k301
 

What is the compression ratio for a k301a 12hp

The service manual does not state. I do not know :bigthink:

Why are you asking? Building a puller I assume... ?

Kind of. I bought a 122 and am wanting to rebuild the engine and i cleaned the top of the piston and it stamped .030.

Looking to mildly build it up bt be able to use it

The .030 means it's bored .030" oversized. Knowing compression ratio is not really important ....... unless you are planning on a SERIOUS build.

Main reason Kohler does not state compression ratio is the compression release built into the engine. For a daily use you need the compression release if you have a starter generator system.

Here is a good write up to build a fun to run/daily use Kohler:
www.kirkengines.com

Look towards the lower right sectin to how David Kirk build his "Killer Kohler" I did a build on a K241 (10 hp Kohler) and like the performace it now has.

One this to remember is when you add ponies to the engine you need to beef up the clutch and transmission to get the best performace out it.

cool info! thanks for the link!

Just need compression ratio. Has starter gen.

I think they are about 7.5:1

Just disconnect the compression release springs on the cam and roll it over with a compression guage hooked up.

Ok........ do you want to know how MUCH compression they make? Like as in how many PSI? Or do you want to know the RATIO?

Stock flat head engines like a Kohler will give you 7 to 7.5 to of you are lucky. A modified one may give you 8.5 to 9.0 to 1.

I wouldn't get too excited about high compression if you want a daily worker. The engine will be a pain to keep going.....been there-done that.

I agree! :beerchug:

K301 engines are 6.1:1, 6.6:1 or 8.6:1 depending on which type of head design you have. most are 6.1 or 6.6 . K241 is lower 5:1, 5.4:1 or 7.1:1. anyway get it to hi and it won't start with a starter gen. come winter then you'll never get it started. our pulling engines use a starter cart. ford 8N starter on 12v. you have to get it spinning then turn the ign on.

now just so you understand what compression ratio is take bore x bore x stroke x 3.14 that gives you your cubic inch's. 30 or 491.61 cc for a K301, then you measure the combustion chamber of the cylinder head including the head gasket and the amount that the piston is short of the top of the block in cc's. then figure how many times you squeeze the bore into the head chamber.
sounds simple? ok now take into consideration how well an engine fills the cyl with air while running. or running compression. usually a bit higher than static. now this number is also affected by your cam timing or more important where your intake opens and exhaust close's. this is one of the reasons cam timing changes are noticed and can affect your performance. you look for that magic spot . make 2 degree changes either advance or retard . more torque you usually retard . more revs , advance. When I say advance or retard I'm referring from what's known as split overlap or when at TDC both valves are open the same amount. or the cam is installed straight up.
compression is the actual number of PSI you get when you crank the engine over. only reason its there is to judge the condition of the cylinder. you tell me you have 150 psi of compression that don't mean much . tell me you have 14:1 compression ratio , that tells me something. now tell me your engine has 14:1 comp ration and 150 psi of cranking compression then I can say that's kinda low for that ratio don't you think?
take it for what its worth. This would probably fit better in the pulling section but I got carried away.

Don thank you for getting carried away, :beerchug:.