air to water conversion

[Alan_Cheatham]

Has anyone attempted to convert an air-cooled engine such as a Hirth 2706 or similar to water-cooling?

[Chuck Roberg]

Interesting question Alan, But I believe it would be impractical to even attempt this. You would need a complete machine shop to be able to bore out the water cooling channels and jackets in the engine. Thats even considering there's enough metal left on an aircooled engine to do that.

I believe trying to enclose the cooling fins in some type of cooling jacket would be impractical also.

But, that's only my opinion. Lets see what others say.

[MikeBoyette]

I remember seeing an article in the PRA Mag where a guy converted a mac to watercooling. I don't remember what year it was maybe someone can. I don't think it would be very practicle. It would probably be to buy a provem watercooled engine. Just my 2cents.

[rfonseca]

Why bother, unless you already have the engine? Hirth now offers watercooled engines.

[Alan_Cheatham]

Yes, I do have a low hour 2706 which I purchased for a great price. I also have access to a machine shop complete with a TIG welder. The problem with some Hirth engines is that the head temperatures can run so hot that the spark plug threads can give way and then the plug is ejected out of the engine. That is what happeded to the previous owner of this engine (man and machine survived the forced landing without damage).
Being the mechanical type I thought I would do some research and maybe give the conversion a try.

[gcrisler]

Seems to be a common problem with these engines, I know another guy in West Illinios who also had a forced landing from the same exact thing. He was forced down and banged up his machine but he was fine. I wonder if the standard 14 mm. spark plug could be adapted?? Are helicoils available for the small plug threads??

Garret Crisler

[GyroRon]

We had two Hirth 2706 powered gyros eject sparkplugs resulting in engine out landings at Bensen Days last week.