Tips and tricks needed for k-341

[Forest Road 594]

I've finally begun! Just finished tearing down a perfectly good motor. So good the cross hatches are still visible!

Looking for some feedback from our motor heads!!!! Good, bad, or ugly. Let me have it.

Im going to be putting Magnum parts back on this block. I plan to tap the points plunger hole and stick a screw in there and use a Magnum bearing plate. I'm willing to gamble on the camshaft NOT leaking any oil. The PTO side was dry.

Plan is to clean up the rough spots in the valves from the casting. Also planning to blend the deck into the valves. Have the head checked and possibly cut down for a hair more compression.

Balance gears IN or OUT?

I considered having the cam ground for cheater specs. I just don't want to spend another $200.

Original piston, rings, valves are going back in. Doubt this thing had 100 hours. Agree??

If you've got any other low budget suggestions I'm all ears.

Thank you

Kevin

Edited October 24, 2014 by Forest Road

[Aldon 4,826]

I will follow this thread with interest.

[Shynon 7,459]

Why are you tearing it down? I would leave the balance gears out, they do nothing.

 

                 Tom

[wallfish 16,980]

 Just finished tearing down a perfectly good motor. So good the cross hatches are still visible!

 Doubt this thing had 100 hours.

If you've got any other low budget suggestions I'm all ears.

Thank you

Kevin

If it ain't broke, Don't fix it

[oldredrider 2,548]

Let me get this straight. You tore down a completely good K-341. You are going to convert it to a Magnum style engine. You are thinking about decking the block but don't want to spend $200 for a cam grind.

Frankly, and you said you wanted tips, even if it was "ugly", you are wasting your time and money. You had a perfectly good engine good for at least 20 years if taken care of and haven't got a clue about building an engine. Now you are asking for suggestuons? Next time you run across a K-341 in that kind of shape, PM me and let me get it away from you. You asked.

[WH nut 553]

All I can say is WHY. What is your plan for this motor?

[Desko 608]

First off why must we beat others ideas down this is a forum for help not ball busting it's just an engine nothing more. Second I think it is a creative idea and something to try. Third maybe some people like the m series with a mag and no points because that would make it easier to trouble shoot and not have to check and adjust points or worry about getting water in them. Can't wait to see this engine finished.

Edited October 24, 2014 by Desko

[Forest Road 594]

All I can say is WHY. What is your plan for this motor?

Finally the big $$$ question!!! The tractor is a very clean worker at our family vacation home. General chores are no problem for the existing 225 hour Magnum 14. I WANT more power for the two stage blower. I'm no fan of Onans and refuse to spend $1200+ on a new V-twin.

Although a standard K or Mag 16 would've been better than what I have. I really wanted to try my hand at minor motor modifications.

I've read quite a bit on various pulling sights concerning these builds. Yet my favorite is David Kirk's Killer Kohlers. Short sweet and to the point. I've also spoken with a couple guys who build pullers and they pointed me down a similar path.

Now back to the Cam. I'm definitely having second thoughts. @ $100-150 I was all in. $200+ shipping has me second guessing.

[bmsgaffer 2,043]

I would like SOMEONE to make a supercharged K series... maybe that will get you your extra HP?

[km3h 543]

I don't see you improving horsepower enough to make much difference. The ability of the snow blower to throw snow is directly rated to the RPM of the impeller, which is dependent on the speed of the engine, which should turn at 3600 RPM. If the engine is at its proper speed, additional horsepower won't make a difference. At least that's my theory.

[oldblue1993 98]

I will admit, I have taken a perfectly good engine and tore into it for "more power" . What I found out was, that it was never the same again. The engine was just never as good as it was. Yes I was able to get more but it was a poor trade off,

 If using for pulling or short runs, I would say build that B!@tch up! as for everyday running, nothing beats the origanal. First thing I would suggest is reading http://gardentractorpullingtips.com/index.htm He explains all tips and tricks, but read it with the mind set of what you will be using this for.

[Forest Road 594]

Thanks guys! I've got one guy who says leave the balance gears out. Nyone else for or against balnce geas? I  found a few online builds which state the same. To the spare parts drawer they go. 

 

Unfortunately i misspoke earlier in reference to wanting more power. What i really want is more torque. My goal here isn't to build some insane single. I just want a better breathing slightly more efficient motor. I've seen Brian Millers website. Thank you. 

 

I've read this several times over http://www.kirkengines.com/downloads/KillerK241PartIII.pdf and its essentially my template at this point. One of our members from Maryland built a beautiful 14 hp a few years back and was kind enough to share his buildup with me. I spoke with an Engine builder in Ohio who reinforced Kirk's version and recommended a cheater cam from his machine shop. Its really not a big deal for me to swap out an engine. So Im going to go ahead with the stock cam for now. As much as id like to try a new one I just can't justify the money at this time. 

[bmsgaffer 2,043]

I don't see you improving horsepower enough to make much difference. The ability of the snow blower to throw snow is directly rated to the RPM of the impeller, which is dependent on the speed of the engine, which should turn at 3600 RPM. If the engine is at its proper speed, additional horsepower won't make a difference. At least that's my theory.

 

These engines actually develop peak torque at a lower RPM (2800 maybe? i forget). So when you dig into a huge pile of snow the rpms drop down (in theory) to the peak torque range and the governor gives it more fuel/air until the load is removed.

 

By modifying some engine characteristics you can change this range... It may help marginally if you are loading the blower way down all the time.

 

*This is just my understanding of the theory.

[baerpath 517]

 So other than changing external parts your just having fun ? Leave the balance gears out

It's your engine go for it. 

 Would I do it no,  Never would I deck a block other than for short term use. (2 to 4 min track runs) Your setting it up for cracking between the valves  I would swap engines and put a 16hp in then it would make a difference

[AMC RULES 37,125]

Enjoyed the read over at Kirk's site...    

thanks for the link, good luck with your project. 

[tbarnhart 240]

Obviously, power and torque can be improved with a few simple tweaks. Think of an engine as an air pump. The more flow through, the more air/fuel is burned and the more power. People have been porting and tuning engines forever. The question is, how much can be gained. The basic valve-in-block architecture of the Kohler is not the most efficient design for airflow, but as the pullers have proved, can be helped considerably. Your biggest gains will come from some simple port and valve work, decking the head or head gasket elimination for more compression and the ability to adjust the ignition timing. The Magnum ignition is not adjustable without offset flywheel keys or slotting the mounting holes on the magneto. Faster ignition would give a fair bit more power, but could cause difficulty starting. Some of the fancy electronic automotive conversions have a bypass that retards timing for cranking then advances it for running. Works, but not cheap. The cam is another big piece of the airflow puzzle. Big percentage gains to be had there as well if your willing to take the plunge. For that two-stage, I would think you would want peak torque to be in the 3000 rpm range close to operating speed. You don't want the motor bogging to 2400 just to pull through a drift. The low rpms would limit the blower. Best of all, get a dyno and do the mods one at a time and share the results.

[Callen 64]

If you are staying in the same RPM range, port work and relieving the top of the block will most likely hurt it. If it were me doing this project, I would get a timing wheel and dial indicator and run the profile on the cam. You can shim the cam more left or right to advance or retart the centerlines. 106-108 is good torque centerline on the intake. then set ignition timing to 26-28 degrees for bottom end torque. Crane cams has good info on doing all that and explains camshaft dynamics. The cam is the heart of your engine followed by a great carb.

Chester

[Forest Road 594]

If you are staying in the same RPM range, port work and relieving the top of the block will most likely hurt it. If it were me doing this project, I would get a timing wheel and dial indicator and run the profile on the cam. You can shim the cam more left or right to advance or retart the centerlines. 106-108 is good torque centerline on the intake. then set ignition timing to 26-28 degrees for bottom end torque. Crane cams has good info on doing all that and explains camshaft dynamics. The cam is the heart of your engine followed by a great carb.

Chester

Thank you. I'm curious how porting and polishing the valves would harm a stock motor? Or relieving the deck?

I won't be changing the size of the valves. So theoretically no more air will be permitted into the engine.

[Callen 64]

Your engine relies on atmospheric pressure to push air into the cylinder during the intake stroke, it doesn't suck air in. You need to maintain velocity through the port to carry and pack more air in before the valve closes. Grinding in the port if it's already borderline on the size needed for the rpm range will slow the velocity. Keeping the walls of the port slightly rough will help remix fuel when the valve opens and motion starts again, it does this 1800 times/min at 3600 rpm. You will probably be good just removing casting flash.

For relieving the top of the block, I would just knock off the sharp edge of the eyebrows. I wouldn't mill the head. Anytime you move the top of the combustion chamber closer to the top of the block the flow over the edge of the cylinder is restricted. Getting the cylinder pressure up by filling it with air is better than trying to get the compression ratio up.

[Forest Road 594]

Thanks again! I'm onboard with you. Builder I spoke to said dam near same thing. You explained it better.

I'm not going nuts with the valves. Just eliminating the rough spots leftover from casting. The lip on intake was so bad it felt like a finger nail hanging out just under the valve.

Can you recommend a shop to have the cam done? Hackman gets almost $250 w shipping. I wont buy from Miller.

Edited October 27, 2014 by Forest Road

[Callen 64]

sent a pm

[Forest Road 594]

When it rains it pours! Magnum sixteens that is. I found one locally off a turf mower. The bore looks good. Appears to have been decarbonned recently.

The down side is its got the wrong crank. I just happen to have the proper crank from he k341.

I'm considering swapping cranks. As much as I'd like to go through with the modifications previously discussed I'm too dam cheap to spend the money on the cam right now. And it does seem that any mods would be a virtual waste without the reground cam.

I should be able to swap the crank and button her up in a couple hours. Then it's an easy swap to my 314.

Maybe I'll get around to building the k341 someday.

[diamondred 63]

There is no replacement for displacement. I'm sure the folks at Kohler back in the day did a great job designing engines. I have a C-81 (1979) that I just finished plowing the garden with. Although probably would not use it with a snow blower, point being it's 35 years old and still does the job. As far as getting rid of the points... bad idea. Points , coils and spark plus are easy to find. Points run off the cam, therefore only firing on the compression stroke. Point gap can be deviated from to adjust timing somewhat, can't do that with a Magneto. Only advantage of a magneto ignition is you don't need a power source, but the magnets could weaken.

Along with the M series Kolhers came the non-adjustable main jet carbs If I had a choice between the two, it would be a K series, although I have both.

Onan? ...thats the Horse on the other side of the fence, have them too. But don't cross that fence til you're ready! :ychain:

Edited October 30, 2014 by diamondred

[Forest Road 594]

Went ahead and pulled the trigger. It's not "if" it's "when" I'll get around to it. Had some time to grind the reliefs tonight. With 3 boys under the age of 6 time is precious.

I was really surprised at how little it took to grind. A gentle hand and a lot of patience pays off here.

Another issue with this block is lack of a WH dipstick. It does have a short tube at the base. Id prefer to have a standard set up. I have a tube and stick from a magnum. The castings are in place for the tube bolts. I'm contemplating installing one. This may be better left to a machine shop.

[Forest Road 594]

Christmas came a little early. Had some communication with David Kirk. It would seem that I now own his last cheater cam.

Dropped the block off at a local machine shop. Hope to have it back next week. It's amazing how some things have come together in the past two weeks.

With a little luck I might be ready for assembly by Thanksgiving

.