1956 Gas and oil mileage on early birds

[ron56]

Hi, I was wondering what range of gas and oil mileage you guys get. I have a 56 bird auto with 312 engine. I added the PVC system to my car to eliminate the oil drops from the road draft tube. Because the standard set up for the 312 doesn't have a very good oil air separator I'm thinking that I might be pulling a little more oil into the intake using a system with higher vacuum than would ever have existed with only the road draft tube. I've been driving the car on the freeway at 70 mph (3000 rpm) quite a bit lately and I think I'm getting about 750 miles/qt oil. At those same speeds my mileage is around 12 mpg. I did rebuild the engine and used cast rings to get it to break in quickly and figured I never would put on enough miles to wear them out. I didn't run the car much before I added the PCV to have any idea about the oil mileage stock.

 

[BirdGuy]

Hi, I was wondering what range of gas and oil mileage you guys get. I have a 56 bird auto with 312 engine. I added the PVC system to my car to eliminate the oil drops from the road draft tube. Because the standard set up for the 312 doesn't have a very good oil air separator I'm thinking that I might be pulling a little more oil into the intake using a system with higher vacuum than would ever have existed with only the road draft tube. I've been driving the car on the freeway at 70 mph (3000 rpm) quite a bit lately and I think I'm getting about 750 miles/qt oil. At those same speeds my mileage is around 12 mpg. I did rebuild the engine and used cast rings to get it to break in quickly and figured I never would put on enough miles to wear them out. I didn't run the car much before I added the PCV to have any idea about the oil mileage stock.

I have a 56 312/auto. Rebuild unknown but old, compression is a nice even 120ish on all eight, pretty low, but she runs smooth and steady. I don't calculate I gas mileage regularly but took her cross country last year on a rt66 run with our club and watched it pretty carefully. On a mix of freeway and mostly old highway I got about 16MPG. That was on the high end for our club. We were all running 12-16 MPG over a 2800 mile run. I don't think i get that in my "everyday" about town runs. I didn't need to add oil.
I hope that helps.
Cheers,
Guy

 

[Ward 57]

That sounds like good gas mileage but I think you are burning too much oil. I've got over 50K on my rebuilt engine and don't remember having to add any oil. If you have oil dripping from the tube too have too much blow by. No PVC will correct that.
You said you wanted cast rings to break it in quicker. Never heard of that. The rings are supposed to have flex to seal properly like springs and cast doesn't flex. Live with it or have a very detailed discussion with your engine rebuilder and ask why he would even recommend cast rings. How many miles on the rebuild?

 

[OhioTbird]

57 with the same 312 engine. Getting about 12-15 MPG.

Had the car a year, not sure of the mileage, but haven't added any oil yet.

 

[Critterpainer]

Used to use cast iron rings on older engines that were drinking oil and not worth re-boring. I have used them on engines with lots of taper to just keep farm trucks going for "just one more year" til a new engine could be found. They would seat quickly and wear out quickly on worn engines.

 

[Ward 57]

Used to use cast iron rings on older engines that were drinking oil and not worth re-boring. I have used them on engines with lots of taper to just keep farm trucks going for "just one more year" til a new engine could be found. They would seat quickly and wear out quickly on worn engines.

Interesting. My Dad had a ranch and the foreman had an old hough front loader that used gear oil in the crank case to keep it running. I'm afraid his rings are gone. So sad on a recently rebuild engine. Sounds like his rebuilder was really 'old school' and was thinking preservation instead of making it like new.

 

[Jim P]

Our car in family since new. 57 w 312. About 14 to 15 mpg.

 

[Douglemmo]

I have a 312 with overdrive and got 20 mpg with highway driving at 65 to 70 mph using the overdrive.

 

[Ward 57]

I have a 312 with overdrive and got 20 mpg with highway driving at 65 to 70 mph using the overdrive.

WOW! that's double of anything I've heard. And another WOW that a car has been in the same family since new.