I was over at one of my friends house and he showed me the new snow blade on his old JD mower. Looked nice, then I noticed that he had a piece of burlap taped over the air shroud intake...I said what the heck is that for ??? He told me that it restricted the air flow enough that his engine ran as warm in winter as it does in summer, better for the engine & oil.
Any thoughts on this ?
Air cooled engine in cold weather ?
- Thread starter FastGame
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Here's my first thought -- your friend is crazy. Even when temperatures are very low, aircoolong needs to work.
Sound like an attempt at a make-shift thermostat.
Air cooled engines run at higher temperatures than liquid cooled engines. The additional cooling from winter conditions is likely a good thing. I wouldn't do anything to inhibit air flow through the engine fan. He should run a 5W30 oil in it for winter use and concentrate on warming the engine prior to starting if he concerned about getting the oil up to temperature. That's where most engine wear is caused on a well maintained engine.
Sack the sack and put a heater under the engine on real cold days.
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He told me that it restricted the air flow enough that his engine ran as warm in winter as it does in summer, better for the engine & oil
I agree this is a pretty ridiculous thing to do. How many millions of air-cooled snowblowers run just fine when it's 10 degrees out?
Originally Posted By: dparm
I agree this is a pretty ridiculous thing to do. How many millions of air-cooled snowblowers run just fine when it's 10 degrees out?
Hmm: I'm not so quick to condemn here. My old air cooled Porsche's & VWs restricted cooling air intake in colder weather. The issue here, is how much to restrict, so we really need a temp measurement on the cylinder to do it correctly.
My chainsaw came with a cold air kit too that restricts airflow but I don't use it even the odd time I cut in -20C.
I guess if it was -30C and I was cutting all the time I could see needing it, but you'd have to remember to take it off for a -10C day...
Air cooled motorcycles are fair weather machines but sitting in a traffic jam in hot weather isn't healthy for them either, they need air flow to cool the cylinders.
What about a VW beetle or Corvair? They ran in all seasons without restricting the air flow in cold weather.
I just looked at the ring end gap and piston skirt clearance and its the same on the snow engines as it is the lawn engines.
It appears the only real difference is the snow engine uses no air filter and the carb is shrouded to prevent icing by getting warmer air.
Originally Posted By: Trav
Air cooled motorcycles are fair weather machines but sitting in a traffic jam in hot weather isn't healthy for them either, they need air flow to cool the cylinders.
What about a VW beetle or Corvair? They ran in all seasons without restricting the air flow in cold weather.
I just looked at the ring end gap and piston skirt clearance and its the same on the snow engines as it is the lawn engines.
It appears the only real difference is the snow engine uses no air filter and the carb is shrouded to prevent icing by getting warmer air.
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My old air cooled Porsche's & VWs restricted cooling air intake in colder weather
I assume this old JD lawn/garden tractor has an 8 to 12hp Kohler K-series engine?
The K's do move a ton of air over the cylinder jug and you can really feel the heat pouring off of them in the summer.
Restricting them is not necessary. If your buddy has cold starting issues, he should use something along the lines of a synthetic 5w30.
Joel
I'm not so quick to say, "give an air cooled engine all the air it can handle regardless of temperature." Air cooled radial airplane engines have cowl flaps that can close to restrict air flow for a reason- to keep the engines warm enough so that piston clearances don't get huge and so that the oil continues to flow.
That said, radial airplane engines have temperature measurements (usually both cylinder head temp and oil temp) to control the cowl flaps and oil cooler doors. Snowblowers don't, so restricting the flow too much will certainly overheat them. But burlap is pretty open material, I doubt he's going to roast the engine with it.
What he's doing is certainly not necessary and probably not very helpful, but its not going to be deadly harmful either.
Story time... I spent a LOT of hours in my youth mowing with my Dad's old K181S powered 1966 JD tractor (which has quietly been sitting in his shed since he retired it in the late 90s and I would love to restore some day, but I digress...). Just a few minutes of mowing with the old Kohler K would result in a layer of grass clippings covering its fixed air intake screen. I would always scrape it off every so often, but it would still cake over with clippings regularly. That engine ran for ~15 years without a hiccup other than eventually turning into an oil burner, at which point we honed the cylinder and re-ringed it and it ran for another 10 years before he parked it (I was married with a kid by then- that was a TOUGH old iron-block engine!).
There's quite a bit of difference between an aircraft cruising at 180 mph or more in -40F temperatures and a lawn tractor working relatively hard pushing snow.
We're not breaking new ground here. Engines are designed to perform certain tasks. Engineers build in components/characteristics for them to perform and survive. I doubt very much that throwing a rag over the cooling air intake would be considered as being innovative engineering. Particularly when a seat of the pants thermometer is being used to measure engine temperatures.
Sack the sack.
FastGame, whatever you end up telling him, dont let this friend of yours join BITOG. This is an OCD-free forum, it doesnt need crazies like him polluting the place by second guessing the manufacturer with DIY shadetree re-engineering and stuff. No one here does that kind of thing. 
Originally Posted By: boraticus
There's quite a bit of difference between an aircraft cruising at 180 mph or more in -40F temperatures and a lawn tractor working relatively hard pushing snow.
We're not breaking new ground here. Engines are designed to perform certain tasks. Engineers build in components/characteristics for them to perform and survive. I doubt very much that throwing a rag over the cooling air intake would be considered as being innovative engineering. Particularly when a seat of the pants thermometer is being used to measure engine temperatures.
Sack the sack.
Originally Posted By: quint
FastGame, whatever you end up telling him, dont let this friend of yours join BITOG. This is an OCD-free forum, it doesnt need crazies like him polluting the place by second guessing the manufacturer with DIY shadetree re-engineering and stuff. No one here does that kind of thing.
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