The International Cessna^® 170 Association

Autogas.
Is there a specification for suitable autogas used in 170's?
Are there preferred brands?
Preferred octane?
Any types not suitable?
Years ago I sought out Amoco regular unleaded to use in a Taylorcraft powered by a Continental 65.
Thanks for any advice.
Jim

Here.....we...go....again

I use 87 octane. Any brand seems to work for me. Just do an alcohol content test. Instructions are on the http://www.EAA.org website. basically you put 4 oz of water (mark this point on the glass tube)in a glass tube you can see thru and a given amount of gasoline 36 oz(9 to 1)(from your favorite station), shake for a few moments. Let sit for 10 minutes. The alcohol and the water will combine and you might/might not see an increase in the amount of water-above the mark-and you'll know if you have alcohol in your gasoline. Do not put alcohol laden gas in your 170. I do not leave autogas in for more than 30 days. What I mean is I don't let it set. As long as I'm putting in fresh gas and flying. I havn't seen or had a problem. You will get brown stains at the filler necks and the vent.

George is a big car gas advocate, I'm sure he'll pontificate on the subject.

Eric

If you're going to use mogas, be sure you do not fly very high or over anything that might be damaged when you fall out of the sky. Fast is not good, either! It's probably safest to just taxi around the airport and go "Vroom, Vroom, Vroom", but not too fast.

How right you are, Dave Clark!

Well, everyone has an opinion - here's mine. I have had zero problems using auto gas in my 170, winter, summer and high altitudes up to 11,000 feet. Over 350 hours on car gas. I pre-mix Marvel Mystery Oil in my 110 gallon fuel trailer - it can't hurt (as evidenced by 60 plus years of MMO use in airplanes.) It does make for cleaner exhaust stains on my cowling.

I sometimes think this auto fuel debate comes down to the feeling that you can't get something for nothing. Sure, avgas is more stable over a period of months, but I fly enough for this to be a non-issue. The savings are real, my low compression engine thrives on it, and ECI has no problem with auto gas and their warranty. (Ironically, my 1964 Studebaker Avanti runs much better on 100 octane Avgas!) It's a function of compression ratio, and my C-145 has a lower compression ratio than some lawn mowers I have owned. 87 octane is fine for your stock 170.


Check for alcohol, don't let it sit for a couple of months, buy fresh name brand fuel (I use Union 76 and BP) and filter it. If you use the can buy the filter funnel from Aircraft Spruce. Enjoy the savings, not to mention the end of lead problems like plug fouling and valve sticking. Russ Farris

P.S. Dick, do you have any personal negative experience with mogas? I'd like to hear about it...

Russ,... Dick is joking, in reference to a post made long ago by another member at the yahoo club who is still with us, and now wears an FAA badge. So look out below....

Eric, ... Since my triple tiara has been retired, I'll just don my miter.......

Jim, ...you can do a search (see the icon at the top of the page?) .... make certain you fill in the phrase or words you wish to search for and then click on "search for all terms" and, if you wish, you can also limit your search to particular authors....

(One of the more spirited discussions occurred at:
http://cessna170.org/phpBB2/viewtopic.p ... gas++avgas )

My sarcasm detector, usually running at razor's edge, was inoperative last night! Russ Farris

Russ,
I have something over 2000 hours on mogas in a C-170 and the only problem I've ever had is trying to find it away from home.

blueldr wrote:Russ,
I have something over 2000 hours on mogas in a C-170 and the only problem I've ever had is trying to find it away from home.

You've always had a problem finding "it" away from home, Dick! But the subject is MOGAS!

One way to help solve the dilemna is to use http://www.airnav.com and select the "Aviation Fuel" tab, then select "Plan a Flight with Fuel stops", then select "Mogas", and type in your point of departure and arrival. For example, I did so, using a fuel range of 300 miles and it came up with a route that would supply mogas between my home and Salt Lake (a planned stop on the way to the convention later this year) and save me $25.98 over direct routing. (That savings is due to fuel pricing as opposed to DIRECT ROUTING....not due to use of mogas. The route it chose was: 8TA3, 7T7, TCS, U96, U42. By using mogas instead of avgas on that route, I would save about $27.50. That's a direct-cost difference of $1.70 by using mogas where available. It'd be difficult to assess any savings due to using an unleaded fuel VS leaded fuel. Almost as difficult as determining how much I'd have saved using avgas instead of mogas, should the mogas cause a failure in the mountains due to quality problems.)
It listed 174 airports which offer mogas, and gives the prices at each.

So by using AirNav to flight plan one could then find places to get Mogas. Then one might use said Mogas and save enough money in one year’s time to pay the $10.00 dues increase.

I’m using AirNav from now on.

Bill Hart wrote:So by using AirNav to flight plan one could then find places to get Mogas. Then one might use said Mogas and save enough money in one year’s time to pay the $10.00 dues increase.

I’m using AirNav from now on.

Bill, I'm glad to see you're learning to stir the pot.

Miles

I just got my EAA STC for auto gas, for what it's worth it also covers the new 82UL. If you've got an older STC for auto gas, I believe they will provide you with the paperwork and a new set of stickers stating that your plane can burn 82UL.

Holy-Moly!! The new stuff is supposed to be 82UL ??? I thought it was going to be 87UL. Hell, I just may go back to using bacon grease and ham fat.

russfarris wrote:My sarcasm detector, usually running at razor's edge, was inoperative last night! Russ Farris

My sarcasm detector burnt out a long time ago, due to being redlined to often on this site.....

Eric