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Discussion Starter #1
Hello I am really upset with a vibration problem with my car since I changed the exhaust completely. I experience vibration in the car. I just installed a flex tube and it diminished but its still there and one can`t accelerate fast.
The car was a blast to drive (except for the loud sound) before I changed the exhaust. It was replaced from the header (it came with the car) to the tailpipe, it only has the rear muffler. I don´t know what causes the vibration since the pipe is not in contact with the car. If someone has any idea, or any pics of how its exhaust is installed it will be really appreciated.

I had my flexjoints changed, driveshaft balanced and transmission mounts changed.
 

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Sounds like you've covered everything that would be suspect already...perhaps it's at the manifold downpipe joint? Can you recreate the vibration with the car in neutral and just revving the engine, or is it only when the car is on the move? If possible, I'd have some one sit in it and rev it to the point of vibration while I'm poking around outside the car trying to figure out the location...
Also - perhaps the balanced driveshaft was inproperly installed?? Just taking wild guesses here... :)
 

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Discussion Starter #3
Regarding the unproper installation of the balancesd driveshaft, I dont think its probable since the car had all of those "goodies" with the old exhaust system. Onces I changed it, the **** thing started. :mad:

The exhaust moves freely, too much for what I expect, but doesn´t touch anything. I will try what you say on saturday with a guy that did the exahust to car´s old mechanic (the one the previous owner recommend me). Probably he can fix it.

I must say that after the header (non-stock exhaust manifold) I have the flex tube, then the exhaust is hanged by two rubbers before the trans, has one mount over the suspension and one mount at the back. I am missing one? does the exhaust is moving too freely?

The vibration is present is the car is still and I rev it, while still and reving and letting the revs down and while dribving when I accelerate hard, I can feel it, the rearview mirror vibrates too!!!

This is by far the most unpleasant thing the car has undergone!!!:(
 

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Yeah, vibrations can really kill your mood. I'm not familiar with the '82 GTV's as they were no longer imported to the US after '79. If the cars didn't change exhaust hangers specs, then it sounds like you have all of them in place. They do move around a lot and I don't have a flex tube installed on mine (also with aftermarket Shankle headers). Usually you get a banging noise when you hit a rough patch of road and the exhaust is loose.
How are your engine mounts?? Check all three of those - they can cause all sorts of scary noises when they begin to sag...
 

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Discussion Starter #5
Jeff, the engine mounts are new, since I had trouble with them, the rear mount was really shot, so I had very strange noises from the driveshaft. Then I changed the side mounts and the rear engine mount. Then changed the flexdiscs, had the driveshaft balanced. And the mechanic told me about the trans mounts (they were original!!!) so all of that is in order.

Its very very strange indeed, I must look at it with lots of attention. I guess that there isn`t much change from the previous alfetta US versions, since all of the stuff I bought for the car was purchased at the US (alfa history in Peru is quite a story so I buy my stuff on your shores).

I will have some pics so you can figure it. This is my first Alfa and I love it!
My next mods are paint, tyres...laaaaaater polybushes,steel braided hoses for brakes and clutch.
 

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How are your engine mounts?? Check all three of those -...
I agree! And in particular, the left engine mount. If it is broken/weak, the engine will twist (more than normal) in a clockwise direction under acceleration which could result in the exhaust hitting the body.
 

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Jeff, the engine mounts are new, since I had trouble with them, the rear mount was really shot, so I had very strange noises from the driveshaft. Then I changed the side mounts and the rear engine mount. Then changed the flexdiscs, had the driveshaft balanced. And the mechanic told me about the trans mounts (they were original!!!) so all of that is in order.

Its very very strange indeed, I must look at it with lots of attention. I guess that there isn`t much change from the previous alfetta US versions, since all of the stuff I bought for the car was purchased at the US (alfa history in Peru is quite a story so I buy my stuff on your shores).

I will have some pics so you can figure it. This is my first Alfa and I love it!
My next mods are paint, tyres...laaaaaater polybushes,steel braided hoses for brakes and clutch.
Well, you sure aren't making this easy! ;) I think you'll need to go with my first suggestion of having someone rev it while you investigate the location. Let us know your findings...I'm really curious now, knowing all the work that you've already done. :confused:

Regarding future mods: Welcome to the never ending life of "I wanna do (insert project/upgrade) next on my Alfa". It seems no matter how much you do, there will always be more! :D
 

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Discussion Starter #8
Thanks for the support Jeff, I know this is not going to be easy, but I will check them again. ANd follow your method, to see what comes along and kill this vibration!!!:)
Yes I think the car will nevre be finished, always wanting more. But know it has cams, header (both came with the car, don`t know brand or specs), came with a spare of Dellortos 45mm (it has 40mm installed) and with independent filter casings ( I just took the stock box out and installed those with Ram Flo elements), NGK iridium plugs, Accel coil and 8mm wires and a mallory hy-fire ignition...its a very nice car!! jeje
 

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Two rubbers at the transmission doesn't sound right from my memory with our Alfetta Sedan - I thought there were four different rubber rings used to support the exhaust under the car, plus one at the rear suspension, plus one at the rear muffler. Just before or just after the flex joints of the exhaust they should have anchor points to the body either with black rings or bolted up. Get an exhaust shop to put it up on the rack and you should be able to find either the hooks on the underbody of the car or a bracket where the exhaust should be anchored in that area. On our sedan it had a bracket that it was bolted to.

Is this just vibration or noise of the exhaust hitting the driveline? If the exhaust is not secure enough or the joint of the exhaust at the rear suspension is not in the right place it will hit the rear donut of the driveline. This has happened to me before.

GV
 

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Discussion Starter #10
Its just vibration. I will take pics so ywe can figure out if there is a support missing. One guy told me that there should be a support by the rear engine mount which the car lacks.
 

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Usually this is caused by having exhaust mounts that are too stiff and don't allow for the extreme amount of engine movement in an Alfetta.

A way to diagnose is to alternatively disconnect mounts and see if the vibes change. Start from the front and loosen/disconnect.

The factory mounts are really soft and most exhaust shops don't understand and replace with hard rubber strap or similar.

The support by the rear engine mount is often omitted, esp with aftermarket extractors, without a lot of drama. My guess would be the middle or tail mounting is too stiff.
 

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there is an original mount with rubber bushing at the front pipe wich conected to the rear engine mount.
check for wear in that bushing, or the rear engine mount itself.
 

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Discussion Starter #13
Here are the pics...just went under the car this night and have them shot... I will let you know what was the cause...but I think that the rear section hangers are very very stiff, and that in addition of only two donuts before the tranny could be causing this pain in the butt.
 

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Ennio
Do you have this vibrations all the time or only when trying to climb up hill in first gear or reverse ?
I can see the front mount isnt conected so that is probably not the reason, unless it thouches something.
 

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i have experienced increased vibration from wrongly packing up a sagging rear engine mount and also putting on stiffer rubber mounts(2) before the transmission...it is much better to let the exhaust move around freely
 

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While it's hard to tell from the very last picture - it seems to me that your rear muffler is awfully close to the spare tire well. It looks like it was mounted so that the can is tucked up right next to it. I've never seen that done before, I know mine hangs flat & below the spare tire well. Still - that would seem to cause more of a banging noise than a vibration?
 

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Discussion Starter #19
Thanks for your help. Answering in and orderly basis:

1)The vibration is present at all times. If the car is still and I rev it it also is present.

2) I will try to see what happens if I take those mounts before the tranny, or try to install something more flexible (softer)

3) Yes the muffler is in the middle between the gas tank and spare tyre. I`ve benn pushing it, at it bangs with the tank. I will have to see carefully if this causes the vibration, banging or comething else.

Seems that there is lots of work to be done, taking off the various rubber hangers to see if there is a change. If so replace them with softer mounts, and try to hold the muffler with softer mounts too!! Or add the mounts that are lacking...seems that I should have a talk with the guy who installed it (someone who thinks that the job is donde correctly, that the car is okay, that I am crazy....lazy guy who thinks my Alfa treasure is a ick-up or a truck!!!)
 

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Another thing to consider is perhaps something found it's way inside the exhaust tubing? Take a rubber mallet and lightly knock around and see if you can hear anything rattling around.

You definitely should have a talk with the guy who installed it. In my experience, even people familiar with Alfa's, have a hard time working out the Alfetta's system on the first try. Just be thankful you're not in California and have to add a catylist to the mix!
 
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