1957 gas cap--vented or unvented
My 57 was restored approximately 25 years ago at which time the gas tank was replaced. I had a heavy raw gas smell coming from it. My mechanic says the tank used to replace the original was a later model tank that was vented differently. He re-routed the venting and replaced the gas cap with NO VENTED locking gas cap. I don't know if it should be vented or non vented?
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Re: 1957 gas cap--vented or unvented
Early caps (to approx VIN 1900) were vented then changed to non-vented with addition of a vent tube added to top of tank towards right side. That was routed to a rubber hose exiting the body in the filler recess. Early tanks were not vented so originals wouldn't have the vent hose in the filler recess. If you don't see evidence of the vent hose in the filler recess, you may have to remove the tank cover form the convertible top well to see if/how the tank is vented. -
Re: 1957 gas cap--vented or unvented
Darryl------
You definitely need to remove the cover as Rod suggested and inspect the venting system and ensure that whatever the venting system, it is intact and properly installed. A problem with the venting system is the only reason I can think of for the gas fumes you are experiencing, assuming that you know there is no underhood source. Certainly, the non-vented gas cap, assuming it is intact and properly gasketed, is not a source of the problem.
Gas fumes in the passenger cabin take away a lot of the joy of driving a Corvette.In Appreciation of John HinckleyComment
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Re: 1957 gas cap--vented or unvented
Hi Darryl, I have attached a few pictures showing the way an original vented tank is set up.
Pictures taken from a very original late 1957 with a vented tank and a non vented gas cap.Comment
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Re: 1957 gas cap--vented or unvented
My car is V.I.N. 2890 and has the vent hole in the gas door recess. Who ever put the new tank in had the vent line going to the bottom of the car, hence the gas smell. It is now back where it should be so I guess the non-vented locking gas cap will be OK.
Thanks for the responses.Comment
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Re: 1957 gas cap--vented or unvented
Would #1825 have had the hole with grommet for the hose (although no hose)?Comment
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Re: 1957 gas cap--vented or unvented
Kent your #1825 car is very close to Vin # 1900.
#1900 is the approximate date for the change over.
That being said I would be interested to hear if you can see the hole that
would have been drilled for the screw for the mounting strap.
Have you ever looked at the top of the tank to see if there is a vent pipe.
DaveComment
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Re: 1957 gas cap--vented or unvented
Only going off pictures for now. I'll update when I can.Comment
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Re: 1957 gas cap--vented or unvented
Locking gas caps are infamous for not having a tight seal, thereby allowing gas and fumes past, especially on hard right hand turns.Comment
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Re: 1957 gas cap--vented or unvented
Mike------
I totally agree. I was not aware that the C1 locking caps were so bad but the 1963-74 locking caps are REALLY BAD for this. I learned a long time ago to never use one on the road. Use them only when the car is parked overnight in an exposed, threatening location.In Appreciation of John HinckleyComment
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Re: 1957 gas cap--vented or unvented
Mike & Joe that is the same experience I had with my locking cap. The odor was there for years until I put the original back on. No one ever stole my gas but someone did break in and take my tools.Comment
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Re: 1957 gas cap--vented or unvented
I know what you mean Joe. I got my locking cap back when I lived in an apt. and there was a rash of sugaring tanks. Now it has a safer place in the garage. Also, a friend who owned a body shop showed me how to remove the cap while it was locked. So much for that safety device.
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Re: 1957 gas cap--vented or unvented
On my original non-vented cap on 2968 I had to put two gaskets in to keep it from leaking out on hard right turns when the tank is full.Comment
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