Re: The Duchess Project: 1940 Super 8 Convertible Sedan
Posted by Joe Santana On 2015/12/4 0:48:10
CARBURETOR/AIR CLEANER COVER. JayDub, I, too, thought those little holes were letting air in because the air cleaner wasn't down enough over the carburetor horn. But it was. And the lip or seating height of the Carter carb and the Stromberg are the same, so not sure why there would be vents. I mean they built this humongous oil bath air cleaner. The slits in the air cleaner appear to be there so you can cinch it up tight. Still they didn't close up, so I covered them with a strip of black electrical tape.
I have a bigger problem.
DIFFERENTIAL RATIO: The problem with my speedometer reading correctly is due to 2 things. 1. I have an ambulance rear-end and 2. I have the wrong speedometer pinion gear. The reason I have the ambulance rear-end is because I broke an axle in 1975 and the ambulance rear-end was the only 1940 one available locally. When I called Don Figone to see if he had a 20-tooth pinion gear that might correct my speedometer, he didn't have one, but suggested putting in the correct 1803 rear-end. I started looking for one among the usual suspects. The flackmaster suggested just replacing the differential. So that sounded like a much better idea (and probably what Don was actually recommending).
I spent some time today reading up on gears and came across a video on determining the differential ratio. From the parts manual I had numbers like 4.7, 4.9 with OD, 5.22:1 for 120 Ambulance and 4.54,4.7with OD for the 160 Ambulance, and finally 4:36 for 1803 with OD. Other 1803 could 3.92 std or 4.09 spl.
So you put a piece of tape on the wheel and a piece on the drive shaft. The car is jacked up on stands and out of gear. As you rotate the wheel, you count how many times the shaft goes around and you count the number of times the wheel makes a complete revolution as you go until the wheel has gone around 10 times. Then divide by 10.
I was a little shocked when the shaft had only gone around 2 times and the wheel was already 1 revolution. I finished this anyway and made 20.5 shaft revs to 10 wheel revs. So my differential ratio is 2.05:1?
I obviously missed something, so when you're finished laughing, please tell me where I went wrong. I'm sure it's something simple.
Attach file:
(82.60 KB)
I have a bigger problem.
DIFFERENTIAL RATIO: The problem with my speedometer reading correctly is due to 2 things. 1. I have an ambulance rear-end and 2. I have the wrong speedometer pinion gear. The reason I have the ambulance rear-end is because I broke an axle in 1975 and the ambulance rear-end was the only 1940 one available locally. When I called Don Figone to see if he had a 20-tooth pinion gear that might correct my speedometer, he didn't have one, but suggested putting in the correct 1803 rear-end. I started looking for one among the usual suspects. The flackmaster suggested just replacing the differential. So that sounded like a much better idea (and probably what Don was actually recommending).
I spent some time today reading up on gears and came across a video on determining the differential ratio. From the parts manual I had numbers like 4.7, 4.9 with OD, 5.22:1 for 120 Ambulance and 4.54,4.7with OD for the 160 Ambulance, and finally 4:36 for 1803 with OD. Other 1803 could 3.92 std or 4.09 spl.
So you put a piece of tape on the wheel and a piece on the drive shaft. The car is jacked up on stands and out of gear. As you rotate the wheel, you count how many times the shaft goes around and you count the number of times the wheel makes a complete revolution as you go until the wheel has gone around 10 times. Then divide by 10.
I was a little shocked when the shaft had only gone around 2 times and the wheel was already 1 revolution. I finished this anyway and made 20.5 shaft revs to 10 wheel revs. So my differential ratio is 2.05:1?
I obviously missed something, so when you're finished laughing, please tell me where I went wrong. I'm sure it's something simple.
Attach file:
(82.60 KB)
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