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914World.com _ 914World Garage _ Coolant Tank

Posted by: tyler Aug 4 2005, 08:01 AM

On some of the conversions I see what looks like an air separator tank instead of an in line fill cap. Looks to be about an 8" deep, 4" diameter tank with full size coolant hoses connections; in on top, out on bottom and a standard radiator fill neck/cap.
Does anyone know if these are really air separators and whoi sells them?

Posted by: neo914-6 Aug 4 2005, 08:19 AM

Renegade sells them for ~$75 and are designed to fit on the right side of the engine bay. There is also a Dedenbear tank that mounts on the engine but restricts air cleaner size...but has a nice sight tube to show you the level of the coolant. Drawback is when it get's "muddy" you will need to change the tubing.

Posted by: John2kx Aug 4 2005, 08:40 AM

I've seen at least 6-8 different approaches used in installing air separators in v8 conversions. The "in line" fill port mounted high in engine bay appears to be installed as a method of removing air and what I used in my installation with a expansion tank. This is the method recommended to me by Renegade and the fill port used was purchased from them.

BigKat83 (Bob) has a different approach at removing air and it works great for him. It requires more pieces/plumbing and appears to be a better mouse trap. He and I used to run our cars together and neither suffered from cooling problems. His setup is much easier to remove air from system if ever breached or upon initial fill.

Which is better? I'm not sure and think many factors can cause cooling problems with the v8s in our application. You may have a less than adequate radiator or fans, flow problems caused by improper hose size, insufficent burping of system, incorrect timing, lean fuel mixture, and the list goes on as to the cause of overheating issues.

There also seems to be different methods or locations as to where air should be removed i.e., engine bay or front trunk.

This would seem to be a simple problem to solve with so many water cooled cars on the road, but our configuration complicates things and does push a cooling system beyond its capabilities if not properly installed.

I'd suggest installing a simple fill port and overflow tank to start with. If that does not work, you could change your design and add a swirl pot, expansion tank, overflow tank etc..

There is some good info on this thread as well.

http://www.914world.com/bbs2/index.php?act=ST&f=2&t=35807&st=40

I'm sure you have seen my setup. This one belongs to Bob.

John

Attached image(s)

Posted by: andys Aug 4 2005, 09:34 AM

Tyler,

I would suggest you read this; in fact, read everything in their technical section:

http://www.crracing.com/apparel/jackets.html

This kind of system configuration gives the air in your system somewhere to collect without creating a problem. I prefer this system for race applications, and plan to incorporate it into my V8 conversion as well.

Andy

Posted by: tyler Aug 4 2005, 09:35 AM

Guys,
Thanks for the info. I didn't see the tank on the Renegade site so I'll call them. Whether it works or not, it seem like a better way to do the installation. I'm replacing my old green stripe (pieced together) hoses with the marine/blue stripe/internal spring type and making them one piece all the way. I've played around with the cooling system quite a bit and other than those deadly zinc fittings that I found in the "blocked in the block" I believe the real solution to cooling is lots of air flow. My 944 fans work fine as pullers but now I'm going to try a pair of 2400cfm pushers and see how they work.

Posted by: Terryst1 Aug 5 2005, 08:27 PM

TYLER:

I have been trying to shout this from the rooftops for 2 years: the ONLY way to do the cooling system is with a
header tank placed as high as possible in the ENGINE BAY ABOVE THE ENGINE. NOT IN THE FRONT TRUNK. I learned this 40 years ago with my dad's 289 Cobra.....and in fact am using that original tank in my 914!
The header tank is plumbed in parallel with the main output hose from the t-stat housing with a 3/8" hose coming from the t-stat area of the manifold and bleeding into the top to the tank. As the engine runs, it AUTOMATICALLY separates the air from the water while the tank is also providing and expansion volume for the cooling system.
When I fired my engine for the first time 2 years ago, I filled the tank to the to top, ran the engine, let the excess barf out and when cool found the tank was 1/2 full. I HAVE NOT HAD TO ADD WATER NOR BLEED AIR FROM THE SYSTEM SINCE. IT IS A NO-BRAINER!!

Best of luck,
Terry Stewart

Posted by: John2kx Aug 6 2005, 08:55 AM

Terry,

Post some pics of your cooling system if you get a chance. It's always interesting to see how others get er done.

John