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Author
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Topic: Motor running hot (Please Help)
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Tommy
Journeyman Posts: 59
From: loretto,tn 38469
Registered: May 2003
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posted 09-16-2003 09:55 PM
   
I have a new motor in the car and #7 & #8 header pipes are trying to turn red.Heck I have tried everything I know.Called Demon today about the carb.I had the timing set at 6 degrees idling and the mixture screws at 1 1/4 out,and evently worked them out to 2 1/2 turns in 1/4 turn intervals.The tech guy at Demon said my problem was the mixture screws were out to far,3/4 turns out he recommended and to set the timing at 16 to 18 degrees at idle.He also said the problem with the pipes turning could be to lean and also could be to rich.I understand the lean part ,but to rich?Someone PLEASE HELP.Don't have a clue.I have a 351W,Edelbrock Performer RPM Heads,Air gap intake,10 to 1 forged pistons,650 Speed Demon Carb,Mallory distributor & coil.Float level is half way in sight window with 7.5 fuel pressure.TOMMY
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Buster
Gearhead Posts: 1437
From: Hurricane alley
Registered: May 2002
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posted 09-16-2003 10:44 PM
Don't go by turns out for the carb.....use your ears!
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kid vishus
Gearhead Posts: 6098
From: middle of NC
Registered: Oct 2000
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posted 09-17-2003 07:55 AM
First of all, there is a reason a lot of respected speed shops stopped carrying Demon carbs.That being said, if it is WAAAY too rich, it could be turning the pipes red from burning excess fuel in the pipes after it leaves the head.
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V8 Thumper
Gearhead Posts: 4377
From: Arizona
Registered: Dec 2001
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posted 09-17-2003 07:56 AM
What head gaskets did you use? What is the steam hole pattern on those RPM heads, early or late?------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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Tommy
Journeyman Posts: 59
From: loretto,tn 38469
Registered: May 2003
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posted 09-17-2003 11:23 PM
Ipulled the plugs and all look the same.They are a little black ,like running rich.I got the distributor set tonight and set the mechanical advance to 34 degrees and idle at 16 degrees.If you get to much lower at idle the motor sounds lazy.Let the motor run for a few minutes and couldn't tell any difference in the pipes by the eye.Checked the heats on the pipes with a info red pierameter and the rear was about 125 to 150 degrees hotter.The heads are the edelbrock performer 5.0 & 5.8 for the late model.And I am using the fel pro gaskets.The smog ports have been blocked of.Edelbrock said they were the same as the performer rpm except for the smog ports and they use the pedestal mount rockers.I don't no about the steam hole pattern????But the only cylinders trying to turn is #7 & #8.If it had something to do with the steam hole pattern wouldn't it also try to do the same thing on #3 & #4 cylinders?Also checked the compression on the cyclinders and they were all the same.We thought we might have a valve not fully seating.I think my problem is it is just to rich.I am going to haul it tomorrow and get the exhaust put on it.The motor sounds good,very responsive,it's just the turning of the pipes,if it had factory exhaust manifolds on it you wouldn't know anything was wrong.Someone let me know about the steam ports,this is new to me.THANKS TOMMY
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V8 Thumper
Gearhead Posts: 4377
From: Arizona
Registered: Dec 2001
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posted 09-18-2003 09:03 PM
On early blocks & heads, the steam hole is straight up or 12 o'clock in relation to the cylinder bore. On later models, they're at about 1:30 or 2. If your gasket steam hole embossment does not align with the steam holes in both the heads and block, it'll form an air pocket at the back.
I'm not saying for sure this is the problem, just a possibility. It might be worth looking into.------------------
1965 GT coupe, 333ci aluminum headed/solid cammed stroker, four speed, 3.70:1 9" All Blue Oval, no blue bottle
http://mustangsandmore.50megs.com/V8Thumper.html
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Tommy
Journeyman Posts: 59
From: loretto,tn 38469
Registered: May 2003
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posted 09-18-2003 09:29 PM
I went back by the machine shop and asked about the steam hole pattern.He said he checked that and assured me they were fine.Had the exhaust installed today.When the car is running you can smell the gas fumes.It is running really rich.We think what it is doing is burning the unused gas outside the head.The headers didn't turn while it was running today.Had the 40 series Flowmasters installed and car sounds very good.Temp barely moved off of 160 degrees on the gauge.Thanks for everybody's input.TOMMY
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