driving speed and RPMs?
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Postmaster
Joined: Sep 2005
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driving speed and RPMs?
I know this is going to sound really stupid to everyone. I am deaf, but I have a cochlear implant. I hear ok....but not great while driving my 56. Its sort of loud (to me). Its probably quiet to everyone else. I cannot tell by sound what the engine is doing.
Everything works (spedometer, guages, etc) and the original steering box is tight. I just rebuilt the master cylinder, so the brakes are what they are supposed to be (not power). Its holds good oil pressure (has a guage).
I have no clue how many RPMs its turning or if I am hurting anything driving it out on the highways.
Its a 272 (?) y-block with a 3 speed standard on the column. It is supposed to have a 3.73 gear ratio rear end. The tires are the same height at they were originaly (funny size though-like g78 15????).
Can someone give me approximate RPMs at certain speeds? I am afraid to drive it at highway speeds without knowing.
I know...somone will tell me to buy a tach, but I have no extra funds at all for a long time.
Everything works (spedometer, guages, etc) and the original steering box is tight. I just rebuilt the master cylinder, so the brakes are what they are supposed to be (not power). Its holds good oil pressure (has a guage).
I have no clue how many RPMs its turning or if I am hurting anything driving it out on the highways.
Its a 272 (?) y-block with a 3 speed standard on the column. It is supposed to have a 3.73 gear ratio rear end. The tires are the same height at they were originaly (funny size though-like g78 15????).
Can someone give me approximate RPMs at certain speeds? I am afraid to drive it at highway speeds without knowing.
I know...somone will tell me to buy a tach, but I have no extra funds at all for a long time.
Posting Guru
Joined: Mar 2003
Posts: 1,734
Likes: 2
From: Kansas City area
Generally speaking the stock old trucks can run 50-55 mph without problems. You might try www.smokemup.com to see some formulas for calculating rpm. Someone will be along soon to offer more indepth help I'm sure.
Lead Driver
Joined: Apr 2002
Posts: 8,813
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From: Littleton, New Hampshire
Brian,
With your particular situation I don't think you can afford NOT to have a tachometer. You could even get distracted and forget to change gears. You don't want to buzz that y-block at 5 grand driving in first instead of third down the freeway. When I had my 5-speed Wrangler I would ocassionally forget to shift from 4th to 5th so I know it can happen! I think a tach in your case is probably more important than some of your other gauges...
With your particular situation I don't think you can afford NOT to have a tachometer. You could even get distracted and forget to change gears. You don't want to buzz that y-block at 5 grand driving in first instead of third down the freeway. When I had my 5-speed Wrangler I would ocassionally forget to shift from 4th to 5th so I know it can happen! I think a tach in your case is probably more important than some of your other gauges...
Cargo Master
Joined: Jan 2005
Posts: 2,497
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From: Tucson AZ
Originally Posted by LEckart
Generally speaking the stock old trucks can run 50-55 mph without problems. You might try www.smokemup.com to see some formulas for calculating rpm. Someone will be along soon to offer more indepth help I'm sure.
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Postmaster
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Thanks guys. I am not going to be driving it fast. Its not a race car. Just typical highway driving at or near the speed limit (50-55) so at not too impeded traffic. So far I have not had it over 45.
Eventually, I will get a tach. There is no doubt that I need one with my hearing problem. Money is just way beyond tight at the moment (will be for a month or two) and I don't want to damage anything until I can get one.
I will play with the calculator that LEckart posted as well as an excel one that Joe Hoffman sent me. They will keep me out of trouble (I hope).
I drive standards with no problems. Usually, I can hear (or at least feel) what the engine is doing. I guess I am not used to the truck yet and I am more nervous.
Eventually, I will get a tach. There is no doubt that I need one with my hearing problem. Money is just way beyond tight at the moment (will be for a month or two) and I don't want to damage anything until I can get one.
I will play with the calculator that LEckart posted as well as an excel one that Joe Hoffman sent me. They will keep me out of trouble (I hope).
I drive standards with no problems. Usually, I can hear (or at least feel) what the engine is doing. I guess I am not used to the truck yet and I am more nervous.
Lead Driver
Joined: Oct 1999
Posts: 6,776
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From: Kalispell, MT
With 3.73 gears you should be fine up to 55. Just ballpark, but I'd guess you're in the 2500 rpm area. When you said highway, I was thinking freeways.
Funny, I grew up with tires like G78-15's - without doing the math, it probably compares to a 235-75R-15.
Funny, I grew up with tires like G78-15's - without doing the math, it probably compares to a 235-75R-15.
Fleet Owner
Joined: Dec 2000
Posts: 25,376
Likes: 5,386
From: Central PA
My '54 F-100 which is all original I have driven at highway speeds off and on since I got it in 1977. It has a 239 V-8, and 3.92 rear end. It has 16 inch tires (radials). The engine was rebuilt in 1979. The speedometer did not work when i bought the truck and I did not get a working one in until about 2001. I go faster than some cars, slower than most, and actually pass some cars. I do try to keep it no faster than 60. Sometimes I do find myself going too fast (engine sounds like it is winding out) and I slow up a bit.
Anyhow, I have not had any engine problems (yet) and hope I do not. your rearend is geared lower than mine but you have 15 inch tires...
abe
Anyhow, I have not had any engine problems (yet) and hope I do not. your rearend is geared lower than mine but you have 15 inch tires...
abe
