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Old 07-18-2012, 11:26 AM   #1
dan
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Default Exhaust/Intake leak(s)

I asked this on the HAMB, but since it's about an almost-stock car I haven't received any replies. This 1931 coupe is my daily driver/commuter car, which I put between 500 and 600 miles a month on.

The car has a set of Reds headers and a Weber carb on a cast aluminum intake manifold on the otherwise stock motor. I keep getting exhaust/intake leaks that I can't seem to permanently cure.

I've replaced both sets of gaskets and torqued the manifold nuts to 30 ft/lbs and everything's fine for a couple hundred miles or so, but then the leak comes back and I get acceleration/deceleration popping again.

Things I've tried:
- Permatex copper spray on the gaskets
- Switching between the copper vs. steel gaskets

Still no joy.

My sort-of guess is that the weight of the Weber, cast al intake, and headers is too much for the manifold studs/nuts to hold and that I need to do something to hang more of that weight off the frame...

Any advice from someone with a similar setup?
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Old 07-18-2012, 11:46 AM   #2
fordfixer
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Default Re: Exhaust/Intake leak(s)

The original exhaust and intake, with carb, I'm sure weights more than what you have on there now. It sounds to me like your not tighting them enough. I would re torque several times.
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Old 07-18-2012, 11:49 AM   #3
dan
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Default Re: Exhaust/Intake leak(s)

Quote:
Originally Posted by fordfixer View Post
The original exhaust and intake, with carb, I'm sure weights more than what you have on there now. It sounds to me like your not tighting them enough. I would re torque several times.
Thanks. Do you think I should go higher than 30 ft/lbs? I'm afraid I'm going to pull the studs out if I really crank it (to say 50)
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Old 07-18-2012, 12:09 PM   #4
Bob C
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Default Re: Exhaust/Intake leak(s)

You are probably doing it wrong, check out the video that [email protected] posted.
http://www.fordbarn.com/forum/showthread.php?t=77141

Bob
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Old 07-18-2012, 04:10 PM   #5
Duffy1
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Default Re: Exhaust/Intake leak(s)

May need to mill the manifolds to make sure they are flat .
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Old 07-18-2012, 05:28 PM   #6
fordfixer
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Default Re: Exhaust/Intake leak(s)

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No, you won't pull the studs out at 50 #. They are basically the same as the head studs and they go much higher than 30 #.
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Old 07-18-2012, 10:33 PM   #7
mass A man
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Default Re: Exhaust/Intake leak(s)

Dan, are you using the old style thick, concave manifold washers? Are you certain you're getting an even amount of torque to all points of the manifolds? I may have mis- understood something with the modified set-up you have, I can't quite picture it since I only run stock A's. No big deal.
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Old 07-18-2012, 10:58 PM   #8
Russ/40
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Default Re: Exhaust/Intake leak(s)

In my opinion you are not tightening enough. Go the 50 ft lbs. Like ford fixer said, they are the same size studs as the head.
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Old 07-19-2012, 12:46 AM   #9
BILL WILLIAMSON
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Default Re: Exhaust/Intake leak(s)

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Originally Posted by Russ/40 View Post
In my opinion you are not tightening enough. Go the 50 ft lbs. Like ford fixer said, they are the same size studs as the head.
Russ,
When I post that I ALWAYS torque mine to 55 ft lbs, folks come out of he woodwork & YELL at me.
After 3 re-torques, mine never leaks & never loosens up!-----But what do I know?? Bill W.
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Old 07-19-2012, 12:51 AM   #10
Brentwood Bob
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Default Re: Exhaust/Intake leak(s)

Try double gaskets and 55 lbs. That is what i have seen used for your setup. Bob
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