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Trying to squeeze out a little more gas mileage #1281012
Fri Sep 21 2018 03:45 AM
Fri Sep 21 2018 03:45 AM
J
Jeff Ogden  Offline OP
Shop Shark
Joined: Feb 2003
Posts: 1,292
Dayton Ohio
57 truck 235 with a T-5 and 3.55 gears in a 37 1/2 ton,it seemed like it done better with the original 3 speed and 4.10 gears so I played with the jet size and installed softer power valve spring and its better. I am thinking those engines were designed to be screaming going down the road and gas mileage was not that big of concern back then so probably a waste of time and money but would like to to do a little better,I was told that the cam was changed in 59 for better low end torque and do have a 60 car 235 so would that be the one to use and work from.

Re: Trying to squeeze out a little more gas mileage [Re: Jeff Ogden] #1281019
Fri Sep 21 2018 05:06 AM
Fri Sep 21 2018 05:06 AM
H
Hotrod Lincoln  Online
Boltergeist
Joined: Feb 2004
Posts: 18,552
Dellrose, TN
How about some facts and figures to work with instead of all the generalizations? Try documenting every drop of gas used and mile driven over a 3-month period. Then make ONE change and do the same thing. Until you do that, any results you supposedly see are totally worthless. How about if you change a jet size and get an improvement, and offset it with a different power valve spring? Since the carb was calibrated for use with a direct drive transmission, a truck engine, and probably taller tires than you're running now, won't making a change in the camshaft, using an overdrive transmission, and a few other differences mean the carb calibration needs to be calculated from square one?
Jerry


The murder victim was drowned in a bathtub full of Rice Krispies and milk.
The coroner blamed the crime on a cereal killer!

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
Re: Trying to squeeze out a little more gas mileage [Re: Jeff Ogden] #1281025
Fri Sep 21 2018 10:28 AM
Fri Sep 21 2018 10:28 AM
C
coilover  Offline
Shop Shark
Joined: Apr 2005
Posts: 2,200
Plano, Tx
When gas was $4 I decided I was going to make some mileage improvements with my 37 Buick with the old straight eight engine with 16mpg being the goal (never got there). First I put it up on the chassis dyno and dialed in the best possible settings. I have an Oldsmobile V8 HEI distributor in the straight 8 which I matched the distributor curve and rate of the Buick distributor which proved to be wrong and was corrected to give a better reading. The guys at GM hit a home run with the Stromberg 2bbl and trying others gained nothing. Going from a 180 T-stat to a 195 gained a tiny bit as did an electric fan but I've gone back on both. Switched to the high dollar Torqo synthetic fluids and lubricants in engine/trans/differential and after chasing all the leaks down did gain about 1mpg. The biggest gains came from removing the sun visor, outside mirrors, Breezies, and anything that caught air. The 8.25/15 bias ply tires to 2.25/75/15 radials inflated to 38psi resulted in the largest gain---a bit over 2mpg. As Jerry advised; you have to make several trips spread out over at least a couple months time to really show whether your efforts worked. Mine took the old girl from a 12mpg glutton at pump to a not so embarrassing 15.8 at 70mph highway steady cruising. I think peoples belief that there is magic in camshafts and carburetors often hides the woods behind the trees.


Evan
Re: Trying to squeeze out a little more gas mileage [Re: Jeff Ogden] #1281031
Fri Sep 21 2018 12:10 PM
Fri Sep 21 2018 12:10 PM
W
WE b OLD  Offline
Master Gabster
Joined: Feb 2001
Posts: 6,336
marion, in. usa
I may not be the one to suggest this with the issues I have had with mpg but I added E3 spark plugs and increased my mpg by about 15% for 10 years. Then other issues decreased it.


Ron, The Computer Greek
I love therefore I am.

1960 MGA Roadster Sold 7/18/2017
1954 3100 Chevy truck in the Gallery
2015 GMC terrain.
Pix on Photobucket
Re: Trying to squeeze out a little more gas mileage [Re: Jeff Ogden] #1281034
Fri Sep 21 2018 12:24 PM
Fri Sep 21 2018 12:24 PM
J
Jeff Ogden  Offline OP
Shop Shark
Joined: Feb 2003
Posts: 1,292
Dayton Ohio
I know the gas we have is partially to blame.

Re: Trying to squeeze out a little more gas mileage [Re: Jeff Ogden] #1281040
Fri Sep 21 2018 01:45 PM
Fri Sep 21 2018 01:45 PM
H
Hotrod Lincoln  Online
Boltergeist
Joined: Feb 2004
Posts: 18,552
Dellrose, TN
Try some Beano to help with that little problem!
Jerry


The murder victim was drowned in a bathtub full of Rice Krispies and milk.
The coroner blamed the crime on a cereal killer!

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
Re: Trying to squeeze out a little more gas mileage [Re: Jeff Ogden] #1281047
Fri Sep 21 2018 03:38 PM
Fri Sep 21 2018 03:38 PM
J
Joe H  Offline
Shop Shark
Joined: Feb 2000
Posts: 3,932
Lee's Summit Mo. 64086
I can tell you after driving my '37 for 18 years now, wind and speed hurt the mileage more then you think. Drive at 55 and it will go up, hit a head wind, it drops a lot. The design of the truck looks good, but aerodynamically it's terrible. The straight up windshield and big fenders really hurt it.

Now for the engine, if the overdrive brings the rpm down under 2400 or so at highway speeds, you mileage will suffer. Even my " late " model 250 likes 2500 -2700 rpm out on the road. I would guess you are running well below the optimal torque of the engine. Run around in 4 gear for a while and see what the mileage does. I run a 3.08 gear with 28" tall tires and automatic trans, 1 to 1 final drive, at 65 mph the engine runs 2600 rpm, this will get me about 21 mpg if the wind is not to strong. As Jeff mentioned, if you fuel has more then 10 to 15% ethanol your mileage will suffer.

Re: Trying to squeeze out a little more gas mileage [Re: Jeff Ogden] #1281048
Fri Sep 21 2018 03:59 PM
Fri Sep 21 2018 03:59 PM
H
Hotrod Lincoln  Online
Boltergeist
Joined: Feb 2004
Posts: 18,552
Dellrose, TN
One of the best gas mileage improvers I can think of is a simple vacuum gauge. Mount it in the driver's line of vision out of the windshield, and practice moderating the throttle position to keep the vacuum as high as possible as often as possible. Just a tiny bit of heavy right foot will cause the power valve to kick in and cut the gas mileage in half, or worse. If it's just impossible to keep the vacuum up in the cruising range, it's time to downshift - - - - -which is something the OD transmission fanatics just can't seem to process. There's a reason these old rigs were produced with a rear end ratio beginning in "4". Stacking a T-5 transmission in front of a 3.08 rear end ratio and pulling them with a low-torque engine, and expecting good fuel economy is an exercise in stupidity.
Jerry


The murder victim was drowned in a bathtub full of Rice Krispies and milk.
The coroner blamed the crime on a cereal killer!

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
Re: Trying to squeeze out a little more gas mileage [Re: Jeff Ogden] #1281059
Fri Sep 21 2018 05:44 PM
Fri Sep 21 2018 05:44 PM
J
Jon G  Offline
Shop Shark
Joined: Mar 2014
Posts: 932
Dallas, TX
What are the 5 gear ratios in the T5? Tire size? As Jerry said, more facts are needed. How often is it driven?

I've spent about 8 or 9 weeks studying the Rochester B and BC carburetors and roughly 5 weeks studying the Carter YF models. Through it all I've remained as objective as possible and I promise this was not simply drinking beer, looking at the carburetors and scratching my head. I was as thorough as possible...read as much data as I could find, measured everything I could, compared this/that, talked to several knowledgeable people, built jigs, straightened castings, etc, etc. And at the end of the day: There are aspects of the Carter design that make it a better scheme if running leaner, more smoothly and with better gas mileage are important things to you. But there are aspects of the Rochester that might be appealing also. If you are driving the pickup very infrequently, the gas in the float bowl will evaporate and this will not be good for the Carter accelerator pump. Getting wet with ethanol gas and drying out will cause it to crack and go bad. If that's the way you're driving, I'd say you'd have less to worry about with a Rochester.

And Joe is 100% right. Example: If we drive our Subaru Forester at 57 mph on a relatively flat road with no wind, our gas mileage will be as much as 42 mpg. If we drive at 65 in a crosswind we will get 32 or so. If we're driving into a headwind at 65 mph we can see it go to 27. Big swings.

Now for more about gasoline. Ethanol gas (evidently no matter where it is stored) will undergo changes over time. And these are not good changes. I believe they would affect your gas mileage, spark plugs, valves, performance, etc. Take a look if you're curious:

http://i1154.photobucket.com/albums/p535/JonGoodman/MVC-727F.jpg

The vial on the left is gas right out the pump. The vial in the middle is gas removed from the gas tank of my pickup (vented cap, naturally). It had been in there for 6 weeks or so and the tank is new...a galvanized tank made in Canada. The vial on the right is some gas I poured from the 2 gallon plastic gas container I use with the lawn mower. It had been in there about 2 months or less. The left one is pretty clear. The others look more like strong urine. If you take these darker ones, pour a tablespoon or so into the divot in the bottom of a soda can and light it, you'll see a fire burning with heavy black smoke and a lot of soot. A nasty fire like a wellhead fire. I should have taken a picture of it. It also burns more slowly and the residue left is dark brown and sticky...almost caramelized looking. If you do the same with the fresh gas, it will burn with less smoke and it seems to burn more a bit more rapidly. There will be notably less residue left. Naturally you might think the darker ones are evidence of evaporation causing a concentration of the crap that is now in the gas, but the lawn mower jug isn't vented, it is plastic and there's not much there to react with gas. So I can't say if the air in the jug (and gas tank) exacerbate this change or not but the change definitely occurs and the old gas is not good.


Jon

1952 1/2 ton with 1959 235
T5 with 3.07 rear end
Re: Trying to squeeze out a little more gas mileage [Re: Jeff Ogden] #1281067
Fri Sep 21 2018 06:24 PM
Fri Sep 21 2018 06:24 PM
H
Hotrod Lincoln  Online
Boltergeist
Joined: Feb 2004
Posts: 18,552
Dellrose, TN
A few years ago a former student called me up to ask for some advice on getting an engine started, one he had just rebuilt and reinstalled in a friend's car. The engine had been out of the car for a little over two months, as he was doing the rebuild as side work to his day job in a dealer shop. After several phone conversations with no luck, I met him at the job site and participated in the startup effort- - - - -with no success whatsoever! Gas, spark, valve and ignition timing, compression, etc. all checked out OK. Still, we've got a "crank- - - -no start" situation. Double check everything- - - -and again- - - -and again! "Hmmmmm- - - - -the gas smells a little funky" Pour a little out on the ground- - - -toss a march- - - -it puts the cotton-pickin' match out! In about two months, the gasoline had gotten stale enough it would not burn! We rigged a gravity flow fuel supply to the carburetor and the engine fired up on the first try!
Jerry


The murder victim was drowned in a bathtub full of Rice Krispies and milk.
The coroner blamed the crime on a cereal killer!

Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
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