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Idle RPM
- Thread starter BOBBYR
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Most factory specs call for around 500 rpm.
I think you normally want it to idle fast enough to keep the generator charging. This usually comes out to be more like 700 rpm.
If the only problem is off idle hesitation the problem is more likely slightly retarded ignition timing, or you need a little heavier oil in the dashpot dampers, or the idle mixture is a bit too lean.
D
I think you normally want it to idle fast enough to keep the generator charging. This usually comes out to be more like 700 rpm.
If the only problem is off idle hesitation the problem is more likely slightly retarded ignition timing, or you need a little heavier oil in the dashpot dampers, or the idle mixture is a bit too lean.
D
bob hughes
Luke Skywalker
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Hey Bobby
I have the same problem, I think that it should be set around 700 but I place it at 1000 and sometimes it falls away with time. I know the carbs may need an averhaul and the engine has a real bad carbon foot print - needs a re bore, so I have put down my problems to those two things.
Bob
I have the same problem, I think that it should be set around 700 but I place it at 1000 and sometimes it falls away with time. I know the carbs may need an averhaul and the engine has a real bad carbon foot print - needs a re bore, so I have put down my problems to those two things.
Bob
OP
BOBBYR
Jedi Trainee
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Hi Guys,
I appreciate your response.I think Andy may be on to something.The tach in my healey,I would think,is not accurate.While I was driving the other day, the tach was up to 5000 rpm's and it felt like I could go alot further with that gear.I guess it's time to get these gauges rebuilt.
Thank for your help,
Bobby R
I appreciate your response.I think Andy may be on to something.The tach in my healey,I would think,is not accurate.While I was driving the other day, the tach was up to 5000 rpm's and it felt like I could go alot further with that gear.I guess it's time to get these gauges rebuilt.
Thank for your help,
Bobby R
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I like to adjust the idle with taped paper across the tach. I adjust it when the light goes out and a scosh more.
Don't throw away the tach though because it's a good 60's car period piece and a mount for the gen. warning light.
Patrick
Don't throw away the tach though because it's a good 60's car period piece and a mount for the gen. warning light.
Patrick
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I wouldn't worry about it too much, these cars vary their idle speed, usually going up a little bit as the combustion chamber and oil warm up, then going back down a bit as the ambient air temp under the hood rises.
If it wont idle well until you set it at over 1000 or 1200 you probably have other issues, but anything below 1000 or in that ballpark, as long as it runs fairly smooth and doesn't stall.
If it wont idle well until you set it at over 1000 or 1200 you probably have other issues, but anything below 1000 or in that ballpark, as long as it runs fairly smooth and doesn't stall.
HealeyBN7
Senior Member
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glemon said:
Do you have any suggestions for managing this variation. I have a near fresh 3000 with a mild cam, lightened flywheel and in good tune. I shoot for around 900 RPMs at idle, but when it is dry and the ambient air temperature rises above 95 degrees the idle drops considerably. If it is over 100 degrees it might stall. A little choke seems to help which tells me that it is too lean, yet at normal temps it runs great.
Thanks in advance!
Dean (HealeyBN7)
healeys4me
Senior Member
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Dean, my BJ8 is like yours. Depends on the weather if it idles at 600 or 800 rpm. I do run a little lean with no negative effect at speed..
John
John
Ed_K
Jedi Knight
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I am glad to hear that I am not the only one with the problem of the idle getting very low and wanting to cut off on very hot days in the 90s or after a long stop at a traffic light.
I have it adjusted perfect for 80 degree days and if it is hotter than that outside, it idles lower and lower as the temp rises. At one time I had it adjusted perfect for 90 degree days but then it idles at 1100 RPMs or more on days when the temp is in the 70s.
I guess the only way to cure this problem is to build some kind of cold air induction piping to the carbs with the inlet very low in the engine bay or perhaps from in front of the radiator air dam ? Perhaps a louvered hood would cure some of this ? Yesterday it was above 90 here and I had to use the emergency brake at all stop lights so I could keep my toe on the gas pedal. I don't use my choke to overcome this as mine currently doesn't lock in place and it really stinks when running it rich to overcome hot idle difficulty at a stop light !
I wonder if a layer of Thermotec heat insulation on top of the layer of asbestos on the carb heat shield would help this problem ?
Ed
I have it adjusted perfect for 80 degree days and if it is hotter than that outside, it idles lower and lower as the temp rises. At one time I had it adjusted perfect for 90 degree days but then it idles at 1100 RPMs or more on days when the temp is in the 70s.
I guess the only way to cure this problem is to build some kind of cold air induction piping to the carbs with the inlet very low in the engine bay or perhaps from in front of the radiator air dam ? Perhaps a louvered hood would cure some of this ? Yesterday it was above 90 here and I had to use the emergency brake at all stop lights so I could keep my toe on the gas pedal. I don't use my choke to overcome this as mine currently doesn't lock in place and it really stinks when running it rich to overcome hot idle difficulty at a stop light !
I wonder if a layer of Thermotec heat insulation on top of the layer of asbestos on the carb heat shield would help this problem ?
Ed