Head question

[dropzone]

Is there any difference in the CH20 and CV20 heads? It's a CH20S Spec 64510 S/N 3319007311 The engine has a bad valve guide. Also will say a CH25 Head work on this motor?

[StarTech]

Is there any difference in the CH20 and CV20 heads?

Yes

It's a CH20S Spec 64510 S/N 3319007311 The engine has a bad valve guide. Also will say a CH25 Head work on this motor?

Nope.

I would need which head you need and the spec number of the donor to see if the head will fit from another CH20. Not all are the same.

Another option would be to access kolherplus.com and use the "where used option" on the part specs. There is over 200 different CH20 specs that will work just got know the donor's spec number.

[dropzone]

Sorry for the confusion the model and spec numbers I posted is my motor. I have found a set off heads of a Model CV675S Spec 75544. According to kohler parts look up they will fit a CH22S, but there is no mention of my engine. I am trying to understand the differences in the heads. I am not concerned with the heads being the exact match as long as they will bolt to the block and the exhaust and intake will bolt up also. I have read that the CH25 heads will bolt up to the CH20. But the 25 and up have a bigger combustion chamber and will drop the compression on the smaller engine.

[KE4AVB]

I don't usually piece mill an engine here I try to as close to the specs as I can so that other techs later that work on the engine won't have problems that are introduced by such actions.

Maybe this will help explain some the differences. I don't access to the actual engines here to measure them but the difference may include the bolt mounting distance for the main head bolts since they have different blocks with different bore sizes. Note there are two versions of the CH/CV22 one with a 77mm bore and one with a 80mm. For now I am going to stay out this conversation as it is getting beyond my knowledge and maybe others here can help that have done this.

[StarTech]

Sorry for the confusion the model and spec numbers I posted is my motor. I have found a set off heads of a Model CV675S Spec 75544. According to kohler parts look up they will fit a CH22S, but there is no mention of my engine. I am trying to understand the differences in the heads. I am not concerned with the heads being the exact match as long as they will bolt to the block and the exhaust and intake will bolt up also. I have read that the CH25 heads will bolt up to the CH20. But the 25 and up have a bigger combustion chamber and will drop the compression on the smaller engine.

Thanks AVB, I can see where they get that CV675 can work on the CH22 but I can also see where it won't sometimes.

Strange most people are want more HP and not less out of an engine. A drop in compression ratio should cause a equal amount of hp loss at least is the complaint I get when an engine brought for repairs that has a blown head gasket or bad valve.

Would they work; I just don't know I haven't tried it either I seldom have two engines apart at the same time. The way I know to find without for sure to do a dry run. That is assembly everything but just don't torque down just see if things will bolt up. That way you wouldn't damage new gaskets. No warranty on if it will run safety later when you do torque things down and try an actual start-up.

I definitely don't have much spare time here to experiment as I live alone and have a mini farm to take of care. I wish I did have the time like when I was younger and had help.

[Deere2me]

There is usually a difference in the oil drainback holes between vert. and hor. heads. Ya need to check into that carefully!