Changing Crossover Pipe Donut Gaskets: Questions

[GM Guy]

Hey all,

I am changing crossover pipe gaskets on one of the 6.5L fleet, and had a question.

Just how clean does the inside of the manifold need to be? I have scraped, dug, and chiseled rust till I am perfectly smooth on the flange, but on the inside, where the neck of the dout gasket slides in, there is some really tough soot or rust that will not break loose down in the bottom (deeper in) of the machined groove. I have gotten rather mean with a 21oz ball peen and a long chisel about 3/4 inch wide at the blade, and most of the rust has finally broken free, but not this.

That said, I can slide the gasket in with minimal force and the backside of the donut sits flat on the flange. Is this good enough, or will the rust at the bottom of the machined groove promote the exhaust to try and sneak around the donut over time? luckily it slides in, no beating necessary.

This is on the RH manifold BTW, the left one (drivers side) looks great, didn't take much to get it to perfection.

Also, one final question. does this have an insert or some sort of treatment? it looks like there is a ring of different colored metal inside the end of the manifold.

Any input appreciated,
Thanks!

 

[tanman_2006]

Sub'd

 

[ak diesel driver]

I think they're supposed to be a snug fit.

 

[NVW]

The donut has a metal ring that presses into the manifold, if it fits it should be good.

 

[Burning oil]

Got pic's? Im wondering if the metal ring is part of the old doughnut? (Mmmn doughnut! )

 

[GM Guy]

the metal ring comes with the new donut, looks identical to the donut I removed. the metal ring slides into the manifold. It is not loose, but it does slide in without a alot of effort. The term "firm" describes it well.

Here is a pic of the GM donut gaskets I am using.
http://www.ebay.com/itm/GM-OEM-Exha...538-/321793702847?hash=item4aec663bbf&vxp=mtr

 

[NVW]

You're good, no need to worry

 

[WarWagon]

Got a pic of the manifold? Maybe rust has eaten everything away but that one spot?

 

[GM Guy]

also, I am planning on putting a light dab of anti-seize on each bolt, would it be wise to put some on the metal ring that slides in the manifold?

We thought about no anit-seize at all, and just a little bit of penetrating oil on the bolts, but figured the anti-seize would be better as long a guy re-torqued them. Thoughts?

I am definitely going to be re-torquing after a hundred miles or so, had an incident involving losing a bolt on dad's 98 when we dropped the crossover to check torque converter bolts.

 

[Burning oil]

I used antisleeze in the same way on mine. I use it on most exhaust components.

 

[GM Guy]

OK, antiseize on the bolt tips, a little on the metal ring where it fits into the maifold, and what was left on my fingers got smeared on the backside of the pipe flange where the metal plate contacts it.

Lets hope it holds together.

 

[bison]

I antiseize the whole bolt shank and treads.
I use SS bolts as well.
No antseize on the donut sleeve, i like that gap to fill in with carbon to prevent a potential leak path

 

[WarWagon]

Antiseize as Bison says. It makes the job so much easier for me that many times the exhaust has come back off. Only issue I have had is the inside rear turbo nut is usually loose or missing.

 

[schiker]

Like others said you should be fine. My take is the metal ring part is just for holding the doughnut in place. The soft "metalized" gasket is what seals flat on manifold side and taper on crossover side. As long as it it smashes / deforms to mate the geometries soot will seal the hair cracks/gaps. I don't think the ring does much sealing maybe helps with labyrinth seal don't know.