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dvogt
Guest
it can't hurt bot you need to work on the seats also.
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dvogt
Guest
Tyler , sounds like you need a battery. most peopkle make the weight frames to attach to the same points that the mower deck sub frame would go.
Wyatt, On a engine that runs at goverend speed I don't think theres much there . you could smooth it out. I think most guys are carful not to take much off anymore since most engines that run without a gov. tend to have the piston pop out of the bore. theres also the trade off that you get . lose of compression if you do alot. you need to make up enough air flow to keep the running compression up
Wyatt, On a engine that runs at goverend speed I don't think theres much there . you could smooth it out. I think most guys are carful not to take much off anymore since most engines that run without a gov. tend to have the piston pop out of the bore. theres also the trade off that you get . lose of compression if you do alot. you need to make up enough air flow to keep the running compression up
Wyatt:
Doing the valve undersizing on an engine that will be used for general purposes is not healthy. THe valves will either bend or break. The valve temperatures will be such that the numerous sudden changes in temperature when stopping and idling, etc will cause it to warp/bend at the narrow point. Eventually it will break or severly bend to the point of damaging something else.
Doing the valve undersizing on an engine that will be used for general purposes is not healthy. THe valves will either bend or break. The valve temperatures will be such that the numerous sudden changes in temperature when stopping and idling, etc will cause it to warp/bend at the narrow point. Eventually it will break or severly bend to the point of damaging something else.
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farmall gray
Guest
I'm having a little trouble with my newly rebuilt
149 engine. It is built along the lines of David's
killer engine. I used the same cheater grind cam
from madsens. It has the small chamber k241 (not lp) head. I mildly ported it and the valves are stock (both 1-3/8"). The carb is the stock #30 rebuilt with a new throttle shaft and bushing kit.
I can't get it to idle. I have played with the float level and that didn't help. It kind of "hunts" at idle and dies. If I try to increase the idle speed it dies. It will almost idle at about 500 rpm, but if I try to set the idle speed any higher it dies. It seems like if I go past that, it is out of the range of the idle circuit.
I did make sure all the passages in the carb are clear. I have some more things to try but I have never had this much trouble with one of these carbs before.
149 engine. It is built along the lines of David's
killer engine. I used the same cheater grind cam
from madsens. It has the small chamber k241 (not lp) head. I mildly ported it and the valves are stock (both 1-3/8"). The carb is the stock #30 rebuilt with a new throttle shaft and bushing kit.
I can't get it to idle. I have played with the float level and that didn't help. It kind of "hunts" at idle and dies. If I try to increase the idle speed it dies. It will almost idle at about 500 rpm, but if I try to set the idle speed any higher it dies. It seems like if I go past that, it is out of the range of the idle circuit.
I did make sure all the passages in the carb are clear. I have some more things to try but I have never had this much trouble with one of these carbs before.
Frank-
This would be for the intake valve only. Running the numbers with heat and a factor of safety, I think that the intake valve stem can be undercut 20% without ill effects. The exhaust could be undercut but won't last long without elongation. Luckily they're not some sort of exotic case hardened valves. I'm going ahead with it, just wondered if it'll contribute towards my end goals.
This would be for the intake valve only. Running the numbers with heat and a factor of safety, I think that the intake valve stem can be undercut 20% without ill effects. The exhaust could be undercut but won't last long without elongation. Luckily they're not some sort of exotic case hardened valves. I'm going ahead with it, just wondered if it'll contribute towards my end goals.
Todd,
Sounds like either an air leak or the carburetor idle circuit is plugged up. Did you pop out the welch plug that covers the idle progression holes when you rebuilt the carb? I've found goobers in there in past experience - they mess with your idle quality.
Sounds like either an air leak or the carburetor idle circuit is plugged up. Did you pop out the welch plug that covers the idle progression holes when you rebuilt the carb? I've found goobers in there in past experience - they mess with your idle quality.
bpalsgrove
Member
- Joined
- Oct 25, 2002
- Messages
- 13
- displayname
- Bruce Palsgrove
What is the end goal you are trying to acheive with undercut stems? Lighter weight? Better flow? Grinding them on a bench grinder will not do the valves any good for "valve life" the little grooves the grinding wheel makes leaves ridges, ridges promote stress risers, stress risers promote cracks and we know what happens with cracks.
There are better things to work on for flow than undercutting stems. You will see better gains in other areas ie 3 angle grind, 30 degree seats, back angle of head etc . . .
There are better things to work on for flow than undercutting stems. You will see better gains in other areas ie 3 angle grind, 30 degree seats, back angle of head etc . . .
Wyatt Bruce
Bruce is correct. To do it correctly, you would need to configure a valve grinding stone for a coarse cut and then configure a second for the fine cut to finish. Anything short wiull di wha Bruce indicated. Also, anything that may get on the seat for one stroke tends to bend the valve and that is the end of a good seal.
I agree with Bruce and the valve angles. In racing we have found that a three angle valve job results in more gain than a lot of grinding in the ports.
Bruce is correct. To do it correctly, you would need to configure a valve grinding stone for a coarse cut and then configure a second for the fine cut to finish. Anything short wiull di wha Bruce indicated. Also, anything that may get on the seat for one stroke tends to bend the valve and that is the end of a good seal.
I agree with Bruce and the valve angles. In racing we have found that a three angle valve job results in more gain than a lot of grinding in the ports.
Bench grinder, sure I'd use that.
Valve stems from my experience tend to be fairly robust, especially considering the low spring rate I'm using. If I were using a spring rate for higher RPMs it might be an issue.
Besides, on a flathead there's no piston-valve interference and if a valve does bend the worst that would happen would be that I'd need to buy a $7 set of guides and $25 for valves, a valve grind, and time. It's not a pulling engine and I like to experiment and see the results any out of the ordinary work. So it pops off a valve head and quits, well then we'll know someone for sure that tried something that doesn't work and why. I'm not going to be content not trying something if there's nothing concrete that says it won't work.
Valve stems from my experience tend to be fairly robust, especially considering the low spring rate I'm using. If I were using a spring rate for higher RPMs it might be an issue.
Besides, on a flathead there's no piston-valve interference and if a valve does bend the worst that would happen would be that I'd need to buy a $7 set of guides and $25 for valves, a valve grind, and time. It's not a pulling engine and I like to experiment and see the results any out of the ordinary work. So it pops off a valve head and quits, well then we'll know someone for sure that tried something that doesn't work and why. I'm not going to be content not trying something if there's nothing concrete that says it won't work.
bpalsgrove
Member
- Joined
- Oct 25, 2002
- Messages
- 13
- displayname
- Bruce Palsgrove
Well u asked for opinions on undercut valves on Kohlers and we gave u opinions, if u already made up your mind why ask the question? (not trying to be combative)
Looking at your pic of the sample valve u ground, looks to me that it was done on a very course grinding wheel, the surface was not too uniform for a ground surface. I realize this was a "sample" and not the actual valve for your engine.
I offered what I felt were valid opinions, U will not see alot, if any performance on a stock motor undercutting the stems. Well none that u will feel in your "butt dyno". Want some "grunt" put in some 30 degree seat angles, I've seen double flow numbers up to .100 on the flow bench (depending on seat location). Personally I machine Ti valves for my performance motors. They take the same amount of time to machine as Stainless Steel and they are so much lighter.
I'd say in future posts be more specify on what u are looking for in answers and that this is for a "stock engine" and I'll leave my opinions out of it then so as not to confuse anyone
Looking at your pic of the sample valve u ground, looks to me that it was done on a very course grinding wheel, the surface was not too uniform for a ground surface. I realize this was a "sample" and not the actual valve for your engine.
I offered what I felt were valid opinions, U will not see alot, if any performance on a stock motor undercutting the stems. Well none that u will feel in your "butt dyno". Want some "grunt" put in some 30 degree seat angles, I've seen double flow numbers up to .100 on the flow bench (depending on seat location). Personally I machine Ti valves for my performance motors. They take the same amount of time to machine as Stainless Steel and they are so much lighter.
I'd say in future posts be more specify on what u are looking for in answers and that this is for a "stock engine" and I'll leave my opinions out of it then so as not to confuse anyone
F
farmall gray
Guest
Steve, Kenny, and David,
Thanks for the suggestions. The condenser is hooked up right. The tiny holes in the main needle
are clear and the holes in the main jet tube are clear. I didn't check for air leaks. I assumed with a new gasket and throttle shaft it should be ok. I'll try spraying some carb cleaner around it and see if that makes it speed up or die. I'll take the carb off and pop the plug out. The idle mixture screw will make it run better or worse, so I don't think the idle circuit is completely
pluggged. It does run ok at part/full throttle. so I think the problem is just with the idle circuit.
Thanks for the suggestions. The condenser is hooked up right. The tiny holes in the main needle
are clear and the holes in the main jet tube are clear. I didn't check for air leaks. I assumed with a new gasket and throttle shaft it should be ok. I'll try spraying some carb cleaner around it and see if that makes it speed up or die. I'll take the carb off and pop the plug out. The idle mixture screw will make it run better or worse, so I don't think the idle circuit is completely
pluggged. It does run ok at part/full throttle. so I think the problem is just with the idle circuit.
Bruce-
I don't think I ever referred to the engine as stock. I had already planned on grinding the intake seat at 30, exhaust at 45, and the the ports are worked a little, as well as the valve reliefs are smoothed into the deck some. You're looking for other information about my setup now but were fine to assume it beforehand. The block is a former "Quiet" engine K321, this engine runs similar sized valves not the later 14hp with the one bigger valve. Cam is K361 w/ stock stroke & 6" rod (I think it's a Lakota rod). I'm tempted to run larger base lifters but I don't know if the cam has enough ramp to take advantage of the larger base. I've got 3 heads I'm going to play with, an old 10hp head without the dump relief, a newer 10hp head with the dump and the plug between the valves, and a head with the dump and the plug over the ex. valve. Engine will have a carb modified already by VPE, no muffler, Midwest Super Cub straight pipe. The engine will be pretty much run in cooler weather (like Plow Day type weather) and will not run with a load on the non-tapered keyed end (no PTO). Will be buying a Kirk ign unit for this engine and will start out running somewhere around 23 degree timing. Will probably run some of the same high octane gas I have for my turbo'd car if it ends up needing it. The engine will be run for extended amounts of time, so I'm going to stay with the cast flywheel with air vanes, as a result and for safety's sake I'll not run it over 4000 RPM. I didn't really want to spill the beans over what I'm doing so I can have my own fun, but if I'm going to look for information from people who are more knowlegeable in small engines I'll have to make my sacrifices.
I like to have the mindset like the engineering group I worked in at Waukesha Engine, I don't want to hear that something just won't work if it won't work I want to know that there's flow numbers or dyno out there to back it up, if not I'm going to have the fun of getting the numbers on my own.
BTW-
The valves were done on a drill press with an angle grinder, I didn't see much sense in taking a junk valve to work to put on the lathe and dirty up one of their stones.
I don't think I ever referred to the engine as stock. I had already planned on grinding the intake seat at 30, exhaust at 45, and the the ports are worked a little, as well as the valve reliefs are smoothed into the deck some. You're looking for other information about my setup now but were fine to assume it beforehand. The block is a former "Quiet" engine K321, this engine runs similar sized valves not the later 14hp with the one bigger valve. Cam is K361 w/ stock stroke & 6" rod (I think it's a Lakota rod). I'm tempted to run larger base lifters but I don't know if the cam has enough ramp to take advantage of the larger base. I've got 3 heads I'm going to play with, an old 10hp head without the dump relief, a newer 10hp head with the dump and the plug between the valves, and a head with the dump and the plug over the ex. valve. Engine will have a carb modified already by VPE, no muffler, Midwest Super Cub straight pipe. The engine will be pretty much run in cooler weather (like Plow Day type weather) and will not run with a load on the non-tapered keyed end (no PTO). Will be buying a Kirk ign unit for this engine and will start out running somewhere around 23 degree timing. Will probably run some of the same high octane gas I have for my turbo'd car if it ends up needing it. The engine will be run for extended amounts of time, so I'm going to stay with the cast flywheel with air vanes, as a result and for safety's sake I'll not run it over 4000 RPM. I didn't really want to spill the beans over what I'm doing so I can have my own fun, but if I'm going to look for information from people who are more knowlegeable in small engines I'll have to make my sacrifices.
I like to have the mindset like the engineering group I worked in at Waukesha Engine, I don't want to hear that something just won't work if it won't work I want to know that there's flow numbers or dyno out there to back it up, if not I'm going to have the fun of getting the numbers on my own.
BTW-
The valves were done on a drill press with an angle grinder, I didn't see much sense in taking a junk valve to work to put on the lathe and dirty up one of their stones.
F
farmall gray
Guest
David K,
Where would be a good place to get a replacment
for the welch plug? Kohler doesn't service it separatly and the auto parts stores don't have anything that small. It is 3/8" according to the parts book. I looked in stens and they list
5/16" and 7/16" plugs but no 3/8". I don't want to take it out till I have a replacment. I haven't checked Mcmaster carr, but from them I would probably have to buy 100 of them.
Where would be a good place to get a replacment
for the welch plug? Kohler doesn't service it separatly and the auto parts stores don't have anything that small. It is 3/8" according to the parts book. I looked in stens and they list
5/16" and 7/16" plugs but no 3/8". I don't want to take it out till I have a replacment. I haven't checked Mcmaster carr, but from them I would probably have to buy 100 of them.
D
dvogt
Guest
you could just go out & buy some nice small stem nail head titanium valves of stock size. you increase your air flow & be able to reduce valve spring tension dramatically to reduce rotating friction.
Wyatt
Nichols Performance has Titanium Valves. e-mail is "[email protected] Can't find an online catalog or site for Scott.
Valves are listed at $95.00 ea.
Nichols Performance has Titanium Valves. e-mail is "[email protected] Can't find an online catalog or site for Scott.
Valves are listed at $95.00 ea.
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dvogt
Guest
You could check with Super Cub, He's adding stuff all the time.
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