1955 idle rpm

R

Rmbreitkreutz

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Jun 18, 2022
Thunderbird Year
1955
New BabyBird owner.

Working the tune up. Where should the RPM be set.

292 with 3 speed auto.

Vacuum 17
Timing 6° BTSC
plugs .032
points .015
waiting on meter to check dwell

RPM is currently at 700

Thanks for the cross check.
 

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Mine 560rpm in park
480 in drive.
 
Most tachometers, whether mechanical/electric could easily be off by 100-200 rpm.

Many Y-block owners have found that they prefer a higher idle speed than what's listed in the tune-up specs in the Ford service manual. A higher idle may provide a smoother idle and reduction/elimination of off-idle hesitation/stumble.
 
Plus provide more water circulation since the stock wp spacer restricts flow at idle speeds. Some say there is little water flow under 800rpm’s? I put in a modified spacer, HO water pump, 6 blade fan, bigger radiator, high flow thermostat which helped some, but she still doesn’t like hot day idling! Thinking of a smaller WP pulley?
 
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JRH said:
Book says 475 to 500 I can't get my 1955 below 600 going by the tach in the car. # speed automatic 292ci
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I would make sure the linkage isn't binding or it could even be your fast idle screw out of adjustment and is stopping the throttle return before it sets on the warm idle set screw.
 
Yup, just readjusted the kick down linkage and noticed that. It wouldn’t let the throttle plate (butterfly) close all the way.
 
700 is a bit high, 650 is probably optimum. Shifting from N to gear will shock the drive train if the idle Rs are too high.
 
zeroroadkill said:
Plus provide more water circulation since the stock wp spacer restricts flow at idle speeds. Some say there is little water flow under 800rpm’s? I put in a modified spacer, HO water pump, 6 blade fan, bigger radiator, high flow thermostat which helped some, but she still doesn’t like hot day idling! Thinking of a smaller WP pulley?
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If after you have accomplished the above and your car still runs hot you may have a different problem. Having your engine tuned properly and also diagnosed for engine operation problems should reveal these problems. I personally use: a standard thermostat, a standard radiator, a standard water pump spacer,and standard pulley. I do have a fan from a Lincoln. My '57 292 runs between 190 and 195 degrees. That is even on an all day highway drives at 70 to 75 mph with or with out air-conditioning in use. An exampe is the trip from my home in Sacramento California to Flaggstaff and beyond for the last great convention I attended. I do not have any trouble in parades or in urban traffic. I have worked to make sure all systems pertaining to the engine operation are proper working condition.. This is not a criticism. it is a report on the operation of my single car. A number of years ago I did talk with the late Walt Nuckels of the Dallas area and Jimmy Scruggs of San Antonio, who were very helpful regarding engine tuning and cooling system advice.
 
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My ‘55 292 runs fine while moving. On cool days about 60% on the gauge. On hot days about 80% under load. Driving is not the problem it’s idling in traffic On a warm day she’ll get to the end of the white scale just before the blank spot to H.

Tune is perfect, timing 6° to 7° BTDC. Pertronics ignition. Carb adjusted for maximum vacuum at idle. 18psi. Total advance 35° if I remember.
 
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zeroroadkill said:
My ‘55 292 runs fine while moving. On cool days about 60% on the gauge. On hot days about 80% under load. Driving is not the problem it’s idling in traffic On a warm day she’ll get to the end of the white scale just before the blank spot to H.

Tune is perfect, timing 6° to 7° BTDC. Pertronics ignition. Carb adjusted for maximum vacuum at idle. 18psi. Total advance 35° if I remember.
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Sounds like you have it dialed in. I've found that each of these cars have a personality and the advice here just demonstrates that even though they were production line products, they are not exactly alike.
 
zeroroadkill said:
My ‘55 292 runs fine while moving. On cool days about 60% on the gauge. On hot days about 80% under load. Driving is not the problem it’s idling in traffic On a warm day she’ll get to the end of the white scale just before the blank spot to H.

Tune is perfect, timing 6° to 7° BTDC. Pertronics ignition. Carb adjusted for maximum vacuum at idle. 18psi. Total advance 35° if I remember.
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what temp thermostat are you using?
 
I was running a 180° And changed it to a 170° Widemouth. No difference.
 
zeroroadkill said:
I was running a 180° And changed it to a 170° Widemouth. No difference.
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The 292 and 312 was designed for a 160 and that is the best to use, as a aside did you rebuild the motor? Some brand head gaskets had undersized water port holes and can cause problems. I ran Y blocks in a 55 bird and a a 63 f100 for well over 25 years with all levels of builds and never had a issue in any car with a 160 in summers with 100 degree days.
 
I’ve tried them all, no difference. I’ve even tried removing it, no difference. Some say rust around #3 water jacket can reduce water flow, not too sure about that, but I have laser heat tested all cylinders and there is no significant temperature difference as well as exhaust and intake manifold temperatures. I know this engine has been out of the car, for what I do not know, but maybe it was rebuilt and the head gaskets replaced with those you mentioned?

One thing I haven’t heard was if anyone noticed a big difference after installing an electric fan in front of the radiator?

I can see I’m getting a good airflow through the radiator for she will suck a nylon sheet into the grill at idle.
 
zeroroadkill said:
I’ve tried them all, no difference. I’ve even tried removing it, no difference. Some say rust around #3 water jacket can reduce water flow, not too sure about that, but I have laser heat tested all cylinders and there is no significant temperature difference as well as exhaust and intake manifold temperatures. I know this engine has been out of the car, for what I do not know, but maybe it was rebuilt and the head gaskets replaced with those you mentioned?

One thing I haven’t heard was if anyone noticed a big difference after installing an electric fan in front of the radiator?

I can see I’m getting a good airflow through the radiator for she will suck a nylon sheet into the grill at idle.
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I can’t be of too much help with your underlying issues, but to share my experiences (‘57, 312 engine):

1. My idle is about 600 RPM in park once it kicks down off of fast idle; about 500-550 in drive.

2. My car came with an auxiliary electric fan in front of the radiator. Because it came with the car, I don’t know what brand or design it is. Nor do I know what kind of thermostat I have. Once it’s warmed up to full operating temperature, my engine pegs right at 180 degrees without the electric fan running. Will usually go down to around 170-175 if continuously in motion for a long stretch; but in stop-and-go/regular city driving, it’s at 180 and stays there. This has held true so far in drives ranging from 15 minutes to 1.5 hours (I’ve never driven it longer than that) and in all ambient temperatures (well, all the temperatures I’ve actually driven in: so, high 80s in summer to, say, high 40s in the fall). In hot weather, it will go up to 190 once parked, as the engine “heat soaks.”

Running my electric fan will decrease the temperature around 6-8 degrees pretty consistently, again holding true so far regardless of ambient temperature.
 
Thanks for the info. This might be my last resort. My temp gauge is analogue and doesn't have temp numbers on it. I'll have to laser test the tank or hoses to get a true degree reading. I assume 190° would be at 85% up the scale and >200° at the gap to "H"?

I just get nervous in traffic or at a long light on a hot day, the temp needle starts creeping up towards the end the longer I sit there. Putting the car in neutral and bringing the rpm's up to 1000 doesn't seem to help either.
 
zeroroadkill said:
I’ve tried them all, no difference. I’ve even tried removing it, no difference. Some say rust around #3 water jacket can reduce water flow, not too sure about that, but I have laser heat tested all cylinders and there is no significant temperature difference as well as exhaust and intake manifold temperatures. I know this engine has been out of the car, for what I do not know, but maybe it was rebuilt and the head gaskets replaced with those you mentioned?

One thing I haven’t heard was if anyone noticed a big difference after installing an electric fan in front of the radiator?

I can see I’m getting a good airflow through the radiator for she will suck a nylon sheet into the grill at idle.
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If you have taken the thermostat out and the engine still runs at the same temps then you have a radiator problem, or restricted engine waterflow. with no thermostat in the car will run cold . if hoses are new and radiator is new you have took look at the engine for the problem after also scoping the radiator tubes top and bottom for any blockage, good luck../
 
zeroroadkill said:
Plus provide more water circulation since the stock wp spacer restricts flow at idle speeds. Some say there is little water flow under 800rpm’s? I put in a modified spacer, HO water pump, 6 blade fan, bigger radiator, high flow thermostat which helped some, but she still doesn’t like hot day idling! Thinking of a smaller WP pully?
Click to expand...
I have all of these improvements + the smaller WP pulley, but won't be put to the test until the engine is rebuilt. A quality aftermarket temperature gauge also recommended.
 
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