Anyone know if GM originally used a seal around the "tanker" fill neck where it penetrated the rear bulkhead? The AIM doesn't show or list a seal to close off the space (which is about 1"-1.5" wide all around the neck). Obviously, the tank cover helps to keep much of the road dirt and wandering critters out of the interior, but...
C2 Rear bulkhead - seal around "tanker" fill neck?
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Re: C2 Rear bulkhead - seal around "tanker" fill n
No seal was ever used on the opening. As you mentioned, the tank cover isolated the entire area from the passenger compartment. The reason no seal was used was to provide a vent, of sorts, so fumes from minute fuel seepage couldn not build up inside that area. The tank and compartment would be completely covered in dust/dirt after a few years of driving.- Top
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Re: C2 Rear bulkhead - seal around "tanker" fill n
Here's a shot of the fuel filler area and opening on the rear bulkhead. No attempt was made to seal the compartment.
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Re: C2 Rear bulkhead - seal around "tanker" fill n
Here's the tank, covered with dust/dirt after many miles of driving. The tank cover would be sealed to the bonding strips to prevent dust and fumes from entering the passenger compartment.
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Close-up of 36gal filler piping at rear bulkhead
Took this pic about a half hour ago.
Click on following link for general view (taken 4 years ago when my diff was out for a rebuild).
As Michael says, the seal is all important. Every linear inch of the tank cover has to be gas-tight, including all the cover bolts. This is why the factory fills the groove at the interior of the vertical bulkhead ribs to affect a flat seal surface at the edge of the cover.
I've put about 10,000 miles on long trips with mine, and I always detect exhaust odor, in spite of my efforts.
About 20 years ago I removed the cover to clean the inside surfaces, as Michael describes; that's why the top of the filler assy where it goes through the bulkhead is clean and the bottom isn't.- Top
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Close-up of 36gal filler piping at rear bulkhead
Thanks guys for your thoughts & the pic of the "tanker" fill neck/bulkhead opening!
I know how extremely thorough & detailed the GM designers/engineers were/are. Therefore it was just alittle surprising to me they didn't at least spec an "open cell" foam seal for the bulkhead opng - to restrict infiltration of dirt, etc, while simultaneously allowing, as Michael theorized, ventilation of residual fuel vapor. Can't change history, so that's the way it will be...
It's logical that most "tanker" owners wouldn't be concerned about the huge gap around the filler neck, as it's completely hidden. But since this particular Z06 is being prepared to its "as-raced" point in time (ie no spare tire carrier) that huge gap is quite visible when one looks under the rear valance.
Wayne makes a good point about exhaust fumes weeping in around the tank cover joint (in-spite of an abundant use of sealant around the edges). That won't be too much of a concern in this case though - since the effects from the side exhaust should more than adequately burn the eyes and deafen the ears!- Top
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Re: Mike do you know the vin on the Z06
Phil,
Yes, the car is in the high 8xxx range, built aprox 14 Feb. Did you happen to notice that the tank and surrounding area was painted red?- Top
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Re: Close-up of 36gal filler piping at rear bulkhe
In principle, this design isn't that much different than the C1 fuel tank arrangement - it was also mounted in the passenger compartment under a cover panel with sealer around the edges, and it had two ventilation holes below it in the underbody so fuel vapors couldn't be trapped in an enclosed space in the tank compartment (and become a bomb).- Top
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Re: Mike do you know the vin on the Z06
Hi Dick,
No, that's a different silver/red Z06. Believe that car still lives in your area. Pretty sure it was in the 9xxx VIN range. Originally from Minnesota.
The silver/red car in the pic's that I posted is in the 8xxx range and originally from Texas.- Top
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Re: Mike do you know the vin on the Z06
Just curious. I did a body off on the car bout 15 years ago. Real neat car. Absolutely had a ball preparing the car for a PV. I went through the PV 6-8 times before we went to the meet. Those brakes, once warmed up were fantastic.Dick Whittington- Top
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Re: Mike do you know the vin on the Z06
Dick,
I'm sure we're talking about the same car. I'm a little surprised Russell decided to completely restore the car. It looked very good the last time I saw it in the early 80's. Had incredible original interior and carpet at that time but I know he decided to replace the carpet anyway. Had nice original KO's and NOS correct B F Goodrich Silvertowns when he bought it. Real car, real engine.
The other silver/red Z originally came from Texas. Was basically a body and frame and a car load of parts in the early 80's.- Top
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