Archive through September 01, 2009

[dross]

Matt, I am under the impression a 10, 12 and 14 were all the same block. Back when Dad had the mower shop and I had access to micro fisch(sp) from a long ago memory you could take a standard 10 all the way out to a 30 over 14. If I'm wrong I'll say so but you got to show me.

 

[rpalmer]

Dave Ross,

This is borrowed from Brian Miller's web site. You might want to form your impressions with this rather than your memory.

How to Tell the Differences Between the 10hp, 12hp, 14hp and 16hp Kohler Engine Blocks -

* The 10hp (model K241 or M10) blocks have a bore of 3.250" and the stroke is 2.875". Some rare 10hp blocks have a casting embossed above the PTO end reading "K301." These have a thicker cylinder wall than ordinary 10hp blocks. All 10hp blocks have an exhaust valve diameter if 1.125" and the intake is 1.375".
* The 12hp (model K301 or M12) blocks have a bore of 3.375' and the stroke is 3.250". There are no other differences between the 10hp and 12hp blocks. The 10hp and 12hp blocks have the same size valves, and all of the external parts will interchange. The 10hp and 12hp engines use a #26 (1.07" throttle bore) carburetor.
* The 14hp (model K321 or M14) blocks have a bore of 3.500' and the stroke is 3.250". There are no other differences between the 10hp, 12hp and 14hp blocks, except in the 14hp, the valves are the same diameter, 1.375". All the external parts will interchange with the 10hp, 12hp and 14hp engines, with the exception of the early style 10hp cylinder head and the carburetor. The 14hp uses either a larger #28 or #30 (1.17" or 1.2" throttle bore) carburetor.

What makes an engine produce more noticeable power and torque is not necessarily a larger diameter piston, it's having a longer stroke. For example: there's a world of difference in power and torque between a 10hp Kohler engine into a 12hp Kohler engine. Unlike a strong 10hp, a good 12hp engine will actually pull you back in the seat when you punch the gas. Not only because the 12hp has an 1/8" larger bore than a 10hp, but it has a much longer crankshaft stroke, 3/8" longer, to be exact! 12hp engines are able to produce 2 more horsepower than the 10hp because of three things: 1) 1/8" larger bore, 2) 3/8" longer stroke, and 3) higher compression because the 12hp use a cylinder head with the same size combustion chamber as the 10hp. But there's not that much of a noticeable difference in power and torque between a 12hp engine and a 14hp, because the 14hp has an 1/8" larger bore, but it has the same length stroke as the 12hp. 14hp engines are able to produce 2 more horsepower than the 12hp because of two things: 1) 1/8" larger bore, and 2) higher compression because they use a cylinder head with the same size combustion chamber as the 12hp.
Many people (pullers) believe that an engine will produce more noticeable power and torque simply by boring the cylinder and installing a maximum of .030" oversize piston assembly. But there's really no need to do this, and it won't give it anymore noticeable power. The best thing to do is just bore the cylinder to the next oversize, if needed. Or if it's worn beyond .030", have it sleeved back to standard size.

 

[bnolte]

At one time I had all three blocks. Unfortunately the k321 I had was not a Cub-Spec engine, although it was in good shape. I ended up trading it for a k301 block. I believe there might be differences in the casting wall thicknesses, it's a shame I didn't think to take a caliper or even a ruler to it to check.

Except for the balance gears on the 12 and 14, I bet it didn't cost more than a couple of bucks to build the 14 than the 10 or 12. My dad let me in on a dirty little secret about a similar cost/price structure with diesel engines, and I expect this is true with many automobile engines as well. A 400 hp diesel engine cost about the same to build as a 500 hp engine, the main difference would be things like fuel pressure and Turbo boost, but they expected the 500 to have a higher warranty cost. The rest is profit!

I had a 1991 Honda Civic that the original 70 horsepower D15B1 engine wore out on after 224,000 miles, and replaced it with a D15B2 engine, which was a year older and rated at 92 horsepower. Both were 1.5 liter 16 valve engines, and used the same throttle body injection system. The B1 engine was rated at 70hp@4400 rpm, the B2 engine was rated at 92hp at 6,000 RPM.

It would be very nice if it were true.

That being said, there are only a couple of real differences between the 12 and 14 horsepower motors besides the carburetor.

The 12 and 14 horsepower engines both use the same basic crankshaft, with the same stroke. The difference is that the 14 horsepower crankshaft has fewer and shallower holes drilled in the counterweights to compensate for the heavier piston of the 14.

 

[dtanner]

Bruce N , (. A 400 hp diesel engine cost about the same to build as a 500 hp engine, the main difference would be things like fuel pressure and Turbo boost, but they expected the 500 to have a higher warranty cost.) on the diesel i was told that fuel pressure and timmed delivery of the fuel is what gave more horse power. so more fuel and timming change will give more power. Is this wrong.
Cub D given more fuel and air will give more power? later Don T

 

[bnolte]

Donald T.
It was probably a combination of factors, turbo boost being one of them, and timing/fuel pump dwell being another. I believe Turbo boost was probably the biggie, you can only get so much power from an optimized fuel mixture at a given air pressure and RPM. Perhaps the 500 had a higher governed speed as well.

 

[lhinds]

Bruce; I had the point insulator melt down on a K301 two years ago. A friend was using my tractor and stalled the engine and left the switch on about 4 hours. The point insulator was completly melted, the points welded closed, and the coil was burned up. Another time the kids left a key on and welded the points on my 128. Then i learned to remove the key.
Luther

 

[wmiller]

Bruce,Richard, I have a 126 and 147. Both have fresh o'hauls,one is .020 over and the other is .030 over (don't remember which is which)that I use for heavy off lawn mowing. I use the same deck for both. I can not tell any significant difference in power between the two. I never used the 147 before I o'hauled it. I ran the 126 two seasons before o'haul. The difference in its performance after o'haul was dramatic.

 

[rpalmer]

Well the 129 that had me in fits and ready to scrap no less that three times, is now on stand by for snow removal. I'm still undecided on the tires I'll use. That's why you don't see the chains yet.

 

[dross]

Richard, I've read that before and he's talking about classes in pulling, not whats possible. What you have to do is use the appropiate crank, and rod, with the bore your useing more for balance than anything.
Wayne, The hydro is your difference, if that 14 is running good in a gear drive they are a lot more fun.

 

[kmcconaughey]

The K301 that David Kirk rebuilt for me to his Killer specs has a K321 crank in it. David suggested that I go with that crank as it provides better balance then the K301 crank would especially since we were removing the balance gears. Here's a quote from an email from David when we were discussing what mods to go with, I ended up going with full out Killer Kohler mods. The engine David built for me is awesome!

<blockquote><hr size=0><!-quote-!><font size=1>quote:</font>

A K321 or K341 crank is ideal as they have the full counterweights versus the machined flats found the K301 part. The full weights improve the balance factor and will make up for lack of balancers.<!-/quote-!><hr size=0></blockquote>

While we didn't put my Killer Kohler K301 on a dyno, David calculated that it might put out as much as 17hp! All I can say after running it for nearly a year is it sure has lots of power.

I should also mention that we had to bore it to .030 over due to wear.

 

[rpalmer]

Recap:

I have a K301 that will be rebuilt through this upcoming winter. Does anyone have any experience over boring up to the K321 bore and thus getting a 14 HP engine?

By Matt Gonitzke (Mgonitzke) on Monday, August 31, 2009 - 07:04 pm:

Doug W.-

I wouldn't do that, as the cylinder wall gets thin when you punch a 12 out to a 14. If you want a 14, then get a 14 block.

Matt, I am under the impression a 10, 12 and 14 were all the same block. Back when Dad had the mower shop and I had access to micro fisch(sp) from a long ago memory you could take a standard 10 all the way out to a 30 over 14. If I'm wrong I'll say so but you got to show me.

Richard, I've read that before and he's talking about classes in pulling, not whats possible. What you have to do is use the appropiate crank, and rod, with the bore your useing more for balance than anything.
***************************************************************************

A. Matt is correct.
B. You are wrong. The blocks are different
C. The question was never what is possible.
D. Engine specs are just that. Pulling or cutting grass does not change them.

 

[dross]

I'm going over to a machine shop this afternoon, a place I've used infrequentlly for 20 years, he's got a 14 on the floor he just bored, he's agreed to allow me to measure it. I'll pull the head off the 10 in my 72 if I have to, we'll get it figured out.
Richard, C, the question is always "whats possible"

 

[bnolte]

A little OT from the block specification thread, I had a productive trip to my favorite scrapyard today. I scored a 20 foot long piece of 1 1/2 inch wide 1/8 inch thick steel, and an 8 foot long piece of 1 inch box section for $20. For an extra $10 he threw in a good center console top and cupholder for my Accord, which will replace the damaged ones in there.
The steel will make nice mower baffles.

I also have a question about a clutch pressure plate: The clutch on my 102 rattles loudly when it is released, and I traced the problem to the bore on the pressure plate (the one on the spring side), which appears to be badly worn. I was wondering if any of you gear drive people have machined this part for a bronze bushing, or if I should just get a new one?

Charlie, I saw used and reconditioned pressure plates on CC Specialties. Do you know if they check the bore on these?

 

[dwhipple]

HELP!!! I bought a qa42a snowthrower for my 1250. I replaced the bearings due to wear. when I hooked it up to my 1250 for a test run at idle speed. When I turned on the pto it started to make a clunking sound and you could see the gear box jumping around on the mount. The mounting bolts for the gear box were tight, the auger and main housing showed no signs of shaking or vibration when off the ground. I tried increasing the throtle and as the engine increased in speed the clunking sound went away and the gear box stopped jumping around on the mount. Could I possibly have a bad u-joint or two? I checked the gear box, I am changing the gear lube, the gears, bearings, and the shafts are all in good shape with little or no play. Does anyone have any other information that might help me slove this problem????? Please email me at [email protected] . Thanks everyone.

 

[dross]

I just got back from the machine shop. He loaned me a digital caliper. I measured the outside of the cylinder, I found the narowest measurment inside the cooling fins. On three blocks a 10 3.58, A 10 that had K301 stamped in the PTO end of the block that was 3.96, A 14 that measured 3.97. I'll say I was wrong as far as all 10's can be bored out to 14's. What I believe now is some can be bored out to a 14 and some can't. The smaller of the 3 did not have the K-301 cast into the block.

 

[kide]

Interesting side note on the boring possibilities / wall thickness question - I took a (OT) Cushman block to a local race shop a couple years ago as it was originally a 2 7/8 bore and had been bored several times - last time to 3.050. We were going to check it with their high $$$$ ultrasonic bore checker, but discovered that the only place we could get a reading was in the valve chamber area, as the fins cast to the OD of the jug gave an "infinite thickness" reading on the rest of the cylinder. Where we COULD read it, it showed about 1/8 inch, which was deemed thick enough at the 7:1 compression this motor was to be run at..

 

[mfrade]

"a question about a clutch pressure plate: The clutch on my 102 rattles loudly when it is released, and I traced the problem to the bore on the pressure plate (the one on the spring side), which appears to be badly worn. I was wondering if any of you gear drive people have machined this part for a bronze bushing, or if I should just get a new one? "

Bruce, I bored and bushed mine. If you have a lathe & stock it's easy to do or, if you have a machine shop close by that won't mind a small job. If you use someone local don't forget to bring the shaft so it can be fitted as needed.

 

[digger]

Bruce N.
I dunno what they do, but since I'm the one that does it, I know I do.

 

[bnolte]

Mike T.
I'm probably not going to take it apart again before the Arcadia Steam Show in about 2 weeks. I'll see if I can find a better one there, while I noisily putt around on my 102. I actually made the driveshaft out of cold rolled 5/8 inch round stock. I have the excess length of the shaft, which I can use to size up anything I run across there. If not, it might be a good excuse to get my engine lathe functional and try it out

 

[mfrade]

If not, it might be a good excuse to get my engine lathe functional and try it out

Always a good excuse to get more tools & equipment!! 5/8" is real stout! And I thought I always went in for overkill! LOL!! I used a length of shafting stock that a friend got me. It was oversized and I only had to turn the ends. Hope you have a great time at the show!