Topic: Kohler V-Twin discussion

[sporty]

Thinking of exploring Kohler as a future build so, I've been searching and reading.  Haven't seen much discussion on what engines (blocks/heads) are most desireable.

If a guy was looking to build a strong running Kohler, what is the best block/engine to look for?

Are there certain heads to look for that are better?

This engine would be for an F/XT style machine, not sure if I'd go verticle or horizontal at this point.

Thanks

[Burton for Certain]

The 18-30 hp blocks are all the same, minus bore. So use whatever one ya want and bore it to whatever ya want. Stay away from the closed chamber heads. Tons of parts suppliers out there. You can build a stroker, or a big bore lil stroke, or big bore big stroke. Whatever ya want.

[sporty]

Can you elaborate on the heads a little?  Are the closed chamber heads used on any particular engine (HP rating/model)?  Is there an easy way to tell them apart?  Or, will I have to CC the chambers?

Thanks for the help.

Chris

[Caseracer]

The closed chamber heads are from the 30hp motor. That engine is also the one with the two barrel carb.  The combustion chamber is heart shaped on the closed chamber head.

[sporty]

So all the other heads from 18-28HP are the same?

How much can each be bored? Or, do they all need re-sleeved?

18/20HP stock 3" bore can be bored to ???
23 HP stock 3.2" bore can be bored to ???
25-30HP stock 3.3" bore can be bored to ???

Thanks,
Chris

[Burton for Certain]

The bore depends on if you want to runs sleeves or not. All blocks can be bored to the same size. Heads are pretty much the same. You're going to rework them anyway. You can get 56 cubes out of any of them.

[Caseracer]

I don't know the max bore on the smaller engines but the 25-30 blocks can be safely bored to 3.307.  The actual original bore is 3.27.  I have a 3.307 bore with the 3" billet stroker crank for a total 51.5 cubes.

[Burton for Certain]

My 18 hp block with no sleeves is 3.39 I want to say.

[sporty]

The bore depends on if you want to runs sleeves or not. All blocks can be bored to the same size. Heads are pretty much the same. You're going to rework them anyway. You can get 56 cubes out of any of them.

I'd prefer not to re-sleeve...for now.  When you say all of them can be bored to same size, is that with stock sleeves?  Or, do the smaller bores need re-sleeved?

What kind of interchangability is there between horizontal and vertical?  Heads?  Cranks?

Thanks for the replies, it's very helpful.  I have a line on a couple CV23's I'm gonna pick up and do some experimenting.

As for major part suppliers, I know about these guys.  Are there any others I should know about?

Vogel Manufacturing
MWSC
Lakota Racing
Zach Kerber Machine

[Burton for Certain]

As the hp blocks go up you'll have to change sleeves. If you don't want to run sleeves, you'll have to nikasel coat it. The internals interchange, but not the block itself. As for suppliers, that should cover ya.

[sporty]

Don't these engines have cast iron sleeves from the factory?  Is there not enough material to bore the stock sleeves at all?

When you said you are running with no sleeves, I thought you meant without replacing the stock sleeves.  Apparently you are running on aluminum bore with Nikasil plating?

Chris

[Burton for Certain]

Correct. And you can change different sleeve sizes by boring block and putting a bigger sleeve in.

[NICK]

So mwsc built my motor and supposedly the bore on my 25hp block is 3.385 nikasil plated cylinders no sleeves I was wondering if that was the biggest I could go on this block ? Then again I haven't looked at what size bore they really did do! but yet have I even started this motor up yet sense I got it back from them 5 months ago I can't wait to hear it run and get be hind it hope they did good work.

[Burton for Certain]

That's as big as you can go. It'll be more than ya need. Get to work on the chassis to be able to use it.

[Rooster]

.... hope they did good work.

You won't have to worry about that from MWSC - they have been building them right for a long time!