Exhaust Leak, Slight smell of fumes in the cabin Options

[Britain Smith]

I went through the painful process of replacing both rear wheel bearings and CV joints this last weekend and to do this I decided to remove the heat exchangers. It was actually a lot less painful to remove the heat exchangers that I thought it would be, however I now think I may have an exhaust leak. I was surprised that when I removed my heat exchangers, there were no copper gaskets or anything. They did have copper exhaust nuts however, which probably is the reason they came off so easily.

So, should I order up some copper exhaust gaskets and install them with some new copper exhaust nuts? Do orignal 1.7L motors supposed to have the copper gaskets there? What does and exhaust leak on these motors sound like exactly? If I have one, it is very slight cause I can hear something but it is hard to distinguish over the valve ticking.

Any assistance?

-Britain

[SGB]

Its possible those gaskets were hung up in the exhaust ports and didn't fall out. Did you look up in there? You do need 'em. There was a good thread recently that discussed heating the gaskets and allowing a slow cool down (not quenched) to make the copper more maleable. When I reattached the HEs recently, there was a Pinto like POOP POOP POOP from one side. I figured out which exhaust by getting under the running car and sticking a piece of rubber hose up next to the exhaust ports and listening at the other end.. The leaker was WAY apparent. Those studs should be tightened to 17 ft-lbs- no more! I did not soften my copper gaskets before I put 'em in there, but did learn that the torque on the bolts had dropped after a few heat/cool cycles, and the rubber hose test indicated some minor leaking too, so I retorqued a couple of studs.

[Britain Smith]

Yea, I thought I looked up there and didn't see any gaskets. Any idea where I can get a set?

-Britain

[Chris Pincetich]

I just replaced my 1.7 HEs and didn't see the gaskets in there either - BUT they were there! You can feel them, with a flashlight you MIGHT see them, but they are hard to see. I had some extra metal from battery hold-down strap project and bent the tip 90 deg, filed/grinded sharp edge, and used my new tool to delicately pry the gaskets out.

Sealing the leaks - I was SUPER nervous torquing the nuts tight. My studs had lots of corrosion and some even twisted out and were screwed back in. My torque wrench set at 20 lbs still felt super stiff when I tested it on a wheel lug, so I used a small socket handle instead. I tightened gingerly, drove a day, tightened again, drove, and every time I got them a little tighter. However, now they are on REAL tight (not sure exact torque) and I still feel hot air comming down from the heads as if they leak a little - IS THIS NORMAL? I think they still leak a tad but barely. (IMG:style_emoticons/default/beerchug.gif)

[ChrisFoley]

... I still feel hot air comming down from the heads as if they leak a little - IS THIS NORMAL? I think they still leak a tad but barely. (IMG:style_emoticons/default/beerchug.gif)

You can't tell by the feel of warm air if the exhaust ports are leaking or not. The cooling system pushes enough warm air through there to mask any small exhaust leaks. I like Scott's recommendation of using a rubber hose kind of like a stethoscope.

[McMark]

Britain, I agree that the gaskets are probably there but you couldn't tell. It's common for them to be so covered in soot that it's hard to see them.

I recently installed a set of heat exchangers that were a PITA to get seated against the copper. You have to make sure that the exhaust pipe does not get hung up on the head before it seats. If the HE pipes are slightly tweaked it can make it extra challenging. I had to use a large screwdriver to pry the pipe into location. Hard to explain and hard to see for the first time. But once you realize what you're looking for, then it's easy to tell if they're seated.

Also once you get the new gaskets in there you'll see any leaks easily because there will be traces of soot/carbon. You shouldn't see any black marks on your new copper.

[MartyYeoman]

Hi Britain,
You can remove the old gaskets with an o-ring hook.
Be careful not to mar the sealing surface on the head.
Add a dab of silicone seal to the new gasket to hold it
in place until you can bolt up the exchanger. It works
best if you don't have the output end of the exchanger
attached to anything.
Take your time.

[Britain Smith]

So, are you both saying that I should replace the gaskets with new ones? Where can I get a set?

-Britain

[Twystd1]

Order 2 sets of copper nuts from pelican.

Then "double nut" the studs.

And use a SMALL inch pound or Small foot pound or N/M torque wrench to tighten to spec.

If by chance you have a large torque wrench, (goes higher than 50-60 lbs) Your torque wrench usually doesn't work for shit on small nuts or bolts. Most torque wrenches are most accurate in the middle of their torque range.

That is unless you have a BIG BUCKS torque wrench.

If your torque wrench is big enough for lugnuts. (1/2 inch drive) It's TOO BIG for exhaust studs.

I have a 1/4 drive torque wrench just for these small nuts and bolts. It has a dial indicator on it rather than a click type. It'svery accurate and one of the right tools for these kinds of jobs.

Check your wrench (length would do for comparison) against others on the web via Snapon or Matco. And see for yourself. Read the usage of a torque wrench. I think you will find it interesting reading.

If ya have any friends with motorcycles or VWs. They might have what you need as far as a proper torque wrench.

If ya already have the right one.... Your ahead of the game.

IMnotHO

C

[McMark]

You can get new gaskets from any of the main sources.

[dmenche914]

HPH house has them. Be sure you anneal them before install. Heat on your kitchen stove on high 9we used an electric stove, just poop them downon the element. then allow them to slow air cool. they will become much softer, and seal much better. anneal one, and do a drop test on a concrete floor with one not annealed, you notice a difference in the sound they make, and how they bounce!!!
I recomemend new ones, cause when used, they often get a groove in them, I suppose if on the cheap you could file it off.

the aftermarket heat exchangers =sometimes need some filre work to shorten the mounting tangs, cause sometimes they can hang up, and prevent a good seal, no matter how tight you crank them down. good advice is a torque wrench, the heads are fragile,

DO NOT allow the heat exchangers to hang all cantilevered out with out some support, as their wieght will torqure the studs out of teh heads.


good luck

[TROJANMAN]

don't forget to torch the new gaskets before you install them
it will soften them up for a proper fit (IMG:style_emoticons/default/welder.gif)

[Britain Smith]

For some reason when I was looking for the exhaust gaskets, I failed to check Pelican...parts are now on order. I am going to go ahead and replace the muffler gaskets also to freshen everything up.

So the procedure when I get them is to heat them up and let them cool slowly before installed them...no problem.

-Britain

[SGB]

As an alternate to siliconing the gaskets into the head, I set the gaskets on top of the exhaust pipe and put a little aluminum foil tape (the stuff you peel the backing off) at a few spots around the circumfrance of the pipe to hold in place on the pipe.

[ChrisFoley]

A couple dabs of grease on the gaskets is usually enough to hold them up to the port while the exhaust is raised into position.

[Britain Smith]

Thanks for all the help guys. I should get the parts on Monday and I will do the install over the Thanksgiving break.

-Britain

[Chris Pincetich]

(IMG:style_emoticons/default/agree.gif)
Some motor oil did the trick for me. When I started her up, the puffs of black smoke started and I thought it was the oil burning off. The LOUD pop put pop put told me there was a leak too. It still sounds loud to me, but I also switched from heavy steel stock HEs to SS HEs. Thanks for the info about all the hot air not being from leaks...I'll have to do the hose listen thing some time and see what happens, and put that micro torque wrench on my Xmas list! (IMG:style_emoticons/default/beerchug.gif)