All Big Six 240 mods and tuning to increase economy (Open to all 240 owners & interested members)

[63 Sprint]

Added: 6/27/2023
“This thread is open to all 240 owners and interested members.
Members, even if you don’t have a 240. Feel free to share your experiences, ideas and suggestions.“

Throughout the past few years I’ve been working to get a 1989 F150 running well and it is running very well. And economy is pretty good.

There are three major issues:

1• The engine needs 93 octane fuel and I’m starting to feel the pinch. Prices in some areas are selling 93 octane fuel over $1.00 more a gallon compared to 87 octane.

2• The engine is cold blooded at temperatures below 45 F. The heat from the coolant at 195 F on the Offenhauser C/ Holley 390 setup is not enough. And drivability and fuel economy suffers. I have to think about operating it in very cold temperatures that get to -20 F.

3• The 300 engine is tired. It turns out that the truck originally had about 167,000 miles when I got it. Not 67,000.


So my original plans were to overhaul the 300. I started thinking how to possibly squeeze more fuel economy from the truck. Well I started thinking about a 240 engine. I Went on Craigslist and I found a 1971 240 engine with 41,000 or 48,000 original miles. The engine came out of a beautiful F100 that was purchased recently by the second owner. The 2nd owner did not want the 240. So he is doing a 302 conversion. So I bought the unmolested low mileage 240 engine.

lt turns out that I don’t need all the Hp that I thought. I would think that towing a trailer once a year with a 240 powered F150 will be ok. The 3.08 rear gears will be changed to 3.55.

I’m thinking about keeping the stock one barrel intake & exhaust manifolds on. Reason is HEAT.

I’m thinking about economy and I’ve been looking into the Weber 32/36 DGV with the adapter. I Would think fuel economy would improve with a properly tuned Weber 32/36 progressive secondary setup over a stock Carter YF. I’m still working on getting a custom ground cam and I hope to hear news soon.

Just picked up a NOS DSll that will be sent for recurve later.

I will not be beating the 240. Keeping it de-tuned should also help prolong the engine life.

The goal is to have an engine that will run on 87 octane while cruising and possibly have to use 89 octane when pulling a trailer while on vacation.
If the truck gets 2 MPG less, that is ok. Cheaper fuel cost will make up for the loss.

I would like to know if anyone has used a Weber 32/36 progressive carb on a 240 or 300?

I just found out the carb has ported vacuum. This is good for the DSll vacuum advance. The carb is rated at 240 CFM. The 240 engine requires 234 CFM @4500. This is at 75% volumetric efficiency.

The adapter for the carb is easy.

Fuel pressure is not a problem. I can turn down the pressure regulator down to 3 psi. Or whatever it calls for.

Here is the specs of the transmission in the truck:

I do know that fuel economy suffers greatly at speeds over 65 with this truck.

 

[InlineDave87]

It was actually your post about this that got me to ask about doing an mpg and economy section on the forum. I myself care about fuel economy and right now im battling >11 mpg while running my truck with AC on or 16mpg with it off. Problem is i live in south texas and i actually got a call from a fire department to get their old truck running cause the AC in that was better. Im a fire truck mechanic is why they called me. I found out my truck has 3.55 gears and i also have the mazda m5od r2 trans. Im looking for issues that may be causing the poor fuel mileage. I do have a truck in my garage with 3.08 gears in the rear end that i can swap but dont know if i want to. Another option is Gear Vendors as they have overdrive systems that bolt to the back of the trans to give you an overdrive in every gear. They do say tho that if you already have a 3.08 rear end their system will only give you .5 mpg more. So theres that.

 

[agave248]

If you are after good economy a diesel is the clear choice. The site 4BT swaps has lots of information.

 

[InlineDave87]

If you are after good economy a diesel is the clear choice. The site 4BT swaps has lots of information.

Oh trust me i have thought about it… i even wanna put one in a mustang and call it the BT GT

 

[agave248]

In Mexico cummins has sold the ISF2.8 for many years, one place to look is the Mercado libre app.

 

[63 Sprint]

I looked into a 4BT swap before I joined this forum a few years ago.The 4BT is a good engine once the role pin design flaw is corrected in the valve train gear case. It would have cost more to convert than I was willing to spend. Plus, diesel is much more expensive than gas.

The stock drive train in my truck would never hold up to the Cummins combustion impulse. The input shaft bearing and others would be beaten and prematurely fail. I thought of it for a long time and decided against it. That 4BT would work fine in an F250 with the heavier drive train.

A conversion would be $5,000.00 or more to find a good used engine and then to build it right. Plus how would it look if I start a topic on a Cummins conversion here on fordsix? I think I’ll have a hard time redeeming myself here.

 

[63 Sprint]

Guys, I want to keep life simple. Life is already too complicated as it is.

 

[InlineDave87]

Plus how would it look if I start a topic on a Cummins conversion here on fordsix? I think I’ll have a hard time redeeming myself here.

Oh thats easy, start it on the orphans inlines section of this forum. or even on the Other Rides

 

[63 Sprint]

It was actually your post about this that got me to ask about doing an mpg and economy section on the forum. I myself care about fuel economy and right now im battling >11 mpg while running my truck with AC on or 16mpg with it off. Problem is i live in south texas and i actually got a call from a fire department to get their old truck running cause the AC in that was better. Im a fire truck mechanic is why they called me. I found out my truck has 3.55 gears and i also have the mazda m5od r2 trans. Im looking for issues that may be causing the poor fuel mileage. I do have a truck in my garage with 3.08 gears in the rear end that i can swap but dont know if i want to. Another option is Gear Vendors as they have overdrive systems that bolt to the back of the trans to give you an overdrive in every gear. They do say tho that if you already have a 3.08 rear end their system will only give you .5 mpg more. So theres that.

I appreciate this section on the forum. More members are looking to save on fuel costs and hopefully this section on the forum will help.

 

[Jesse73]

One thing I would like to try is adding a 205 degree thermostat to my 240 and see if it has any measurable difference in economy. I think my cooling system is up to it and it would also apply more potential heat to the heater core and manifold.

Another thing that could be done to increase heat to the manifold is to insulate the heater hoses with foam pipe coverings. We did this on the old jeep as an experiment and gained 5 degrees at the heater core. Granted the core takes a lot of heat out of the system, but insulation could potentially hold just a little more in before it passed the manifold heater port.

 

[sixtseventwo4d]

One thing I would like to try is adding a 205 degree thermostat to my 240

I would advise caution doing this, you may shorten valve and seat life. Oil temp will go up also.

 

[alwill923]

This topic has been discussed since ford made the first car.
A lot of time we get consumed with gas mileage and the cost to get it better. New cars get much better gas mileage than vintage or classic cars get, but what price do we pay? Try getting one fixed or making repairs yourself.

Just as a point of conversation:
Lets say we buy an old car or truck as we hot rodders do. Lets say for a truck it gets 12 mpg. Lets say we fix it to get it reliable total cost of truck, any repairs and upgrades, 10,000 dollars. Cost of a new truck 50,000 dollars, difference 40,000 dollars.
New truck gets 18 mpg (my son just bought a new F250 and got a little over 15 mpg on a trip), difference is 6 mpg. Is the additional cost for the fuel make up for the 40,000 dollars you did not spend on the new truck. 40,000 dollars in a money market account at 5% interest is 2,000 dollars. Will the 2,000 dollars cover the cost of the additional fuel required?
Let's say you drive 14,000 miles a year.
14,000 divided by 12 = 1167 gallons.
14,000 divided by 18 = 778 gallons
difference = 389 gallons, round up to 400 gallons.
cost of gas per gallon = 4.00 dollars.
cost for additional gas = 400 times 4 = 1,600 dollars, less than 2,000 dollars and you still have the 40,000 dollars in the bank.

Lets add to this the difference in insurance. If the truck is new you will want collision, old truck none. I have no idea what the cost would be so I am guessing say 1,000 dollars a year for the collision rider that you do not have to spend. The cost of the collision would pay for the insurance on the beater if you get one.

If you buy on credit and make a monthly payment for a new car take that amount and put it in a bank account every month for yourself.

If you want good gas mileage buy a cheap beater car for commuting. Honda civic, Hyundai accent, etc. I have a 2003 hyundai that I paid 3,000 dollars for maybe 7-8 years ago with 70,000 miles and it now has 182,000
miles. No problems, I get 32-35 mpg and it doesn't burn any oil. It has the original injectors and exhaust system

Getting back to the point on improving gas mileage, use the same logic for the cost. Now we are talking maybe 2-3 mpg for moderate changes or maybe 5 mpg depending on how much money you want to spend. Also we have to consider if it is an efi motor which makes improvements more complicated and costly. My point being, is the cost to make the improvements less that the money saved on gas. If this a daily driver it may be worth it. If we are just talking about basic maintenance items like, spark plugs, wires, cap and rotor, new injectors or carb rebuild, yes do it and start with cheapest first. The trap is replacing parts thinking they will improve mpg and find out when done there is no change. We should also not expect a large gain and be disappointed.

My advise is always have a second beater car. It is so stress relieving to know that if one breaks you have the other. Just keep the beater reliable and do the right maintenance on it.

BTW my wife has the new car (masda). I do not drive it or maintain it. She takes it to the dealer for all maintenance and so far no repairs but is out of warranty.
Enough rambling!

 

[63 Sprint]

Edited:
alwill923, after reading your post again. I understand what you’re conveying. You brought up some very important points.
Thanks,

About another vehicle. I don’t have that luxury. Only have enough room for one vehicle. Have to make the best of what I have.

 

[Frank]

alwill923, we appreciate your reply. But it doesn’t pertain to the topic. For example, my truck is used every day, work and pleasure. Some members such as myself do not have the luxury to have another vehicle. I only have room to park one vehicle.

The heading of this topic reads: “240 mods and tuning to increase economy”

63 Sprint- I disagree. He speaks exactly to the reality that owning old vehicles is miles ahead of newer, so the lower economy is not as much of a loss. Applying this principle to improving economy on our old trucks the same proportional difference remains. Example, if I spend $2000 installing EFI on an old truck, and it nets 1 or 2 mpg, this is an unwise investment. Often the truck is only worth $2000 (in the eyes of the public).

 

[63 Sprint]

Edited:
Thanks Frank,
With the cost and headaches of owning a new vehicle, I believe we are way ahead of the game by keeping our older vehicles operating.

 

[InlineDave87]

And an ! After his last comment. No, that’s not right. Keep it civilized.

That’s all,

I think he saying that to himself. Looks like he spent a lot of time and effort into his comment. I know i talk to myself a lot.

 

[63 Sprint]

Ok, guy’s, I get it . My apologies, The posts have been edited. Sometimes it’s best to reread a post a few times in order to understand.
Thanks, I appreciate everything.

 

[InlineDave87]

I can see both sides of the coin. End goal is to save money at the pump but we cant drive mopeds all the time to do so. Its a balancing act of power, utility and economy. What im hoping to do with this section of the ford six forum is get tested economy improvers out there and what the cost is.

 

[63 Sprint]

Is there any way to clean up my mess? There are times I put my foot in my mouth. Life is too short. Time to move on, So, what else is new?

 

[Frank]

Is there any way to clean up my mess? There are times I put my foot in my mouth. Life is too short. Time to move on, So, what else is new?

Henry, we're all good my friend. Because we have a relationship from our phone conversations there is trust that we don't take what we say personally. I don't. And I did not mean to offend. . . You are right, what alwill said is not directly on topic.

But I was glad for his post, because the point is huge IMO. As a kid I learned car mechanics because I was into it. Little did I know that it would save me hundreds of thousands of dollars over my lifetime since I have never had a vehicle payment, ever paid more that a few grand for one, or ever had a bill paying someone else to repair them, in 48 years of driving. Right now my wife and I have 4 registered vehicles in the yard. Their combined average age is 40. All are paid for. Insurance/tags/taxes on all of them combined is about $1500 a year. Two get mediocre fuel economy. What I invest to improve that economy has to be calculated, or the investment is out of proportion to the net cost of owning/operating them.