Does my /6 sound right?

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porksoda

porksoda

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Well I recently went on a trip that was a round trip of like 231 miles.
I calculated the MPG and I got 12 MPG and this whole trip was almost all highway.
Whats weird is the speed limit is 70MPH and the fastest I could go was 66-68MPH. That was flooring it the whole way!
I am assuming something could probably be wrong if I am wasting that much gas and I had to floor it the whole way.
Does this sound about right?

Specs on the car:
The car is a 225 /6 (single barrel carb), factory exhaust, it has a 7 1/4 rear end, auto transmission, and points ignition.
I did clean out the whole fuel tank a few days before and filled it up with new gas.
I changed the oil in the car a few days before(10w30 castrol and purolator One filter), replaced fuel filter (purolator), replaced thermostat/flushed cooling system, did alignment, rebuilt brakes/properly adjusted them, and I inflated all my tired to 32 PSI.

I am just a bit confused at the moment on what could have been wrong to waste that much fuel.

Any ideas?

Thanks!
 
Check the following things
Brakes make sure they are not rubbing
Front bearings could be too tight

Try just pushing your car on a level surface to see if there is too much resistance.

Check your heat riser (?) the flapper that blocks off your exhaust while your car warm up. Make sure it isn't stuck shut.

Make sure your choke isn't stuck shut

check your timing and spark advance.
 
Yeah. Something's wrong.
 
stuck e-brake but i would think you could have smelled that,
clogged/collapsed exhaust, jumped time.....
 
I had a little rust in the return hole of my master cylinder. The brakes worked fine but after a few miles the brakes would start draging after a while it actually blew the front two tires and I always had mileage problems.

Check the temperature of your rims next time you are driving around.
 
What do the spark plugs look like? Pull a few of them and see if the firing tips are black and sooty indicating a rich mixture or tan/grey as they should be. For reference, Tune-up parts and technique suggestions in this thread and Carburetor operation and repair manuals and links to training movies and carb repair/modification threads are posted here for free download.

Check for a slack timing chain: Pop off the distributor cap and, using the belt and fan blade, manually rotate the engine in one direction until you see the distributor rotor begin to turn, then see how far you can manually rotate it the other direction before the distributor rotor starts turning. Use the timing marks as a guide/gauge to how many degrees the crank turns before the distributor moves. If there is more than a degree or two of perceptible lag, the T-chain is slack and/or the cam sprocket is worn.

Other things to check: make sure the mechanical and vacuum advance mechanisms on the distributor are working, make sure the manifold heat control valve is not stuck, and make sure there's no excessive exhaust restriction.

Once all that's checked, you will need to move on to things like compression or leakdown tests. How many miles are on this engine?
 
If you're running 4.56 gears, that sounds about right but if you have 2.76 or 2.93's, you have one or more problems. Like has been mentioned......exhaust restriction or retarded timing (those will also cause the exhaust manifold to crack), poor compression, or stuck mechanical or vacuum advance are the most likely.
 
trapster said:
I had a little rust in the return hole of my master cylinder. The brakes worked fine but after a few miles the brakes would start draging after a while it actually blew the front two tires and I always had mileage problems.

Check the temperature of your rims next time you are driving around.
Click to expand...

Are you kidding! You blew the front tires is alot of drag. You got to fix the brake system so you don't have this drag as this will kill your mpg. Watch out as I had a problem like this and stopped to check brake drums. Yeh it was hot as it bistered my finger tip and I won't do that again.
 
cudamark said:
If you're running 4.56 gears, that sounds about right but if you have 2.76 or 2.93's, you have one or more problems.
Click to expand...

It should be noted for benefit of the original poster that the original rear axle ratio on his car was 2.93 or 3.23, and if a later rear axle has been swapped in it's almost certainly a 2.76 or 3.23.

exhaust restriction or retarded timing (those will also cause the exhaust manifold to crack)
Click to expand...

Not necessarily; a car can go for years with a restricted exhaust or retarded timing without the exhaust manifold cracking.
 
dusterny said:
Are you kidding! You blew the front tires is alot of drag. You got to fix the brake system so you don't have this drag as this will kill your mpg. Watch out as I had a problem like this and stopped to check brake drums. Yeh it was hot as it bistered my finger tip and I won't do that again.
Click to expand...

Maybe blew was too harsh, they both split the belts and not at the same time, but then again this was the 80's and they were firestone 721's.
 
Thanks for all the information everyone!

We are unsure if it is timed correctly cause we can't find anything on the timing chain cover to line the crank pulley timing mark to.
Any idea what to do about that?

Also we checked out the brakes and they are not grabbing or anything like that.
 
A friends distributor was hooked to the wrong ported vacuum (?) it didnt like to rev past about 2500 in gear. Sure thats not your prob,but check your vacuum hose diagram. Sounds rich indeed!
 
The timing indicator was a separate sheetmetal stamping secured to the timing cover by one of the bolts from '61-'66. For '67, the timing indicator was spot-welded to the timing cover, and now on the distributor side rather than on the manifold side. So you'd either need to pick up a replacement timing indicator from someone who has a spare lying around, or pick up a '67-up timing cover with indicator and install that. The later setup makes it easier to check and adjust the timing, but requires a different timing mark on the crank pulley; the earlier setup won't require you to R&R the timing cover.

Be advised the outer ring member of the crank pulley can slip with age and use relative to the inner hub, making the timing mark inaccurate. Once you having a timing indicator you'll want to put it at 0° (TDC) and verify that is in fact TDC in the frontmost cylinder. This can be done by removing the spark plug and using a piece of coat hanger wire to watch the movement of the piston as you rotate the engine towards and past indicated-TDC in both directions.
 
Much easier to do the repair correctly rather than making a hassle for yourself futzing around with timing tape -- which, by the way, will not work on a slant-6 crank pulley.
 
You've taken the chassis out of the bad fuel mileage equation. All seems to be OK there, for now.

Suggest:
  1. Get the spark timing adjusted properly, check the coil, wires, and plugs.
  2. Check distributor vacuum hose to carb connection. Check for a vacuum leak, e.g. hoses, carb-to-manifold seal, intake-to-cylinder head seal. Check intake manifold for cracks.
  3. With the above accomplished, run the engine a bit to check carburetion. Pull a plug to "read" it. There are on-line sites that will give examples for reading plugs. Beats anything I could describe with words.
If the original carburetor has been replaced by a re-man, if my experience is any guide, it is jetted WAY too rich. My Holley reman for the '73 came with a 65 jet when it should have been a 51 according to my manuals. (Summit had the jet[sold in pairs]. Rock Auto had the rebuild kit needed to replace the carb gaskets.)

My manuals are archives. They do not account for the 10% ethanol in the fuel supply.
 
If the brakes check out, the next things I'd check is ignition, cam timing and fuel systems (carb condition and tuning etc).
 
I bought a Super6 set-up yesterday. I found it on a Volare wagon.
Me and my friend pulled it at the yard.
They ended up just charging me 25 for everything so SCORE!
The onlything I lack is the air cleaner. The air cleaner was a crushed.
I am thinking I should probably order a carb rebuild kit and freshen it up.
Also I was thinking of dressing up the intake and exhaust manifold.
What colors should I paint them?
 
Also while in the yard I found a 4-door Dart(maybe 70-71?).
It was a slant6 car. When I first saw it I said to myself that there is going to be nothing for me on the car because it was painted with house paint and a brush lol.
I pop the hood and I see some wires hanging from the distributor.
So I pull the distributor and find a PerTronix Ignitor kit inside the distributor.
I ask the guy at the yard and he said I can have the kit!
So I took some pictures on how it was installed on the distributor and pulled everything out. I made sure to look up on my phone to see what all I needed for the kit.
It was kinda weird because the guy said dont take the distributor but you can have the stuff inside it. lol.
Well that my update so far.
 
slantsixdan said:
Much easier to do the repair correctly rather than making a hassle for yourself futzing around with timing tape -- which, by the way, will not work on a slant-6 crank pulley.
Click to expand...

Wow you are right, ( I am sure you haven't heard that before :) )
I can't believe no one makes tape for the SLANT-6.

I guess you would have to make your own tape. should be easy enough.

Measure circumference divide by 72 make every other mark larger.
Should be good enough for setting timing.
 
trapster said:
I guess you would have to make your own tape. should be easy enough.
Click to expand...

…except that it still won't work, because there is noplace on the slant-6 crank pulley to put it. The belt groove takes up the whole outer circumference. I wonder if you might be trying to answer a slant-6 question by reference to your V8 knowledge.
 
Here is my $25 junkyard find.
Hopefully this will help pep up my /6. lol

101_1587.jpg


101_1589.jpg


This super6 set-up was in a Volare Wagon. A friend and I pulled it off like a few minutes before they were going to crush it. lol.
 
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