PULLERS got a Kohler LP head question
 

I just found out the 10HP engine I have has the #235461 high compression head on it. I was thinking about selling it but then the "man I bet I could build a hot engine" bug bit me. I dont pull but thought I might put this head on the 12hp in the 105 my daughter and I are building. Many Google searches only confused me. Question is this. Is there noticeable gains in power by using this head? Do I have to switch to high octane fuel as some people are saying? I just though it would be cool to build a yard tractor with a mildly hopped up engine for fun.

Nobody using one of these heads that can tell me a little bit about them??

They do increase the performance but I think most pullers myself included prefer to mill down a regular head .050 .

Lp Head
 

I have used the LP Head, But I like the head with the spark plug over the exhaust valve, helps to keep the plug from fouling out too.I agree with Austin8214, my .02

I know i've read where people think the small combustion chamber kills the air flow.

Thanks for the answers guys!!
I actually just found out mine is the second generation 235461 head so its not a true LP. Im not a puller I just thought it would be cool to have a "built" engine with a mild cam in one of my Cubs. Ive been reading up on building engines but alot of it is over my head.

Take that head to a local machine shop and have them take .040 off of it. Then see if you can find a good used 18hp cam and a good carter carb and you'll have a mean mowing machine!

Austin that's just the info I needed. Ive got a #30 Carb already. What cam should I look for exactly? I have access to some good used parts but I need to know what I should look for. Thanks!!!!

dsmithjr I run a milled lp head on my 10hp puller. Can't say that there is any difference with it being miled, but it does compete with most 12hp tractors. I run 110 octane fuel. Maybe this helps!

CC102, what I want to do is build a yard tractor just for driving around the yard and playing with. I might pull my wagon or maybe go to a plow day. I just want it to run good and sound good. I would like to stick with "stock" parts. Example: use my head maybe milled, a larger cam out of a different engine and a larger stock carb. I know you pullers have a lot tips and tricks and can set me in the right direction. Keep it coming! CC102 ive got a 10hp engine I can use also what kinda set up can I use on it?

I'm pretty sure there was only one type of LP head so what you have is indeed an LP head. They're better than any of the other ones when running a stock RPM engine. If you mill that head you'll have to run race fuel, the stock LP head you can run 93 from the pump. If you're just using it around the yard I would keep it stock, it'll be cheaper.

If you stick a #30 carb on there you are definitely going to want a 18hp cam.

We have a dyno, a flow bench and build allot of engines and have played around with a ton of different things. the big thing you want to ask your self is governor or no governor . on a 3800 rpm engine the second gen head is pretty decent. shave it like a few guys mentioned and it works a little better. compression gives you torque, torque turns the tires. the head with the plug over exhaust valve shows better numbers at a higher rpm but hurts where a 3800 rpm engine would need to run. same for carbs. on a 12 a #26 is much better on a 3800 rpm engine. better torque. turn it higher, then a 30 benefits you. advance your ign timing to 24 deg helps allot. you really need to be carful with what you run for gas. on most stock engines race gas actually hurts , running a regular gas is best. a stock 12 only has around 6.5-1 comp. one thing that can really help is to advance your cam timing. there's allot of good aftermarket cams much better that a 18 cam. Hackman, Lacota, vogel to name a few. Super Cub is working on one right now. not sure when they will have it for sale. another thing you could do is deck around .015 to .020 off the top of the block and do a good 3 angle valve job, under cut the heads of the valves. the LP head is a nice head and depending on how you are going to build the engine can work out very well. one note some of these mods give starter / gens difficulty starting, but putting the ignition on a separate switch so you can get it spinning then hit the ignition helps allot. if you can find a governor out of a generator engine those work very nice. they cause a surging or hunting problem when wide open but respond quicker than the regular governor does.

LP
 

If you just want it to sound good, Just Put a stack on, it will sound good:biggrin2:

jmroy- Ive been reading everything I can on those heads and even though mine has the right part number it is not a LP head its a second generation head. The combustion chamber is different.
austin- I have #26 or #30 so i can go with which ever is best
dvo- I dont need a competition level engine I just something that runs good,sounds good and has a little thump to it for my yard tractor. I do like the cheater cams better than the 18hp cams idea.
Donny- you may be right. I may just put the head on the 12hp make sure its tuned correctly and add a straight stack. I was just hoping for a little thump out of the cam so it didnt sound completely stock.
I really like the article David Kirk did on the Hot Rod K301 its just a little more involved than I have been in rebuilding an engine.

What carb works best on a 12hp turning 4000 rpm? The #26 or the #30? I'm using a mwsc cheater cam.

I'd recommend a 26. a 30 would give you a little better numbers over 3800 but the 26 would outshine it in the 3000 to 3400 range which is where you will need it when the load comes on

What does a generator governor gear look like compared to a standard gear?

the weights are off set. I think they went NLA a couple years ago. if you looked up governors for a kohler single there were only 2 listed. the one was for only 3 or so different spec numbers listed, that was the generator gov.

Looking for help
 

( advance your ign timing to 24 deg helps allot.)

Can you tell me how to do this ?

Running reg. preimum gas is better than race gas?

I was also looking at vogel cams. What do u recommend n y.

Also wondering ur thoughts on weight of flywheel. Is hevier better?

Do velosity stacks help?

I have a stock 12hp and am looking to slowly up grade. (due to cost.) LOL
any help/idea's r welcome

the most accurate way to advance your timing is with a degree wheel. you take the head off, dial indicate TDC then adjust a pointer that you bolt to or clamp to the block to TDC on your degree wheel. locate 24 deg before TDC and mark the flywheel in line to the cast mark n the bearing plate or some other form of pointer. or just set your point gap at .024. it don't mean you are at 25 deg but it gets you close.

yes, regular is better than race gas. a kohler single is really very crude. 6.5 - 1 comp ratio. you need a fast burning fuel . race gas is meant to slow down the process and prevent detonation . at 6.5 - 1 you aren't going to have detonation unless you have a whole lot of other issues

cam, depends on what you are doing to it. designs to cams are meant to function in certain range's and conditions. a cam for a 3800 engine is worthless when you take the governor off.

flywheels. heavier and larger diameter.

velocity only on a ungoverned engine

Thank you, tat helps a lot