Installed new carb, now overheating
Thread Starter
Cruising
Joined: Apr 2005
Posts: 13
Likes: 0
Installed new carb, now overheating
HELP!
I replaced thecarb yesterday with a Holley 1850C carb. It ran good afterwards (327 engine.) Now today after we found a vacuum gauge I was adjusting the idle by following the directions (hook up a gauge and adjust to max vacuum.) It was running for maybe 10 minutes. I had increased the vacuum from 12.5 to between 14.5 and 15 inches. The tach showed an increase from 9700 to 12000. Then it overheated. Shot anti freeze out the overflow and temp gauge jumped to 250. We have replaced the water pump and thermostat over the last coulple weeks. I do not beleive it is a problem with the cooling system.Can't call Holley tech today. Anyone know the approx. preset of the idle mix screws? And any idea's if overheating was caused by my seting idle?
thanx.
I replaced thecarb yesterday with a Holley 1850C carb. It ran good afterwards (327 engine.) Now today after we found a vacuum gauge I was adjusting the idle by following the directions (hook up a gauge and adjust to max vacuum.) It was running for maybe 10 minutes. I had increased the vacuum from 12.5 to between 14.5 and 15 inches. The tach showed an increase from 9700 to 12000. Then it overheated. Shot anti freeze out the overflow and temp gauge jumped to 250. We have replaced the water pump and thermostat over the last coulple weeks. I do not beleive it is a problem with the cooling system.Can't call Holley tech today. Anyone know the approx. preset of the idle mix screws? And any idea's if overheating was caused by my seting idle?
thanx.
Drifting
Joined: Sep 2004
Posts: 1,959
Likes: 1
From: North Bend Ohio
Originally Posted by 3cargm
HELP!
I replaced thecarb yesterday with a Holley 1850C carb. It ran good afterwards (327 engine.) Now today after we found a vacuum gauge I was adjusting the idle by following the directions (hook up a gauge and adjust to max vacuum.) It was running for maybe 10 minutes. I had increased the vacuum from 12.5 to between 14.5 and 15 inches. The tach showed an increase from 9700 to 12000. Then it overheated. Shot anti freeze out the overflow and temp gauge jumped to 250. We have replaced the water pump and thermostat over the last coulple weeks. I do not beleive it is a problem with the cooling system.Can't call Holley tech today. Anyone know the approx. preset of the idle mix screws? And any idea's if overheating was caused by my seting idle?
thanx.
I replaced thecarb yesterday with a Holley 1850C carb. It ran good afterwards (327 engine.) Now today after we found a vacuum gauge I was adjusting the idle by following the directions (hook up a gauge and adjust to max vacuum.) It was running for maybe 10 minutes. I had increased the vacuum from 12.5 to between 14.5 and 15 inches. The tach showed an increase from 9700 to 12000. Then it overheated. Shot anti freeze out the overflow and temp gauge jumped to 250. We have replaced the water pump and thermostat over the last coulple weeks. I do not beleive it is a problem with the cooling system.Can't call Holley tech today. Anyone know the approx. preset of the idle mix screws? And any idea's if overheating was caused by my seting idle?
thanx.
You may have made the idle too lean. How is the timing set? Retarded timing will make them run hot. Do you have a speed sensing clutch on the fan? The increase in idle speed may have unlocked it.
BigBlockk
Later.....
Thread Starter
Cruising
Joined: Apr 2005
Posts: 13
Likes: 0
Water pump was replaced about four weeks ago and it has been run plenty since then.
But I did go back out after it cooled and reset the idle screws to where they were. I did turn the distributor counter clockwise a very tad bit. Seems to make it run a bit smoother. And now i do not have an overheating problem. Vacuum guage reads 12 inches agian and idles at 10 greand. Is this normal for a 327?
But I did go back out after it cooled and reset the idle screws to where they were. I did turn the distributor counter clockwise a very tad bit. Seems to make it run a bit smoother. And now i do not have an overheating problem. Vacuum guage reads 12 inches agian and idles at 10 greand. Is this normal for a 327?
Team Owner
Joined: May 2001
Posts: 29,745
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From: Exiled to Richmond, VA - Finally sold my house in Murfreesboro, TN ?? Corner of "Bumf*&k and 'You've got a purdy mouth'."
CI 6-7-8 Veteran
CI-VIII Burnout Champ
St. Jude Donor '06-'10, '13
make sure to go back and set your idle mixture as you did before. Turn the idle speed down to around 900 RPM. Then set you timing to about 10 degrees with the vacuum advance disconnected. Reconnect the vacuum advance and make sure that the timing has not changed, as you should not be getting a vacuum signal at this low of an RPM if you have it hooked up correctly. It should not be overheating if all is set correctly.
Melting Slicks
Joined: Apr 1999
Posts: 2,675
Likes: 13
From: Sudbury MA
What year and horsepower 327 do you have? Is it manual or automatic transmission? My 327 ( with 350 horsepower and standard transmission) calls for an idle speed of 750rpm and I just checked several motor manuals and most of the small blocks I saw also had idle speeds ranging from 600rpm to 750rpm; why is yours so high?
Last edited by ksbunting; Jun 12, 2005 at 06:32 PM. Reason: spelling
Le Mans Master
Joined: Oct 2002
Posts: 5,714
Likes: 6
From: Silver City NM
St. Jude Donor '05-'07
Originally Posted by BigBlockk
If it's really idling that fast I would say that's your problem. What's your secret for keeping the bottom end together at that speed?
BigBlockk
Later.....
BigBlockk
Later.....
See...I KNEW smallblocks could be revved up HIGH!!!!! I dunno...12000...he may be in the F1 range with that!!!!!
Dep
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Melting Slicks
Joined: Jan 2005
Posts: 3,028
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From: Madison Ms
Originally Posted by DJ Dep
See...I KNEW smallblocks could be revved up HIGH!!!!! I dunno...12000...he may be in the F1 range with that!!!!!
Dep
Le Mans Master
Joined: Jan 2003
Posts: 6,575
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From: Tuttle OK
Cruise-In VIII Veteran
Originally Posted by MsVetteMan
Always a smart **** in the group, he just seems to be appearing alot lately however.
Melting Slicks
Joined: Jan 2004
Posts: 2,672
Likes: 1
From: New Cumberland PA
Originally Posted by DJ Dep
See...I KNEW smallblocks could be revved up HIGH!!!!! I dunno...12000...he may be in the F1 range with that!!!!!
Dep
Le Mans Master
Joined: Oct 2002
Posts: 5,714
Likes: 6
From: Silver City NM
St. Jude Donor '05-'07
Originally Posted by Avette4me
looked to me like dep was just laughin at some elses joke...(both he and bigblok were just kidding, IMO)
Dep
Racer
Joined: Dec 2003
Posts: 304
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From: Pasadena Maryland
check for vacuum leaks. This will cause the engine to idle high. I'm having the same problem with a 327 in my son's T-Bucket. Won't idle below 1100 rpm. narrowed it down to a vacuum leak on the intake manifold where it mates to the head runners. Seams they require a special manifold to seat properly. Although the cam could be some of our problem too. It's a Comp Extreme with a 274/286 Duration with a .487/.490 lift with a tunnel ram and three dueces on top of it. It's been a nightmare trying to get this thing to run right. Taking off the aluminum heads and putting on a fresh set of Double Hump Camel heads when they get here this week.
