Toro Zero Turn smoking

[Bertrrr]

Replacing the head will not do anything for a smoking engine, sounds like the valve guides are leaking a bit, it's really not an issue for most people - unlikely the owner wants to throw more money at it if it's doing what you say

 

[Bertrrr]

Replacing the head will not do anything for a smoking engine, sounds like the valve guides are leaking a bit, it's really not an issue for most people - unlikely the owner wants to throw more money at it if it's doing what you say

 

[TobyU]

Replacing the head will not do anything for a smoking engine, sounds like the valve guides are leaking a bit, it's really not an issue for most people - unlikely the owner wants to throw more money at it if it's doing what you say

I'm sure the owner would be quite happy at this point but he has some weird shop owner who wants it perfect and is going to put a lot more time and money into it or at least drive this tech nuts without even consulting the customer and seeing how happy is the situation currently which is what he should do.
But about the head replacement.. it probably is a leaking valve guide but the valve guides are in the head on this machine so a new head would solve the problem of the leaky valve guide. Lol
It's just the hard, annoying, expensive way of fixing it.
Pop that spring off and put a nice new umbrella stem seal on the intake or heck, do the exhaust too if you want, and make sure it has 30 weight oil in it and not full synthetic or some multigrade and call it fixed.
The owner was using something like
a half a quart or even more per hour so at this point it will feel like a new machine to him.

 

[STEVES]

That too, good old 30w, lets not worry about gas mileage!! Seals & oil!

 

[TobyU]

That too, good old 30w, lets not worry about gas mileage!! Seals & oil!

I have a fairly High hour woods mow n machine that's really a grasshopper with an underpowered bridge vanguard 12 horsepower or maybe it's a 14 but I think it's a 12 with a 44 inch deck and they should have stuck with the 16 they did a lot of or even the 18th but I run straight 40 Valvoline vr1 racing all in that because of the extra high zinc content.
It doesn't really use that much but it was for a while because the dipstick o-ring was leaking and the dipstick top hold down screw had been messed up and wasn't tight so it was wiggling and that caused it to puke a little bit of oil out of the breather tube into the air filter housing.
I ended up using the straight 40 and then I just stayed with it or maybe I put some straight 30 in a while back but it was definitely VR1.
I like that extra layer of zinc cushioning metal to metal contact just in case you know since these stupid little engines don't actually have babbit coated rod bearing inserts.

 

[sgkent]

just for what it is worth, if valve guides are worn on any engine, no valve job will seal properly because the valve will not stay centered in the seat. All one is doing is cleaning things up a bit.

That said, this horse has been pretty beat down. If the owner complain still about smoke then it is a classic promised more than could deliver. Dreaming of restoring a machine with lots of hours to what it was like when new is just not viable these days.

 

[TobyU]

just for what it is worth, if valve guides are worn on any engine, no valve job will seal properly because the valve will not stay centered in the seat. All one is doing is cleaning things up a bit.

That said, this horse has been pretty beat down. If the owner complain still about smoke then it is a classic promised more than could deliver. Dreaming of restoring a machine with lots of hours to what it was like when new is just not viable these days.

At this point I don't think the owner has any idea what's going on other than the mower isn't fixed yet.
The guy who owns the shop is insistent on it being perfect from what OP has posted and he's the one with unrealistic expectations.
I bet the owner would have been happy right after it was put together and it's current situation and would have an operable mower right now using almost no oil compared to what it was doing before but it seems they have been too far removed from the loop and that's a bad idea.
As you said, you don't want to promise more than you can deliver but you also don't need to to promise anything more than what makes them very happy!

You are correct about the valve job but you said seal properly. That's a pretty loaded word. Adequately, properly, correctly, perfectly can be all very different.
That gets back too my earlier comments about lawn mower engines being low performance little turds that are very forgiving.
These valves don't really have to seal all the way to properly for the engine to run quite well for many years. Lol
That's fortunate, because it seems most lawn mower valve jobs have been a single angle one forever, (there might have been a two angle about job but not common in a shop environment) whereas cars were getting a three angle valve job back in the 80s and maybe before that at every local speed shop and even your standard performance engine builders and machine shop head places.
I was told just a couple years ago from an old friend I ran into who used to do many of those built engines and did machine shop work for me back in the 80s and early 90s.
He said these new cars have like a six angle job or something equivalent to that and that doing the old three angle valve job we used to do to one of those valves today would be a severe downgrade to what comes from the factory.
Somehow, I don't think lawnmower engines have kept up.....

 

[The Specialist]

Now you know you're going to make some people's heads spin around talking about cleaning up valves and even daring to mention touching the sealing surface with something so unprecise as your finger!!!
I don't actually think I've used Emery cloth on them or sandpaper but I have used the fairly fine wire brush on the grinding wheel to clean them up I do however, recommend using some course grit lapping compound and then some fine grit lapping compound and lap them decently in the head once you do this because you're probably going to round off the sharp angles a little bit even though cleaning up the crap and making the surface smooth probably outweighs any problems you could cause by getting the angles off a little but then when you go and lap them you will be increasing the sealing ability quite a bit.
When I officially opened my shop in 2011 I looked around and thought about buying one of the old school valve grinding apparatuses but found out they're still pretty expensive and I'm a cheapskate and there's not really that big of a demand or need to do it and I don't rebuild inches anyways and most of those jobs that would require that are simply too labor intensive and time involved for me to bother doing when I can sit here all day long doing annual services and carb cleanouts and make a lot more money in less time and help a lot more people overall.
So I gave up on the idea but if I'm ever at a garage sale somewhere and see one that they're basically giving away I will pick it up.
The only time in my life I ever actually used one was in junior high school in the metals and small engine class where are we did a complete rebuild and ground the valves whether they needed it or not.
The fact is, lawn mowers are low performance little turds!
This makes them very forgiving and you just don't see that many burnt valves or valves that really need to be ground.
You find far more popped valve seats and way more slipped valve guides causing valve train issues but it's not the actual valve cut angle sealing surface at all.

Within minutes, I can tell how good a mechanic is on these small engines of walking into a shop. Believe it or not, many shops don’t know what they are doing! I’ve done small engines for 35 years. I was in it from the old school of points and condensers and that 2 strokes always used reed valves. My instructor back then in college stated “ if you don’t know the secrets of the engine, you will never fix it” and he was right! The valves are the most important thing, but are always over looked. As you own a shop, the next time that you get a smoker engine or one that runs with a surge, take the valves out and have a look. I agree with you in using a wire brush on the cylinder head to clean them up, but the valves, I use emery cloth. I have not used valve lapping compound in over 25 years as I got that good at doing valves.

 

[TobyU]

Within minutes, I can tell how good a mechanic is on these small engines of walking into a shop. Believe it or not, many shops don’t know what they are doing! I’ve done small engines for 35 years. I was in it from the old school of points and condensers and that 2 strokes always used reed valves. My instructor back then in college stated “ if you don’t know the secrets of the engine, you will never fix it” and he was right! The valves are the most important thing, but are always over looked. As you own a shop, the next time that you get a smoker engine or one that runs with a surge, take the valves out and have a look. I agree with you in using a wire brush on the cylinder head to clean them up, but the valves, I use emery cloth. I have not used valve lapping compound in over 25 years as I got that good at doing valves.

I'm sure it works fine for you and like I said, cleaning up deposits and other crap like that and the carbon buildup probably far outweighs any slight variation of the margin and the sealing surface from the angles being a little off or not quite as crisp .
However, I think we can both agree that on a brand new perfectly manufactured valve and seat or a freshly ground valve and seat, you wouldn't be doing it any benefits by scratching on it or touching it with emery cloth or a wire brush or anything other than maybe a shop cloth.
But since we don't get many of these, anything that you can find that makes stuff work out better is a plus.
I would say most people don't use lapping compound because like I said in the earlier post the valves aren't that really big of an issue because the engines are so forgiving that good enough works out okay and that's what most of the valves do is seal up good enough.
After you clean them up with the emery cloth you would probably get an even better seal if you then lapped them but again, they're already plenty clean enough to seal up properly so it runs like it should and you've cleaned off the carbon deposits and stuff so they're sealing better then when you started.

I don't use lapping compound over two or three times a season in fact the kit I have now of the two small tubes is just about empty especially on my fine since I have used that multiple times to polish out some carburetor seats when I didn't have or couldn't get a replacement like on some of the Kawasakis that aren't removable or at least aren't available as a replacement.. that kit is just about empty and I purchased it in 2011 so I obviously don't do very many because those tubes are small.
Same size tubes as the small tubes of JB weld.
I certainly don't think you could harm an old already used valve and seat my by lapping it some but I don't think it is the cure-all or as necessary as some people make it out to be.
In the old days it was a requirement after the valves were ground and automotive heads but sometime in the mid to late '80s or some are very close to that the machines were much better and they stop doing that time consuming process because it just wasn't necessary also.
You will still hear old guys talk about how you have to do it and it's a must but I beg to differ....
Personal experience says otherwise just like you with using your finger and a piece of crocus cloth soaked in gasoline to clean up your valve surfaces.
Many would say that's a big No-No but your experience having great results doing it proves otherwise.
When it works...keep on doing it.
When it ain't broke......