Octane in Super H?

Just curious. What grade octane do you run in your Farmalls'? I have a SH but I'm sure they all use the same or am I wrong? A's,B's,C's,M's etc...... 87, 89, 90?

Mostly 87 octane, no ethanol, with a cup of 30 weight low ash oil to 5 gallons for standard pistons in Iowa or Wisconsin. Big bore with high altitude pistons- might need 89 octane if pinging on 87. Can"t get leaded fuel around here unless you go to airport supplier and cost is extra $1.00 a gallon. Pullers with extra high compression fire craters might need 91 octane premium. RN

I run 87 in ALLLLLLLLLLLLL my old tractors as none have anywhere near the compression that would require the use of higher octane gasoline.... Nowwwwwwwwww perhaps if you built a super puller and bored n stroked and milled the head or used domed pistons etc to achieve very high compression, then high octane gas may well become necessary, but a Stock Super H or M etc. still dont have real high compression UNLESS the aforementioned has been performed.

PS I have NO SPECS as to compression on a Super H or M so no warranty (just a semi educated guess) butttttttt Id be surprised if they actually needed it

John T

Wether you are pulling or farming you get the most power and efficiency from the lowest octane you can run w/o pinging.

*With the ethanol blends today I sometimes run premium in my seldom used machines to obtain a longer shelf life of the fuel. They say ethanol fuels have a shelf life of 2-4 weeks. I figure I might have a few less fuel related problems that way and I don't go through much fuel so I don't miss the money. A lot of guys (including me) don't use these tractors like they were meant to be used. Ex. My H hasn't moved from the shed since March when I disked my garden.

I don't have the data for the Super H. But the Nebraska test on the H as run using 71 octane gas, the 300 used about 81 octane. The Super H would have used something in that range. These are MON, so add about 5 to match the pump labels. I use 87 as it is the cheapest I can find.

Well back in the day it was made they had fuel that was very low octane and that what was used in tractors most of the time. So as low as you can find will run it just fine unless it has had major things done to the engine to get more HP out of it

(quoted from post at 19:09:39 09/15/10) Just curious. What grade octane do you run in your Farmalls'? I have a SH but I'm sure they all use the same or am I wrong? A's,B's,C's,M's etc...... 87, 89, 90?

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According to the original owners manual for my 1940 H, on page 15 under the heading of, "GASOLINE OPERATION FOR HIGH COMPRESSION ENGINE", it has the following. "This engine is designed to operate on gasoline with a minimum of 70-72 Octane rating." Mine has the special 8,000 ft altitude piston set in it, with a later, Super H model gas head that was dealer installed in the 1950's when the engine was converted from distillate to gasoline, and I never have knock or run-on issues running the cheap stuff in it, but I do pull the head every two years or so and chip all the carbon out of it. Since I have grown tired of this routine, after the last time I have started running Shell System 3 gasoline exclusively to see if it makes any difference, still the lowest octane stuff though. Just for extra info, the same owner's manual says the distillate engine calls for only 38-40 octane. The Super H came factory with something like 7.1 to 1 compression ratio if I remember right, so the cheap stuff in it should not cause any trouble either. If it does, according to my owner's manual again, it may need the head removed and the excess carbon cleaned from the chamber and the top of the piston.

87 octane regular is fine for all the older letter series Farmalls, including your Super H.

Keep in mind it was designed to run on the 70 octane fuel available back in the day. Modern 87 octane unleaded will "taste" like premium fuel to the old girl!

FWIW my '53 SH has factory installed 8,000 ft (high altitude, high compression) pistons. It runs just fine with no knocking - even under full load - on 87 octane regular.

Water injection might clean up your combustion chambers. Maybe 2-3 quarts over 1 tank of fuel in one days time. After 3-4 days see if your pistons are not clean.

It's a good thing Tractor Vet isn't around. All you guys would be getting a serious scolding about running the low octane fuel...

Myself, I was not happy with the performance I was getting with 87 octane fuel in my M so I went to 89, and it seemed to really smooth it out when it was WORKING. I may have other issues that cause the need for higher octane fuel, but it did smooth the old girl out under load.

Ben

Just curious, but can someone explain why, when I go to Colorado, the "regular unleaded" is 85 octane, but here in Kansas (and all the mid-western states I have seen) it is 87? All the fuels at high altitude seem to be rated 2 points [u:2484ce04a8]lower[/u:2484ce04a8]... I thought it would be the opposite.

(quoted from post at 00:31:41 09/16/10) Just curious, but can someone explain why, when I go to Colorado, the "regular unleaded" is 85 octane, but here in Kansas (and all the mid-western states I have seen) it is 87? All the fuels at high altitude seem to be rated 2 points [u:4b5dc96493]lower[/u:4b5dc96493]... I thought it would be the opposite.

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Is it because we cut ours with ethanol which raises the octane rating?

I dont doubt your claims but bring the Tractor Vet on. Theres no advanatge in using higher octane fuel then is necessary to prevent pre ignition (spark knock). Of course if you raise the compression to a level that requires it then YES it has an advantage. Higher octane is purposely harder to ignite to avoid pre ignition, why do you want to use fuel thats harder to ignite and perhaps leave raw unspent fuel versus a more complete combustion if easier to ignite (lower octane) fuel is used???.

I agree there may be other issues (fuel quality etc) accounting for your improved performance (Hey I hear and believe what you say) when using higher octane but I still stand on the proposition one doesnt need higher octane then necessary to prevent pre ignition.

Thats my story n by golly Ima stickin to it lol

Yall take care now

John T

(quoted from post at 03:52:21 09/16/10)

(quoted from post at 00:31:41 09/16/10) Just curious, but can someone explain why, when I go to Colorado, the "regular unleaded" is 85 octane, but here in Kansas (and all the mid-western states I have seen) it is 87? All the fuels at high altitude seem to be rated 2 points [u:f78c223c14]lower[/u:f78c223c14]... I thought it would be the opposite.

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Is it because we cut ours with ethanol which raises the octane rating?

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Yes, adding the ethanol DOES increase the octane rating.

Here in the mid-west, it is next to impossible to find gasoline that IS NOT at least 10% ethanol. Regular unleaded without ethanol does not exist, which is just fine because I have no issues at all with the E-10. I have even stored it in airtight containers for 6 months or longer and it still performs the same as if I bought it yesterday.

You can get by OK with lower octane rating in higher elevations. The same reason IH made higher compression engines for higher altitudes.

(quoted from post at 05:33:45 09/16/10) I dont doubt your claims but bring the Tractor Vet on. Theres no advanatge in using higher octane fuel then is necessary to prevent pre ignition (spark knock). Of course if you raise the compression to a level that requires it then YES it has an advantage. Higher octane is purposely harder to ignite to avoid pre ignition, why do you want to use fuel thats harder to ignite and perhaps leave raw unspent fuel versus a more complete combustion if easier to ignite (lower octane) fuel is used???.

I agree there may be other issues (fuel quality etc) accounting for your improved performance (Hey I hear and believe what you say) when using higher octane but I still stand on the proposition one doesnt need higher octane then necessary to prevent pre ignition.

Thats my story n by golly Ima stickin to it lol

Yall take care now

John T

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The dyno backs up your story so I wouldn't be afraid to stick with it!

Colorado is a early adopter of ethanol, and MTBE for a few years. The front range has very bad pollution issues. Jim

That is correct. I live in SW KS, elevation about 2800 ft. I had a 72 Monte Carlo that ran fine up here. My home town is in S Texas, 720 miles south, 2000 or so feet less. In that area I got spark knock (preignition). Not sure the octane rating was even on the pumps in those days, but you need higher octane at LOWER elevations, and power goes down as the elevation increases. Thus the higher altitude/compression pistons in tractors sold in those areas.

Thanks for the idea, but it won"t work in my tractor since I am still running the original separator bulb under my fuel tank. It would just fill with water until there was no gas getting to the engine at all. Though I have had good results squirting water into the open carb while the engine was running using a spray bottle.