PULLERS got a Kohler LP head question - Page 2

jmroy · #11 12-12-2012, 04:23 PM

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.

austin8214 · #12 12-12-2012, 05:02 PM

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

dvogtvpe · #13 12-12-2012, 07:41 PM

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.

Donny Curtis · #14 12-13-2012, 12:54 AM

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

dsmithjr · #15 12-13-2012, 07:26 AM

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.

austin8214 · #16 12-13-2012, 09:16 PM

Quote:

Originally Posted by dvogtvpe

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.

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

dvogtvpe · #17 12-14-2012, 07:40 AM

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

bluecap24 · #18 12-14-2012, 09:37 AM

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

dvogtvpe · #19 12-14-2012, 06:16 PM

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.

jeff k. · #20 02-09-2013, 11:48 AM

( 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