The Ford Barn

oneoldtruckguy · 06-28-2015, 11:45 AM

I have a couple more 1950 F1 questions.

1. My rear end has no tag but is stamped 41. I presumed it was a 3.73 but engine is roaring pretty good at 55mph. What do You think?
2. I drove it for the second time this morning to the gas station and filled with gas but gauge only reads 3/4 full. It has NOS gauge. Do you think sending unit is stuck? It read empty before I filled it. This truck has been sitting in a Montana barn since 1984 and has not been started until recently. It runs Very Well having been rebuilt by an Old time Flathead guy prior to 1984.
3. What's the best oil to run in the Flathead V-8?
4. What's the best spark plugs to use in the Flathead V-8
5. I rewired the truck and put new tail lights on. Brake lights work great but tail light Very Dim!!!! I thought I got them grounded good to the bed but maybe not. What do you think?

JSeery · 06-28-2015, 12:12 PM

1. It is hard to judge engine RPM from "engine roar".
3. Everyone has their own opinion on oil!
4. Lot of opinions on spark plugs as well.
5. Dim lighting is often a ground issue, might try a ground wire to the frame and be sure the frame is clean and bare metal where you connect the ground.

FortyNiner · 06-28-2015, 05:34 PM

On the fuel guage: I would remove the sender and inspect. It is possible that the float is corroded and not sound.

On the oil and plugs, there are many opinions. Keep in mind, especially for the oil that the most humble store brand of today is better than the premium stuff sold in the day.

rotorwrench · 06-28-2015, 05:55 PM

If you have a Dana 41 axle, it could be a 3.73. 3.91, 4.27, or even lower. The Dana 44 came out in 1950 and they start out with a 3.92:1 gear ratio. I've not seen a 3.73:1 listed in the parts books for a Dana 44.

If you have the old 21A 4-speed, it will likely have a lower ratio but many of the 51 & 52 F1
models have the 3.92:1 ratio with a 4-speed. If it has a large fan, it can get louder in operation too.

JSeery · 06-28-2015, 06:09 PM

On an open driveshaft, the rear axle ratio should be fairly easy to check. I mark the bottom of the driveshaft with chalk and then also mark the tire at the point it is in contact with the ground. Slowly roll the truck and count the number of turns of the driveshaft for one turn of the tire. You will get several complete rotations of the driveshaft and then some fraction of a turn. From this you should be able to guess at the gear ratio. 3 3/4 turns would be 3.73, 4 turns 3.91 and 4 1/4 4.27.

Ross F-1 · 06-28-2015, 06:37 PM

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The only way to get my gas gauge to read full is to put gas in until it is right at the filler cap. Not recommended. I like to fill to the bottom of the fill tube (using an LED flashlight to verify), which reads ~3/4 full on the gauge. Most pumps will click off right around there anyway.

WestCoast · 06-28-2015, 10:31 PM

you can find the rear axle gear ratio by just jacking up one wheel and putting a mark at the top, put another mark on the drive line where it can easily be seen, now have a helper watch the drive and count the number of times it rotates as you turn the jacked up wheel 2 full turns. the drive line will turn what ever the gear ratio is, 3.73, 3.92, 4.11, even 4.44, you will have to guess how far the drive line turns past your mark to get a close answer

06-28-2015, 11:45 AM	#1
oneoldtruckguy Member Join Date: Mar 2014 Location: Bozeman, Montana Posts: 56	A couple of F! Questions I have a couple more 1950 F1 questions. 1. My rear end has no tag but is stamped 41. I presumed it was a 3.73 but engine is roaring pretty good at 55mph. What do You think? 2. I drove it for the second time this morning to the gas station and filled with gas but gauge only reads 3/4 full. It has NOS gauge. Do you think sending unit is stuck? It read empty before I filled it. This truck has been sitting in a Montana barn since 1984 and has not been started until recently. It runs Very Well having been rebuilt by an Old time Flathead guy prior to 1984. 3. What's the best oil to run in the Flathead V-8? 4. What's the best spark plugs to use in the Flathead V-8 5. I rewired the truck and put new tail lights on. Brake lights work great but tail light Very Dim!!!! I thought I got them grounded good to the bed but maybe not. What do you think?

06-28-2015, 12:12 PM	#2
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: A couple of F! Questions 1. It is hard to judge engine RPM from "engine roar". 3. Everyone has their own opinion on oil! 4. Lot of opinions on spark plugs as well. 5. Dim lighting is often a ground issue, might try a ground wire to the frame and be sure the frame is clean and bare metal where you connect the ground.

06-28-2015, 05:34 PM	#3
FortyNiner Senior Member Join Date: May 2012 Location: u-rah-rah-Wisconsin Posts: 1,137	Re: A couple of F! Questions On the fuel guage: I would remove the sender and inspect. It is possible that the float is corroded and not sound. On the oil and plugs, there are many opinions. Keep in mind, especially for the oil that the most humble store brand of today is better than the premium stuff sold in the day. __________________ 19 and 49 F1 - jes' like Henry II built 1946 Deluxe - as Henry built it

06-28-2015, 05:55 PM	#4
rotorwrench Senior Member Join Date: Jun 2010 Location: San Antonio, Texas Posts: 16,436	Re: A couple of F! Questions If you have a Dana 41 axle, it could be a 3.73. 3.91, 4.27, or even lower. The Dana 44 came out in 1950 and they start out with a 3.92:1 gear ratio. I've not seen a 3.73:1 listed in the parts books for a Dana 44. If you have the old 21A 4-speed, it will likely have a lower ratio but many of the 51 & 52 F1 models have the 3.92:1 ratio with a 4-speed. If it has a large fan, it can get louder in operation too.

06-28-2015, 06:09 PM	#5
JSeery Member Emeritus Join Date: Nov 2012 Location: Wichita KS Posts: 16,132	Re: A couple of F! Questions On an open driveshaft, the rear axle ratio should be fairly easy to check. I mark the bottom of the driveshaft with chalk and then also mark the tire at the point it is in contact with the ground. Slowly roll the truck and count the number of turns of the driveshaft for one turn of the tire. You will get several complete rotations of the driveshaft and then some fraction of a turn. From this you should be able to guess at the gear ratio. 3 3/4 turns would be 3.73, 4 turns 3.91 and 4 1/4 4.27.

06-28-2015, 06:37 PM	#6
Ross F-1 Senior Member Join Date: Nov 2010 Location: NM Posts: 2,438	Re: A couple of F! Questions Sponsored Links (Register now to hide all advertisements) The only way to get my gas gauge to read full is to put gas in until it is right at the filler cap. Not recommended. I like to fill to the bottom of the fill tube (using an LED flashlight to verify), which reads ~3/4 full on the gauge. Most pumps will click off right around there anyway. __________________ '52 F-1, EAB flathead

06-28-2015, 10:31 PM	#7
WestCoast Senior Member Join Date: Sep 2014 Location: oroville calif Posts: 893	Re: A couple of F! Questions you can find the rear axle gear ratio by just jacking up one wheel and putting a mark at the top, put another mark on the drive line where it can easily be seen, now have a helper watch the drive and count the number of times it rotates as you turn the jacked up wheel 2 full turns. the drive line will turn what ever the gear ratio is, 3.73, 3.92, 4.11, even 4.44, you will have to guess how far the drive line turns past your mark to get a close answer