Greetings, all. I'm a newbie to the group. I just got a '73 Maverick 4-door, 50k mile original (yes, little old lady owned), with a 302, C-4, PS, AC, 3.08 gears. What a great little car. My only disappointment is the gas mileage...12mpg in town regardless of whether I drive it like a little old lady, or have some fun with it. The distributor is spot on, I went through the carb, it's got 125lbs on all 8. I got that kind of mileage from my '80 3/4t van with a 302. I know they dropped the compression in '73, but, still... Any ideas, or is it just my fate to keep some sheik in his Mercedes forever? Thanks. Bob in Portland
First thing is, are you still running the points ignition ? If you are, that's the first thing needs to be replaced with a Pertronix unit (or anyother electronic drop in replacement unit) Next, advance the initial timing to 12*BTC. Then readjust the carb to match the timing. Next, new spark plug wires, distributor cap and rotor (get the brass terminal cap) finally new spark plugs. I would also ditch the Autolite carb for a Holley 350 2 bbl (but that's just me) Also pour a bottle of Lucas transmission treatment in the trans fluid, to free up the sure to be sticky valve body. Then see where the MPG is. If all that doesn't help, I'd recam it with a Comp 268H to regain what Ford took out of it with the smog cam and lowered comp ratio.
I agree with baddad (except I would slap in a new intake and 4bbl 600 edelbrock). You should be able to pull 20 mpg with that setup if you keep your foot out of it.
One thing you could try is tuning the timing and carb with a wideband 02. Just to check in on the afr. Id bet theres some to be had with a tool like this.
That might hurt in city driving instead of help. He didn't say what kind of driving he checked the mileage on.
don't forget good, well inflated tires. And a decent alignment. check the front and rear bearings and brakes(and park brake) for proper adjustment and operation. check the u joints for tightness. Anything you do to the motor is kind of pointless if any of that stuff is off.
Thanks for all the responses. The tires are 195-75x14. Going any bigger would probably kill off hill-pulling ability. I just had the alignment done. I disconnected the EGR, but it's still in place. Disconnected/rerouted all the thermo-switched vacuum lines (no pre-'75 emissions check in Oregon) so the distributor sees only a direct, ported vacuum signal. All the advance comes in correctly. Currently initial timing is 6 degrees. I'm going to try the tried and true method of cranking up the advance until it pings (or until there's a degradation of power), then back it off 2 degrees. The mileage check was 90% city. At some point I might go 4-bbl. I'd also like to go with early ('66-67) closed-chamber heads. I would like to change the cam. As I recall this engine should have the nylon cam timing gear and I'd like to get rid of that, so it might be the perfect opportunity to make some changes then. The one baddad recommended is a good one with good lobe separation. The exhaust is still single, but oversize pipe after the "Y" converges, and just a single, free-flow muffler at the rear. I went through the brake system completely. Again, thanks for the suggestions. Bob
Are you figuring the mpg correctly? Hard to believe that combo would get that mileage if it's running good.
the only other thing not mentioned above is if there are excessive deposits on the intake valves. as the deposits build up over time (a big problem on a little old lady car) they restrict the air flow past the valves. a fuel system cleaner like lucas or cheveron with techron will help break down these deposits. more often than not the heads need to be taken off and need a valve job to completely clean the valves. you can see the valves with the intake off and would be able to see how much build up there is. also these heads didnt have hardened seats and when they took the lead out of fuel this can cause the valve seats to wear out quickly.
the intention of egr was to fill part of the cylinder with an inert gas (exhaust). this allows less fuel and air to achieve higher cylinder pressures thus achieving better efficiency. now the early systems didnt do this very well. once they got computer controls going it really works well.
Agreed but with the EGR non functioning the only thing it is doing right now is causing the intake manifold to heat up from the exhaust gas. The only correct way to get rid of an EGR is to go with a non EGR manifold.
That may have been the intention, but in actual application, it doesn't work. Period. Not then, not now. When you include exhaust gasses into the cylinder, you're also replacing part of the fuel air mixture with this contamination that does not combust. Therefore, you have a reduced amount of fuel/air mix that reduces power production and increases the demand by your foot to make up for it. That decreases MPG. Just as with everything else the goverment does, they think everything's a "zero sum gain" in life, but in reality, nothing is. I drive an 08 Pete tandem fuel truck that's got an EGR equipped 8 liter Cummins engine. When the EGR kicks in, the power goes down. And when it's engaged at idle, you get about half that exhaust gas in the cab, where it's hardly appreciated. Every vehicle I've driven with an EGR system, Performance goes downhill when the EGR system kicks in.
