The $47 Dollar Electric PreHeater

by John Marzulli

Dec 12, 2013

Last week the Seattle area became unseasonably cold. During the past three years that the 7-Oh-Fun has been flying we had not seen temps in the 20s.

Disclaimer: No warranty is implied and no liability is accepted. This sort of preheater will require supervision. Do not leave unattended.

What to do? If necessity is the mother of invention, then the Lowe's next to the airport was the father.

I found  the following cheap items:

  • UtiliTech Cermamic Electric Space Heater ($25 electric heater, Item #485219)
  • Plastic vent ($5, Item #328910)
  • Flexible vent tubing ($10, Item #40529)
  • Aluminum tape ($5, Item #433282)
  • Tube spring clamps ($2, Item #55597) 

Here are all the parts before assembly:

After unpacking the parts I took the aluminum tape and masked off the sides of the heater to prepare for the vent being attached.

I then removed the louvers from the vent and taped it with the aluminum tape over the heater with the round tube adapter pointing out.

Finally I used the clamp to attach the tubing. Towels were used to plug the front of the cowling. The free end of the tubing was inserted into the lower rear area of the cowling. The oscillation feature of the heater was turned off. 

You can also see that I used a VERY low powered hairdryer pointed at the oil tank to assist.

The heater was adjusted to be "not too hot" with the fan on high. The whole system took my oil and engine from 24F to 48F in about 30 minutes.

Good luck!

  • Tim Garrett

    That's great John! Makes me want to try it. Might need a second one ducted to my coat while I wait.:)

    Dec 12, 2013

  • Bob Pustell

    I would speculate that the core of your engine was still stone cold. It takes a long period of heating to get the crank and central sections of the case up to temp. The "short but sweet" method of pre-heating gets the oil and cylinders warm enough that the engine will start, but the heart of the engine is still stone cold. At that heart is where problems can happen -- when very cold an aluminum engine case with a steel crank can cool to zero bearing clearance due to different expansion/contraction rates of the two metals. Everything needs to be up to temp before start if long term damage is to be avoided. At the fairly moderate temps you describe I doubt you had problems. At the considerably cooler temps we get here in NH (6 degrees F and dropping tonight) you can damage your engine without an hours long pre-heat.

    Dec 12, 2013

  • Jesse Hartman

    My wife starts her car up at 0 F and just goes.  200k on that engine.

    Dec 13, 2013

  • Bob McDonald

    Its -20C here these days. Even if you insulated the delivery hose your ability to heat the engine is reduced to ineffective. Remember the colder the air is outside the less "hot" the heater will be able to raise the inlet air. Break the Bank and buy a Rieff ROTAX 912 heater from Aircraft Spruce. It is a 100 watt element epoxied to bottom of engine block, and a 50 watt heater in a gear clamp style around the oil tank. Oil tank element is supervised by a thermostat to prevent over heating...NO Fire hazard. Simply plug in as you would a car engine. At -10F my engine oil is 60 degrees on start up. You can damage a Rotax engine by not preheating it correctly.

    Dec 13, 2013

  • Dan Stanton

    Dec 13, 2013

  • Dan Stanton

    I have been using this setup for several years without any problems. IO360. VW Viking.

    It woarks very well. It is turned on right now for dounuts in the morning.

     

    Dan

    Dec 13, 2013

  • Dan Stanton

    Oh, ;ther box on the floor is a milkhouse thermostat, stick it under the cowel

    Dec 13, 2013