intake manifold end gasket
Thread Starter
Pro
Joined: Feb 2013
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intake manifold end gasket
I took off my intake manifold and cleaned and painted it. Stock L48. Not sure if I should use the end gaskets or use sealant. The end gaskets have raised areas that go into the holes on the front and rear of the block so I think they will stay in place as I have read that it is hard to get the rubber end seals to stay in place without causing leaks. If I go the route of using the sealer in place of the gaskets there are so many different types that I am lost. I have high temperature copper gasket sealer but I'm not sure that it is the best type to use. Should I use the gaskets? Use the sealer? What type of sealer if I go that route?
Tech Contributor
Joined: Aug 1999
Posts: 15,175
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From: Connecticut, USA
I have always used RTV on the "china walls". Years ago there were not as many types as today. I use Ultra Black or Grey. clean the surfaces with acetone, lay on about a 3/8 even bead, let it skin over before installing the intake. Skinning over the RTV will keep it in position and pliable to form to fill the gap while torqueing the bolts. Remember to put RTV around the side gasket water ports.
Le Mans Master
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From: North tonawanda NY
Le Mans Master
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From: Cool Northern Michigan
Nobody has used those end gaskets since the 1800s. Yes, 1800s, on SBC covered wagons.
I don't know why FelPro and others even bother putting those end pcs in the kit. Worthless.
You need to use the right stuff when sealing the china walls. What's the name of it? THE RIGHT STUFF. (made by Permatex)
It comes in different sizes / ounce applicators. Autozone, Summit, etc.
I don't know why FelPro and others even bother putting those end pcs in the kit. Worthless.
You need to use the right stuff when sealing the china walls. What's the name of it? THE RIGHT STUFF. (made by Permatex)
It comes in different sizes / ounce applicators. Autozone, Summit, etc.
Last edited by HeadsU.P.; Jul 26, 2019 at 09:09 AM.
Team Owner
Joined: Jan 2006
Posts: 37,637
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From: Crossville TN
If you only use sealant, clean all surfaces as described above, lay a good bead of it on the end rails, let set up for 10-15 minutes. Carefully set the intake in place and LOOSELY insert the bolts (just to keep it positioned properly). Let set that way overnight, then pull the bolts down in stages: 1/3 of rated torque; 2/3 of rated torque; 100% torque.
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Le Mans Master
Joined: Jan 2001
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I agree. Use THE RIGHT STUFF. (made by Permatex).... You don't have to wait 24 hours either. It's better than RTV.
Be ready to install the manifold after you lay it down. It is wonderful stuff.
Be ready to install the manifold after you lay it down. It is wonderful stuff.
Nobody has used those end gaskets since the 1800s. Yes, 1800s, on SBC covered wagons.
I don't know why FelPro and others even bother putting those end pcs in the kit. Worthless.
You need to use the right stuff when sealing the china walls. What's the name of it? THE RIGHT STUFF. (made by Permatex)
It comes in different sizes / ounce applicators. Autozone, Summit, etc.
I don't know why FelPro and others even bother putting those end pcs in the kit. Worthless.
You need to use the right stuff when sealing the china walls. What's the name of it? THE RIGHT STUFF. (made by Permatex)
It comes in different sizes / ounce applicators. Autozone, Summit, etc.
Safety Car
Joined: Nov 2005
Posts: 3,532
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From: Arizona - If you don’t know CFI, STOP proliferating the myths around it...
Nobody has used those end gaskets since the 1800s. Yes, 1800s, on SBC covered wagons.
I don't know why FelPro and others even bother putting those end pcs in the kit. Worthless.
You need to use the right stuff when sealing the china walls. What's the name of it? THE RIGHT STUFF. (made by Permatex)
It comes in different sizes / ounce applicators. Autozone, Summit, etc.
I don't know why FelPro and others even bother putting those end pcs in the kit. Worthless.
You need to use the right stuff when sealing the china walls. What's the name of it? THE RIGHT STUFF. (made by Permatex)
It comes in different sizes / ounce applicators. Autozone, Summit, etc.
Is the BEST stuff to use on the China rail hands down. BUT only use it on that, NOT on the intake flange gaskets or you WILL have a VERY hard time getting it back off if you decide to do that later.
Le Mans Master
Joined: Sep 2001
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From: Unreconstructed, South Carolina
Dr. Detroit
Joined: Mar 2012
Posts: 10,097
Likes: 4,027
From: New Braunfels Texas
Ditch those gaskets and get Fel-Pro 1204's.....this blocks off the heat riser......unless you are cold weather driving.....it is not needed......unless you HAVE to have the choke.
Blocking this lowers the intake temperature pretty dramatically as it prevents hot exhaust from passing through the intake.....
Put a bead around each water port as stated......this will hold the gasket in position......set the intake on and pay attention to how much gap you have at the ends....this will give you an idea of how much silicone to lay down.......how thick of a bead. I like to use the large tubes for a caulk gun....so much more control.
Jebby
Blocking this lowers the intake temperature pretty dramatically as it prevents hot exhaust from passing through the intake.....
Put a bead around each water port as stated......this will hold the gasket in position......set the intake on and pay attention to how much gap you have at the ends....this will give you an idea of how much silicone to lay down.......how thick of a bead. I like to use the large tubes for a caulk gun....so much more control.
Jebby
Thread Starter
Pro
Joined: Feb 2013
Posts: 572
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Well this thing went south on me. I was installing the manifold and everything was going good. Was on the last 30 lb torque setting and the front bolt on the right side started getting loose as I was tightening it. I tried a slightly longer bolt because the smog bracket is attached at that bolt figuring that maybe it wasn't grabbing the threads but no go. The bolt is not snapped. Now everything has to come off again and either the threads pulled out or the head is cracked.
Le Mans Master
Joined: Aug 2017
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From: Cool Northern Michigan
H-m-m-m-m-m-m-. Can't say "been there / done that".
Just for the heck of it, run a thread chaser down in the hole before you start tearing things apart. Front holes are blind holes I believe so no debris will enter in the lifter valley. How are the threads on the bolt?
Fortunately, intake gaskets are cheap enough if you pull the intake back off. But your labor is costly, right.
May have to install a thread insert repair and hope it holds in the soft aluminum heads.
Just for the heck of it, run a thread chaser down in the hole before you start tearing things apart. Front holes are blind holes I believe so no debris will enter in the lifter valley. How are the threads on the bolt?
Fortunately, intake gaskets are cheap enough if you pull the intake back off. But your labor is costly, right.
May have to install a thread insert repair and hope it holds in the soft aluminum heads.
Thread Starter
Pro
Joined: Feb 2013
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I'll try to chase the thread. I was worried about debris going down into the engine so I didn't try a tap.The heads are the original cast iron. I could repair the thread with an insert or maybe go for new heads which I've been contemplating for a long time.
Le Mans Master
Joined: Aug 2017
Posts: 8,336
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From: Cool Northern Michigan
Ok. Sorry, I just assume everyone has aluminum heads.
I don't believe you can use a longer bolt in the front or rear holes because they are pocket holes. The bolt would bottom out.
I think there might be even better repair products than Helicoil now days. Perhaps someone will chime in. But, like you say, the intake will have to come off, again.
I don't believe you can use a longer bolt in the front or rear holes because they are pocket holes. The bolt would bottom out.
I think there might be even better repair products than Helicoil now days. Perhaps someone will chime in. But, like you say, the intake will have to come off, again.
Thread Starter
Pro
Joined: Feb 2013
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I ran the tap in the hole. The threads felt good all the way to the bottom. Tried a new bolt and the same thing happened. I tried a longer bolt and it held good. I think the bolt was too short since I added the smog pump bracket. I think there was not enough thread grabbing the threads in the hole. I'll take it out tomorrow and measure the depth to be sure it is not bottoming out. Thanks for the help.