coolant swirl tank

[Mike B]

I'm looking for a coolant header tank/swirl pot from an RF95 or newer, or something similar. I have one from my RF93 but I'm looking for something that has a slightly larger capacity. Send me pics of what you have.

[Mike B]

Still looking. This doesn't HAVE to be a VD part.

[RussMcB]

Are you convinced you need it? On my conversion project, I've just added a 1" tee into the hose coming out of the engine and before the first rad. It leads off to a tall filler neck with radiator cap (highest point). The two radiator bleed hoses feed into it.

The filler neck I used was a left over part from the Pinto system. You can see it a little bit here:

http://www.apexspeed.com/forums/atta...1&d=1186365418

Reusing the Pinto part was nice because it already had the bleeder fittings.

A true header swirl tank might be better, but I don't think it is required (at least I'm hoping it isn't :-). Just make sure air always has a route to the cap if it gets into the system.

I guess I'm assuming (hoping) that foaming isn't going to be a problem and I won't need to force separation of coolant & air bubbles. Hmm ...

[T492]

Try Demon Tweeks, I picked one of these AH Fabrication swirl pots last January. it was an exact replacement for my Lola 492. Several types/styles to peruse.

http://www.demon-tweeks.co.uk/produc...33&tlgrp=MS004

[Mike B]

Russ,
I can't see $hit on that photo, but the stock RF95 Pinto tank would work just fine. The RF93 came with just a tube with a radiator cap on it. I'm not sure that it won't work but I want something with a bit more capacity. As completion of everything else draws near, I'll use it if I haven't found anything better.

[RussMcB]

Oops. I linked the thumbnail. Here's the bigger pic (still doesn't show much):

http://www.apexspeed.com/forums/atta...tid=6203&stc=1

Those Demon Tweaks units look pretty good.

[Jon Jeffords]

Russ,

My coffee hasn't kicked in yet this morning, but it sounds like from your description that your filler neck is tee'd into the OUTPUT side of your water pump? A better location for the tee would be on the inlet side of your water pump.

Most coolant systems trap some amount of air during the fill process. If the filler neck is tee'd into the inlet side of the pump, you can fire a cold motor with the cap off, and add cooant as the air "burps" out.

If the filler neck is on the output side of the pump, you will send a geyser of coolant out the filler neck should you ever fire the motor with the cap off. Likewise, the coolant in your radiator bleed lines would flow in reverse.

[RussMcB]

Interesting points. Thanks.

My tee / filler neck is on the pressure side - located after the coolant has run through the engine and before it goes through the two radiators.

When I first got the engine plumbed and running (last month), I ran the engine with the cap off for a short while and it didn't geyser. Thank goodness because I was constantly looking down into the filler neck making sure the level was okay.

I'll check it again tonight to confirm my memory.

[glenn cooper]

Protective Eyewear.

YHS, Coop

[Jon Jeffords]

Does your engine have a thermostat? If so, how long did you run the motor?

A cold engine with a closed thermostat will only send a small amount of coolant to the radiator, which might explain your lack of a geyser.

The fact that your tee is downstream of the engine helps somewhat, as the pressure here is lower as a result of the flow restriction (delta P) across the engine.

Ideally, though, your tee would be in the line between the radiator outlet and the water pump inlet, as this where the lowest system pressure is located (the closer to the pump, the better).

With a gallon of distilled water and a turkey baster in hand (and safety glasses on), you will want to fire the motor cold, then let it idle with the cap off. The coolant level in the filler neck should rise ever so slowly as the water expands. If it gets too high in the filler neck, remove some with turkey baster. You should verify that coolant is peeing into the filler neck from the radiator bleeds (which I don't think will happen with the system plumbed the way it currently is). Keep a close eye on the water temp gage. If all hell breaks loose when you reach the thermostat's temperature rating (180F ?), you may wish to relocate the tee. If you reach 200F without any excitement, and the bleed flow is in the right direction, you're probably OK as long as the system burps adequately.

In my experience, one of the most exasperating aspects of race car maintenance is trying to burp a stubborn frickin' engine coolant system.

[Mike B]

Still looking!

[carnut169]

I went a bit overkill on the coolant tanks with both an expansion tank and a header tank but it all does seem to be working very well. The header tank came from Pegasus- its a Canton unit that I had Comprent modify slightly. I've bolted it to the back of the airbox. From there I've got an overflow tube that runs down to an expansion tank from Summit. I've got about 2" of water in the bottom of this tank, and as the water expands in the header tank it could force water out and down to the expansion tank. As the water cools and contracts the water is sucked back into the header tank instead of air:

[RussMcB]

Sean, where do your radiator bleed hoses go (can't see them in the picture).

My opinion regarding the expansion tank - I considered it then determined it really doesn't add value as long as the cooling system has an area (like your header tank) that can accommodate air without it getting into the flow through the system. In other words, if your header tank can hold 1"-3" of air in the top, then carrying around the extra weight of coolant in the expansion tank is just dead weight. The coolant in the expansion tank only gets reintroduced into the closed system when your car has cooled down in the pits, only to be pushed back out as soon as the engine warms up.

That's just my current opinion, which I can change at the drop of a hat. :-).

[carnut169]

Radiator bleed hoses go to the thermostat housing, behind the header tank. Truth be told, right now there is only 1 bleed hose- I need to run another one for the left radiator.