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Opinions on Leaded Fuel? EA-71

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so i haven't really been able to find much on what fuel an EA-71 likes to run on best, seems that a RON of 100 leaded fuel was the default for the EA-71 back in the 70's?

 

 

seems that the closest we can get to today is an octane rating of 93 at a typical gas station and some fake lead additive for our vehicles at the autoparts store, does the engine really need the additive? what is in it anyways because i doubt its actually lead with all these regulations today. i think i recall reading in the original water damaged owners manual in my vehicle that it prefers an octane of 90 or higher?

 

being a NON-CATALYTIC vehicle as it says on the door tag means it would prefer Leaded Gas, right? and that the engine was designed for Leaded fuel, hence the name EA-71 for 1971 designed engine.

 

any opinions? not sure on my facts.

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Older engines designed for leaded fuel,  will run on unleaded  93 ok  but its harder on the valves  seats  they don't last as long. 

 

Engines since the late 70's / early 80's designed for unleaded fuel use, have hardened  valve seats and don't have this issue.

 

There are fuel additives available to replace lead to protect valves / seats in older engines http://www.penriteoil.com.au/products/valve-shield

 

https://en.wikipedia.org/wiki/Antiknock_agent

 

http://www.city-data.com/forum/automotive/1074988-old-automobiles-running-unleaded-gasoline.html

 

Avgas  (100 RON most commonly used)  still has lead additives  (tetra-ethyl lead)  as aircraft engine integrity is more critical. (used in racing engines also)

 

The EA71 ( from 1976  - 1994  ) with a compression ration of 9.0:1  should run ok on regular fuel.

https://en.wikipedia.org/wiki/Subaru_EA_engine#EA-71

 

Just because it doesn't have a catalytic converter  doesn't mean you can't use unleaded fuel 

As the Ea 71 was produced from the mid 70's   (1976 ) I would imagine it would be ok without unleaded regular fuel.

 

 

Just read though my manuals and there was no info on fuel use / type etc  for EA71 / 81

Edited by subnz
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Hey thanks for the reply and information!

 

So basically the EA-71 is the first engine to be able to handle unleaded fuel, and can handle both types of fuel, but the benefits are so minimal between them that it’s not worth it.

 

So octane rating wise, where should that stand at? Does the engine even care?

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i wouldn't  think octane rating of fuel  would be much of an issue - i would imagine regular would be fine ,  that's what I would use.

Ea engines are fairly robust haven't heard of any  / many valve issues from using unleaded fuel.

 

Setting the correct ignition timing for type of fuel used would be the main issue . 

(10 degrees  BTDC  @ 700/800rpm  with vacuum advance disconnected and plugged for EA71 using 87 fuel - according to my Haynes manual after reading more thoroughly )

 

The best  thing would be to tweek the ignition timing  ie retard it by 2 degrees  if it  is still detonating a bit when accelerating  from low rpms in a high gear.

Edited by subnz
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I don’t recall having any problems running unleaded in the 1400’s. Probably the only Subaru engines to be concerned with in this case might be the earliest ones in the USA. The 360 ? Maybe the pre-1400 boxers too. ??

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Setting the correct ignition timing for type of fuel used would be the main issue . 

 

probably so,

i've just been putting 87 in my vehicle with the timing at 12 degrees, but then again i feel like the flywheels on these things aren't spot on either, my EA-71 Brat likes to be between 9-10 degrees, its just more so an approximation i would say. anything higher than 12 degrees though will cause me to overheat on the wagon, so thats probably the sweet spot on my vehicle, been like that for the last 2 years...

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I don’t recall having any problems running unleaded in the 1400’s. Probably the only Subaru engines to be concerned with in this case might be the earliest ones in the USA. The 360 ? Maybe the pre-1400 boxers too. ??

 

no issues now, just a concern i had since these engines will run forever and since they are bullet proof, just been wondering if microscopically the engine is taking damage from unleaded.

 

ofcourse today's gasoline are killing ALL CLASSIC CARS out there with the sticky residue (ethanol i think?) they are leaving in vehicles not being able to handle today's mixtures of fuels unlike modern cars today for emission purposes, pretty depressing...

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I have only run super non- ethanol in the wagon and the Brat for the last three or four years now just for that reason. I am able to run a little more timing, and even when they sit for months I've had zero issues starting. It's worth the 30 cents a gallon upcharge to me.

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I have only run super non- ethanol in the wagon and the Brat for the last three or four years now just for that reason. I am able to run a little more timing, and even when they sit for months I've had zero issues starting. It's worth the 30 cents a gallon upcharge to me.

 

who sells non-ethanol gas though? everywhere where i live it says the fuel dispensed from this pump may contain up to 10 percent ethanol... the shell, the Valero, the HEB-Gas, and the Chevron.

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Subaru engines have aluminum heads and therefore do not have the valve seat ground directly into the head casting like vintage iron heads would have been made. Therefore the seats are not cast iron and will not require the lead cushion as they are not soft like non-hardened iron heads without seat inserts. 

 

Ethanol will only harm older fuel lines and carb gaskets. If you can get updated carb gaskets made from neoprene, etc and replace the soft fuel lines with ethanol safe hose, the rest should be fine. It won't harm the fuel tank unless its allowed to sit for extended periods and draw moisture, etc. And even then only if air can get to it, which honestly isn't significantly different from what happens to non-ethanol gas left in a tank with airflow. Still turns to a useless mess that looks like the titanic. Trust me I've been down this path more than twice. 

 

GD

Edited by GeneralDisorder
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Subaru engines have aluminum heads and therefore do not have the valve seat ground directly into the head casting like vintage iron heads would have been made. Therefore the seats are not cast iron and will not require the lead cushion as they are not soft like non-hardened iron heads without seat inserts. 

 

Ethanol will only harm older fuel lines and carb gaskets. If you can get updated carb gaskets made from neoprene, etc and replace the soft fuel lines with ethanol safe hose, the rest should be fine. It won't harm the fuel tank unless its allowed to sit for extended periods and draw moisture, etc. And even then only if air can get to it, which honestly isn't significantly different from what happens to non-ethanol gas left in a tank with airflow. Still turns to a useless mess that looks like the titanic. Trust me I've been down this path more than twice. 

 

GD

 

thanks GD!

that concludes the thread i suppose  :)

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who sells non-ethanol gas though? everywhere where i live it says the fuel dispensed from this pump may contain up to 10 percent ethanol... the shell, the Valero, the HEB-Gas, and the Chevron.

In Idaho you can get super with or without ethanol. I do agree with GD after time all goes to tar, but non-ethanol in my brat a year and didn't turn to varnish. 

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In Idaho you can get super with or without ethanol. I do agree with GD after time all goes to tar, but non-ethanol in my brat a year and didn't turn to varnish. 

 

after doing alittle research, there is a few gas stations here that have non-ethanol gas available, but its some weird off brand gas stations in some shady places, including a phillip 66, but we don't have on the fly availability of ethanol or non-ethanol at the same pump unfortunately.

 

and yeah gas thats been sitting for a few years turns into some weird strange tar stuff.

 

 

>oops was looking at some old stuff from 2011, as of 2017 there is no longer ethanol free gas stations anymore in or around my city, enjoy that free ethanol gas you got there buddy!

Edited by Subasaurus

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