C1 gasoline preferences

[Valeria H.]

Believe it or not, I am scheduled to get my 1960 out of the shop this Friday after several takes and 3+ years of restoration. Is there a recommended gasoline to use today in these cars?
Valeria

[Tom P.]

Re: C1 gasoline preferences

Well, you haven't provided any information about what kind of engine is in your car. The gas IS NOT relative to the car, it is relative to the ENGINE!
Is it a stock, hyd cam 1x4 base 283, or a solid lifter FI engine, something in between, a 12:1 compression 454 race engine, or what?

[Stewart A.]

Re: C1 gasoline preferences

Over here we have 92 oct unleaded, 96 and 98 premium. I have 10.5 :1 and find I can run all the above. Although when it gets hot I do find the car will rattle under load with the 92 and 96 octane. My timing is set to 36 degrees. Since I have a C1 and are used to being completely ripped off I always use the dearer 98. I must admit I have not heard any pinging for many months now.
If your know your comp and it's a little low you might get away with the lower octane. Just for now why don't you use the premium and work your way lower when you have time to experiment.
Or you can be like my mate who has a brand spanking GT3 Porsche and use 92 because he doesn't like paying for the dearer premium ? Now I know why Porsche drivers get the middle finger wave. They are unusual people. (tossers)
Stewy

[Valeria H.]

Re: C1 gasoline preferences

Sorry about the lack of info, the engine is a 283 4 speed. That is all that I know (hey, I'm really a girl with an old corvette for 30 years, I'm really trying to get it back on the road in as best shape as possible and running well). Any suggestions?
Valeria

[Tom P.]

Re: C1 gasoline preferences

If it's one of the hyd cam 283 versions, you MAY be able to get by with regular pump gas (maybe 89 octane). But if it is one of the hi-perf solid lifter cam engines, most likely it will run better on 91-93 octane.

[Andre R.]

Re: C1 gasoline preferences

The main issue is no longer octane related. Use of less than optimum octane fuel can be compensated for with adjustments in driving style and or engine timing. Ethanol has now become the main issue for old cars. Always ad a fuel stabilizer with every fill up. Do a search for Ethanol fuel in the threads.

[John H.]

Re: C1 gasoline preferences

Always ad a fuel stabilizer with every fill up. Do a search for Ethanol fuel in the threads.

Andre -

What would you expect to accomplish by adding a "fuel stabilizer" with every fillup? We've had 10% ethanol in our fuel for over 20 years in my area, with no ill effects on any of my cars.

[Duke W.]

Re: C1 gasoline preferences

You only need enough octane to prevent detonation. If the engine is "stock" and the spark advance map including the initial timing is to OE spec start out with the highest octane premium you can find. If there is no detonation add five gallons of the next lowest octane when the tank is near empty and check for detonation. If none add five more and check. If none add five gallons of the next lower grade. Get it? You are looking to find the lowest octane pump gas or blend that won't detonate.

Most 283s of that era except the Duntov cam/FI engine and both '61 FI engines only had an advertised CR of 9.5:1, and as built by Flint probably came in at closer to 9.0.

I have an '88 Mercedes 190E 2.6 (six-cylinder) five-speed. Its advertised CR is 9.2:1, Mercedes calls for 91 PON minimum, and it doesn't have a detonation sensor. For my first four years of ownership when it was my daily driver it would occasionally detonate on hot days with the A/C on. Now I only drive it during the winter, and with the cooler temperatures it doesn't detonate on regular. I changed a trim resistor to quicken the centrifugal curve (more low end torque) but picked up a little transient detonation with my usual "short shifting" (shifting at low revs -2000 to 2500) when the air temperture gets to about 70. I can "drive around" this by feeding in the throttle slower on upshifts or shifting at higher revs.

High load at low revs, higher ambient temperatures, and greater spark advance increase the propensity to detonate, and the opposite decreases the propensity to detonate. In some cases detonation can be mitigated or eliminated simply by adjusting your driving style.

Back in the sixties I had a customer at the gas station I worked at who had a base 283 C1, and it ran detonation free on the "regular" gasoline of that era.

You don't need "fuel stabilizer" at every fillup. Some use it during winter storage. I never do and have never had any fuel system issues in 15 year of storing cars from a few months to a couple of years, sometime in high temperature environments. The colder the storage temperature, the less tendency the fuel has to deteriorate, so a few months of winter storage in unheated or partially heated garages will rarely cause significant fuel deterioration.

Duke

[Valeria H.]

Re: C1 gasoline preferences

Along with same vein, today while I was filling up my Toyota I scoured over the notices placarded over the gas pump. I came across a notice stating that in 1995 regulations regarding gasoline changed and this could impact older vehicles causing leakage in their exhaust systems and posed a possible fire hazard to these older cars.

Is this really a possible concern? Has anyone had any experience with problems with their exhaust systems or a fire?
Valeria

[Stewart A.]

Re: C1 gasoline preferences

Leakage through the exhaust Hmmmmm maybe if the prostate is not working to good ahhh.
I think it was Duke who wrote about the problem with ethanol eating away at some parts of the carby was a problem, causing leakage ? Never heard of leakage through the exhaust. Stewy

[Andre R.]

Re: C1 gasoline preferences

The concern with ethanol has to do with the deterioration of the gaskets in the fuel system. Unless your fuel tank, pump and carb gaskets have been upgraded to ethanol compatible, the alcohol will cause the gaskets to leak. Fuel stabilizer acts to keep the alcohol in emulsion.

[Bruce B.]

Re: C1 gasoline preferences

Since ethanol is soluable in gasoline they would form a solution not an emulsion.
Emulsions, oil in water as an example, are usually unstable and tend to seperate in time.
Someone correct me if I am wrong.

[Valeria H.]

Re: C1 gasoline preferences

Bruce, You are correct on the definitions of solutions and emulsions. After all this discussion and reading the other thread regarding use of aviation 100LL gasoline I have decided to go with a 50/50 mixture of avgas and Shell premium. Avgas is not easy to come by usually unless you own a plane. I fortunately have a connection and will be getting some in the next week. The other thread has some good information about the advantages of avgas for our old cars.
Valeria

[Valeria H.]

Re: C1 gasoline preferences

Thanks for all the information and discussion. After reading and researching the thread on aviation 100LL gas I have reached the conclusion to try a mix of the avgas with Shell Premium which I am told does not contain ethanol. Avgas is difficult to obtain unless you are a pilot. Fortunately I have a close contact who owns his own plane and will provide me with avgas for my old corvette.
The thread on avgas has great information on it's qualities which make it ideal for the older corvettes which are not driven frequently.
Thanks as always for your kind assitance,
Valeria

[Michael W.]

Re: C1 gasoline preferences

Thanks for all the information and discussion. After reading and researching the thread on aviation 100LL gas I have reached the conclusion to try a mix of the avgas with Shell Premium which I am told does not contain ethanol. Avgas is difficult to obtain unless you are a pilot. Fortunately I have a close contact who owns his own plane and will provide me with avgas for my old corvette.
The thread on avgas has great information on it's qualities which make it ideal for the older corvettes which are not driven frequently.
Thanks as always for your kind assitance,
Valeria

Unless you are having problems with pre-ignition and /or vapour lock there is no need to mix aviation fuel with your present fuel. If the car is sitting long enough for the gas to go 'off', simply put in stabilizer.

My own car has been running on ethanol laced gas since 1990 and never have I had a problem either on the road or in storage over the (long) Canadian winters.

The sky is not falling.