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Old 10-17-2019, 06:19 PM   #1
dmjlambert
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French locks for exhaust manifolds

Who uses french locks on their exhaust manifolds? Any opinions on them? Supposedly they allow the outer bolts to have less torque and the manifold will be less prone to cracking. Some discussion of them here:
https://www.camaros.net/forums/18-en...all-bolts.html
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Old 10-17-2019, 07:29 PM   #2
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Re: French locks for exhaust manifolds

They are mandatory of you want the manifolds to be leak and trouble free. Dont use manifold gaskets with them either. Usually the manifold needs to be surfaced for a tight seal.
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Old 10-17-2019, 09:27 PM   #3
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Thumbs up Re: French locks for exhaust manifolds

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They are mandatory of you want the manifolds to be leak and trouble free. Dont use manifold gaskets with them either. Usually the manifold needs to be surfaced for a tight seal.
They where factory installed on all the Ram horns I have ever seen. X2 on not using a gasket on them too!
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Old 10-17-2019, 09:46 PM   #4
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Re: French locks for exhaust manifolds

I have them on my truck, primarily because they were original to the truck. However, they should eliminate the possibility of the bolts loosening.
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Old 10-17-2019, 10:02 PM   #5
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Re: French locks for exhaust manifolds

I use them but I never knew they were called French locks.
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Old 10-17-2019, 10:08 PM   #6
rechinca
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Re: French locks for exhaust manifolds

There were still on mine, had manifolds resurfaced and threw out the stupid gaskets. Reinstalled the French Locks after.
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Old 10-18-2019, 10:18 AM   #7
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Re: French locks for exhaust manifolds

Those are a good idea, most just rip em off when installing new gaskets or working on the exhaust.

I have gaskets on mine, no locks, no issues, Mileage and opinion will vary. Oh I go thru and tighten them about every 6 months, needed or not.
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Old 10-18-2019, 10:35 AM   #8
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Re: French locks for exhaust manifolds

Do you torque the middle bolts to 30-35 ftlb and end-pairs to 15-20 ftlb, to reduce cracking of the exhaust manifold? That is supposedly what the french locks allow you to do.
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Old 10-18-2019, 01:00 PM   #9
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Re: French locks for exhaust manifolds

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I use them but I never knew they were called French locks.
x2, thats why I opened this thread, I have them on my jimmy and just use copper coat on the block and manifold

curious as to the torque numbers
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