Sending unit o ring or gasket.

[Michael K.]

Installing sending unit on new tank in 64. I see the o ring fits nicely between the tank and unit. The sending unit also came with a cork gasket. The AIM doesn't show where the gasket goes. It appears there would be a good seal with the o ring. Is the gasket supposed to go between the o ring and unit? Doesn't seem likely but want to be certain. I don't want to mess with a gas leak. Thanks! Michael Kalogridis 518 248-1105

[Don H.]

Re: Sending unit o ring or gasket.

Michael, If I remember right (dangerous), I only used the o-ring. I don't recall using a gasket. Good luck, Don H.

[Joe R.]

Re: Sending unit o ring or gasket.

Michael,

The cork gasket goes on the fill neck. Only the rubber O rings goes between the tank and the sending unit.
Those two gaskets are packed with the tank and sending unit.

JR

[Frank D.]

Re: Sending unit o ring or gasket.

Prob worth changing the filler neck gasket too though....especially if you're getting a gas smell...
On my 63 the filler neck mounting screws have integrated rubber O rings that go bad too...you'll want those if a '64 uses 'em...

[Joe L.]

Re: Sending unit o ring or gasket.

Prob worth changing the filler neck gasket too though....especially if you're getting a gas smell...
On my 63 the filler neck mounting screws have integrated rubber O rings that go bad too...you'll want those if a '64 uses 'em...

Frank and Michael------


I like cork for lots of things but not for the filler neck gasket even though that's what was originally used. I make up a similarly configured gasket from a sheet of about 3/32" thick buna-N material.

The screws with integral rubber seal, GM #3767804, were used for all 1963-74 Corvette filler necks. They are essential and the seal must be in good condition.

[Dan B.]

Re: Sending unit o ring or gasket.

Ethanol%20&%20E85%20Material%20Compatibility.pdf

Frank and Michael------


I like cork for lots of things but not for the filler neck gasket even though that's what was originally used. I make up a similarly configured gasket from a sheet of about 3/32" thick buna-N material.

The screws with integral rubber seal, GM #3767804, were used for all 1963-74 Corvette filler necks. They are essential and the seal must be in good condition.

In checking out Buna-N, I found this disturbing document regarding Ethanol compatibility. According to this, many of the components in our fuel systems are not compatible like brass, tern plating, and cork. Sorry I looked, but it explains a lot of things I have been seeing. The title "Ethanol Fill up Feel Good" gave me a laugh. Dan

See top of page for link. Was having trouble getting this to post.

[Joe L.]

Re: Sending unit o ring or gasket.

[ATTACH]73240[/ATTACH]

In checking out Buna-N, I found this disturbing document regarding Ethanol compatibility. According to this, many of the components in our fuel systems are not compatible like brass, tern plating, and cork. Sorry I looked, but it explains a lot of things I have been seeing. Dan

Dan------

I made my filler neck gaskets prior to the advent of ethanol-blended fuels. However, I think the compatibility problems with ethanol are likely based upon straight ethanol or gasoline with a high percentage of ethanol (like E-85).

In any event, the Buna-n is better than cork as far as ethanol compatibility goes. Actually, I'd prefer to make the filler neck gasket from a sheet of Viton if I could find it.

GM has approved the use of gasolines with up to 10% ethanol for all of its vehicles going back quite a few years. However, I don't know just how far back this approval goes. Finding widely available gasolines not blended with up to 10% ethanol is becoming increasingly difficult in some areas of the country. In California, it's virtually impossible.

[Dan B.]

Re: Sending unit o ring or gasket.

Joe, well thanks I feel a little better now

Where is a good source to get Buna N?

I'd like to try making some gaskets out of it.

[Joe L.]

Re: Sending unit o ring or gasket.

Joe, well thanks I feel a little better now

Where is a good source to get Buna N?

I'd like to try making some gaskets out of it.

Dan------


I bought mine at an industrial supply company which specialized in elastomers but it was a long time ago and I don't recall the name of it. I think you can probably find it online. Buna-N is a VERY widely used material, especially for fuels and lubricants. Grainger might be one firm that could supply it.

By the way, I did a little online research since I last posted and I did find Viton sheet material. The problem is that a 36" X 36" size piece (the smallest available) of 3/32" thickness costs almost $500.

[Frank D.]

Re: Sending unit o ring or gasket.

The "O" Ring Store has small sheets of Buna N...!

[Michael K.]

Re: Sending unit o ring or gasket.

Thank you all very much. Michael Kalogridis

[Gary B.]

Re: Sending unit o ring or gasket.

Joe,

Amazon has 12"x12"x3/32" sheet Viton for $70.69 + $6.99 shipping. Sourced from Grainger, I think.

Gary

[Joe L.]

Re: Sending unit o ring or gasket.

Joe,

Amazon has 12"x12"x3/32" sheet Viton for $70.69 + $6.99 shipping. Sourced from Grainger, I think.

Gary

Gary-----


That sounds better. A 12" X 12" would be sufficient for me to make the filler neck gasket + several other fuel-resistant gaskets I might want to. This might be worth 70 bucks. While I might be crazy enough to spend this kind of money for a few gaskets that probably amounts to extreme "overkill", I really think that the Buna-N is completely sufficient for the filler neck gasket.

[Duke W.]

Re: Sending unit o ring or gasket.

[ATTACH]73240[/ATTACH]

In checking out Buna-N, I found this disturbing document regarding Ethanol compatibility. According to this, many of the components in our fuel systems are not compatible like brass, tern plating, and cork. Sorry I looked, but it explains a lot of things I have been seeing. The title "Ethanol Fill up Feel Good" gave me a laugh. Dan

See top of page for link. Was having trouble getting this to post.

The title on the sheet is "Ethanol & E85 Material Compatibility", which implies 100 percent ethanol & E85, so it doesn't necessarily apply to either straight gasoline or E10. However Buna-N is listed as compatible and we know it's compatible with straight gasoline, so a logical conclusion is that Buna-N is fully compatible with E10.

Duke