Fuel filler grommet question for oddball CA '70

[dflarsen77]

My '70 C10 has EEC, thanks to the no-fun laws of CA, it's apparently a year early from everyone else. So I'm in the process of replacing my gas tank. The one in it has no vent provisions, and I don't want to run a vented cap, and I don't want to switch to a rear tank right now, so I got a EEC tank from LMC. Well it's pretty lousy. It looks nice...



It takes quite a bit of tension to get it up on the mounts in a somewhat lined-up fashion. But once it is, the filler neck sit's way up at the top of the hole.



I figured that might not be a deal breaker, as I might be able to bend the neck down at the ribbed part and hopefully not break it at the seam to the tank. Although I really don't know if that's possible, and I don't want to try yet. But then I put the grommet on and it's waaaay to big.



I got it from LMC with the tank, and it's listed for 67-70, which made me leary, but it says it's a 2" hole, and the page for the tanks says both of the EEC & non EEC tanks are 2". Made sense to me. But the grommet I took off the truck might be original (has the original color sprayed on it), and it looks like the 71-72 style, which would fit the 71-72 style EEC system.



The LMC grommet hole is like 2 1/16" wide, but the one from the truck is ~1 15/16 (it's pretty stretched out). The neck on the tank in the truck is 1 15/16, but the LMC tank neck is 1 7/8.

So can anyone tell me for sure? It seems pretty obvious that whatever tank I get, if it's EEC or not, I need the 71-72 grommet, and if it's too tight, I can trim some off. It also seems like I should get one of the american made grommets from GMC Pauls.

[71swb4x4]

Buy the filler neck grommet from Wes at Classic Heartbeat. His are made from good rubber, many others are crappy rubber that will quickly go to crap. Wes was the guy that new the grommets sucked, so he went to bat for us with a manufacturer to have quality grommets made.
GMC Paul's may sell the same one Wes does, I am not sure.

[70STOVEBOLT]

My 70 (Fremont plant) had a vented tank with the charcoal cannister, but it had a vented cap. I replaced the tank with a non-vented one and reused the vented cap. The replacement tank was in a 71 cab that I bought and it had the grommet like in your first pic. Both tanks have the 2" neck and I used an NOS GM grommet for 67-70. I thought the 71-72 tanks had a smaller neck.

[Gromit]

I too have a '70 C10 Fremont Truck with the EEC; here are the only photos I have - pretty sure it is original.

I believe you may be able to file the tank mounting holes slightly to get the tank to tip up at the passenger side and down at the filler side. It is common to do this for repo body panel holes.

Bending the filler neck I think you are very right to be cautious - I would not suggest it at all unless there is some special tool to limit the bending forces to just the neck itself and not the thin wall where it is soldered to the tank.

Judging by your original grommet with it's off center wear pattern I think some of your off-center condition at the filler neck is a normal variation of your particular truck and where the mounting weld nuts ended up but that is just an opinion and I am not an expert.

Sounds like people are already giving you good advice as to the source for the more original seals so this is mostly just to offer the photos I have of my EEC 1970 tank.

One other thing to look at is the vibration insulation that goes between the underside of the tank and the floor of the cab - it is possible someone replaced it over the years with something thicker than stock and that raised up the entire tank relative to the filler hole..

[70cst]

Agree -- Times two

http://www.classicheartbeat.com/

Originally Posted by 71swb4x4

Buy the filler neck grommet from Wes at Classic Heartbeat. His are made from good rubber, many others are crappy rubber that will quickly go to crap. Wes was the guy that new the grommets sucked, so he went to bat for us with a manufacturer to have quality grommets made.
GMC Paul's may sell the same one Wes does, I am not sure.

[dflarsen77]

So I have a pretty cool update. First off, I got the filler neck grommet from Classic Heartbeat, haven't had a chance to use it though. Looks nice. But it's good to know they're guaranteed.

But the cool news is that the return process for tank I got through LMC was fantabulous. They got back to me Tuesday. The employee said they'll do the return, says that the filler neck could be bent from shipping, but it's obviously bad. I said I want the $20 truck freight refunded also, and she said it should be fine and she would put in the request. They would get back to me in a day or two with the response on the shipping fee, and a prepaid label, as they would ship the tank back on their dime. Heard from them today, they refunded the truck freight cost, which is great, but they also said I don't even have to ship it back. Since it's bad. Color me impressed.

But now I have this big dysfunctional gas tank taking up space in my garage. I've already bought a new one from my local Autozone to see if it fits, going to pick it up tomorrow or Saturday. But now that I don't have to worry about damaging the tank from LMC, I think I might try to get the filler neck bent into place.

Help me out bros! How should I go about it? I have ideas, but I'm hoping someone out there is smarterer than me. The main concern is cracking the joint at the filler neck to tank.

[Gromit]

Not suggesting you do this, but if it were me I would install the new rubber seal in the opening (without the tank in place), spray some silicone or armor all on the seal and the tank neck, then try installing the original LMC tank again without attempting to bend the steel neck in any way.

On mine the rubber neck seal is initially little bit difficult to get the tank neck through but once it goes through and the tank is lined up with its bolts the entire assembly ends up sitting in the right position.

Holding the opposite end of the tank and standing at the passenger door opening you have quite a bit of leverage to tweak the tank around and through the rubber seal.

If that didn't work I might try calling the actual tank manufacturer and see how their Quality Control workers make that adjustment. There is a youtube video - (it might be the How It's Made episode) where you can see how those tanks are put together..

Good luck and one final observation is if you plan to sell the tank - if I were the buyer I would rather be the one doing any bending - just so I know what the tank has been subjected to..

Hope it works out and thanks for posting and the photos.

[saxart]

I wouldn't try bending the neck. The amount you need it to move would probably crack something. Is there a way you can mount the tank so that it's tipped slightly to the driver's side of the truck? This would lower the fill neck to the center of the hole. I'm imagining a couple of wood wedges to lift the passenger side of the tank up about 1/2". Not sure if it would work, just a thought.

[dmjlambert]

I got a new tank and grommet from Classic Industries and the neck came out through the body at the wrong angle and not centered. I put a large pipe on the neck and gently bent it. The metal was reasonably soft and did not crack or have any problems. I then removed the tank and installed the grommet, and reinstalled the tank. K-Y jelly on the neck to insert through the grommet works well. I think it is OK to bend the neck as needed on these new tanks.