47-55.1 leaded fuel/ octane?

[1948ChevyDumpFixer]

I'm pretty sure I have the original engine in my '48. I dont have any of the history yet to know if its ever been rebuilt.

How important is a lead additive and octane to the longevity of these inline 6 engines?

I have access to 100LL (100 Octane, Low Lead) at my local airport (no ethanol) so I was thinking that this might be a good idea for my truck for as little as it gets driven.

[1project2many]

Unless you're working the truck hard the avgas is proabably overkill. For less $$ you could run a lead substitute or eve mix two-cycle engine oil into the fuel.

[madd0nk3y]

I run UL91 from time to time in my old Chevelle it is cheaper than 100ll or anything else at the AP. I think last time I got some I got it for about $3.25 per gallon 100ll was $4.65. UL91 is lead free, ethanol free, and very stable. Lots of smaller AP's carry it now.

I run 100ll and UL91 in my small engines, no headaches or shoulder pains trying to start some gummed up carb with bad fuel. Just depends if I have to wait for someone who's feeling and I don't want to wait around.

[whitedog76]

It's been 25-30 years since lead has been available at the pump around here. Around the same time, ethanol blended fuel took it's place. Chances are, your truck has had some E10 in it over the course of it's life.

These engines are relatively low compression to begin with, so the extra octane isn't really needed. Unless you're lugging it hard, I can't see running unleaded being and issue either.

Anyhow, I would just go down to Wal-Mart and buy some Sta-bil and some lead substitute and be done with it.

[MiraclePieCo]

Having spent my career in the wholesale petroleum industry, I've seen the damage that ethanol can do to older or unused fuel systems. I highly recommend "clear" (ethanol free) gas for older vehicles or any equipment that sits for prolonged periods. Here's list of ethanol-free gas stations in your state:

https://www.pure-gas.org/index.jsp?stateprov=NC

[mick53]

Originally Posted by MiraclePieCo

Having spent my career in the wholesale petroleum industry, I've seen the damage that ethanol can do to older or unused fuel systems. I highly recommend "clear" (ethanol free) gas for older vehicles or any equipment that sits for prolonged periods. Here's list of ethanol-free gas stations in your state:

https://www.pure-gas.org/index.jsp?stateprov=NC

Thanks, it's amazing how many there are near me and I'm quite rural.

[1project2many]

Not exactly related, but I was surprised to find the carburetor on my 3 yr old lawnmower is almost completely made of plastic. Ethanol=no problem.

[mr48chev]

Octane level in today's or any gas isn't the issue with these old engines.

According to the GM archives compression ratio is 6.5 to 1 Meaning that if it says gas on the pump it will run on it.

As Miriicalpie said above the issue is that old fuel system parts and the ethanol in the gas don't mix well and the old parts usually loose the fight. That isn't just our Chevy trucks that is any old vehicle that hasn't had the fuel system parts upgraded to survive the ethanol.

Some of the Conoco stations around here have no alcohol gas aak the 91 octane. I buy it for my riding mower chain saws weed wacker and my boat. 60 gallon tank in the boat is a budget breaker though.

The lead substitute isn't a bad idea as it lubes the valves a bit and that was the primary reason for lead back then anyhow. Without it the older valves and seats wear faster.

The problem is that if we take our rig very far from home base we may not find stations that don't have ethanol free gas. The last time I had my sailboat over to Poulsbo, Wa I met a gent with a restored 32 Packard roadster who was buying gas at the marina in a pair of 5 gallon gas jugs and wheeling it up the ramp from the dock and putting it in his Packard and after he had it full he filled up the jugs again and hauled that home.
He said that the ethanol had already ruined fuel system parts twice and left him stranded.

[1948ChevyDumpFixer]

Originally Posted by mr48chev

Octane level in today's or any gas isn't the issue with these old engines.

According to the GM archives compression ratio is 6.5 to 1 Meaning that if it says gas on the pump it will run on it.

As Miriicalpie said above the issue is that old fuel system parts and the ethanol in the gas don't mix well and the old parts usually loose the fight. That isn't just our Chevy trucks that is any old vehicle that hasn't had the fuel system parts upgraded to survive the ethanol.

Some of the Conoco stations around here have no alcohol gas aak the 91 octane. I buy it for my riding mower chain saws weed wacker and my boat. 60 gallon tank in the boat is a budget breaker though.

The lead substitute isn't a bad idea as it lubes the valves a bit and that was the primary reason for lead back then anyhow. Without it the older valves and seats wear faster.

The problem is that if we take our rig very far from home base we may not find stations that don't have ethanol free gas. The last time I had my sailboat over to Poulsbo, Wa I met a gent with a restored 32 Packard roadster who was buying gas at the marina in a pair of 5 gallon gas jugs and wheeling it up the ramp from the dock and putting it in his Packard and after he had it full he filled up the jugs again and hauled that home.
He said that the ethanol had already ruined fuel system parts twice and left him stranded.

You can actually "wash" the ethanol from the gas using water and food coloring. There are videos on YouTube

[mr48chev]

Originally Posted by 1948ChevyDumpFixer

You can actually "wash" the ethanol from the gas using water and food coloring. There are videos on YouTube

The last thing I want to do is mix water in with my gas to try to"wash" it. Even if it is water injection.

I watch the RFD tv Farm report a lot of mornings and the corn farmers are pushing for 15 to over 20%.

[mick53]

Originally Posted by mr48chev

The last thing I want to do is mix water in with my gas to try to"wash" it. Even if it is water injection.

I watch the RFD tv Farm report a lot of mornings and the corn farmers are pushing for 15 to over 20%.

I have been reading about water injection to cool the air after the blower. I'm no expert but it seems it would be hard on the engine.

[pvienneau]

So what parts of the fuel system in an original inline 6 216 from 1949? I don't think it's been rebuilt.

[1948ChevyDumpFixer]

Originally Posted by pvienneau

So what parts of the fuel system in an original inline 6 216 from 1949? I don't think it's been rebuilt.

I'd guess any rubber hoses would be a weak spot, as would any steel fuel lines (vs. alum)...

The carb on mine has been recently overhauled, but I won't let it sit without running long enough for the ethanol to hurt anything.

[mr48chev]

Originally Posted by mick53

I have been reading about water injection to cool the air after the blower. I'm no expert but it seems it would be hard on the engine.

Water injection for that purpose is an entirely different thing. It works if it is set up right. I didn't get a close enough look at the blown 292 that was in the late 30's Chev truck I posted photos of In the Billetproof drags thread I posted but that engine flat screams both in speed and sound. Anyhow I don't know if that truck has water injection or not.

[1948ChevyDumpFixer]

no water injection on mine at all, that's good info on the compression ratio, it hasn't been detonating. When I drove it home I filled it with E10 87 Octane without really thinking. Its still almost full after a 60 mile drive, so I guess I'm going to have to drive it some more, oh well. There's a cruise in on Monday, I guess I'll have to go to it.

[mick53]

Is it true that if they sit for a while like over winter that ethanol will collect moisture?

[1948ChevyDumpFixer]

Originally Posted by mick53

Is it true that if they sit for a while like over winter that ethanol will collect moisture?

sure, alcohol will attract water.

[_Ogre]

you would be better off replacing rubber lines and rebuilding the carb with ethanol resistant parts
ethanol free gas is hard to find is most areas and chances are you've already run many tanks of ethanol fuel thru those parts

higher octane fuel actually lowers your performance and mpg, as it's doesn't burn as well
people equate high octane to higher hp due to the fact many high hp motors require high octane fuel
high hp motors are built on the edge of self destruction and need the high octane, less volatile fuel to avoid spark knock

[1project2many]

Originally Posted by mick53

Is it true that if they sit for a while like over winter that ethanol will collect moisture?

Here in New England it can happen overnight! I have to put the cap on my 5 gallon fuel cans so the ethanol doesn't separate out by morning.