EXAUST SMELL INSIDE

[Sagandaga]

Getting exhaust smell in the trunk and interior of my Avanti. Has full stainless system and chrome tips. It is very pronounced in the trunk. The weather strip on the trunk is good. I can move the tips out a little, but not much. Has anyone else had this issue? It seems only to happen when driving not just sitting and running. I don't see any openings other than the trunk lid.

[studegary]

I am thinking that you are possibly getting fumes from the engine compartment that pass through the body and accumulate in the trunk while driving (assuming no leaks in the exhaust system).  Do you have A/C?  That will (when used) create a partial vacuum in the passenger compartment (due to the cooling).  Remember that the Avanti does not have flow through ventilation or a fresh air A/C system (as on cars today).  

[Avanti83]

By trunk lid seal good, do you mean it's in good shape or you have checked the seal with the old dollar bill trick. If it passes the dollar bill test, I agree with Gary. There are a number of places that fumes can get past the firewall. Start with the accelerator pedal seal and go around the firewall. There is a lip seal on the rear of the hood, be sure it's good and lastly, if you can get the car up in the air - check for leaks in the exhaust system. Stainless steel is harder to seal than mild steel, in my experience, so check all the connections including the exhaust manifolds both at the block and pipe connections.

[grobb284]

I had a similar problem years ago with an Avanti I had restored. The exhaust tips had to be several inches beyond the lower edge of the body to correct the problem. The symptoms were similar, problem was with car moving.

 

I assumed that the exhaust slip streamed up the rear of the car rather than dispersing behind the car due to the Avanti shape. 

Extending the tips seemed to alleviate this.

[studegary]

"Avanti83" got me to re-read your post.  If by; "The weather strip on the trunk is good." you are only referring to the condition of the weather strip and not how it is functioning, then that is likely where your problem is.  I also noticed that your trunk lid appears to sit high.  It may need to be brought down to get a better seal.

[Sagandaga]

I have a lift in my garage. I have looked at the exhaust system from front to rear, no leaks. I will test the trunk seal for contact with the trunk lid. I will also move the tips as far rearward as possible. Thanks to all for their insight. Sorry about the sideways pic, my phone sends them sideways.

 

[brad]

If the tips are "slotted" where they slip over the pipes, (not stock) then you will get fumes. Some silver or grey silicone over the slots might be a fix.

[regnalbob]

On ‎9‎/‎20‎/‎2018 at 10:22 AM, brad said:

If the tips are "slotted" where they slip over the pipes, (not stock) then you will get fumes. Some silver or grey silicone over the slots might be a fix.

The original stock tips from the factory are slotted.

 

Edited October 14, 2018 by Regnalbob

[brad]

But if the slots are not covered by the tip being slid over the slots, then the fumes will leave the slots, into the car.

[Stan Gundry]

The caption with the tip shown above seems to suggest it is a factory tip. I do not believe it is. On a factory tip the transition from the larger diameter to the smaller is muc more gradual.

[JLBKY]

What Stan said  X2

[regnalbob]

16 hours ago, Stan Gundry said:

The caption with the tip shown above seems to suggest it is a factory tip. I do not believe it is. On a factory tip the transition from the larger diameter to the smaller is muc more gradual.

 

8 hours ago, JLBKY said:

What Stan said  X2

Yes, it is a factory NOS tip. I have 4 of them that are fifty years old. They were ordered from Studebaker when my family was still a Studebaker Service Dealer.

They are identical to the factory tips on my 1963 Avanti that I have owned for over 53 years.

I also have a complete NOS exhaust system that was ordered at the same time.

[Stan Gundry]

Well, I do not want to get into an extended argument about whether or not the exhaust tip shown above is the exact style as originally came with Avantis from the factory. But in 1978, George Krem told me that the type of exhaust type shown above was not original and that the type I described was original. Even though Krem probably knows more about Avantis than all of us on this forum combined, I suppose he could have been wrong, or I could have misunderstood him, or I just do not remember what he said accurately (I admit it was 40 years ago he told me that). But my assertion seems to be supported by the photo on p. D-138 of the 1963/1964 Studebaker Avanti Authenticity Manual. Of course the Authenticity Manual could also be mistaken. I have found a very few things in it I believe to be mistakes, but even so, it is the most accurate and authoritative source of authenticity questions in print. If you are concerned about authenticity and do not have a copy, you should buy one.
 

 

[Sagandaga]

My tips are the slotted type as shown in the picture. I tried to move outward on the pipes but it exposed the slots. I pushed them back in and clamped them. If I let the car run without moving it there are no fumes entering the trunk. It is only when you drive it the fumes are sucked into the trunk, then the passenger compartment. It appears a vacuum is created at speed sucking the fumes in. I will try some silicone and see if that helps.

[studegary]

As has been previously mentioned, have you checked how tight the seal is all of the way around?  I am still concerned because your trunk lid appears to sit high when closed. 

[studegary]

Is your gasket attached to the trunk lid, as it should be, or is attached to the trunk opening, where it will not seal properly?

[iamrgh]

I had the same problem with my Avanti and added a slim additional gasket (still looks stock) to the stock trunk lid gasket and the problem was solved. The Old gasket, though pliable, didn't have enough "meat" to completely seal the trunk from exhaust fumes.

[Stan Gundry]

Speaking of the trunk lid gasket/weatherstrip, what should be its orientation to the trunk lid when glued on. I am in the process of gluing on a new one to replace the one that has been in place for 35 years. See the cross section of the new weatherstrip below. I have always assumed that the rounded lower right corner that you see below in the cross section fits into the similarly rounded corner against which the weatherstrip fits when it is glued onto the lid. this would mean that the open part of the U faces outward all the way around. 

However, after looking at the photos in the AOAI's 1963/1964 Studebaker Authenticity Manual, pp J265-268, I am wondering. The photos are not not real clear on this question, but the rounded corner on the lower right of the cross section you see below does not appear to be glued to the rounded inside corner of the lid. Instead it appears to be facing out (see especially the photos on p. J266). The other photos seem to suggest that the U actually faces in toward the center of the lid all the way around, although that is less clear.

How is the weather strip glued to you trunk lid? Does the open part of the U face in or out? Does anyone know for sure what the factory correct way is?

 

[Sagandaga]

My gasket is attached to the trunk lid, as it should be. The gasket, as in Iamrgh's post, is lacking in its dimension to properly seal at the lower trunk opening. All of the rest of the gasket perimeter passed the paper test except the horizontal  lower lip. Iamrgh, do you have a picture what you used on top of the existing trunk gasket? The space is 3/8" to 1/2" that there is no gasket contact with the lower trunk opening. No animals were harmed but you could throw a cat through it  

Edited October 7, 2018 by Sagandaga

[Avanti83]

3 hours ago, Sagandaga said:

My gasket is attached to the trunk lid, as it should be. The gasket, as in Iamrgh's post is lacking in its dimension to properly seal at the lower trunk opening. All of the rest of the gasket perimeter passed the paper test except the horizontal  lower lip. Iamrgh, do you have a picture what you used on top of the existing trunk gasket? The space is 3/8" to 1/2" that there is no gasket contact with the lower trunk opening. No animals were harmed but you could throw a cat through it  

I'd try to bring the trunk lid down more initially. While I've not done this on a Avanti I have used this from a Big Box store on other vehicles. It comes in several diameters.