finally

[keithm]

the majority of the work is finally done, engine, exhaust, and trans, this thing will move and i didnt put the hot motor in it, problem is gas mileage is terrible, about 12 miles to the gallon, with the 3.45 diff, the lincoln that trans came out of had a 2.81, that would be great but I dont know if that was a 7.5 in the lincoln, so im thinking 3.08, any input would be great.

keith

 

[lairdt]

the majority of the work is finally done, engine, exhaust, and trans, this thing will move and i didnt put the hot motor in it, problem is gas mileage is terrible, about 12 miles to the gallon, with the 3.45 diff, the lincoln that trans came out of had a 2.81, that would be great but I dont know if that was a 7.5 in the lincoln, so im thinking 3.08, any input would be great.

keith

With those gears I'd say you're not running an overdrive trans, so 12mpg is about what I'd expect. You've got to get those revs down and build torque to keep things moving. You can get 2.80 gears for almost any diff, but 3.08's would be a better option if you can swing it.

 

[keithm]

aod

its an aod out of the 83 towncar, it soes shift thru all four gears, do you think the 3.08 will be much of an improvement? I think I'll hold off on replacing the speedo driven gear till I get that final drive right, right now it reads 10mph fast

keith

 

[dangerranger83]

If it reads 10 fast hopefully you are acounting that in what the odometer says or it will say that your MPG's are off from what they really are.

 

[lairdt]

its an aod out of the 83 towncar, it soes shift thru all four gears, do you think the 3.08 will be much of an improvement? I think I'll hold off on replacing the speedo driven gear till I get that final drive right, right now it reads 10mph fast

keith

Ok, if you're running an AOD, then your mpg is too low. My '77 F250 400 with 3.73 gears gets 13mpg, with a carb and no overdrive trans! You should be better.

As for 302s... My '89 Towncar running a Mustang 302 HO EFI MA computer and Lunati cam gets 22mpg with 3.27 gears (235/70R15 tires) in a 4600lb car on the highway at 60mph. With 3.45 gears (and about 26" tire) you should be running about 2400rpm or so in 3rd @60mph, and 4th should put you about 1700-1800rpm (depending on converter slippage). With the shorter gears and shorter tires it should rev easier, and I'd expect you'd be in the high teens.

10mpg fast, at what speed? Could be a huge percentage error. Work with the existing gears first, then see where you are so you knwo if you should do 3.08's or something more like 3.27's. Unless you have an 8.8 already, I wouldn't bother changing gears without also going to an 8.8.

 

[baddad457]

the majority of the work is finally done, engine, exhaust, and trans, this thing will move and i didnt put the hot motor in it, problem is gas mileage is terrible, about 12 miles to the gallon, with the 3.45 diff, the lincoln that trans came out of had a 2.81, that would be great but I dont know if that was a 7.5 in the lincoln, so im thinking 3.08, any input would be great.

keith

Other than the rear gear ratio, you really haven't given us much to work with here to answer your question. You've got a motor (I'm assuming its a V8 ?) and an AOD transmission and a 3.45 rear. What's the motor, what's it's build ? Is it carbed ? Or is it EFI ? How much does your right foot weigh when you start the engine and put it in gear ?

 

[keithm]

sorry about that, its an 84 302 out of an E150 2bbl carb AOD trans from a 83 town car. 3.45 rear end, speedo reads 10 mph fast, I realize the odo will be off, i'm driving over a known distance, I'm not exact about the mpg without actually running it out and then refilling. I dont have a tach hooked up still have to get mine calibrated, i can put a temparary under the dasht o get some references,

keith

 

[keithm]

btw the gpps track is 70 to 75 mph

 

[baddad457]

The speedo won't be off unless you changed tire sizes. All Ford automatics used the same spline count for the speedo gear on the tailshaft, they're either 7 teeth (most are) or 8 teeth. As for the motor combo, try bumping the initial timing to 12*BTC if you haven't already. What carb's on it ? And unless you actually clock the miles and divide by actual gallons used, trying to estimate it off the fuel gauge is a complete waste of time. On every Ford fuel gauge I've seen, once you fill the tank (completely too, not just stopping when the nozzle automatically clicks off), they'll all take forever to come off full, then drop a little faster from 3/4 to half, then plunge to the E after 1/4 is reached. Might also verify the converter is actually locking up once in OD too. That alone will net (or cost)you 2 mpg. Adding a bottle of Lucas Transmission treatment will help to insure the AOD is doing what it's supposed to be doing too. You can recalibrate the V6 tach to read a V8 by adjusting the "doohickeys" (or thingamabobs) on the backside of the tach while it's running and comparing it with another tach's readings.

 

[keithm]

I have a friend that is a police officer that clocked me I tried 3 passes, one was 55which he showed 45, one at 65which showed 55, and one at 75 which he showed 65. I was thinking of changing the driven gear which I believe was a 21 tooth, I did set initial timing to 12 degrees engine idles and runs very smooth. I'll work on getting a little more accuracy on the mpg and let you know. Does the standard aod have a lock up converter?

 

[baddad457]

As far as I know, all the modern OD automatics have a lockup converter. The non OD C-5 had it, the AOD replaced it.

 

[lairdt]

I have a friend that is a police officer that clocked me I tried 3 passes, one was 55which he showed 45, one at 65which showed 55, and one at 75 which he showed 65. I was thinking of changing the driven gear which I believe was a 21 tooth, I did set initial timing to 12 degrees engine idles and runs very smooth. I'll work on getting a little more accuracy on the mpg and let you know. Does the standard aod have a lock up converter?

The standard AOD is lockup in 4th.

 

[keithm]

tach and temp

on the carbureted 84 302 there were 2 temp sensors one next to the thermostat the other in the intake at the front of the motor. itook one out of the 01 2.5 that was in it and put it in the 302 i believe the temp is to low as the fan comes on 3 or 4 minutes after start up, i need to change that, any idea which wire i need to take to the coil to activate the tach?

keith

 

[baddad457]

Tach wire is attached to the negative side of the coil.

 

[keithm]

i understand the negative, the wiring harness for the previous engine went with the engine i was going to run a lewad to the harness on the chassis and use the tach