french locks question
Thread Starter
Racer
Joined: Jun 2005
Posts: 377
Likes: 3
From: N. Tonawanda NY
french locks question
I am restoring a '72 big block coupe and don't know if french locks are used on this engine exhaust manifolds because of the smog system. can anyone answer this for me. thanks..
Thread Starter
Racer
Joined: Jun 2005
Posts: 377
Likes: 3
From: N. Tonawanda NY
french locks
i have them on my big block 66, but they will not fit on the 454 with the smog tubing. My question is: are french locks used on big block cars with smog systems. I have not seen anything advertised in the vendors' catalogs to descriminate.
Last edited by MAGRED02; Apr 7, 2010 at 12:51 PM. Reason: fix typo
Team Owner
Joined: Jan 2006
Posts: 37,637
Likes: 3,116
From: Crossville TN
If the exhaust manifold bolts already have lock washers on them because of holding other equipment on the engine, you don't need french-locks. You do need some form of locking system on the manifold bolts, because of the heating-cooling cycle they experience and the vibration level they see. French-locks or lock-wire are a more reliable method to lock them in place...but a split lock-washer will probably suffice.
Thread Starter
Racer
Joined: Jun 2005
Posts: 377
Likes: 3
From: N. Tonawanda NY
french locks
sorry, i didn't make myself clear enough. i am putting together a car for Top flight judging and I am looking for what is "Correct" as originally left the factory. Does anybody out there have an original big block 72 with smog tubing intact that can post some pics?????
thanks.
thanks.
Burning Brakes
Joined: Mar 2006
Posts: 915
Likes: 2
From: Lima, OH -- 69 L71 427/435hp
Be sure to get the steel french locks, many of the aftermarket ones are aluminum or some thin cheap *** metal. I used them on my halfshafts, and even with never sieze under the head of the bolt and where it contacts the french lock, they still twisted up like a soft pretzel...waste of money and junk. 
I got a good set off a forum member here, not sure where he get's them (or if he still has more), but they were night and day difference than the aftermarket junk I initially bought.
Just a heads up.
I got a good set off a forum member here, not sure where he get's them (or if he still has more), but they were night and day difference than the aftermarket junk I initially bought.
Just a heads up.
Team Owner
Joined: Feb 2003
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From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
sorry, i didn't make myself clear enough. i am putting together a car for Top flight judging and I am looking for what is "Correct" as originally left the factory. Does anybody out there have an original big block 72 with smog tubing intact that can post some pics?????
thanks.
thanks.
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Team Owner
Joined: Sep 2006
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From: Westminster Maryland
Hi M2,
The info I have indicates for 454 engines:
No locks on 454 engines in 1970.
Intermittent use of locks on 454 engines in 1971.
All 454 engines used locks in 1972.
I don't think the AIM could/would show the locks because the engines arrived in St. Louis with the exhaust manifolds already installed. ( I know you knew that Keith!)
Regards,
Alan
The info I have indicates for 454 engines:
No locks on 454 engines in 1970.
Intermittent use of locks on 454 engines in 1971.
All 454 engines used locks in 1972.
I don't think the AIM could/would show the locks because the engines arrived in St. Louis with the exhaust manifolds already installed. ( I know you knew that Keith!)
Regards,
Alan
Last edited by Alan 71; Apr 7, 2010 at 07:11 PM.
Burning Brakes
Joined: Jun 2003
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From: Apple Valley Minnesota
Team Owner
Joined: Jan 2006
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From: Crossville TN
You are correct that the car assembly plant AIM will not show the detail on the engine, since it was purchased as a completed sub-assembly from another GM division. I do not know if the engine factories had a similar document that you could use for reference. Clearly, if you want to apply for NCRS awards, you need to use NCRS documentation to configure your car/components. That's what they will be using to judge your car, so you should use it to dress it properly.
Team Owner
Joined: Feb 2003
Posts: 54,056
Likes: 9,393
From: Sitting in his Nowhere land Hanover Pa
2024 C2 of the Year Finalist - Unmodified
2015 C2 of Year Finalist
You are correct that the car assembly plant AIM will not show the detail on the engine, since it was purchased as a completed sub-assembly from another GM division. I do not know if the engine factories had a similar document that you could use for reference. Clearly, if you want to apply for NCRS awards, you need to use NCRS documentation to configure your car/components. That's what they will be using to judge your car, so you should use it to dress it properly.
Team Owner
Joined: Sep 2006
Posts: 31,213
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From: Westminster Maryland
Hi Keith,
Yes, the AIR equipment was put on the engine at St. Louis, but I still believe the exhaust manifolds were installed at Flint and Tonawanda. The engine plant knew what engine they were building so they knew what manifolds to install... with or without the tapped holes for the AIR pipes.
That's what I believe.
Regards,
Alan
PS: If the manifolds weren't on the engine at Tonawanda the issue of some orange paint on BB manifolds wouldn't exist. At Flint the SB engines were painted with the manifolds off.
Yes, the AIR equipment was put on the engine at St. Louis, but I still believe the exhaust manifolds were installed at Flint and Tonawanda. The engine plant knew what engine they were building so they knew what manifolds to install... with or without the tapped holes for the AIR pipes.
That's what I believe.
Regards,
Alan
PS: If the manifolds weren't on the engine at Tonawanda the issue of some orange paint on BB manifolds wouldn't exist. At Flint the SB engines were painted with the manifolds off.
Drifting
Joined: Aug 2003
Posts: 1,327
Likes: 16
From: Fl
Hey guys ---
My 72 came from the 1st owner - engine never touched.
There were no locks on the outer ends at all.
The bolts were never broken, had rust and all.. matched the rust on the manifolds.
My car is an A/C car, maybe that makes a difference.
My 72 came from the 1st owner - engine never touched.
There were no locks on the outer ends at all.
The bolts were never broken, had rust and all.. matched the rust on the manifolds.
My car is an A/C car, maybe that makes a difference.
Safety Car
Joined: Dec 1999
Posts: 3,598
Likes: 837
From: PA
Production variation.
The NCRS TIM&JG states exactly what Alan posted.
The reality is that French locks were used intermittantly during the 1970-1972 period. Yes, there seem to be more engines with exhaust manifold french locks that show up in late 1971 and 1972, but we have also found original cars during that time period that obviously did not have them installed.
What I would look for (if I was still actively judging the mechanical section) is either steel french locks on the outer manifold ports with hex head bolts at all locations OR no french locks, but with special shouldered bolts on the outermost ports and regular hex bolts on the inner ports.
Not to say that is what the current judges will do, but if asked for my opinion, those are my thoughts.
I must be slipping...
Regards,
Stan Falenski
The NCRS TIM&JG states exactly what Alan posted.
The reality is that French locks were used intermittantly during the 1970-1972 period. Yes, there seem to be more engines with exhaust manifold french locks that show up in late 1971 and 1972, but we have also found original cars during that time period that obviously did not have them installed.
What I would look for (if I was still actively judging the mechanical section) is either steel french locks on the outer manifold ports with hex head bolts at all locations OR no french locks, but with special shouldered bolts on the outermost ports and regular hex bolts on the inner ports.
Not to say that is what the current judges will do, but if asked for my opinion, those are my thoughts.
I must be slipping...
Regards,
Stan Falenski
Thread Starter
Racer
Joined: Jun 2005
Posts: 377
Likes: 3
From: N. Tonawanda NY
French locks
Thanks for all the help guys. I guess I will have to find an original car with big block and smog system to see what it has. The big block french locks that I bought DO NOT fit with the smog system tubing. that is why I am thinking they did not use french locks on b/b cars that have the smog system on them.
