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Sealing intake bolts

Old 01-11-2019, 03:32 PM
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DB Cooper
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Default Sealing intake bolts

Quick question. I've got a little oil seeping around a couple intake bolts; and since I'm pulling the carb to insert a heat shield anyway, I figured it's a good time to seal up those intake bolts.

Should I pull them all, and re-torque as if I were reinstalling the manifold ? Or pull one at a time, re-torque, pull the next, etc?

Last edited by DB Cooper; 01-11-2019 at 03:33 PM.
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Old 01-11-2019, 03:55 PM
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Originally Posted by DB Cooper View Post
Quick question. I've got a little oil seeping around a couple intake bolts; and since I'm pulling the carb to insert a heat shield anyway, I figured it's a good time to seal up those intake bolts.

Should I pull them all, and re-torque as if I were reinstalling the manifold ? Or pull one at a time, re-torque, pull the next, etc?
One at a time is fine. I used teflon pipe dope.
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Old 01-11-2019, 04:13 PM
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gkull
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First of all those so called heat shields are a gimmick and don't work. A week ago or so someone posted some thermal images. Because aluminum conducts heat. The whole intake manifold is basically the same temp. and the carb is much cooler because of the incoming air and fuel. It also shows what I've said for years about the fallacy of air gap manifolds to actually have any noticeable temperature differential at the carb base because of the conductivity of heat through aluminum. Also the A/F temperature change because of the tiny amount of time from the throttle plates to the intake valve. Cold air intake tracks and carb thermal spacers actually work.

Thermal wood 4 hole 1/2 inch spacers under the carb will actually stop fuel from boiling in the bowls!

As to oil around intake manifold bolts. I would tend to say that you have an intake gasket sealing problem. You could attempt to pull and clean them one at a time and then put sealant on the threads and reinstall them
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Old 01-11-2019, 04:19 PM
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try ''ARP'' thread lube-sealent,,

but first wash out the threaded holes with carb/brake cleaner and an air hose
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Old 01-11-2019, 04:51 PM
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DB Cooper
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Originally Posted by gkull View Post
First of all those so called heat shields are a gimmick and don't work. A week ago or so someone posted some thermal images. Because aluminum conducts heat. The whole intake manifold is basically the same temp. and the carb is much cooler because of the incoming air and fuel. It also shows what I've said for years about the fallacy of air gap manifolds to actually have any noticeable temperature differential at the carb base because of the conductivity of heat through aluminum. Also the A/F temperature change because of the tiny amount of time from the throttle plates to the intake valve. Cold air intake tracks and carb thermal spacers actually work.

Thermal wood 4 hole 1/2 inch spacers under the carb will actually stop fuel from boiling in the bowls!

As to oil around intake manifold bolts. I would tend to say that you have an intake gasket sealing problem. You could attempt to pull and clean them one at a time and then put sealant on the threads and reinstall them
The 'heat shield' I referred to is a 1/2in phenolic spacer. I completely agree anything aluminum you put between the carb and intake is just going to conduct heat straight through.

Thanks!
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Old 01-11-2019, 04:53 PM
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Thanks for the other replies too. I was guessing I'd be ok to do one at a time, but why assume when there's an experience base to ask?
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Old 01-11-2019, 04:56 PM
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Pull the intake. Clean and paint the intake and replace the gasket. Valve covers too. The whole top-end will look a lot better. The
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Old 01-11-2019, 06:14 PM
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resdoggie
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Don't forget to drain off some coolant.
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Old 01-11-2019, 06:15 PM
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Some of the intake bolt holes in the block are open at the base so if you don't use sealer you will have oil wicking up the bolt and just enough seepage to make it look bad. Your plan to do the bolts one at a time is the right one with sealer on the bolts. Intake manifold gaskets do not seal against the bolts and have nothing to do with oil seepage.

Last edited by CanadaGrant; 01-11-2019 at 08:27 PM.
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Old 01-11-2019, 06:30 PM
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Originally Posted by gkull View Post
First of all those so called heat shields are a gimmick and don't work. A week ago or so someone posted some thermal images. Because aluminum conducts heat. The whole intake manifold is basically the same temp.
Heat crossover and EGR were blocked off in that image. I'd venture a guess and say if the crossover wasn't blocked there'd be 'hotter spot' in the center. Once I get it all back together I'm going to take 'heat sink' pics. Should be interesting.
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Old 01-11-2019, 08:11 PM
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Do not spray any cleanser in the bolt holes. That chemical would go directly into your oil.
Get a copy of the intake bolt torqueing sequence. Starting at number one bolt, remove, wire brush threads, apply ARP Thread Sealant, (small, white plastic tube).
Torque bolt to about half the foot pounds needed. Move on to bolt number two, repeat. Afterwards go back over all the bolts, in order, to proper torq specs.

There is no need to change out the gaskets just for a few weeping bolts.
The intake bolts thread right into the oil system so they should never be installed dry.

Last edited by HeadsU.P.; 01-11-2019 at 09:05 PM.
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Old 01-11-2019, 10:11 PM
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Teflon tape is not really suitable for use in sealing petroleum product leaks. Permatex Ultra Black RTV is a much better choice.
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Old 01-11-2019, 10:19 PM
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I don't care for rtv there. It wont stick to oily surfaces, and it flakes off inside. More than once I have found that **** in oil pans.

I said dope, not tape. PTFE is fine for oil, gasoline.

Last edited by Big2Bird; 01-12-2019 at 07:52 AM.
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Old 01-12-2019, 12:09 AM
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CanadaGrant
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I just use Permatex Thread Sealant. Thick white stuff in a little can with a brush. Says it "seals and lubricates". It seals great but no idea how it lubricates... Must be referring to use for proper bolt torque. I removed the intake off a new never run GM ZZ4 crate motor a few years ago and all the intake bolts had what looked like the same white sealer on them.

Last edited by CanadaGrant; 01-12-2019 at 12:48 AM.
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Old 01-12-2019, 01:04 AM
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Originally Posted by CanadaGrant View Post
I just use Permatex Thread Sealant. Thick white stuff in a little can with a brush. Says it "seals and lubricates". It seals great but no idea how it lubricates... Must be referring to use for proper bolt torque. I removed the intake off a new never run GM ZZ4 crate motor a few years ago and all the intake bolts had what looked like the same white sealer on them.
That is PTFE as well.
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Old 01-12-2019, 01:25 AM
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I am not a fan of using RTV down an "open out the bottom" bolt hole that is also contaminated with oil and just the mention of thread tape scares me. Thread tape should never be used anywhere near the internals of any engine. Getting a piece of thread tape into an oil passage is like the kiss of death. Actually, it is...

Last edited by CanadaGrant; 01-12-2019 at 01:56 AM.
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Old 01-12-2019, 02:33 AM
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Originally Posted by DB Cooper View Post
The 'heat shield' I referred to is a 1/2in phenolic spacer. I completely agree anything aluminum you put between the carb and intake is just going to conduct heat straight through.

Thanks!
wood thermal spacers Óre better than phenolic*
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Old 01-12-2019, 08:53 AM
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Originally Posted by gkull View Post
wood thermal spacers Óre better than phenolic*
Not in Termite country!
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Old 01-12-2019, 10:58 AM
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Originally Posted by gkull View Post
wood thermal spacers Óre better than phenolic*
Hmm interesting. I sort of wondered, never had considered wood in contact with fuel a workable idea.*
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Old 01-12-2019, 11:14 AM
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I ended up having to torque those intake bolts by 'feel' with an end wrench too. It's an Edelbrock dual plane aluminum intake, and there wasn't clearance to get a short 3/8" drive socket over the middle 4 intake bolts. Turned out 3 of those 4 bolts were in there finger tight, or less.

Come springtime when I'm driving the vette more, I'll keep an eye on those, I just sealed those 4 bolts with permatex #2 for now, those 4 spots on the intake looked oily. I don't remember for certain if I had seen any pooling around any others. Anyway for now at least all the intake bolts are tight.

I thought I had play doh around to check clearance between the air cleaner and hood, but couldn't find any around. A wqad of aluminum foil worked fine as a substitute though. Thamkfully I didn't run out of room under the hood.

Last edited by DB Cooper; 01-12-2019 at 11:17 AM.
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