Gasket or not?????

[Daytona Guy]

Got some questions anyone ...

Can I bolt these new exhaust manifolds right up to new aluminum heads without a gasket like the factory does? (Both are machined surfaces) What bolts do I use 8's? (are they too hard?) 5's (allowed to strech or expand?) 

Also, the manifold ends where the pipes connect, they seem rough, do I need to sand that area smooth for it not to flutter or leak?

Dane

[earnie]

i would have to say that with coefficeint of heat expansion, gaps will open up because of the different material thicknesses thus causing leaks,
i would use gaskets, that way you dont run a risk of burning exhaust valves
just my 

[tan top]

i would have to say that with coefficeint of heat expansion, gaps will open up because of the different material thicknesses thus causing leaks,
i would use gaskets, that way you dont run a risk of burning exhaust valves
just my 

use gaskets ,   

[bobs66440]

i would have to say that with coefficeint of heat expansion, gaps will open up because of the different material thicknesses thus causing leaks,
i would use gaskets, that way you dont run a risk of burning exhaust valves
just my 

use gaskets ,   

I use the FelPro gaskets with a light coating of ultra copper RTV. Remflex also makes very good quality ones that don't need sealer.

[Daytona Guy]

what about the bolts. 8's OK?

Dane

[JB400]

I favor studs personally.


I'm talking hardware, just to clarify.

[tan top]

 are the threads helicoiled in the heads ?  even then i would want to use studs in aluminum heads   ,  

[bobs66440]

I favor studs personally.


I'm talking hardware, just to clarify.

I'm glad you clarified that! 

[Daytona Guy]

Not sure studs matter when it is all tight - the head doesn't know, as long as one utilizes all the thread in the head. Not going to helicoil these heads and ruin them. If I strip one down the road the. You have no choice.

Are 8's the way too go?

Dane

[dmann]

i would definitly recomend gaskets with  bolts with the correct conical washers

[earnie]

if the heads are aluminum and the manifolds are cast iron, i would worry about dissimilar metal corrosion, and with what i mentioned above about the differnces in heat expansion, will require gaskets, as for the hardware a real good set from arp should suffice
but please use a good anti sieze for the hardware as to prevent galling and corrosin should you have to dissasemble it in the future

[Daytona Guy]

thanks guys  

[bull]

Nah, high temp copper RTV for me. http://www.dodgecharger.com/forum/index.php/topic,67290.0.html

[A383Wing]

I would use studs in the aluminum heads, threading bolts into aluminum and tightening kinda distorts threads....... plus I would use the copper seal gaskets

Bryan

[Daytona Guy]

How does copper react to aluminum? I have never seen those two together now that I think about it. I have read all over the place - and the Felpros blow out all the time. I got some real good gaskets from "Classic" but they do not match my manifolds- nice waist of 50.00  - their ports are tooooo big. One builder recommends only using the "Gold" RTV (or whatever the abbreviation is) and no gasket. He guarantees no corrosion or blow by. He said it works every time. Thoughts?

As for studs - They only recommend 20 lbs on the bolts - that should not be much of a stress. After the turn and initial load - the poundage is the same on the threads regardless.

No one commented on this - so I went ahead and sanded this area smooth - for the TTI's to seat up too instead of the pores surface.

Dane

[John_Kunkel]

Manifold exhaust leaks with aluminum heads are more serious than with iron heads because the escaping hot gasses can erode a channel in the mating surface...use a gasket.

[A383Wing]

and screwing bolts into aluminum threads when tightening parts together distorts the threads. Not so with studs, those are screwed in and set with no "chewing" of threads like bolts.

I would use gaskets & studs & nuts

Bryan

[Daytona Guy]

I would use studs in the aluminum heads, threading bolts into aluminum and tightening kinda distorts threads....... plus I would use the copper seal gaskets

Bryan

This sounds the way to go, but I can't find copper seal gaskets for a stock manifold size.

Dane

[Chryco Psycho]

I would use a thin layer of ultra copper silicone & no gasket , if you do use a gasket coper or the alum gaskets are the way to go for sure , studs are better as well

[Daytona Guy]

OK - this is what I will do and keep you informed on how it works. I'm using studs (soft - not grade 8's) and copper high temp with no gasket. If the gaskets are what blows out, then the risk is the same with damage to the head if not caught in time. Many HEMI guys are saying that with no gasket there is no leak to have the problem of damage, for it has to blow the head a part to leak (the iron is not going anywhere).

Dane

[4aThrill]

use Studs and I second Remflex best gasket there is, guaranteed no leaks with Remflex. 

[A383Wing]

use Studs and I second Remflex best gasket there is, guaranteed no leaks with Remflex. 

yea..but they look like crap when installed and squished

Bryan

[A383Wing]

OK - this is what I will do and keep you informed on how it works. I'm using studs (soft - not grade 8's) and copper high temp with no gasket. If the gaskets are what blows out, then the risk is the same with damage to the head if not caught in time. Many HEMI guys are saying that with no gasket there is no leak to have the problem of damage, for it has to blow the head a part to leak (the iron is not going anywhere).

Dane

Personally, I would not use "soft" studs...they will stretch with heat...grade 8's are always used on exhaust. Soft studs are used for carb mounting. If you use soft studs on the exhaust, you will have a leak down the road

Bryan

[Daytona Guy]

use Studs and I second Remflex best gasket there is, guaranteed no leaks with Remflex. 

Can't use Remflex - they don't fit stock manifolds. Also Bryan, I have used 8's and had them snap off once heated up, then I was told to use grade 5's, that allow for expansion with the heat, and will not create the gaps. We will see.

Dane

[FLG]

Thats the thing about 8's and 5's...8's will hold more but when there pushed past the limit they snap, 5's will have some stretch/bend before they go.