Sunday, February 15, 2009

Auxiliary fuel tanks

I installed the two auxiliary fuel tanks that I had made, after looking at how to fill the tanks, I thought the easiest way would be to put a T fitting on the original tank and have a small pump transfer the fuel into the left tank first until it is full and then through an overflow fill the right side tank.

If both tanks are full, it will overflow into a T connection on the filler neck back into the original tank. The other options would have been to put an additional filler neck where the 2 wheel drive version has it and then pump it into the other tank from there on, or to install a third filler neck on the driverside.

This pump is a vane pump that pumps about 5 gallon/min, so to fill both aux tanks should take about an extra 7 minutes.


Jason said...

I have an 81 Audi 5000 diesel and would like to know more about your your prelube pump, how and where does it take the oil from crankcase and where is it returned. A schematic and some more pictures of the pump would be fantastic. Also, tell me more about the pump itself, where did you get it, any modifications. Your help would be great


Herman said...

Hi Jason, all the pictures that I had about the pump are posted on the 'Vanagon album' site, I got the pump from an auto wrecker that had some HD trucks and school busses.
This pump is used as backup if the V-belt from the power steering pump, that supplies the pressure to the brake booster, breaks or if the engine stalls. It fits right under the hydraulic brake booster and it comes off with just 2 bolts.
I mounted it on a block of aluminum where I had some channels drilled into, that go through a spin-on oil filter. The pump is really simple, it only has an inlet and a discharge opening. You could just use a small block of aluminum or steel and put some hose fittings on it.
You could use a remote oil filter housing instead of drilling and tapping an aluminum block that I have used, it is a lot of extra work.
The suction hose comes out of the side of the oil pan where I drilled a hole and put a hydraulic fitting in that I made myself, the pressure side of the pump goes to the opening in the block that the oil pressure sensor fits in.
You will have to use a hose that can handle about 80 PSI.
I have used a T fitting to put the oil pressure sensor back in.
It will bring the pressure up to 45 PSI before I start the engine. You can really hear the oil squirting around under the valve cover when the engine is cold.
I have a manual timer on the dashboard that lets it run for 30 second or so and then shuts it off.
It is nice that I can run the pump also after I have shut the engine off to give some extra lubrication and cooling for the turbo that is winding down.


Dave said...

G'day from Brisbane, Australia.

I would be very interested in details of how you constructed the extra fuel tanks and their size. You indicate more than one extra? Could you put up (or send) a diagram of the filler set up as I can't quite follow what you say. I want to do a similar thing, hence my post.
thanks Mate,

Herman said...

Hey Dave, I have drawn a simple schematic of the tank size and the lines and put it up on my picture site.
Sorry for the delay.


Dave said...

Thanks Herman!

Excellent! Well done and very helpful.

All the best from downunder.

matt said...

Herman, first of all, what a kick-ass vehicle and thanks for sharing on your web site.

How did you seal your two auxillary fuel tanks? Is it sealed just with good welds, or did you have some ruberized stuff on the inside?

Thanks, matt

Herman said...

Hey thanks Matt!

I just made sure that all the welds were right so that I would not have to seal it.(it is easy to get some pinholes in the welds) I then filled the tanks with water and watched for a day to see if there were any leaks.

Cheers Herman

bees/n/syncro said...

Herman, Could you pass along the brand and model of the transfer pump you used for the auxiliary tank? I am going to add a similar tank on my gas burning syncro. Great idea to eliminate the extra filler set up.

dan b said...

do you have a diagram of the system for fuel tank auxilary on your Vanagon and how do you know that your 2 fuel tank is full (you install a fuel gauge?).
and have you more photo