Intake manifold leak (1968)
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Joined: Jul 2010
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Intake manifold leak (1968)
Hello, I just built up my engine(327) with some new parts ... intake manifold, carb and everything that go's along with them... I just got my distributor put together and was trying to tune it. It is the first time it has been started since all the new part were added. During the tuning I noticed a little smoke from the rear wall .... so I looked and seen anti-freeze! So Im guessing I did not put enough compound on the back wall 
So I guess my question is can do anything to fix it without taking everything back off? Thank you all for your help
Adam
So I guess my question is can do anything to fix it without taking everything back off? Thank you all for your helpAdam
Last edited by capth4u; Oct 14, 2010 at 04:37 PM.
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Adam,
If your getting antifreeze from the back on the china wall, then you've got antifreeze in your oil. The china wall should never see antifreeze. It only sees oil. That's your first problem. Sounds like you don't have your intake torqued down to specs and coolant is leaking past the water jacket passage between the head and the intake. I would change the oil, re-torque all your intake bolts by manufacturer order and torque setting and try again. Good luck!
If your getting antifreeze from the back on the china wall, then you've got antifreeze in your oil. The china wall should never see antifreeze. It only sees oil. That's your first problem. Sounds like you don't have your intake torqued down to specs and coolant is leaking past the water jacket passage between the head and the intake. I would change the oil, re-torque all your intake bolts by manufacturer order and torque setting and try again. Good luck!
Thread Starter
Advanced
Joined: Jul 2010
Posts: 89
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Adam,
If your getting antifreeze from the back on the china wall, then you've got antifreeze in your oil. The china wall should never see antifreeze. It only sees oil. That's your first problem. Sounds like you don't have your intake torqued down to specs and coolant is leaking past the water jacket passage between the head and the intake. I would change the oil, re-torque all your intake bolts by manufacturer order and torque setting and try again. Good luck!
If your getting antifreeze from the back on the china wall, then you've got antifreeze in your oil. The china wall should never see antifreeze. It only sees oil. That's your first problem. Sounds like you don't have your intake torqued down to specs and coolant is leaking past the water jacket passage between the head and the intake. I would change the oil, re-torque all your intake bolts by manufacturer order and torque setting and try again. Good luck!
Melting Slicks
Joined: Apr 1999
Posts: 2,675
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From: Sudbury MA
I rebuilt my stock 1968 L79 327 motor .
Intake manifold bolts should be torqued to 30 foot lbs but you have to follow a certain sequence starting from the center of the manifold and working outward in a circle.
Threads should be CLEAN & DRY to get correct torque.
Kurt
Intake manifold bolts should be torqued to 30 foot lbs but you have to follow a certain sequence starting from the center of the manifold and working outward in a circle.
Threads should be CLEAN & DRY to get correct torque.
Kurt
Le Mans Master
Joined: Oct 2006
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From: Gladstone MO
C3 of Year Finalist (appearance mods) 2019
I would not try and salvage an intake gasket set that has already shown a leak. The $15-$20 for new gaskets seems cheap compared to fighting a recurrent leak.
I use a thin bead of 3M Weatherstrip Adhesive around the water jackets- just to hold the gaskets in place, and then a fat bead of RTV on the china walls. After wiping the whole thing down with alcohol to remove all traces of oil.
When you torque the intake, start in the center and work a circle to the ends- double check, but if IIRC, the torque is 25-35 ft-lbs.
I use a thin bead of 3M Weatherstrip Adhesive around the water jackets- just to hold the gaskets in place, and then a fat bead of RTV on the china walls. After wiping the whole thing down with alcohol to remove all traces of oil.
When you torque the intake, start in the center and work a circle to the ends- double check, but if IIRC, the torque is 25-35 ft-lbs.
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Joined: Apr 2009
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Adam,
TimAT is right. Do it over again, do it right and you will feel better about it and have no worries in the long term. I use Gasgacinch on my felpro 1207 intake manifold gaskets on my sbc early block on the head side only. I use the "Right Stuff" on the china walls. Don't know if you have vortec heads on that 327 or not so make sure you order the right intake manifold gasket for your application. You really really need to get the install instructions for your particular intake manifold. If it's an edelbrock aluminum their manuals are available for download. Even if you can't locate the manual for your particular application, the Edelbrock manuals are very informative. This is if you have an aluminum intake ONLY and not an iron intake. If you have an iron intake, just Google it. Tons of stuff for the sbc. Don't forget to torque wrench it, torque it again and follow up one more time just for good measure. The intake gasket compresses and you will need to follow up with a couple of retorques with a correctly set, quality torque wrench. Good luck.
TimAT is right. Do it over again, do it right and you will feel better about it and have no worries in the long term. I use Gasgacinch on my felpro 1207 intake manifold gaskets on my sbc early block on the head side only. I use the "Right Stuff" on the china walls. Don't know if you have vortec heads on that 327 or not so make sure you order the right intake manifold gasket for your application. You really really need to get the install instructions for your particular intake manifold. If it's an edelbrock aluminum their manuals are available for download. Even if you can't locate the manual for your particular application, the Edelbrock manuals are very informative. This is if you have an aluminum intake ONLY and not an iron intake. If you have an iron intake, just Google it. Tons of stuff for the sbc. Don't forget to torque wrench it, torque it again and follow up one more time just for good measure. The intake gasket compresses and you will need to follow up with a couple of retorques with a correctly set, quality torque wrench. Good luck.
