Any Consensus On Sealing Intake 2 Vortec Heads

tbauer03

tbauer03

TRBOBOX
Sorry to make another post about this but I have read numerous posts and it seams like everyone says something different. Use right stuff, Black RTV, Red RTV etc etc.

I can't remember what i originally had used to seal the lower intake but i took it off to powder coat the outside. When i put it back on I used Grey RTV because it matched the aluminum color. It developed a leak at the back china wall after a few hundred miles.

Jim gave me hand the 2nd time around and we used black RTV because it is designed for oil. It sealed for awhile now after sitting for the winter it is leaking oil into the combustion chambers and I am getting some smoke at start up and if i let the car idle in one spot the exhaust leaves traces of un-burt oil on the ground. It does not appear to be loosing antifreeze.

Anyway what i read about the right stuff it sounds like a good solution but perhaps a last resort. I have read horror stories on corvette forums about getting the stuff unbonded after it sets. And I am a little concerned about its quick set time.

Also the bolts that I have to seal the lower intake to the heads vary in length for some reason. I don't have the stock studs they are all bolts but why would they vary in length? What length should they be? and I was browsing for ARP bolts and they have a set for vortec heads but they are 5/16-18 shouldn't they be 3/8-16, sorry I haven't started pulling it apart yet.
http://www.summitracing.com/parts/arp-134-2002/overview/

Thanks for your input
 
randy merritt

randy merritt

Donating Member
Re: Any Consensus On Sealing Intake 2 Vortec Heads

tbauer03 said:
Sorry to make another post about this but I have read numerous posts and it seams like everyone says something different. Use right stuff, Black RTV, Red RTV etc etc.

I can't remember what i originally had used to seal the lower intake but i took it off to powder coat the outside. When i put it back on I used Grey RTV because it matched the aluminum color. It developed a leak at the back china wall after a few hundred miles.

Jim gave me hand the 2nd time around and we used black RTV because it is designed for oil. It sealed for awhile now after sitting for the winter it is leaking oil into the combustion chambers and I am getting some smoke at start up and if i let the car idle in one spot the exhaust leaves traces of un-burt oil on the ground. It does not appear to be loosing antifreeze.

Anyway what i read about the right stuff it sounds like a good solution but perhaps a last resort. I have read horror stories on corvette forums about getting the stuff unbonded after it sets. And I am a little concerned about its quick set time.

Also the bolts that I have to seal the lower intake to the heads vary in length for some reason. I don't have the stock studs they are all bolts but why would they vary in length? What length should they be? and I was browsing for ARP bolts and they have a set for vortec heads but they are 5/16-18 shouldn't they be 3/8-16, sorry I haven't started pulling it apart yet.
http://www.summitracing.com/parts/arp-134-2002/overview/

Thanks for your input
Click to expand...
For china wall, right stuff worked very well for me. No oil leaks. Very good product.
 
djsy934

djsy934

Active member
Re: Any Consensus On Sealing Intake 2 Vortec Heads

tbauer03 said:
Sorry to make another post about this but I have read numerous posts and it seams like everyone says something different. Use right stuff, Black RTV, Red RTV etc etc.

I can't remember what i originally had used to seal the lower intake but i took it off to powder coat the outside. When i put it back on I used Grey RTV because it matched the aluminum color. It developed a leak at the back china wall after a few hundred miles.

Jim gave me hand the 2nd time around and we used black RTV because it is designed for oil. It sealed for awhile now after sitting for the winter it is leaking oil into the combustion chambers and I am getting some smoke at start up and if i let the car idle in one spot the exhaust leaves traces of un-burt oil on the ground. It does not appear to be loosing antifreeze.

Anyway what i read about the right stuff it sounds like a good solution but perhaps a last resort. I have read horror stories on corvette forums about getting the stuff unbonded after it sets. And I am a little concerned about its quick set time.

Also the bolts that I have to seal the lower intake to the heads vary in length for some reason. I don't have the stock studs they are all bolts but why would they vary in length? What length should they be? and I was browsing for ARP bolts and they have a set for vortec heads but they are 5/16-18 shouldn't they be 3/8-16, sorry I haven't started pulling it apart yet.
http://www.summitracing.com/parts/arp-134-2002/overview/

Thanks for your input
Click to expand...

Did you use thread sealant on the intake bolts? May not be coming from the china wall if you didn't.
 
D

Damian

Member
Re: Any Consensus On Sealing Intake 2 Vortec Heads

I used the black rtv and its been working great. You just have to make sure you let it cure before you start the engine up.
 
C

CC801

Donating Member
Re: Any Consensus On Sealing Intake 2 Vortec Heads

GM used a grey rtv called assembly adhesive i believe, on the lt1's because they had common leaks at the china wall. They would also have you dimple the wall with a punch, to give the adhesive something the grab onto. I remember having to pull one after this was done, took allbthe bolts out, had to use a 4 ft prybar against the core support and all 230lb of my weight to get it to break the seal.
 
tbauer03

tbauer03

TRBOBOX
Re: Any Consensus On Sealing Intake 2 Vortec Heads

djsy934 said:
Did you use thread sealant on the intake bolts? May not be coming from the china wall if you didn't.
Click to expand...

I pulled a bolt, there wasn't much of anything on it, just a thin line where the rtv hit at the point of the gasket. Can I just pull one bolt out at a time, add RTV, then reinstall it without breaking the lower intake seal or is that just asking for more problems? It would save me some money on gaskets and potentially save some time.
 
djsy934

djsy934

Active member
Re: Any Consensus On Sealing Intake 2 Vortec Heads

tbauer03 said:
I pulled a bolt, there wasn't much of anything on it, just a thin line where the rtv hit at the point of the gasket. Can I just pull one bolt out at a time, add RTV, then reinstall it without breaking the lower intake seal or is that just asking for more problems? It would save me some money on gaskets and potentially save some time.
Click to expand...

When you pulled the bolt did you notice if the tapped hole is drilled all the way through into the valley area? If it is a blind hole then there would be no need for sealant. We just went through this with Lens truck. Chasing a leak thinking it was the china wall when he noticed the holes are drilled through into the valley area. I'm not familiar with Vortec heads, but if they are drilled through it could be a potential leak if the bolts aren't sealed. If you can get the threads clean enough for the sealant, you should be able to do one bolt at a time I would think.
 
Don W.

Don W.

Stab it and steer it
Re: Any Consensus On Sealing Intake 2 Vortec Heads

Vortec heads modified for our manifolds are drilled through. I believe stock head holes are blind. ?? I have not had any dificulity using the following procedure. Red RTV on both head surfaces and manifold surfaces around ALL openings. At the back of the manifold be sure to also go around the water passage block-off area. At front and rear block area (China wall?) I use black RTV. I bring some black up on the heads a bit. As I recall black RTV is called for here in the manual. (The big one, not the supplement.) I use the dist to center the manifold in position.

Use red RTV on the bolt threads. (I have Vortec heads.) Using this method I have never had any difficulty. There are a couple places with Vortec heads where the manifold just barely mates up. Using the dist to center the manifold helps, I think.

One issue you might check. (Requires removal of the manifold.) With the manifold just sitting on the motor there is a specified gap between the manifold and the block. If that gap is not there you're gonna have all kinds of problems.

IMHO stock bolts are just fine. Especially since a few are "studded" which are needed in a few of the locations.

HTH
 
dgoodhue

dgoodhue

BuSTeD 4.3
Re: Any Consensus On Sealing Intake 2 Vortec Heads

I am also very careful torquing the couple bolts that go into newly drilled holes of the Vortec heads that only a couple threads. I torque down all the other bolts first and then torque those bolts slightly less than the manual calls for.
 
Neelsonwheels

Neelsonwheels

Donating Member
Re: Any Consensus On Sealing Intake 2 Vortec Heads

I did this project last spring and used Don W's meathod and I have had no
Issues to date. This was also my first time doing a lower intake.
Take your time and definately let the RTV cure overnight before you
Run the engine. Good luck!!
 
ajt86

ajt86

Member
Re: Any Consensus On Sealing Intake 2 Vortec Heads

black or grey rtv is is both fine for engine assembly. when sealing the valley with rtv, make sure to put an extra blob in the corner where it meets the head/intake gasket.
 
tbauer03

tbauer03

TRBOBOX
Re: Any Consensus On Sealing Intake 2 Vortec Heads

tbauer03 said:
I got it sealed up yesterday using Flex Seal saved me money on gaskets.
Click to expand...

Man tough crowd on the April Fools Department.:cry:

Joking aside I took the manifold off yesterday. The bolts are Fine Thread 3/8-24 grade 8
Not sure why the machine shop went with those but 8 are 1.5" long, 3 are 1' long (noted as short), and 1 is about 1-1/8 long (noted as Med). and two had 2 washers (noted by 2x). I noted how I pulled them out in the picture below. 1 being nearest to cylinder one and 12 being closet to cylinder 6.

Should these bolts vary in length like this? What is the correct length? Were they in the correct holes?

They are all bolts no studs and the egr and engine lift brackets are still intact.

Thank You

2015_03_30_18_26_40.jpg

2015_03_30_18_41_49.jpg
 
Last edited:
tbauer03

tbauer03

TRBOBOX
Re: Any Consensus On Sealing Intake 2 Vortec Heads

Over 2 years later... I started the truck from a fresh rebuild and after getting up to temp it starts leaking coolant up from bolt holes 8 and 2 (as pictured above or the 2nd bolts counting from the radiator on both the drivers and passenger side.)
I didn't pull them yet but was going to pull them soon and reapply RTV and allow them to set. But I am not sure what length of bolts I will be pulling out as the machine shop last installed the lower intake.
Can anyone confirm the proper length for these bolts on vortec heads?
Thanks
 
S

Sparkz#0535

Member
Re: Any Consensus On Sealing Intake 2 Vortec Heads

tbauer03 said:
Over 2 years later... I started the truck from a fresh rebuild and after getting up to temp it starts leaking coolant up from bolt holes 8 and 2 (as pictured above or the 2nd bolts counting from the radiator on both the drivers and passenger side.)
I didn't pull them yet but was going to pull them soon and reapply RTV and allow them to set. But I am not sure what length of bolts I will be pulling out as the machine shop last installed the lower intake.
Can anyone confirm the proper length for these bolts on vortec heads?
Thanks
Click to expand...

I dont know the bolt length deal but you may want to try not using RTV .... try #2

https://www.permatex.com/products/gasketing/gasket-sealants/permatex-form-a-gasket-no-2-sealant/
 
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