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> Exhaust Leaks, Need Guidance
2-OH!
post May 24 2004, 01:06 PM
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75 - 2.0

Dave Hunt and other victims:

Just got 2-OH! started this weekend, still runs shitty, but that's another story...

What I'm bothering you about is your exhaust leaks...I assume you had a bad seal between the heads, the copper gaskets and the manifolds...

How did you know...and a quick and dirty on how you fixed em'...The nuts are torqued correctly, and honestly, I would hate to torque them any more...Afraid of breakage...

With the car running, I get a pretty good downdraft of hot air if I hold my hand under the manifold area...Not scorching enough so that I have to move my hand but hot none-the-less...But is that blow-by or just the cooling fan/tin/ducting/cooling air moving over the cylinder heads doing it's job and exiting under the car...

When running, it doesn't backfire or spit...How can I tell if the manifolds are sealed or not...

New gaskets, new nuts, old manifolds but they fit right in, fresh head rework with a couple of new studs...

2-OH!
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mike_the_man
post May 24 2004, 01:59 PM
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When my exhaust was leaking, it was very noticable. It was sputtering and backfiring, even at idle. I torqued all of the studs up to 16ft/lbs, and that seems to fix it. I'm betting that what you're feeling is just cooling air, but I could be wrong.
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TheCabinetmaker
post May 24 2004, 02:05 PM
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Engine cooling air will be a constant velocity. Exhaust manifold leaks will have a "beat" that will quicken with engine rpm. The stock 75 headers are hard to seal, and can require a retorque after warmup.
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SirAndy
post May 24 2004, 02:19 PM
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QUOTE(vsg914 @ May 24 2004, 01:05 PM)
Engine cooling air will be a constant velocity. Exhaust manifold leaks will have a "beat" that will quicken with engine rpm.

yupp, he's right ^^^ ...

cooling air is a constant flow at constant rpm, exhaust leak will oscillate ...
Andy
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rhodyguy
post May 24 2004, 08:14 PM
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rick, lightly dress the tops of the flanges with a big file. do both on one he at the same time. push the he up tight and look to see how it will sit using the studs as gauges. now put all 4 nuts on. whist pushing up, cross tighten the nuts so they are barely snug and there is no rocking of the he. torque in a cross pattern. when i put ss hes on the 75' i took the torgue up in three stages. 1/3 2/3 and the final at full value. heat the engine up well, let it cool down, and recheck the torque. took me three trys and a full day to seal things up.

kevin
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RustyWa
post May 24 2004, 10:55 PM
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QUOTE
rick, lightly dress the tops of the flanges with a big file. do both on one he at the same time. push the he up tight and look to see how it will sit using the studs as gauges. now put all 4 nuts on. whist pushing up, cross tighten the nuts so they are barely snug and there is no rocking of the he. torque in a cross pattern. when i put ss hes on the 75' i took the torgue up in three stages. 1/3 2/3 and the final at full value. heat the engine up well, let it cool down, and recheck the torque. took me three trys and a full day to seal things up.

kevin


^^^^^^^^^^What he said^^^^^^^^^^
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rhodyguy
post May 25 2004, 06:50 AM
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the reason it took a full day was, i did it as i discribed the 3rd time and i cushed the he to muffler gaskets pretty well. then i had to go to the parts store for some new ones (IMG:style_emoticons/default/rolleyes.gif)

kevin
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2-OH!
post May 25 2004, 07:10 AM
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Thanks guys...

Kevin, thanks for the tip, sounds like a good proceedure...

Thanks,

2-OH!
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DNHunt
post May 25 2004, 07:21 AM
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Rick

I did all of the above and still had leaks. It always popped on decel at the same stop sign about a mile and a half from my house. It didn't leak when cold and it didn't leak when hot just on warm up.

I was so pissed the next time I had it in the garage I said to myself I'm either gonna fix it or bust it so I grabbed the HE's and started shaking them around. Enough so I could see the engine moving on the mounts. I tugged and pulled then tried to take up a little on the exhaust nuts. I got a little on a couple so I the whole thing until all were snug again. No exhaust leak.

I supect that stuff was cocked a little and wrestling with it loosened the binding.

Some people wrestle other people, some wrestle gators, I wrestle cars

Good luck

Dave
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DuckRyder
post May 25 2004, 07:31 AM
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On a related note,

What is the trick to holding the gaskets in place while raising the HE's into place? (IMG:style_emoticons/default/headbang.gif)
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DNHunt
post May 25 2004, 07:44 AM
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Little dab of RTV, unless you run an O2 sensor downstream like I do. RTV kills them.

Dave
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tat2dphreak
post May 25 2004, 07:46 AM
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I just stuck my gaskets up in the head, and gave them a slight twist, they stayed long enough to mount up the H/E... or is that wrong?
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DNHunt
post May 25 2004, 08:07 AM
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Nothin wrong with that. Whatever works.

Wayne

This is the other half of the love hate relationship with my car. Give her a little love with the valves and a lot of hate with the exhaust.

Dave
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Bleyseng
post May 25 2004, 08:11 AM
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All of the above and pound on them to seat them into the head with a hammer (IMG:style_emoticons/default/smash.gif)

The j tubes are a bitch to seat right!

Geoff
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914werke
post May 25 2004, 09:51 AM
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Take a BIG flat file and run it over the HE tube mating surfaces. then check with a square or flat stock. I used Vasoline to "stick the coppers" into the heads while assembling.
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2-OH!
post May 25 2004, 10:26 AM
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The J tubes are a bitch and thats where I'm feelin' the air...But it's not pulsing, or spittin', or burpin' so I think i'm OK...It's just fan cooling air...I haven't had a chance to check it out since all the suggestions...

I used a small smear of high-temp RTV to hold the copper gaskets in place let it dry while I "persuaded" the J tubes onto the studs...But, they were not that hard...

2-OH!
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