FE-FC Holden Discussion Forum

I know I need a vaccum tank to help store excess vacuum, as I'm running a lumpier cam and manifold vacuum will be reduced....but what I can't get, is how a vacuum tank works.

Can anyone provide pics and info on how a vacuum tank works, and what is plugged in and out of it ?

Cheers

Mark

A vaccuum tank as the name suggests stores vaccuum for when you need it.  When you put the brakes on the booster takes vaccuum from the manifold, if due to your engine setup there is no vaccuum available at that time then brake performance will suffer if you have to repeatedly use the brakes.
A vaccuum tank continues to store vaccuum all the time your engine is running so that you will have it when you need it.

Ken

Mark
The one I have seen fitted to a V8 Crummydore had an inlet and outlet hose fitted, the inlet hose ran from manifold to the tank which had a one way valve fitted to the tank end, the valve was the same as the one fitted to the booster, the other hose ran from the tank to the booster same hose same one way valve but fitted at the booster end not the tank end.
Motor runs sucks the guts out of the tank and booster, when you put your foot on the brakes vacuum is drawn from the tank.
Not sure what the tank was out of but very neat and tidy fitted on front frame rail and was about the size of a 'tank' loaf of bread.
Some diesel's had tanks fitted to them try landcruiser or such?

Would't think it would be too hard to make one using grommets and fittings from brake boosters.

John M

Hi Guys,
VL to VS Commodore run a vacuum reservoir for the vacuum operated heater controls. Don't know whether one of these would be of any use?? ???

Cheers,

Graham.

Thanks guys.....but....( John M )....excuse me for being so green, but if the engine sucks from the tank whilst running, what stops it from sucking too much and imploding the tank, much the same way if you suck the air out of a drink bottle ?

Is there a relief valve or such ?

Mark

mmmmmm?
Blown FC,
The vacuum tank is made strong enough to wishstand the vacuum from the engine.
The engine vacuum doesn't keep increasing to implode the tank :o
I've had a number of cars with mild to hot cams and have never had the need to add a additional vacuum tank.(The cars have had brake fade though.)
If you are worried about engine vacuum why not fit a alternator of a diesel truck with the vacuum pump attached. ;)
Hope this helps,
Regards ACE 8)

Thanks ACE....not a bad idea.......I like the idea of a Vacuum tank though....( something else to polish up and stick in the engine bay )....any idea who sells them ?

I've seem American Autos selling "Overflow Tanks" which are polished stainless steel....are these the same thing with a different name ?

Cheers

Mark

Mark
Any fabricator of stainless / alloy / steel should be able to make one for you, I would ask the bloke with the cruumydore but he just flew to Darwin to go fishing for a month (lucky barstard).
The tank fitted to the VL is a plastic ball affair stuck up behind the guard, I wouldn't think it would be big enough.
As to implosion the holden motor is just not that efficent to be able to suck that much, otherwise all the rubber hoses to distributor etc would collaspse as well.
John M

PS Try some of the boat yards for fabricators.