Propane engine question

[RetroMower 349]

I've wanted a wisconsin air cooled 4 cylinder engine for a while for a hairbrained project and I found one that's not 5 million dollars. It's a Kohler generator powered by a wisconsin 4 cylinder but it's running off propane. My question for you fine folks is were these dedicated propane specific engines or were they converted and if they were converted, how difficult is it to make them a gasoline engine again? 

[ebinmaine 67,481]

 

 

Food for thought. Not to discourage,  but to encourage plenty of research. 

 

If you're considering removing the generator from the engine you should be aware that  ~some~  generator sets use the engine crankshaft as the mainshaft. 

One continuous piece. Others have a two piece main shaft but will NEED to be balanced by a professional engine shop or it will destroy the engine.  

 

 

 

 

Because it's a Kohler generator powered by a Wisconsin engine one would think it was separable. 

Personally,  I  find it interesting and odd that a manufacturer who made their own engines would use that of the competition. 

 

 

If there's a way to get a Spec number from the ENGINE then maybe you could determine if the original build was for gasoline, propane,  or flex. That was common even then. 

 

 

[Pullstart 62,851]

@Achto…

 

Propane runs a higher compression.  The heads have smaller chambers generally.  You can run LP heads in gasoline applications, but you may find you need higher octane fuel.  Timing may be set differently, but it is able to be changed.

 

In high school, I had an S10 Blazer mud truck with a 366 tall deck big block Chevy that ran on propane.  I read that I could get 15% more power by converting it to gas.  I had it blown up within a day or two of my “conversion” by tosssing a 4 bbl carb on and running it.

 

 

[RetroMower 349]

Hmm engine crank and genny might be one piece... Never considered that but that why I brought this question here to folks that know their stuff. I sent a message for the motor ID plate before I get my hopes up further. 

[Pullstart 62,851]

10 minutes ago, RetroMower said:

Hmm engine crank and genny might be one piece... Never considered that but that why I brought this question here to folks that know their stuff. I sent a message for the motor ID plate before I get my hopes up further. 

Many times whoever, the crank is a tapered end shaft and a snug (press like) fit.  I tagged Dan, and he’ll get here eventually.  He works at a big genny manufacturer blowing up new ideas in the R&D lab.  He’ll know.

Edited May 10 by Pullstart

[Tractorhead 9,064]

I don‘t know exactly how the wisconin Engines works

but the Basics should be identical as on other fuel/lpg Engines.

 

Most Egines i know can run on both gasoline and lpg ( propane) 

typically it was the ignition wich must be retarded little bit on gasoline. About 1-7 deg as a rule of thumb.

 

the intake valves and their seats was mostly inforced on pure propane engines, 

to handle the different heat dissapation better. ( lpg generates more heat when burning) 

 

The knock can be appear much earlier with low octane fuel but that can be prevented.

To dealing with that issue an ignition retard and as @Pullstart allready suggesting

a litle thicker head gasket will drop the compression ratio down. That prevents the knock ability.

 

Most troubles with lpg engines i knew, comes firstly up on permanent higher revs, as result of the higher exhaust heat.

 

Lpg engines have different types of how they work, so they have more or less powerloss compared to fuel.

 

If they use a lpg heater to inject preheated damped gas, the propane was sent thru a heater and

after it, it just suck the gas mixture like a carb but with a nozzle instead that acting if the suction is happen.

Another solution is the fuel like injection what works like a actual fuel injection where a injector nozzle is directly 

mounted short before the intake valve and spit liquid lpg as close as possible into intake.

the last version is the better solution because of less powerloss.

 

At all it can be said fuel engines they run on lpg needs little more lpg but the burning is much cleaner and hotter.

 

That reduces gunk in combustion camber but the lpg itself can provide some gunk in the preheater over time and 

a LPG Filter imho is recommended.

 

if the diaphragma of the preheater is fine i would keep it on lpg.

 

 

 

[Pullstart 62,851]

 

[Achto 27,571]

Being that this is a Wisconsin engine mated with a Kohler generator, the likely hood of the crank & gen shafts being one piece is low. I would venture to say that it will have a tapered end on the crank shaft. Don't know for sure without taking it apart. Also not a big issue thanks to adaptors from taper to keyed shafts.

 

A far as converting it to gasoline - It looks like they simply plumbed the LP into the intake and used the original carburetor to meter the air. Simple task when you only plan to run the engine at one speed, as you would do with a generator. The original carb might still work if you plumbed gas to it. The timing may have to change but they might have just left it as it was. We used to convert Vanguard engines to LP, all we did was add a plate under the carb to give a place to plumb the LP in. Did not change anything else on the engine. Kohler LP engines came with different heads & flywheels. The different fly wheel was to change the timing. The heads had harden valve seats & higher compression, but still used a basic plate under the carb to get LP in. Design variables on the Wisconsin are unknown to me, sorry.

Edited May 10 by Achto

[RetroMower 349]

Thank you everyone for the input on this subject as I now have a lot to consider because these setups appear more frequently for sale than just the wisconsin engines alone. As far as keeping it LP as tractorhead suggested, I wouldn't want to keep it that way as my hairbrained idea wouldn't allow. I was thinking repowering a WH into a monster or something more exotic 🤭

[Tractorhead 9,064]

3 hours ago, RetroMower said:

 I wouldn't want to keep it that way as my hairbrained idea wouldn't allow. I was thinking repowering a WH into a monster or something more exotic 🤭

 

 

Exotic huh?

need Power huh?

Ready for a Man‘s choice -  How about a suzi busa Engine ?

Definitely More than just a plennty of Power and definitely exotic.

need some ideas?

few guy‘s here made this little Monster - a hard drug - only for fearless speedjunkeys

Get good nerves?  ok, here we go ....