The Stovebolt Site Forums The Shop Area Engine Shop What octane gas recommended for 1946 chev pick up

Just curious to find out what type of gas is recommended for the 1946 chev pick up? Are additives necessary? The engine is an original 216. Here in Scandinavia we have 95 and 98 octane
gas at one euro and 7 cents a litre.

Thanks
Classic Finn

The 216 is pretty low compression so the 95 should be fine, in fact 85 is fine if you can get it. I know that the US has differant octane standards than europe, our typical lowest is 87 (RON+MON/2) at lower elevations and 85 in high elevation places like Colorado. You might consider a lead additive to protect the valve seats if you can't find leaded gasoline. You can run a little more timing advance for better economy if you can't get low octane gasoline.

4onthefloor,
You had mentioned advancing the spark to acheive better milege. I've only had my truck (235 ci) for a half dosen tankfulls. If my odometer is anywhere close, I'm only getting about 10 mpg.
Sound about right? Or?

I get 17-19 with mine, averaging about 50 mph, even with a full load. My truck will missfire if the timing gets off too much, but the fuel milage will not get that bad. Advancing the timing a little gets me about 1-3 mpg increase.
A lot of Rochester B carbs have stuck power valves. You can fix it without pulling the whole carb (It's in the top casting), but check to make sure that it moves freely. Also make sure that you have the carb spacer at the base, between the carb and manifold, there is a vacuum port hole in the flange that has to be kept uncovered so the power valve can see vacuum. The spacer is about 1/2" thick and has notches on the inner diameter. If you don't have one that is your problem. The power valve should get pulled upward when vacuum goes up. It is a piston in the air horn casting that has a needle that pokes open a ball valve next to the main jet. The spring in it keeps the ball valve open, allowing more fuel for a rich mixture with low vacuum. If the piston is hanging up or not getting a vacuum signal it will run too rich. To check the mixture: Put new (or cleaned) spark plugs in the truck and drive for a while at about 50 mph, push in the clutch and shut the engine off, and coast to the side. Pull the plug and make sure it's kind of a chocolate color. If it's black and carbon fouled then it's too rich.

Hauskaa Joulua!! I'm half-Finn but that's the only Finn I know. Well, my dad did have some Finnish cuss phrases but I won't do them here....unless I have Chiphead's experiences when I start my new 261. (We're with you, Chiphead!!!!)

94 and 98 octane must mean you have small but high compression engines there. How do they get the octane that high? Benzene? Toluene? Tetraethyl lead? Reforming? Alcohol?

I have heard of folks putting in spacers between the head and block to lower the compression ratio where only straight-run gasoline (octane about 73) is available. Too high octane is just a waste of money. It shouldn't hurt the engine but it won't help mileage either. I use the 87 octane.

Thanks for all your replies! Stayin with you on this great site will certainly give me an educational treat during my restoration project.
First for all of you, I called One of the largest
gas disributors here in Finland to ask how they get their "High Octane" gas. In our country "Leaded Gas" isnt found.High content of "Tolulene is used in the gas. Another system that is used in measuring Octane heere is plain "RON" when in USA you use RON+MON/2 So 95 and 98 Octane
is actually 90 and 93 in your measure.
So this is what info Ive found for us all.
An additive was recommended by the Info Center as well to make the engine burn right.
I believe Wally/Montana and 4 on the Floor were correct in their advice. I,ll be receiving a booklet on this in a day or 2 which I,ll be happy to share with you.
Thanks For all!
Classic Finn
PS Wally/Montana KEEP UP THE FINNISH! TERVEISIÄ SUOMESTA-Greetings from FINLAND! Where in Finland are your parents or granparents?

Dusty in New Zealand told me about a tool called color-tune. it lets you see the color of the combustion in the cylijnder while the engine is running.You adjust the carburetion so you get the best burn and most power and mileage out of each drop of fuel.
I saw one of these tools at a parts store somewhere(I occaisionally do repairs out of town) and I did not have the funds to purchase at the time.Now I cannot remember which store I was at or which city, It was either Roseburg, Eugene/Springfield, Salem, or Olympia Washington :confused: