Exhaust ports and sealing...., ..how do you know? Options

[falcor75]

How do you know you get a good seal at the exhaust port?

The only way to really know is to take down the heaterbox and look for soot on the copper gaskets. But by then you will need to anneal the gasket again and hope that you get a good seal the next time you mount the heater box too....

Tips and tricks are most welcome....

[MartyYeoman]

I've taken to using McMark's feather technique. Pressurize your exhaust system using the output from a shop vac and probe about the head ports with a feather. It's surprisingly accurate at locating even the smallest leaks. Plus there's the bonus of not working on and around hot heat exchangers. I recommend trying it.

[falcor75]

Aaah thats clever, my shopvac cant blow but I guess I can hook up the compressor to pressureize the exhaust a bit.

[Bartlett 914]

you can use a piece of hose and use it as a stethoscope. This is not perfect but I did use this the other day on a friends car and found a leak. Compare the sound difference from bank to the other. I used a 5/8: ID hose.

[bandjoey]

OK this might be crazy but what about a torque wrench? I heat mine, push them in place with a small screwdriver handle, and they always stay put. quickly put on the exhaust and torque. Have installed about 4-5 x this way and (so far) no leaks. The first time i discovered some crud on the seating area. Carefully cleaned the seating surface and no problems yet.

[JFJ914]

How do you know you get a good seal at the exhaust port?

The only way to really know is to take down the heaterbox and look for soot on the copper gaskets. But by then you will need to anneal the gasket again and hope that you get a good seal the next time you mount the heater box too....

Tips and tricks are most welcome....

The really loud noise goes away.

[Rand]

OK this might be crazy but what about a torque wrench?

Nothing crazy about that! The nuts should absolutely be tightened appropriately. For anyone who isn't sure what that feels like, a torque wrench is important.

The mating surfaces being clean and flat is most important. I've seen all kinds of things, from old gaskets left in, to erosion that started because of leaks at the head. Exhaust leaks at that location are a time bomb.

Sometimes the tops of the pipes need filing to make sure the surfaces are flat and smooth. (Long file strokes across both pipe ends at the same time (per side pair) to make sure they are flat with each other.) Sometimes you need to keep the rear mounts loose so you can adjust the angle as you torque at the heads to preserve the flat mating at the heads first before tightening up the rest. Depends on your exhaust system though - this is why I love stub pipes.

[N_Jay]

On this topic:
Is there really any difference between the early and late sealing rings?

They have different part numbers, but I thought the exhaust ports were all the same.

If you hunt you can get rings at about $1 so why bother reusing?

[stugray]

- this is why I love stub pipes.

(IMG:style_emoticons/default/agree.gif) I put them on while the engine is still on the stand and I can flip it upside down

[rgalla9146]

If you have a leak at a port it is usually pretty obvious.
You hear a pop at idle each time that cylinder fires.
To find which cylinder it is remove one spark plug wire at a time with the engine idling.
The pop will go away when the leaking cylinder is not firing.

[Rand]

If you hunt you can get rings at about $1 so why bother reusing?

I would never re-use! They CRUSH and fatigue. I would way rather use a new ring without annealing than try to re-anneal and re-use and old collapsed one as some have suggested.

And to bandjoey Bill's point, you should RE-torque after a couple heat cycles on a new install.

[yeahmag]

[iankarr]

I love the idea of the shop vac...but isn't there a concern about blowing soot from the muffler into open exhaust valves? I'd imagine that reversing the flow of exhaust would dislodge all kinds of nasties. No?

[IronHillRestorations]

That stuff would come out faster than a broken chop stick (IMG:style_emoticons/default/happy11.gif)

I love the idea of the shop vac...but isn't there a concern about blowing soot from the muffler into open exhaust valves? I'd imagine that reversing the flow of exhaust would dislodge all kinds of nasties. No?

[iankarr]

not sure I get the reference (IMG:style_emoticons/default/wink.gif)

[MartyYeoman]

You wooda hadda been there.

[N_Jay]

On this topic:
Is there really any difference between the early and late sealing rings?

They have different part numbers, but I thought the exhaust ports were all the same.

Anyone? . . . Anyone? . . . .

. . . . Beuler?

[Bartlett 914]

Sometimes the tops of the pipes need filing to make sure the surfaces are flat and smooth. (Long file strokes across both pipe ends at the same time (per side pair) to make sure they are flat with each other.) Sometimes you need to keep the rear mounts loose so you can adjust the angle as you torque at the heads to preserve the flat mating at the heads first before tightening up the rest. Depends on your exhaust system though - this is why I love stub pipes.

One has to be careful doing this. You really need a BIG file. A standard 12" file is too short. I have seen where this has created a problem that may not have been there before. It is very easy to get these surfaces uneven. I have a surface plate I can use. I use abrasive paper on the plate (or a really good flat surface) and sand the ends in smooth strokes. I feel going in a single direction works best. Using a permanent marker can help see the high spots. You need two sets of hands works best here or a good way to hold the paper in place while working.

[McMark]

On this topic:
Is there really any difference between the early and late sealing rings?

They have different part numbers, but I thought the exhaust ports were all the same.

Anyone? . . . Anyone? . . . .

. . . . Beuler?

Yes, but it's negligible. The early ones have a slightly smaller ID. You'd be hard pressed to identify one vs the other without having them next to each other.

[7TPorsh]

Do any of you use any sealant of any kind? or is it only HEAD-COPPER-EXHAUST