VCCA Home Forums TECHNICAL - 1945 AND EARLIER 1912-1928 Fuel Issue and Vac Tank question

Gidday fellas.

I have a question for you all that are running a vac tank but first you might want to read this off my blog as it will put you in the picture where we are at....

http://montythe1928chevrolet.blogspot.com/2011/11/endurance-run-results.html

Ok then, just one question:

The little nut/hole at the top of the tank?? should this squirt out fuel?? and it has only done this a couple of times when winding over the engine?? Y/N

There is the fuel in line/connection and also the breather line to the manifold and then this small nut/hole....that is the one I have in question....

Any thoughts on the matter would be great and please don't say remove the tank and run a fuel pump, that is not want I am here for, the tank is staying.....

What vacuum tank do you have? Is it the stamped steel top with four screws or the die-cast top with 8 screws? I am not familiar with the small nut/hole on the USA '28 Chevy vacuum tanks. The stamped steel top has a round vent near the outside edge that is a ~1/8 dia and ~ 3/8" high. The hole in it must be open but gas should never come out. If it does then the tank is getting too full. Same for any gas in the vacuum line to the manifold. Check the float to see if it has any gas in it. Or check the valves to make sure they open and close and seal closed.

die-cast top with 8 screws

As already stated no fuel should come out of the overflow tube. If it does there is a good chance the seat has become dislodged in the top and does not allow the float to shut off the flow. Gotta say it, tank must come off again and take a look at the seat. This happened to me and I had to make a jury rig to get back to camp by filling the vacuum tank, closing off the vacuum line and put the top back on loosely to keep the fuel from sloshing. Something to put in your note book. A 28 will run 7 miles on the fuel in the vacuum tank full.

The single most common problem with the die-cast top vacuum tanks is the brass seat dislodges from the casting. The solution is to use super glue (cyanoacrylate) to put it back in place. A small amount of glue and quickly push the seat back in place. Has worked many times and is a long term fix.

Monty, you have 27 vac tank, get rid of it and find a tin top 29 tank, much better
Chris

'29 tank?

I think he means a four screw vacuum tank that was installed on '28 Chevys in the USA.

I have the 4 screw tin to tank on my 28. At the vac in fitting there is a small hole. I think it is for venting the inner tank so it will drain to the outer tank. It may be closed off when the vac turns on and opens when the vac is off but not sure without pulling my tank apart to check. There is the other small brass pin that I think is the vent for the outer tank.

Yes I have known for a while that I have the wrong model tank on Monty and that the correct 28 one is simpler, Ray pointed this out on his first visit to my house and I must look about for the correct one and buy it, anyone got a spare for sale??

Anyways without me sounding like a dumb [bleeped], where is this "seat" located on my tank that might of come loose, can you please narrow down my search if possible fellas..

There are two valves on the rocker assembly. The one under the tube fitting going to the manifold is most likely the seat that you will need to glue back into place. Once you take the top off it should be obvious.

Gidday fellas,

I have posted a photo and also a video on my blog of the working internals of my vac tank for you to inspect and tell me what looks a little worn or needs reglueing..




Here is the link http://montythe1928chevrolet.blogspot.com/2011/11/resto-vacuum-tank-trouble.html

I didn't see anything in the video that looked out of the ordinary. Test the vacuum port (hooks to tubing to manifold) and gas port (hooks to gasoline line to tank) to see if both seal off and fully open when float is raised and lowered.

I don't see evidence of a seat being loose.

Gidday Chipper,

Many thanks for the reply, HHHmmmmmmmmm you have got me thinking a little harder now as I thought that would of been the problem, the connections are all good on all ends, but ya never know just the same.
i went to start the car this morning and i wound it over but it did not fire, I gave the vac tank a little knock on the side a couple of times, hit the starter and it fired up right away and ran lovely..... so somethings not right inside there!!

Hi Grant,

I am sure you will get it sorted. After all we dont want to embarsass the boys over here, do we?

Cheers

Ray

That top looks to be so warped as to be unserviceable.

New ones are available, or better yet, search for the 4 bolt vacuum tank as it is less prone to have problems.

Good eyes Ray,
I didn't pay enough attention to the photo posted. Focused on the video and operation of valves. With out vacuum to the inner tank no fuel will be drawn from the tank.

Gidday Fellas,

yep its a little warped alright when you have a good look... I will start looking for the other sort to put on there, anyone got one for sale with a "used patina" look about it

Grant,
Sent you a PM.