Rebuilding Kohler
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Kubmech
I took the new ring and put it in the cylinder. the gap at the top was .03, Middle .035, and bottom was .023. I thought the bottom was supposed to wear more than the top. I guess that was why the crank was easier to turn in the middle of the stroke. There was a very little ridge at the top of the cylinder. No scoring was on the walls. The ring sealed the cylinder perfectly so i dont think its oval shaped. The manual says the maximum taper is .002 and the maximum wear limit is to 3.378 from 3.3755. Could i have measured to far down in the cylinder since the stroke is only 3.25? Should i have measured above the ridge or right below it?
I took the new ring and put it in the cylinder. the gap at the top was .03, Middle .035, and bottom was .023. I thought the bottom was supposed to wear more than the top. I guess that was why the crank was easier to turn in the middle of the stroke. There was a very little ridge at the top of the cylinder. No scoring was on the walls. The ring sealed the cylinder perfectly so i dont think its oval shaped. The manual says the maximum taper is .002 and the maximum wear limit is to 3.378 from 3.3755. Could i have measured to far down in the cylinder since the stroke is only 3.25? Should i have measured above the ridge or right below it?
StoneHeartFarm
Veteran Member
I would say if it is tapered or out of round, you should consider a machine shop. Remember, the machine shop will bore the cylinder out, which will require a larger piston and/or rings. The cylinder walls were shiny? That's the glaze we've talked about. The reason for honing is to break that glaze up so that the new rings can grab onto the cylinder walls and seat themselves (shape to fit).
If the only reason that the engine is being rebuilt is oil control, then you need to work hard on the areas where oil can be lost/used. These would be the rings, gaskets, seals, and valve guides. If you decide to take the cylinder for boring, consider having the machine shop grind your new valves and seats. It probably won't cost that much and you'll know the job is professionally done. Also, don't be afraid to shop around for the machine work, and talk to people to find out how the shop works. I've got several within 30 minutes of me and there is only 1 that I wouldn't hesitate to recommend. The others all have varying levels of "issues".
SHF
If the only reason that the engine is being rebuilt is oil control, then you need to work hard on the areas where oil can be lost/used. These would be the rings, gaskets, seals, and valve guides. If you decide to take the cylinder for boring, consider having the machine shop grind your new valves and seats. It probably won't cost that much and you'll know the job is professionally done. Also, don't be afraid to shop around for the machine work, and talk to people to find out how the shop works. I've got several within 30 minutes of me and there is only 1 that I wouldn't hesitate to recommend. The others all have varying levels of "issues".
SHF
The ridge at the top will be about 1/4 to 3/8 of an inch down. Measure just below it. The cylinder at the bottom should show no signs of wear due to the piston not riding all the way down the cylinder. You should be able to see where it stops due to the wear pattern. If you have a very slight, to no ridge at the top, from what you just said it sounds like you may be able to get away with just breaking the glaze. Use a ball hone and clean up the cylinder walls. Use automatic transmission fluid, low rpm on the drill with quick up and down srokes till you have a good cross hatch pattern in the cylinder. Don't spend too much time with the hone, just enough to eliminate all the shiny spots. The reason you have less tension at the bottom or top is that is the point where the rod rocks back and forth on the crank. You will have steady tension with the piston installed due to the friction of the rings against the cylinder wall. With the rod and piston removed, the crank should turn freely all the way around. If the crank is free you should be in good shape. The book probably mentions using plastigauge for checking the connecting rod to crank journal clearance. Do that as well. After honing, clean the cylinder real well with soap and water (tide works good). Get it so if you wipe the cylinder wall with a white towel you don't get any dirt on the towel. If the valve guides are not too bad, go ahead and put it all back together and see how it goes. Run it half throttle for about ten minutes, check for leaks as it runs and don't worry about the smoke at initial start up. Use engine oil to pre-lube all the parts and wipe a thin coat of ATF on the piston and cylinder prior to assembly. If the valve seats look O.K., lap the valves in. Make sure you clean off all the lapping compound. Keep in mind the best option is to bore oversize, cut the crank and replace the rod with an undersize, replace the guides and have the valve seats recut. Don't get me wrong, I have had good results just "refreshing" an engine, which seems to be the direction you want to take.
Re: Refreshing Kohler
SHF
Is it necessary to break the glaze because the rings are really grabbing the walls now? I had a very difficult time turning the crank with the piston installed. I dont think the starter/generator would be able turn the engine over. Is this normal when refreshing an engine?
Frank
SHF
Is it necessary to break the glaze because the rings are really grabbing the walls now? I had a very difficult time turning the crank with the piston installed. I dont think the starter/generator would be able turn the engine over. Is this normal when refreshing an engine?
Frank
s1120
Veteran Member
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- Columbia county NY
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- 87 Ingersoll 444, 84 Ingersoll224/'44 GreavlyL/60'sGreavlyL/49 Ford 8N
Re: Refreshing Kohler
The hone is not that pricy. Last one I got was about $35.00. Also a new motor will be a little tight, but the starter should turn it. Try pulling the pisten and see if the crank turns.
The hone is not that pricy. Last one I got was about $35.00. Also a new motor will be a little tight, but the starter should turn it. Try pulling the pisten and see if the crank turns.
s1120
Veteran Member
- Joined
- Nov 19, 2000
- Messages
- 1,716
- Location
- Columbia county NY
- Tractor
- 87 Ingersoll 444, 84 Ingersoll224/'44 GreavlyL/60'sGreavlyL/49 Ford 8N
Re: Refreshing Kohler
Good, next, after you give a little hone, check ALL the rings in the bore. I have seen some made to big.
Good, next, after you give a little hone, check ALL the rings in the bore. I have seen some made to big.
Re: Refreshing Kohler
Note: if new rings are installed, you should deglaze the cylinder wall with fine emery cloth in a cross-hatch pattern (diagonal strokes). This is needed break in the new rings. Then very thoroughly clean the cylinder to remove all traces of abrasive residue.
Found this on a web site. Would the emery cloth work to deglaze or just buy a hone for 30$?
Note: if new rings are installed, you should deglaze the cylinder wall with fine emery cloth in a cross-hatch pattern (diagonal strokes). This is needed break in the new rings. Then very thoroughly clean the cylinder to remove all traces of abrasive residue.
Found this on a web site. Would the emery cloth work to deglaze or just buy a hone for 30$?
