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Discussion Starter · #1 ·
My solution was to switch to an exhaust manifold and save the header for later. What I've noticed on my 20 minute drive home is that I really miss the sound of my leaking header system. It really sounded mean. Now, I have a deep muted, muffled rumble. I think I prefer the higher pitched, clearer sound of my previous system. Maybe I should get rid of the muffler?

Oh well, as for performance, the car seems slower. Maybe it's a result of the quality of the sound? I don't know. But I will have to drive her more than 20 minutes to find out.

Anyways, thanks to all who helped with advice and to Trent who came thru with the sprint manifold. I'm back on the road again.

Manny
 

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Discussion Starter · #3 ·
calvin said:
I use a bullet glasspack for a muffler from advance autoparts $25 ..yes it is loud on the inside. you will need a good stereo..but it is a solid meaty rumble and not the current coffee can sound of many of todays cars
It's not volume that I appreciate but the quality. Just as with stereo equipment, the less distortion, the louder you can turn up the volume before it gets objectionable. The same with the exhaust. If it sounds good, it can usually be louder and still sound good. Take the Ferrari 360 Challenge Stradale for example. Just about the loudest factory exhaust available but it sounds SOOOOO GOOD!!!

My exhaust just sounds muffled, like a pillow has been put over a speaker. I still notice the various components of my original soud but it's just not as crystal clear and enjoyable as before. I wonder how loud a straight thru exhaust would be (sans muffler).
 

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Opeler
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leak detection

Where was your leak?
I highly suspect my Pacesetter.
I really need to go after this again, as weather warms, the need to have windows open and that's when exhaust fumes enter (at least that's what I think it is, could be hot oil burning off something too yet).
What do you guys think about pouring some ATF into the carb to produce smoke and seeing where it comes though? I'm suspecting right at the header to head junction although the sound isn't very apparent.
I should probably hunt down a Sprint, eh? Too bad really, someone did some time on it to get it too fit.
 

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Opeler
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Other than your ear, ATF in the carb (partially blocked up tail pipe), what about a smoke bomb in the tail pipe, block up the other one and shove a leaf blower up there to pressurize? Is that a stupid idea? Depending on if an exhaust valve is open, would a little sulfur (whatever is in a smoke bomb) in the system hurt for a few seconds?
 

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Detritus Maximus
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j-

Just let the carb run rich for awhile. Then take the header off and look at the gaskets. Wherever you see the black carbon is where it's leaking!
Then block off both ends of the header and fill it with water. Wherever the water comes out is a bad or porous weld.

But before doing any of that (or engineering a smokescreen), check the header to head bolts. How thick is your header flange? Do you have the half circle spacers to bring the header flange bolt surface up to match the intake bolt surface?
How far back does your exhaust go? Currently, mine stops a little short, so the low pressure area under the car tends to hold some exhaust fumes under it and just as yours does, the open window draws the fumes into the car from any hole (rust) or bad body gasket (taillights/fuel tank line fitting boot/clutch cable hole/shifter hole/steering shaft bulkhead hole/etc.) it finds.
 

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A good way to find exhaust leaks is to get a 3ft piece of fuel hose and hold
one end to your ear and move the other end near the exhaust pipe or manifold .HTH
John
 

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Opeler
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Flanges and tips.
I'd like to have a good idea of where the problem lies before I fix it this time. :eek: Last year I redid all taillight gaskets and plugged up every opening I could find except the drainage weep holes.
Be good to know if it's being sucked in from the back or drawn in from a leak further up.
Maybe a shop can run a test for a few bucks. Better that then disturbing a perfectly solid header to head arrangement, no?
I can see a gap between the header flange and the head at #4 and it seems tighter up by #1 so that's why I'm suspecting that area, no other proof though, don't hear, can't feel it.
 

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Detritus Maximus
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You may be able to take the manifolds away from the head far enough to see what is going on without disturbing the other exhaust connections. may have to loosen all the hangers.

Also, tubular headers are noted for leaking thru bad welds and where access is too tight for the welder. namely right around the flange and where the tubes merge. Since two and three do both right at the head, it is a likely spot. If it is leaking there, the header wrap may be muffling the sound and make it impossible to feel.

Look at the tail panel of your car. Does it tend to get dirty from the exhaust or faster than the rest of the car? The tips look a little short, like they don't come out far enough.

Do the fumes you get smell 'exhausty' or 'oily'? If oily, they might be from the breather hoses.

Check your pm's.
 

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Detritus Maximus
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Try this:

Go for a drive and take a nice big, heavy towel or two with you. Get on the highway. Wrap the towel tightly around the gearshift and console, hopefully two or more layers. See if that reduces the fumes.
If it has an affect, lift up the console and check the gearshift boot (torn or it can tend to pop or slip off the metal ring on the trans tunnel. I've also seen them attached only to the console and not seal the hole in the body), the four little rectangular rubber 'pads' (they fit into holes, if they are missing, then you have four holes), the holes the console clips fit into (I think they has some sort of plastic insert or sealer, but not sure), and the parking brake boot.
 

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I highly suspect my Pacesetter.
Tried 4 times to get one to work. Double gaskets, liquid gasket cut the flange brace. NEVER WORKED:banghead: I went back to stock. Now I've got a leak at the connection between the manifold and down pipe connection:banghead::banghead:
 

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Opeler
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Yes, my tail panel gets sooty fast, always has. In fact, just last night, while double checking the reserve light housing, grommets for back up light wires and all that, I noticed again how "stained' it all is on the back panel.
Smell seems like exhaust to me but could be hot oil burning off something too as I do have leaks.
I do not have that lower boot on the shifter, I assume there is supposed to be one under the main shifter boot somewhere? I just installed a new main shifter boot from OGTS and since I no longer have the plastic snap ring, I taped over those holes long ago.
Same old question(s) as last year:
is it exhaust, is it burning oil, is it coming in through the tail or into the cabin from somewhere else, and what is the source anyway?
If there are no oil or exhaust leaks would it all go away?
I don't know. Not much luck fixing oil leaks so far, turned my attention to exhaust again.
Certainly is annoying, just got in from commuting to work and with windows up, nothing, crack my window and instant smelliness.


How far did the stock exhaust tips stick out? Was this ever a problem when these cars were younger or is it due to leakiness of exhaust shorter tips and cabin seals (tailight gaskets, grommets, boots.....) inherent in a 38 year old, heavily tinkered with car?
 

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'72 Opel GT (Sara)
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2,119 Posts
...Smell seems like exhaust to me but could be hot oil burning off something too as I do have leaks...Same old question(s) as last year: is it exhaust, is it burning oil, is it coming in through the tail or into the cabin from somewhere else, and what is the source anyway?
If there are no oil or exhaust leaks would it all go away?
I don't know. Not much luck fixing oil leaks so far, turned my attention to exhaust again...
I don't know if this will help you or not, but FWIW, a couple months ago I added some wooden slats in the spare tire area to hold a plastic bin securely back there with my emergency kit in it. I painted the wooden parts black to match the tray. Anyway, at that time the weather was cool and I was driving with the windows up - no smell of paint. A few weeks later, I started driving with the windows down and all of the sudden - the smell of fresh paint is entering the cabin. It has finally dissipated but I found it interesting that the paint smell was not there with the windows up (even when fresh) but appeared later once the windows were rolled down. There is obviously a change in air flow that occurs with the windows down and it most definitely includes drawing air through the spare tire area into the cabin. I know you already did this, but you may need to go back and check your filler neck hose, fuel sender gasket, vent hoses, etc. (anything back in that area of the car that has to do with fuel).

HTH

Matt
 

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Opeler
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Your experience seems to confirm that whatever fumes are in the rear, get sucked up front as soon as a window is cracked. I don't have fuel smells when underway, it's exhaust (I think). But that makes me more suspicious of normal exhaust out the pipes coming back in, and a bit less leary of leaks up front. I'm seriously thinking of doing some goofy tests with colored smoke bombs. Hang one off the reserve light, light it, jump and drive, open a window, see what comes in. Why not? My 7 year old has been asking to do this since I first mentioned it last year. Having someone drive beside and watch the smoke might be interesting too. If nothing else, I'd have a cool colored smoke trail for a while. There's deserted country roads for this.
 

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Vendor
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Better still, light the smoke bomb IN the car, while you're driving, and have your helper see where smoke is coming OUT as you move down the road. :lmao:
 

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Opeler
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Cool.
Should come out the rear vents above the rear window, no?
This sounds like a poor man's wind tunnel test.
I'd do it but finding someone to ride along side and shoot video while I do insane things might be tough.
I'll hang smoke bombs everywhere, all different colors and take off and see what color I am at the end.:p
 
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