More than one way to skin a cat: Through the hood center gas filler project

[Shuie]

I should probably whip up a batch of these and eBay them for a huge profit, but I figured Id share this thought with you guys since we are all in the same game

Everyone who has ever looked into this mod knows that 100mm Blau caps are impossible to find and expensive. Anyone who has ever succeeded in finding a cap knows that the caps are the easy part. The only available filler necks that fit the cap are old 356 and pre '55 VW bus tanks. The caps are obviously paperweights without the filler neck.

I think I have found an easier way to do a correct looking through the hood center gas filler.

Breakthrough #1:

Check this out:



Looks like the real deal, right? Well, it’s close. It is indeed a 100mm Blau gas cap for a pre '55 VW bus, but it’s made out of steel instead of aluminum. Want one? You will have to pony up $14 + shipping to get one from Bughaus.

Okay, so you have a correct looking cap. Cool, but still a paperweight without the filler neck. A cool paperweight, but lets try to actually do something with it.

Possible breakthrough #2:

Take a look at these:



This is a readily available modern cap and filler neck. You can get one of each for about $20 shipped.

5 minutes and a 3.5" holesaw taken to the Blau cap and we have this:



My current thought is to set the modern cap (3.5" OD) into the knock out and weld it in place. I should be able to attach the filler neck above to a piece of seamless tubing and then have the neck welded to the tank. The catch basin under the hood should be easy.

Total costs so far:

100mm steel Blau cap - $14 + shipping
3" modern cap & neck - $20 + shipping
3.5" holesaw - ~$10 kit from Harbor Freight
3" seamless tubing - ???
catchbasin - ???

What do you guys think? Will it work?

I’m waiting on the cap and neck, but expect an update from me next Friday or Saturday.

[MotoSook]

Nice Sherman...can't wait to see the finished product!

[vanwyk4257]

Sherman,

I've been looking at these caps. I hope you can figure out how to make this work. If you can sort this out it's definitely on my list of things to do with my project!

[Jay Auskin]

Nice sherman...and I thought I got strange looks when I filled my front fender with gas...and rear quarter panel with oil. Just imaging the looks this would get!

Truthfully, I'm impressed!!!!

[KS Carrera]

The extra photos of the filler neck seem to be missing – or is it me? Can you repost them? This is VERY interesting as I am not 100 per cent happy with my smaller 'flip-cap' center-fill conversion.

[GeorgeK]

The filler necks should be easily available from any pro truck rapir supplier (the stuff is after all only truck tank parts). My local shop has them ususally, but it changing suppliers right now. The Blau factory still exists and makes these by the bucket every day.
The is *nothing* rare or precious there.
Now aluminum caps, that's another matter. The only ones I have seen were on genuine RSRs and 908s.

[Martin Baker]

Check this one out....

http://cgi.ebay.com/ebaymotors/ws/eBayISAPI.dll?ViewItem&item=4525775340

[Shuie]

Nice work Martin! Fully functional with the filler neck.

[KS Carrera]

OK, I know GeorgeK has made it clear that 'There is *nothing* rare or precious there' (unquote) but thanks for taking the time to show those of us who aren't aware of the truck repair industry!

Where can you get the 100mm filler neck from? I ran into this problem when I did the center-fill conversion on my car and, short of cutting up an old VW gas tank, I was unable to find a source.

[GeorgeK]

Keith,
See the early S registry, on the tech forum. There is a thread there with info.
Regards

[KS Carrera]

Originally posted by GeorgeK
Keith,
See the early S registry, on the tech forum. There is a thread there with info.
Regards

Thanks! I'll 'switch forums' now!

[Martin Baker]

Hood sealing ring, to retain foam to seal out air and moisture, I am having these manufactured now as well...

[doozer]

Those look GREAT!!



Go Bastardo....

[TRE Cup]

georgek- sent you a pm
db

[Shuie]

Came home from work this week and had a package from the cap and neck people.

Anyone who has been following this thread already knows that the correct filler necks can be sourced from overseas. This is obviously the best way to do the R,ST,917 filler setup. I’m trying to acquire a handful of the correct filler necks just to have them, but I promised an update this weekend.

If this works, it could be a handy reference in the event that the correct Blau necks are NLA in the future.

Okay, so here is the 3" filler neck and the 3.5" OD cap that I’m going to try to set into the knockout of the cheap VW Blau cap.



Here’s a side by side of the Blau and the generic 3.5" cap and then a mock fit of the two caps.



I’ll post another update after I get the knockout in the Blau cap completed and the new cap set in place.

[TRE Cup]

a 3" filler tube lends itself to welding to the oe gas tanks a lot easier than the 3.5. so shuie is on the right track for easier installation

[Shuie]

finished the 3.5" knockout in the Blau cap and found that the dome of the 3.5" cap is a tad too high.



Long story short, I can’t weld the two caps together the way I thought I was going to. Oh well. It’s getting a generous dab of gorilla glue at this point and I’m saying 'done' for now.



TRE, have you guys ever done one of these fillers off centered over the passenger side tank? Like the RSR, but through the hood? There is plenty of room for a 3" neck to be welded into the tank there without getting into anything like the vent system or the sender, but I’m worried I may not be able to seal the hole real well due to the formed section of I would be drilling through.

[billyboy]

It’s getting a generous dab of gorilla glue

Shuie, try Marine tex or JB weld if you were serious about the gorilla glue part.Maybe you could braze or weld a small strip of steel on the inside of the big cap perpendicular to the cap and then saw a slot in the small cap to fit the piece of steel. That will help withstand the strain of turning motion and some epoxy to hold it together. Drilling some small holes in the little cap to allow the epoxy to "grip" better.Roughing up both surfaces helps.I was curious why you cant weld those two together. Could you drill through the part under the gasket in the small cap and do a plug weld?Sorry for rambling, just thinking outloud I guess

[Shuie]

I didnt want to cut into the smaller cap becuase I didnt want to take a chance on ruining its sealing ability. And I didnt want the Blau cap to look modified from the outisde.

Id use JB weld as long as it will hold up to twisting the cap on and off on a weekly basis. Its going to take a better welder than me to weld these two caps together.

thanks again for giving me the heads up on where to find the caps, BTW.

[billyboy]

maybe i'll get some and try welding them, what sort of place did you get the neck and small cap, a truck place? Maybe MB911 can weld them.