cwsttu

Ive been searching for a universal overflow tank and found a few things... this picture was taken off another thread recently discussed.. now is this drawing correct as far as a proper setup for a overflow/recovery tank for our car?



if so i am going to just buy a universal tank with the fittings in those locations and properly install it according to that diagram

djmtsu

iTrader: (3)

That looks fine.

I like my turbo

phoenix7

why don't you ask the guy that posted that pic?? Roen? or TitaniumTT?

cwsttu

i would however the thread i pulled it from there was alot of pissin and whatnot about the proper setup and nobody actually confirmed if it was the correct setup

TitaniumTT

Yeah - kungfuroy got a little bent out of shape when I asked him to explain himself. While that will work just fine and I built mine exactely like that - it's far from ideal. Give me a few minutes - I shall return with pics

phoenix7

this thread?
https://www.rx7club.com/2nd-generation-specific-1986-1992-17/overflow-tank-options-need-relocate-allow-fmic-breath-686054/

TitaniumTT

An overflow or puke is just that - it catches overflow and stores it until you drain it out. Oil catch can kinda thing only for coolant. You'll notice how whatever fluid gets deposited into the tank cannot be siphoned out automatically. It can only be drained. These have no business being on a rotary the way they are plumbed.

turboIIrotary

iTrader: (9)

^^^^^^my overflow tank doesnt work like that mine has coolant in it while my car is turned off then when my car is started the coolant gets sucked in by vacuum i think then when the engine is off it gets pushed back into the overflow tank

TitaniumTT

A recovery tank is used to store coolant while the engine is @ operating temp. A recovery tank holds the coolant that has been pushed past the pressure cap. When coolant heats, it expands. Open a cold radiator cap and there should be no pressure and theoretically a small amount of vacuum. That's becuase as the engine warms the coolant expands. Once the pressure in the system is greater than the cap it is expelled into the recovery tank. Now, when the coolant cools down and contracts it's going to cause a vacuum and pull coolant back into the cooling system. Set-up as the above overflow tank, you will suck air into the cooling system which = bad. If you want to use an overflow tank it needs to be plumbed up like this. This allows coolan to be pulled back into the cooling system not air. It is far from ideal if your coolant gets dirty though becuase all the grit and nastiness will be the first to get pulled back into the cooling system. Regardless here is the schematic. Also... how are you going to fill that with coolant? Throught the vent is about the only way. VERY difficult - ask how I know :tongue:



Here is the tank that I built. I have a nive cap to fill it, the fitting on the back is for the vent, the two on the side are for a sight tube, and the -4AN bung is welded onto the bottom.

cwsttu

ok im wanting to take that setup and instead of it being just open at the bottom to drain, it be a connected to the rad cap so the when the car cools down it will suck back in. your drawing is what it is supposed to do from the factory, the drawing i posted is what i want to turn it into....

phoenix7

Edit: Assumed he had an FD based on the sig. time to go home.

cwsttu

wow posted to late.... thanks titanium for the info, it clears up the questions i had about the two designs.... im still looking to find a tank with a fitting on the underside of it and one up top so it can breathe

TitaniumTT

You don't have an overflow tank.... you have a recovery tank. They are two totally different tanks that have two totally seperate functions. & you are backwards about the way the coolant flows. As your engine warms the coolant is pushed out, as it cools it is pulled back in. It has nothing to do with the engine being on or off now would starting it create vacuum enough to pull coolant back in.

cwsttu

as for filling the tank up look at this one i found

TitaniumTT

Guys - let me finsih posting

TitaniumTT

Now - I feel that the ideal recovery tank would look something like this. A vent to atmosphere on the top, a drain on the bottom, and a siphon tube to pull coolant back into it. I like the idea of a siphon tube becuase it won't let the crude that is in the cooling system get pulled back into the cooling system. The only thing this is lacking is a fill top. I didn't have the machinery nor did I find one to buy that could've replicated this. Plus I just know to stay ontop of my coolant as the engine is hauled every year or two anyways

TitaniumTT

This tank performs a function unlike any of the others. The sole purpose of the expansion tank is to trap air, and get it out of the system. It works like this, You plumb into the block/radiator, or both at thier highest point and route that to the side of the Expansion tank on an uphill run becuase air bubbles rise The tank is there to catch the air but seeing as how there should be a flow, there should be a drain. A much bigger one (I'm using -10 - heater core size) needs to be plumbed from the bottom. This is plumbed into the lower radiator hose as that is the suction side if you will. It helps but is no necessary to have the first line in the pressure side of the T-stat.

The Expansion tank also has a pressure cap on it. If you are using a system like this, this spot needs to be the only cap that leads anywhere. If you have say a koya rad with a pressure cap - PLUG IT! The idea is the expansion tank captures all the air. As the coolant expands the air is forced past the pressure cap into the RECOVERY tank. The bubbles rise so the pickup is still submerged in coolant. When the coolant cools, coolant is pulled back into the system. If you were using an overflow tank, air would be pulled back in. Everyone understand? Here's a few examples and a few pics of the one I built.



Top fitting is after the pressure cap and goes to the recovery tank. Middle fitting is the inflow from the waterpump housing, bottom is the return to the heater hose.

TitaniumTT

I'm done posting for now Ask away - there are usually questions

cwsttu

thanks for the info, i see how the tube pick up would be good as far as dirt and grime its just a matter of finding a universal one that has that, if i had my own house and tig i would do what you did and build one.... guess one day. thanks for the info this was alot more explained than what i found through searching

TitaniumTT

Thanks - It's been asked alot - archive maybe??

The pickup tube is nice - although certainly not essential. Even the one you posted a pic of earlier

Wouldwork just fine. Plumb the top one to a drain tube outside the engine bay and the bottom one to the pressure cap and problem solved. Check out Canton Engineering right here in CT. They have a ton of tanks that you might be able to use. If you wanted to get really trick you could cut those two nipples off and thread them 1/8 or 1/4" NPT and thread in some "T" fittings. This would allow you to put a sight tube in, still maintain the ventedness and have a p/u that wasn't at the bottom. The only drawback I see - no drain

cwsttu

actually i found this, it is cheaper has the sight tube in it and i can install a pickup tube from the right side

cwsttu

oh yeah and after 2 hours of sifting through the searched threads on this topic i would also say archive this thread because you went into depth about all three setups

phoenix7

Hit the little "!" in the original post (#1) and ask for it to be archived. Make sure you give a reasonable explanation as to why it should be archived and edited (to get rid of the junk like my posts).

TitaniumTT

Yeah but that one won't work unless one of the other two nipples has a siphon tube on it. Other wise its just a fancy overflow tank.... actaully - it doesn't even have a drain on it. I wouldn't get that one.

cwsttu

well the nipple on the right side is threaded, i thought about removing that and installing my own siphon tube, that way i have the sight tube, the middle one to vent it out and the right side one with my own personal tube i put in