Intake Manifold Gasket Replacement
#1
Intake Manifold Gasket Replacement
I need to do my gasket on my 95, but I'm having problems finding clear directions anywhere. Is it just remove manifold, clean the surfaces, lay down a 1/4" bead all the way around, let sit for 20 minutes, replace manifold and let sit for 24 hrs? Obviously I'm not including all the various other crap that needs to be moved/removed to even look at an LT1. If not, does anyone have a set of full directions? It seems to be the one thing shbox doesn't have a million pictures and diagrams on. Thanks for the help!
Sincerely,
In Over His Head
Sincerely,
In Over His Head
#2
Re: Intake Manifold Gasket Replacement
#4
Re: Intake Manifold Gasket Replacement
#5
Re: Intake Manifold Gasket Replacement
I saw that before, but I still don't know which is the best RTV, what size bead, exactly how to clean the surfaces, how long to wait until I put the manifold back on, etc. I'm very new to gaskets and I just don't want to screw it up.
Also, is there a physical gasket as well or do you put the RTV the entire way around the intake?
Also, is there a physical gasket as well or do you put the RTV the entire way around the intake?
#6
Re: Intake Manifold Gasket Replacement
Cleaning the surfaces is fairly straightforward. Use a good cleaning solvent (I use a chemical gasket remover) and a razor blade. Be careful with the blade as not to gall the metal (and slit your wrist). Once the blade glides smoothly across the surface it's clean enough. You'll probably notice some "staining" on the surfaces - don't worry about it. As long as the blade doesn't catch it it'll seal fine.
Don't buy into gimmicks like dimpling the walls or slotting them. There's no proof that these tips actually do anything so keep it like the factory intended.
Side gaskets go on dry. Install them first. Make sure they are oriented correctly and that the small plastic locator pins are fully seated.
Put a 1/4" thick bead of Ultra Black RTV on the china walls (front and back part of the block). Ensure the bead goes onto the side gaskets approximately 1".
Put a few short metal dowels into a few bolt holes. I use one front and one rear, opposite sides. Then slide the manifold onto the dowels and let it center itself onto the block/gaskets. Once it is in place it is okay to move it ever so slightly to get the other bolt holes to line up but anything more than 3/16" or so of movement and you'll want to consider starting over.
Tighten the bolts in sequence per shbox.com. Once the manifold is torqued down wait 24 hours before starting the engine.
Don't buy into gimmicks like dimpling the walls or slotting them. There's no proof that these tips actually do anything so keep it like the factory intended.
Side gaskets go on dry. Install them first. Make sure they are oriented correctly and that the small plastic locator pins are fully seated.
Put a 1/4" thick bead of Ultra Black RTV on the china walls (front and back part of the block). Ensure the bead goes onto the side gaskets approximately 1".
Put a few short metal dowels into a few bolt holes. I use one front and one rear, opposite sides. Then slide the manifold onto the dowels and let it center itself onto the block/gaskets. Once it is in place it is okay to move it ever so slightly to get the other bolt holes to line up but anything more than 3/16" or so of movement and you'll want to consider starting over.
Tighten the bolts in sequence per shbox.com. Once the manifold is torqued down wait 24 hours before starting the engine.
#7
Re: Intake Manifold Gasket Replacement
I saw that before, but I still don't know which is the best RTV, what size bead, exactly how to clean the surfaces, how long to wait until I put the manifold back on, etc. I'm very new to gaskets and I just don't want to screw it up.
Also, is there a physical gasket as well or do you put the RTV the entire way around the intake?
Also, is there a physical gasket as well or do you put the RTV the entire way around the intake?
#8
Re: Intake Manifold Gasket Replacement
#10
Re: Intake Manifold Gasket Replacement
I just did this last week, and as far as waiting before start up, I didn't. I finished the job, primed the fuel and started it then drove it home which is about 30 minutes and have no issues. Also a tip for ya, take a mirror and make sure your RTV squeezes out the back side for a good seal. Other than that it'll be ready to drive by the time your done IMO.
#11
Re: Intake Manifold Gasket Replacement
Injuneer and Shoebox, thanks for your help, but there were several of my questions unanswered by the article. For example, I couldn't tell exactly how thick of a bead to lay down from the picture and the most important part, if I needed dry gaskets.
RamAir95TA, thanks, that is exactly what I was looking for. I bought all the supplies today and probably will do this next weekend.
There are still two questions I have unanswered though. When you lay the sealant down, how long do you wait to install the manifold and torque the bolts the first time, and then how long for the second torquing too? And the second, does it matter if sealant gets into the manifold?
Thanks for your patience. I'm just trying to be thorough before I start so I don't screw this up and waste peoples' time.
RamAir95TA, thanks, that is exactly what I was looking for. I bought all the supplies today and probably will do this next weekend.
There are still two questions I have unanswered though. When you lay the sealant down, how long do you wait to install the manifold and torque the bolts the first time, and then how long for the second torquing too? And the second, does it matter if sealant gets into the manifold?
Thanks for your patience. I'm just trying to be thorough before I start so I don't screw this up and waste peoples' time.
Last edited by aj2494; 06-05-2012 at 08:42 PM.
#12
Re: Intake Manifold Gasket Replacement
No need to wait to install the manifold. Don't worry about sealant getting anywhere. A second torquing is better after a few heat/cool cycles, but after everything is together, there is little room to get to all the bolts.
I guess being a visually oriented person, I find it easier to look at a pic and judge the size of the bead. The pic also shows the gasket is dry.
I guess being a visually oriented person, I find it easier to look at a pic and judge the size of the bead. The pic also shows the gasket is dry.
#13
Re: Intake Manifold Gasket Replacement
I just couldn't see the side gaskets in the picture, that's why I was confused. Thanks for the help.
Also, do you guys see any reason to upgrade the intake manifold while I'm doing this? I was thinking of looking fire a used lt4 or something. I don't have any mods that need it or anything, I just think it would be better to do while I'm doing the gasket instead of later on.
Also, do you guys see any reason to upgrade the intake manifold while I'm doing this? I was thinking of looking fire a used lt4 or something. I don't have any mods that need it or anything, I just think it would be better to do while I'm doing the gasket instead of later on.
Last edited by aj2494; 06-06-2012 at 02:12 PM.
#14
Re: Intake Manifold Gasket Replacement
Absolutely no value in going to an LT4 intake, or an aftermarket (Edelbrock) version. The GM LT4 is essentially identical internally to the LT1 intake. There is more metal at the top of the runners so it can be ported to match a set of LT4 heads. But GM never finished the job, apparently after running out of money on the LT4 development. They just bolted a mismatched LT4 intake to the LT4 heads.
The GM LT4 intake will not mount correctly to LT1 heads, because the taller runners interfere with the valve cover rail. The intake can be machined, but there is no purpose, since it's the same as the LT1 internally.
The GM LT4 intake will not mount correctly to LT1 heads, because the taller runners interfere with the valve cover rail. The intake can be machined, but there is no purpose, since it's the same as the LT1 internally.
#15
Re: Intake Manifold Gasket Replacement
I just couldn't see the side gaskets in the picture, that's why I was confused. Thanks for the help.
Also, do you guys see any reason to upgrade the intake manifold while I'm doing this? I was thinking of looking fire a used lt4 or something. I don't have any mods that need it or anything, I just think it would be better to do while I'm doing the gasket instead of later on.
Also, do you guys see any reason to upgrade the intake manifold while I'm doing this? I was thinking of looking fire a used lt4 or something. I don't have any mods that need it or anything, I just think it would be better to do while I'm doing the gasket instead of later on.