2 Lp Head ?'s
 

Just pulled my head from my puller today. The cylinder is perfect with the right amount of carbon and no hot spots. It is still a standard so the motor has alot of life still left in it.

I am changing out my stock 12HP head and installing the old high compression lp head. Comparing the 2 there is such a big difference in the compression area. On the front the ridge is just enough for my fingernail to catch. (makes it legal for my class)

What is the correct spark plug. The old head has a Champion J19LM. It is way too short. The electrode does not even clear the threads. It is way too short. (should get more power just by getting the correct plug)


Then the head bolts are too short. I need to get the correct ones. Will standard grade 8 bolts work or will I have to get purpose made head bolts. What is the correct length for the head bolts for the LP head.

The original plug for a K241-K341 is a Champion H10C or equivalent, IIRC.

The J19 plug is the wrong sparkplug for a Kohler. The champion plug is a H10C. I've had problems with champion spark plugs in the past and will not use them anymore. Autolite sparkplugs work for me. The Autolite plug number is 216.

The Autolite 216 sparkplug works good in stock to slightly modified Kohler motors. Spin the motor by hand to make sure the valves don't hit the head. I had problems with the valve hitting head on a legal cam in my K241 motor.

Thanks. I have my wife on the way to pick up the 216 plugs. Getting a few spares. How much power was I losing with that sparkplug being too short?

Also how much Hp should I gain by
Switching to methanol
Installing LP head
Advancing the timing (points gap)
Installing the correct spark plug.

I figure I will gain atleast 1HP.

Odds are the you had the wrong heat range plug which create a poor fuel burn which hurts power. How much is anyones guess.

I would stay away from the methanol until you get the everything else dialed in. It is hard to say how much power you can gain...air temp and humidity plays a part in making power. Running alcohol can make it harder to dial in.

That is the the part number . I should get it I stalled today or tomorrow. My torque wrench is missing so I ordered one and it should be here today. I just went to the hardware store and bought some grade eight bolts about 3/4 of a inch longer. Will this suffice?

I think I am better on methanol. I raced karts for many years and that is all we ran. I became pretty good at tuning with it. Not so good with gas.