Re: tough one: overheating on the highway
[Re: smos001]
#1719507
01/03/15 11:41 AM
01/03/15 11:41 AM
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Joined: Feb 2005
Posts: 28,312 Cincinnati, Ohio
Challenger 1
Too Many Posts
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Too Many Posts
Joined: Feb 2005
Posts: 28,312
Cincinnati, Ohio
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Quote:
Might be leaning out as you press into the higher speeds. Does it miss at high cruise? faint lean miss? a lean miss also cause a slight hesitation as you press on the gas at a stop sign. You may have to rejet the carb a little.
Vacuum leak?
Do not discount the 2 guys who suggested this. I third this suggestion.
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Re: tough one: overheating on the highway
[Re: FASTBACK340]
#1719513
01/04/15 12:26 PM
01/04/15 12:26 PM
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Joined: Jan 2003
Posts: 1,381 Youngsville, NC
dem440c
OP
pro stock
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OP
pro stock
Joined: Jan 2003
Posts: 1,381
Youngsville, NC
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Quote:
I sure hope we find out what the cause is as the remedies are all over the map….
holy moly you aren't kidding... you guys have a LOT of great ideas. A lot of them I have tried already and I've been taking notes on some things to try that I haven't done yet.
- full length headers, 2-1/2" duals through Flowmasters exiting in front of the axle. I'm pretty confident there is no exhaust restriction.
- gonna try the idea to remove the fan and see what happens. Only problem there is I have to drive 25 minutes to get to a highway, guess I'll bring tools and see what happens.
- I haven't mapped the timing yet to see exactly what the distributor is doing as the RPMs increase, I can do that. It runs perfect so I haven't been thinking in that direction but it wouldn't hurt to see what it is doing.
- pulling freeze plugs is gonna be a sucky job but I agree that the symptoms would line up with that cause so it should be explored. Man, that is gonna take me a whole freakin' weekend to pull all that apart and then get new plugs back in... sigh
- changing the ignition module is easy, I have a box full of them. I'll try that just because it is quick and easy.
- someone mentioned air baffles, I have all the ones in place that cover the gap between the core support and the radiator. What else should be there?
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Re: tough one: overheating on the highway
[Re: dem440c]
#1719514
01/04/15 12:44 PM
01/04/15 12:44 PM
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Joined: May 2007
Posts: 952 Queens, N. Y.
FASTBACK340
super stock
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super stock
Joined: May 2007
Posts: 952
Queens, N. Y.
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Might be easier to pull the water pump and use a bora-scope and peek in through the timing chain cover openings first. Freeze plugs are a chore on an educated guess.
`68 Barracuda 340-S
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Re: tough one: overheating on the highway
[Re: FASTBACK340]
#1719515
01/04/15 02:02 PM
01/04/15 02:02 PM
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Joined: Nov 2003
Posts: 36,041 Lincoln Nebraska
RapidRobert
Circle Track
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Circle Track
Joined: Nov 2003
Posts: 36,041
Lincoln Nebraska
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that if you do not post the solution (when you find it) that there might be a cyberspace lynching . Recently a member lost his life cuz he DELETED his thread . On the timing, in your driveway just run it up to the same RPM you are at on the highway when it is getting hot & see what you get with your dialback or make some marks. 0.0632683" around the circumference is 1 degree on the dampener or can use the tab as a ruler. 2&1/4 (2.246") is 35.5 deg which should get you close to what you have tho the can will kick it higher above that
live every 24 hour block of time like it's your last day on earth
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Re: tough one: overheating on the highway
[Re: dem440c]
#1719516
01/04/15 03:41 PM
01/04/15 03:41 PM
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Joined: Jan 2003
Posts: 3,575 The Netherlands
BigBlockMopar
master
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master
Joined: Jan 2003
Posts: 3,575
The Netherlands
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Quote:
- someone mentioned air baffles, I have all the ones in place that cover the gap between the core support and the radiator. What else should be there?
I don't know what came stock on your car as I don't have any experience with these models. But if you're adventurous you could take a trip simply without the hood mounted and see if the issue remains.
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Re: tough one: overheating on the highway
[Re: RapidRobert]
#1719517
01/04/15 03:49 PM
01/04/15 03:49 PM
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Joined: Jan 2003
Posts: 727 Ottawa, ontario
dd340
super stock
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super stock
Joined: Jan 2003
Posts: 727
Ottawa, ontario
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Quote:
that if you do not post the solution (when you find it) that there might be a cyberspace lynching . Recently a member lost his life cuz he DELETED his thread . On the timing, in your driveway just run it up to the same RPM you are at on the highway when it is getting hot & see what you get with your dialback or make some marks. 0.0632683" around the circumference is 1 degree on the dampener or can use the tab as a ruler. 2&1/4 (2.246") is 35.5 deg which should get you close to what you have tho the can will kick it higher above that
This made me think of something, can you duplicate the overheating in 1st or 2nd gear if you hold it at the same rpm as you run at highway speeds? If the engine doesn't heat up in the lower gears this would seem to eliminate the water pump and pulley possibilities. I would be interested to know the results of that.
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Re: tough one: overheating on the highway
[Re: Rhinodart]
#1719519
01/04/15 04:40 PM
01/04/15 04:40 PM
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Joined: Jan 2003
Posts: 3,054 Bowling Green, KY
cudaboy
master
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master
Joined: Jan 2003
Posts: 3,054
Bowling Green, KY
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Quote:
I still have not read if you checked or replaced your cap...
Its in there. Changed twice.
Dennis
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Re: tough one: overheating on the highway
[Re: FASTBACK340]
#1719522
01/04/15 06:46 PM
01/04/15 06:46 PM
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Joined: Apr 2005
Posts: 4,924 new berlin wisconsin
Mr T2U
master
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master
Joined: Apr 2005
Posts: 4,924
new berlin wisconsin
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I am surprised no one mentioned weak fuel pump. if it cuts out at higher rpm's it can make it run lean. of course if it's lean at the top end it usually surges.
perception is 90% of reality
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Re: tough one: overheating on the highway
[Re: dem440c]
#1719524
01/04/15 08:16 PM
01/04/15 08:16 PM
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Joined: Jan 2003
Posts: 15,565 Omaha Ne
TJP
I Live Here
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I Live Here
Joined: Jan 2003
Posts: 15,565
Omaha Ne
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Quote:
Quote:
I sure hope we find out what the cause is as the remedies are all over the map….
holy moly you aren't kidding... you guys have a LOT of great ideas. A lot of them I have tried already and I've been taking notes on some things to try that I haven't done yet.
- full length headers, 2-1/2" duals through Flowmasters exiting in front of the axle. I'm pretty confident there is no exhaust restriction.
- gonna try the idea to remove the fan and see what happens. Only problem there is I have to drive 25 minutes to get to a highway, guess I'll bring tools and see what happens.
- I haven't mapped the timing yet to see exactly what the distributor is doing as the RPMs increase, I can do that. It runs perfect so I haven't been thinking in that direction but it wouldn't hurt to see what it is doing.
- pulling freeze plugs is gonna be a sucky job but I agree that the symptoms would line up with that cause so it should be explored. Man, that is gonna take me a whole freakin' weekend to pull all that apart and then get new plugs back in... sigh
- changing the ignition module is easy, I have a box full of them. I'll try that just because it is quick and easy.
- someone mentioned air baffles, I have all the ones in place that cover the gap between the core support and the radiator. What else should be there?
At this point I would 1. verify the timing 2. verify the pulley sizing 3. look at lean condition due to jetting or a vacuum leak. 4. pop a freeze plug
What intake / carb setup are you running ??
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