Need a pep talk/help: can't eliminate exhaust leak after 5 attempts Options

[DC_neun_vierzehn]

Looking for some advice and encouragement because I'm ready to say "uncle."

I have a '73 2.0 w/ a fresh 2056 rebuild. Exhaust studs are new. I have new exhaust stud nuts from @rhodyguy . I have new Victor Reinz copper washers and exhaust gaskets. My heat exchangers (HEs) are stock (not stainless).

By using the shop vac blow up the tailpipe method, I have detected exhaust leaks on the passenger side (PS) at both exhaust ports as well as at the muffler gasket.

Here's the method I used on the driver's side (DS) and it worked perfectly: a dab of Elmer's glue on the copper washers to get them to sit in the heads and used the X pattern to tighten the nuts moving to the next nut after 3 rotations. Worked perfectly, no air leaks.

I tried the same method on the PS HE, but it failed to eliminate the air leaks at the head after 5 straight attempts of removing and reinstalling. SO FRUSTRATING.

Based off of past threads I found via the search, the only things left to try:

1. Gently file the HE pipes to square them off (use a Sharpie to mark the tops and only file until ink is gone using a large bastard file that will do both pipes simultaneously). I did not do this yet because the pipe ends look flat and clean. When I set one of the copper washers on the top of the pipes they sit flat and even - when I shine a flashlight behind that I don't see any light coming through.

2. Anneal the copper gaskets using a blowtorch - I have no idea how I would get the copper gaskets to sit in the heads after annealing them and then lay on my back underneath them while trying to install the HE sounds a burn victim waiting to happen. How does one do this safely?

I'll take any suggestions or encouragement because after spending 4-5 hours on this today, I'm feeling a bit hopeless.

[mepstein]

When you anneal them, you get them red hot and then let them cool completely before you install.
I like using superglue to hold gaskets in the heads when you’re working upside down.
To check the flatness of the ends, you need to have something that’s known to be flat, like a piece of glass, granite table, machinist block, ect.

Good luck. (IMG:style_emoticons/default/beerchug.gif)

[BeatNavy]

Mark is right. The only other thoughts I have:

1. It can take a fair amount of wiggling to get those HE's over the head studs.

2. In some cases you may have to open up the ears on the HE slightly with a file to give you enough play.

3. Superglue or grease can help keep it in place, but a second set of hands is also very helpful. (Who's wife DOESN'T want to lie underneath the greasy, smelly car and help with the exhaust???)

4. The exhaust systems on these cars is a real PITA. It is what it is.

5. Take a break and take your time. You'll get it.

(IMG:style_emoticons/default/beerchug.gif)

[rhodyguy]

File the ends. You might see a miss spot on the first pass. A piece of flat steel and some fine Emory cloth might work. Good thing you weren’t fighting with those oval style nuts.

Silly question. Positive both old copper rings removed before the new ones installed? It happens.

[914_teener]

I went through this same issue but with the SSHE's.


made sure everything is in the same plane using the same methods.

Slits gave me this advice:

Took High temp gasket sealer at your FLAPS copper based .. then inserting the copper gaskets and placed them in the ports..made sure there was no excess into the ports by taking your finger and wiping them clean. Then another seal of the high temp gasket sealer...then wiped with your digital meter...finger...then carefully torque the nuts in sequence. I used a floor jack to aligh and hold everything up. Alot easier to do also with a lift...almost a must.

Never leaked after this.

[930cabman]

I said uncle. My recent 2056 build with SS exchangers does not seal properly but I have accepted it. Fit is the key word here and getting them just right is tricky.

I have wondered if doubling up the annealed copper gaskets would correct alignment?

Getting the connections at the head to seal and then rack the HE to connect the bracket/muffler can be trying for sure.
Best of luck

[barefoot]

I have the SSI's and filed the seal surfaces which did need some love.
I also re-torqued them after couple heat cycles, no leaks detected.
Good luck & carry on (IMG:style_emoticons/default/sad.gif)

[Porschef]

Yes, retorque after a run. A little gentle up and down wiggling prior can help, along with a universal socket.

They are indeed a pita (IMG:style_emoticons/default/dry.gif)

[DC_neun_vierzehn]

Thanks everyone for the encouragement/suggestions and sharing your stories of suffering through this process.

I will try again tonight ... will gently file the tops of the pipes as well as inside of the bolt collars since they are super snug as I push the HE up the studs.

If that doesn't work, I suppose I will try a small dab of that copper based high temp gasket sealer on both sides of the copper gaskets as a last resort.

[DC_neun_vierzehn]

Silly question. Positive both old copper rings removed before the new ones installed? It happens.

Yes. Old copper rings were removed. I wish that was the problem though. That would be easy to address : )

[bkrantz]

The exchanger pipe ends need to be not just flat but also parallel and preferably on the same plane. Check this with something truly flat that can lay across both ends at the same time. There is some flex in each tube, but if one end is out-of-plane then you are forcing the flex.

And of course make sure the recess in each exhaust port is not pitted from past leaks.

[ClayPerrine]

I will add my experience here.

Loose assemble everything in the exhaust system. Don't torque the head bolts until the muffler and the hanger are on the ends of the heat exchangers. I have found that forcing the HEs to fit the muffler results in exhaust leaks at the heads.

Get everything assembled. Then tighten up the HE to muffler bolts. Leave the hanger to transmission bolts loose. Torque the heads. Then torque the hanger to transmission bolts. Use a torque wrench on the HE to head bolts (23 Ft Lbs), and don't ever over torque them trying to get them to seal That will cause a pulled head stud and torn HE mounting loops. And that will cause an exhaust leak.

Hope that helps.

Clay

[76-914]

I use a different method to dress the header. As Mark mentioned above get a piece of glass (granite/marble slab) and stick a strip of 80-120 grit PSA sand cloth to it. Then hold the header upside down and square against the sandpaper strip-the longer the better- and slide it back and forth frequently checking the ends. When they are all shiny you're done. Using this method gave me a more accurate solution vs filing in place. You want to make long strokes so shoot for an work surface that is 8"-15" longer than your header. (IMG:style_emoticons/default/beerchug.gif)

[DC_neun_vierzehn]

I will add my experience here.

Loose assemble everything in the exhaust system. Don't torque the head bolts until the muffler and the hanger are on the ends of the heat exchangers. I have found that forcing the HEs to fit the muffler results in exhaust leaks at the heads.

Get everything assembled. Then tighten up the HE to muffler bolts. Leave the hanger to transmission bolts loose. Torque the heads. Then torque the hanger to transmission bolts. Use a torque wrench on the HE to head bolts (23 Ft Lbs), and don't ever over torque them trying to get them to seal That will cause a pulled head stud and torn HE mounting loops. And that will cause an exhaust leak.

Hope that helps.

Clay

The HE to head nuts are 23 FT torque? I read it was 14. Can others weigh in here? There's nothing in the Haynes manual.

[DC_neun_vierzehn]

I will add my experience here.

Loose assemble everything in the exhaust system. Don't torque the head bolts until the muffler and the hanger are on the ends of the heat exchangers. I have found that forcing the HEs to fit the muffler results in exhaust leaks at the heads.

Get everything assembled. Then tighten up the HE to muffler bolts. Leave the hanger to transmission bolts loose. Torque the heads. Then torque the hanger to transmission bolts. Use a torque wrench on the HE to head bolts (23 Ft Lbs), and don't ever over torque them trying to get them to seal That will cause a pulled head stud and torn HE mounting loops. And that will cause an exhaust leak.

Hope that helps.

Clay

The HE to head nuts are 23 FT torque? I read it was 14. Can others weigh in here? There's nothing in the Haynes manual.

I called George at AA and he said 18 was the magic number.

[ClayPerrine]

Standard torque specification for a 8x1.25 bolt is 23 ft Lbs.

And that is what the head bolts are torqued to, so I figure it is close. Most people over tighten them and tear up the heat exchangers and the studs when the engine gets hot.

[rjames]

I'm paranoid about overtightening the exhaust stud nuts. I've been stopping at 15.5 ft. lbs and no leaks.

[mgphoto]

The number I look for here is 122 inch pounds, the pipes expand, the studs and nuts clamp down on the exchanger flanges, heat is a friend, to a point.

[iankarr]

Permatex 81878 max temp gasket maker is your friend.

[r_towle]

I will add my experience here.

Loose assemble everything in the exhaust system. Don't torque the head bolts until the muffler and the hanger are on the ends of the heat exchangers. I have found that forcing the HEs to fit the muffler results in exhaust leaks at the heads.

Get everything assembled. Then tighten up the HE to muffler bolts. Leave the hanger to transmission bolts loose. Torque the heads. Then torque the hanger to transmission bolts. Use a torque wrench on the HE to head bolts (23 Ft Lbs), and don't ever over torque them trying to get them to seal That will cause a pulled head stud and torn HE mounting loops. And that will cause an exhaust leak.

Hope that helps.

Clay

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