don’t know for certain but it’s possible it’s there to keep from swapping the intake and exhaust valve springs. In automotive applications, it’s not uncommon for the intake and exhaust springs to be different sizes and stiffness, so it wouldn’t surprise me if that holds true for small engines as well.

The springs may look identical to the naked eye but have just enough difference in diameter to prevent the intake spring from fitting over that lip.

 

[StarTech]

No it not in this case as both springs on the 20M114-0937-E1 engine in question are the same 694865 spring. What the OP was trying to do was install a valve stem seal on the exhaust valve side and the raise area was preventing the OP from doing that as no stem seal is used on the exhaust valve. The raise section also prevents excessive amounts of oil flowing down the exhaust valve stem.

 

[Gumby83]

No it not in this case as both springs on the 20M114-0937-E1 engine in question are the same 694865 spring. What the OP was trying to do was install a valve stem seal on the exhaust valve side and the raise area was preventing the OP from doing that as no stem seal is used on the exhaust valve. The raise section also prevents excessive amounts of oil flowing down the exhaust valve stem.

Thanks for clarifying that. I understood what the OP was trying to do, but like I said, I didn’t see where the purpose of the lip had been addressed. But I’m also not the most comprehensive reader, and sometimes, learning something new pushes something old out of my brain. You wouldn’t believe how many times I’ve had to relearn my own phone number.

Is it common for the valve springs to be interchangeable (between valves, anyhow)? Not that you’d want to swap them on purpose - I’m just curious.