National Rider

[Fulltilt]

As Brian mentioned, you still have to lap and grind the clearance on a new valve. And all the ones I did needed quite a bit removed.
If the old valve is good ( probably is considering leakdown etc) just lap it in first, then grind the clearance. You usually can file the ends, or use the side of your bench grinder. I clamp my needle nose visegrips to the side shield as a steady rest, I also cut a V in the shield, but usually use the vise grips.
Filing works, done it couple times, though I finished with the valve clamped to a hardwood block (that had a groove cut in it for something) and sanding it on a sheet of self stick DA paper stuck to my granite slab. You could probably just get by with that.

[lefty]

Thanks for all the great info guys. I'm going to get working on it but I'm getting a neighbors riding mower in today so it probably won't be for about a week. (you'll probably be hearing from me on that one I'm sure) I'll keep you posted.

Just use a good flat file and in the service manual you will find a ball park clearance with the valve spring off.

I'm guessing the clearance with spring off is helpful to know so I can periodically check while filing off a little at a time without reinstalling the spring each time?
I don't have a service manual. I found part number 270962, which covers L-heads from 1919-1981. I plan on picking one up.

Would an acceptable method also be to initially check the clearance before and after removing the spring and account for that differential while checking without the spring? Or do you think after lapping, the spring may interact differently with the valve.

[KE4AVB]

Lefty, just go the downloads forum and click on the Briggs service info link. It carry to the directory that has the Repairman's Handbook. You can either view it online or download it to your computer's hard drive.

[bgsengine]

I'm guessing the clearance with spring off is helpful to know so I can periodically check while filing off a little at a time without reinstalling the spring each time?

Should not differ much more than .001 or .0005 - if you get clearance to the mid-point of the range, you should be good once spring and keeper is installed. Just make sure you are checking it with the other valve fully open, or make sure of where the engine is at (1/4" past TDC of compression stroke) or you'll end up with too much clearance - which probably would require another new valve.

[Fulltilt]

I'm guessing the clearance with spring off is helpful to know so I can periodically check while filing off a little at a time without reinstalling the spring each time?
I don't have a service manual. I found part number 270962, which covers L-heads from 1919-1981. I plan on picking one up.

Here's a manual for you to peruse, I'm surprised you didn't already have one. https://www.ganino.com/games/Briggs%20and%20Stratton%20Repair%20Manuals/270962%20Single%20Cylinder%20L-Head%20BRIGGS%20&%20STRATTON.pdf

As I mentioned before, you lap the valve in first, then go ahead and set the clearance. As BG mentioned just press down on the valve while checking, you can use a screwdriver handle.
I have a multi purpose aluminum bar ( actually a couple of them ) about 1" or so wide by about 5/8" or so thick by about 6" long that I drilled a hole in. I bolt that to the head and swing it over the valve and use a big screwdriver to wedge the valve shut while I check, then simply swing it out of the way.
I suppose you could do the same thing usng the cylinder head.

[bgsengine]

As I mentioned before, you lap the valve in first, then go ahead and set the clearance. As BG mentioned just press down on the valve while checking, you can use a screwdriver handle.
I have a multi purpose aluminum bar ( actually a couple of them ) about 1" or so wide by about 5/8" or so thick by about 6" long that I drilled a hole in. I bolt that to the head and swing it over the valve and use a big screwdriver to wedge the valve shut while I check, then simply swing it out of the way.
I suppose you could do the same thing usng the cylinder head.

My way is even simpler - after lapping in the valve you can't easily turn it (press thumb on it and twist) when there's clearance , so you just slip in your feeler gauge (the smallest size in range) and drop valve down on it and see if you can twist the valve - if it twists easily (again just thumb pressure and try to twist with thumb pressing down lightly) then the valve is not seating, and you know the clearance is less than the feeler gauge you have in it. if it wont twist, you can then check with the top range feeler gauge (thickest) and repeat and you should be able to twist valve (or just barely, if your clearance is already at the max range)

If you play around with it a little bit with the tappets out (or known clearance) and no feeler gauge in place, you will get a "feel" for it easily enough. - same method can tell you if you need to grind a bit of clearance before lapping (which you sometimes have to do with a new valve or freshly cut seats)

Just make sure the valve face and seat have been cleaned very well before doing so to eliminate any grit that can throw off your clearance measurement.
You can also put a dab of engineering blue on your feeler gauge and smear it along the blade where it contacts the valve and you can see if your valve stem is seating squarely to the tappet by inspecting the contact area of the tip of the valve stem.

[lefty]

While you got the valve spring off pull the valve up little bit and do a wiggle test with your fingers so as to get a feel for a good valve stem and guide vs one that is worn too much. You will eventually get a feel for worn guides and it don't do any good to install new valve into a wore out guide.
Also sometimes the valve stem will have to be cleaned before the valve can be easily removed while rotating the valve. Be patient when re-installing the valve.

So I'm into this and got the spring and clip off of the intake valve. I do have a briggs spring removal tool. It was still a pain in the but because the engine is still on the machine and the handle bars are kind of in the way. I did the wiggle test on the valve. There is the tiniest...and I mean tiniest bit of play when I wiggle. Almost not detectable.

I am, however, running into some trouble removing the valve. The valve moves nicely in the guide and does not appear to be dirty but when I feel with my finger along the edges on either side of the clip/keeper indentation, I do feel some roughness. Which I'm guessing is catching when I try to pull the valve all the way out. I was thinking I need to deburr that somehow and was looking for advice. I was thinking a fine file held lightly against the valve while I turn it. There is a hole that brings oil up into this area, which I think is called the galley? Of course I would block this off.

On a side note, the exhaust spring, which I have not removed, appears to be secured using a different method. It doesn't have a thin slotted clip at the bottom of the spring. It's a thicker piece. Maybe the two piece keeper style? I've never encountered one so I don't know. The spring appears to be a purplish in color as well. Maybe someone has been in here and replaced it at some point. The head gasket did not look 48 years old for sure. But I can't ask my dad....he's dead.

Thanks.

[bgsengine]

So I'm into this and got the spring and clip off of the intake valve. I do have a briggs spring removal tool. It was still a pain in the but because the engine is still on the machine and the handle bars are kind of in the way. I did the wiggle test on the valve. There is the tiniest...and I mean tiniest bit of play when I wiggle. Almost not detectable.

That's fine - matter of fact that'd be considered fairly excellent

I am, however, running into some trouble removing the valve. The valve moves nicely in the guide and does not appear to be dirty but when I feel with my finger along the edges on either side of the clip/keeper indentation, I do feel some roughness. Which I'm guessing is catching when I try to pull the valve all the way out.

Correctamundo - That'll be a wear ridge that eventually "peens" the valve wider than the guide

I was thinking I need to deburr that somehow and was looking for advice. I was thinking a fine file held lightly against the valve while I turn it. There is a hole that brings oil up into this area, which I think is called the galley? Of course I would block this off.

Correct - a small single cut file (like a chainsaw raker file) would work nicely - yes there is a drain back hole in the valve box so you might want to stuff an oily rag in over the tappets and snug it up against the back of the box to catch filings

On a side note, the exhaust spring, which I have not removed, appears to be secured using a different method. It doesn't have a thin slotted clip at the bottom of the spring. It's a thicker piece. Maybe the two piece keeper style? I've never encountered one so I don't know. The spring appears to be a purplish in color as well. Maybe someone has been in here and replaced it at some point. The head gasket did not look 48 years old for sure. But I can't ask my dad....he's dead.

Thanks.

Yes that will be the "rotator" style of valve keeper, with a shorter and heavier spring, and it is retained with two half-collar "keys" - to do those you'd be better off with a c-clamp style valve spring compressor and have a magnet handy (and keep the oil drain hole plugged) They can be popped off with patience and a couple of screwdrivers, but you won't get them back in without a good valve spring compressor. To reinstall, you'd dab a bit of grease on the inside of the collar keys (cone pointing up) and a dab of grease on a screwdriver blade - install one at a time and carefully let the compressor back down.

Side note - the rotator style valve keeper allows the valve to rotate during operation helping to spread the temperatures along the seat, helps prevent burning, and helps reduce carbon build up on the stem, valve will rotate ever so slightly every time it opens and closes...

[lefty]

Thanks BG. I was thinking, since my leak down was good and my clearance is excellent on the exhaust valve, that I would not "f" with that one. Looking to employ the adage..."if it aint broke, don't fix it".

I was going to lap the intake and file the stem to make my clearance on that one.

Is this a foolish idea. Would you suggest attacking the exhaust valve as well?

[bgsengine]

Thanks BG. I was thinking, since my leak down was good and my clearance is excellent on the exhaust valve, that I would not "f" with that one. Looking to employ the adage..."if it aint broke, don't fix it".

I was going to lap the intake and file the stem to make my clearance on that one.

Is this a foolish idea. Would you suggest attacking the exhaust valve as well?

If your exhaust clearance is in spec and your leakdown "proves out" then I would just lift the exhaust valve (roll engine til it opens) and then with a strong light just have a look at the face and stem for any potential issues - but otherwise just leave it well enough alone and you'd do fine