Cub engine queston?

[Jags]

Don't use any lapping compound unless you are gonna tear down that engine. Pretty tough to insure that some doesn't go where it shouldn't. Lapping is usually done with a tool (power tool). There is an inexpensive method that looks like a dart that kids stick to windows, and it is run with a drill and lapping compound.

If the carbon on the valve seats is not evenly distributed it tells be that there is a hot spot. Just a matter of time before she burns through if it is not addressed.

 

[Jags]

u sure do have a lot of "i" stuff jags

I'm in IT - what can I say?


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[Ashful]

Don't use any lapping compound unless you are gonna tear down that engine. Pretty tough to insure that some doesn't go where it shouldn't.

Easy enough to remove these flat head valves for cleaning. Pull breather, pair of keepers, valve slides out. Not really a big deal, and that's as much tear-down is recommended in the shop manual for doing a valve job on this engine.

Lapping is usually done with a tool (power tool).

??? Not on a Cub engine!

There is an inexpensive method that looks like a dart that kids stick to windows, and it is run with a drill and lapping compound.

Yep... this is all I've ever seen anyone use on these. However, I've never seen one run on a drill. Usually spun between the palms like kids pretending to start a fire with a stick.

If the carbon on the valve seats is not evenly distributed it tells be that there is a hot spot. Just a matter of time before she burns through if it is not addressed.

You nailed it. If there's crap on the seat, it's usually time to re-cut and lap in a new pair of valves.

 

[smokinj]

Don't use any lapping compound unless you are gonna tear down that engine. Pretty tough to insure that some doesn't go where it shouldn't. Lapping is usually done with a tool (power tool). There is an inexpensive method that looks like a dart that kids stick to windows, and it is run with a drill and lapping compound.

If the carbon on the valve seats is not evenly distributed it tells be that there is a hot spot. Just a matter of time before she burns through if it is not addressed.

Haha.....Its consistent and there not much there. Just don't want it falling into the engine. Kerosene rag may have loosen it up enough I can wipe it off. Head gasket will not be here until Friday afternoon so I can really tweak it out. Should even have time to at-least polish the head to.
Guy said it was re-built 4 years ago and everything I am seeing says he is right.

 

[Jags]

Easy enough to remove these flat head valves for cleaning. Pull breather, pair of keepers, valve slides out. Not really a big deal, and that's as much tear-down is recommended in the shop manual for doing a valve job on this engine.

??? Not on a Cub engine!

Yep... this is all I've ever seen anyone use on these. However, I've never seen one run on a drill. Usually spun between the palms like kids pretending to start a fire with a stick.




You nailed it. If there's crap on the seat, it's usually time to re-cut and lap in a new pair of valves.

I watched a machine shop lap the valves on a short block I did years ago. Yes, it was a large machine. I also have the suction cup tool and use it on a drill. Works great. (mine only has one suction cup, not the double ended kind.)

 

[smokinj]

Here you go any questions? http://gardentractorpullingtips.com/valvecam.htm#top

 

[smokinj]

Pulling the valve and cleaning it does not a lap job make. You have to lap the valve into the seat. The seat is integral to the block.

I watched a machine shop lap the valves on a short block I did years ago. Yes, it was a large machine. I also have the suction cup tool and use it on a drill. Works great.

That is correct other than most would use the hand tool for the kohler flat head. I don't think its going to take much other than cleaned.

 

[Jags]

That is correct other than most would use the hand tool for the kohler flat head. I don't think its going to take much other than cleaned.

That is good news.

I actually pulled the first part that you quoted, Jay. I think I misunderstood Joful.

 

[Ashful]

I watched a machine shop lap the valves on a short block I did years ago. Yes, it was a large machine. I also have the suction cup tool and use it on a drill. Works great. (mine only has one suction cup, not the double ended kind.)

Grinding/cutting valve seats is usually a machine operation, while lapping valves to those seats is generally done by hand on garden tractors.

To respond to your first sentence (deleted), you actually can buy new valve seats for the K301, which are pressed into the block. If your block already has replaceable seats, you can pull them and press in the new ones. On a stock K301, you first have to machine the rebate to accept the replacement seats.

 

[Jags]

Grinding/cutting valve seats is usually a machine operation, while lapping valves to those seats is generally done by hand on garden tractors.

To respond to your first sentence, you actually can buy new valve seats for the K301, which are pressed into the block. If your block already has replaceable seats, you can pull them and press in the new ones, but on a K301, you first have to machine the rebate to accept the replacement seats.

Yep - that is what they did on the short block I had work done on. Pretty interesting operation. Since they already had the mill setup for the proper seat position, they just hooked up the lapping tool and did the job right there.

 

[smokinj]

grinding/cutting valve seats is a machine operation.

lapping valves to those seats is generally done by hand on garden tractors.

To respond to your first sentence, you actually can buy new valve seats for the K301, which are pressed into the block. If your block already has replaceable seats, you can pull them and press in the new ones, but on a K301, you first have to machine the rebate to accept the replacement seats.

I hopping it not be needed. Here is a line from Brian's Cub page see what you all make of it?

"FYI - In most cases, worn valve guides don't necessarily need to be replaced. They can be repaired with a thin-wall bronze liner, like the ones installed in automotive cylinder heads. Also, a bronze liner will last longer than a cast iron guide because bronze retains more oil for better lubrication for the valve stem."

 

[Jags]

I would imagine to use a liner of that type you would need to ream the guides to a specific spec. Dunno, never used the liner stuff.

 

[smokinj]

I would imagine to use a liner of that type you would need to ream the guides to a specific spec. Dunno, never used the liner stuff.

That makes since now. Thanks

 

[Ashful]

Those guides are too easy to replace to bother re-lining. You basically tap them with a thread using a hand tap, thead a piece of all-thread into them, and use a nut with washer to draw them out. Then you hammer the new ones in (can do by hand, but I prefer to use a $10 drive tool for the pneumatic hammer) to a specified depth. This is the only tricky part, as you don't want to overshoot that depth (easy to do). Then you hand ream them (I can loan you the reamer, which was a little 'spensive), and drop your new valves in. Easy peasy.

Actually, I can loan you the drive tool, if I'm already sending you the reamer. Otherwise, buying your own drive tool is probably about the same as the cost shipping mine.

 

[smokinj]

Those guides are too easy to replace to bother re-lining. You basically tap them with a thread using a hand tap, thead a piece of all-thread into them, and use a nut with washer to draw them out. Then you hammer the new ones in (can do by hand, but I prefer to use a $10 drive tool for the pneumatic hammer) to a specified depth. This is the only tricky part, as you don't want to overshoot that depth (easy to do). Then you hand ream them (I can loan you the reamer, which was a little 'spensive), and drop your new valves in. Easy peasy.

Actually, I can loan you the drive tool, if I'm already sending you the reamer. Otherwise, buying your own drive tool is probably about the same as the cost shipping mine.

I will get a much more detailed look tonight. I learned a lot and if it needs it I will take you up on that.

 

[MasterMech]

I highly doubt a recently rebuilt K series engine has any significant wear on the valve guides. If the guides and the valve stem are tight, there is no reason you can't lap the valves if you want. Remove the keepers and springs, which you probably already have done to check for valve guide wear, and clean things up the best you can. The seats can be re-cut by hand with a special set of tools (which can also be used in a drill press or Bridgeport) but try to borrow them as they can be a bit pricey if this is a hobby job. In your case, I'm betting the seats are clean with no pitting anyways so recutting them will not be necessary. Lap the vales in using fine compound and either the suction cup type to or a lapping tool that kind of resembles an egg beater. Do not do so with a drill. A light touch is necessary and reversing direction as well. Grind by rotating in one direction and then rotating a bit farther in the other, keeping the valve in light contact with the seat. Continue until you see a light grey band appear all the way around the valve face that's a consistent width. Use the compound sparingly and when you are done, make sure you get it all off. DO NOT ATTEMPT TO FLUSH THE COMPOUND OUT WITH A SOLVENT. You are likely to rinse grit into places you definitely do not want it.

 

[smokinj]

I highly doubt a recently rebuilt K series engine has any significant wear on the valve guides. If the guides and the valve stem are tight, there is no reason you can't lap the valves if you want. Remove the keepers and springs, which you probably already have done to check for valve guide wear, and clean things up the best you can. The seats can be re-cut by hand with a special set of tools (which can also be used in a drill press or Bridgeport) but try to borrow them as they can be a bit pricey if this is a hobby job. In your case, I'm betting the seats are clean with no pitting anyways so recutting them will not be necessary. Lap the vales in using fine compound and either the suction cup type to or a lapping tool that kind of resembles an egg beater. Do not do so with a drill. A light touch is necessary and reversing direction as well. Grind by rotating in one direction and then rotating a bit farther in the other, keeping the valve in light contact with the seat. Continue until you see a light grey band appear all the way around the valve face that's a consistent width. Use the compound sparingly and when you are done, make sure you get it all off. DO NOT ATTEMPT TO FLUSH THE COMPOUND OUT WITH A SOLVENT. You are likely to rinse grit into places you definitely do not want it.


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Yea its is just a hobby for sure and full time wood hauler. I am into this tractor so far under 600.00. Right is right and cheap is better. I still got paint and tires to go. But I will get a better look at it tonight.

 

[smokinj]

Looking closely and wipe it down again it looks good real good. I THINK the rest will come off just by wiping it with paper towel and kerosene

 

[Jags]

Jeesh - no love for the drill. A reversible with an accurate trigger and it is done in no time.

 

[smokinj]

Jeesh - no love for the drill. A reversible with an accurate trigger and it is done in no time.

On these kohler doing it by hand takes just a few seconds to a couple mins. That it. Drill or press would be to much of a chance of over kill quick.

 

[Jags]

I guess I will have to go tell the engines that I have done this to, to quit running right.

 

[smokinj]

I guess I will have to go tell the engines that I have done this to, to quit running right.

Well my engine dose not need it at all......After cleaning it up again last night it looks brand new. Have you done a flat head kohler before?

 

[Jags]

Well my engine dose not need it at all......After cleaning it up again last night it looks brand new. Have you done a flat head kohler before?

At least 4 of them. I currently run two - my yard hauler and my small mower (both 12hp). I have freshened up both at some point. (1976 and 1977 with mega run hours).

 

[smokinj]

At least 4 of them. I currently run two - my yard hauler and my small mower (both 12hp). I have freshened up both at some point. (1976 and 1977 with mega run hours).
View attachment 106929

I would not quite then. Nothing quite like the Sound of a 301k. Is that an Allis?

 

[Jags]

I have also done a 10hp that was on a high wheel case and a 16hp that currently mows my mothers yard (same AC tractor as mine, just the 16hp version and a bit newer).