Replumbing Raceline water rail

[JohnCh]

I’m thinking of modifying the Raceline water rail set up on my Duratec to address some issues I have with the design. Specifically I would like to move the thermostat back to the stock location in the water pump, and swap out the catch tank for a sealed expansion tank.

 

Below is a Duratec cooling diagram with heater I found on the internet, followed by a mockup of what I am planning to do (no heater for me). Does this look like it will work, or am I missing something?

 

http://home.comcast.net/~cobar/webphotos/duratec_cooling_layout.jpg

 

 

http://home.comcast.net/~cobar/webphotos/duratec_cooling_layout_revised_2.jpg

 

Thanks,

John

 

[pierats]

John, Do you need two hoses going to the expansion tank?

 

It looks like the expansion tank would be mounted on the scuttle? Would it be the highest point in the system? If so it might use less hose (and therefore save some weight if you did a take off from the rear of the engine, where the water rail connects.

 

If you want to have some flow through the expansion tank, you would want to connect the black line like the heater in the diagram above.

[JohnCh]

Doh! When I looked at the original diagram (shamelessly liberated from your site) I thought the bypass line was hooked up to the over flow tank. I didn’t catch the line color changed and that the bypass wasn’t going directly through the little block at the rear of the engine. Thinking this through a little more, I know think I understand how the factory setup works. I’m just not sure it will be worth the effort to convert the water rail so that I can put the thermostat back in the water pump and go to a true sealed coolant system. Time to do more research – or just stick with what I have.

 

-John

[pierats]

John,

 

One of the things about my setup is that the overflow tank gets quite a bit of coolant flowing into it under full throttle. I suspect this is from that vent line (the little blue one on the diagram). Coolant is flowing from the back of the engine (where it is under high pressure from the water pump) into the overflow tank through this small hose. This may or may not be desirable. It has not hurt anything so far!

 

Interestingly I have an aluminum expansion tank that I have been thinking of fitting for a while now. It would use an overflow bottle, which my current system does not have. In the current system if the coolant overflows, it just comes out the cap. Not ideal for trackdays! Anyway, this expansion tank only has one inlet (on the bottom). On the top it has a rim to fit a radiator cap and this rim has a small outlet for the overflow tank. I would think that a setup like this would be ideal for getting the excess air out of your cooling system (if the expansion tank was the highest point in the system). It should also allow you to run a higher pressure radiator cap - thereby giving you a bit more wiggle room before it overheats (not that I have heard of any Duratecs with overheating issues).

 

What are your reasons for changing the cooling system?

 

 

[pierats]

One more thing, there is a new water rail available:

 

SBD Duratec water rail

 

I like it!

[JohnCh]

This is more of a change for change sake. The water rail has always seemed under engineered and given the price that just bugs the crap out of me.

 

- You need to modify the head with a cut-off wheel so it will actually fit

- The thermostat creates a dead end, so you need to drill a hole in the flange to allow some water to always pass through

- The location of the thermostat makes bleeding a pain (no bleed screw in the system and a lot of air gets trapped behind the thermostat when you fill it up)

- The use of an overflow bottle in lieu of a sealed system seems a step backward to me. The smell of coolant seeping out of the overflow bottle always triggers an “uh oh, something is wrong” reflex in me.

 

Although my temperatures get hot pretty quick at a stop light, the car never overheats. Even in the traffic jam during PNW2007, when I only moved about ½ mile in 45 minutes and the under bonnet air temps reached 65C, the engine never went above 102C. So do I need to make a change? Absolutely not. I just want to see if using a factory setup keeps the temps more stable and reduces maintenance hassles.

 

Your expansion tank sounds interesting. Where did you get it?

 

The SBD piece looks good, but where do you mount the coil pack? Do they offer another mounting location, or do you need to use that with a coil-on-plug setup?

 

 

Thanks,

John

[pierats]

Hi John,

 

I understand. The cooling system, although it works fine, seems to have room for improvement.

 

I got my expansion tank from MSI motorsports a couple of years ago. It is fine, but they are making some more attractive units now - check with Woody. They are just the right size for a se7en. If I convert my system at some point in the future, I'll get a new tank from them.

 

Regarding the SBD water rail, I was asking myself the same thing: "where does the coil pack go?". I suspect you are right and they use the coil on plug setup. Either that, or you have to fashion some kind of bracket for the coil pack.

[Sean]

Excuse me, don't mean to hijack, but what is the advantage of a water rail over the traditional method of just using a hose?

[Al N.]

Excuse me, don't mean to hijack, but what is the advantage of a water rail over the traditional method of just using a hose?

 

Sean...in my case, I had a few too many hoses slip for my taste in the first few years of ownership (yes, my head gasket is fine), so I looked into it...it eliminated many of the hoses and joints.

 

Read this thread....

 

With the Raceline, which I've had on since just before the Tail of the Dragon meet, no problems.

 

Some of the other benefits are outlined here:

 

Raceline Web Page

 

From what I understand, on some of the the Birkins, it was necessary to use the Raceline solution because the normal installation wouldn't fit.

 

 

[Alaskossie]

After seeing Skip Cannon's expansion tank mounted on the scuttle, I decided to go with two small rectangular Canton aluminum tanks, mounted on the scuttle side-by-side. One will serve as the expansion tank and the other the overflow bottle. (I'll bin the Land-Rover sourced "flying saucer" overflow bottle mounted on top of the front frame cruciform).

 

I will plumb the expansion tank into the heater hoses. It will easily be the highest point in the cooling system. It would be nice if the expansion tank had a sight glass, but I guess one could be added.

 

No photos yet, since much of the layout is still in my mind's eye, but I'm working on the bracketry right now.

 

In my build, I have tried to maximize the available space on the scuttle, instead of following the haphazard, wasted-space Caterham layout. In other words, a smaller battery (Odyssey) down in front of the driver's footwell, the ICU mounted inside the roof of the passenger's footwell, the windshield washer bottle mounted to the side of the heater housing, etc. I'm even hoping to have room left over to mount a modified aluminum Coleman camping stove container on the scuttle, to hold a basic toolkit.

 

Sorry for the digression....

 

Tom Meacham

[bsimon]

Tom,

 

One of the things about my setup is that the overflow tank gets quite a bit of coolant flowing into it under full throttle. I suspect this is from that vent line (the little blue one on the diagram). Coolant is flowing from the back of the engine (where it is under high pressure from the water pump) into the overflow tank through this small hose. This may or may not be desirable.

 

This may or may not apply to Duratec;

The bleed line from the expansion tank needs to have some restriction to prevent anything from flowing other than air. In the VX we use a check valve the allows air into the engine but stops coolant from flowing back out into the top of the tank. Without it, there is a constant flow of coolant from the engine into the tank through the bleed line.

 

I would also try to get the bleed line as high in the system as possible. Could it be tapped into the head or intake manifold?

 

I have the schematics for Cosworth's recommended Duratec water circuit on my computer at work. I could make them available Monday if anyone would like to see them.

[JohnCh]

Bob,

 

I'd love to see what Cosworth recommends. I did some research on WSCC and the following is apparently the way folks are plumbing an expansion tank in a pressurized system that employs the water rail. I took a look at pictures of my old crossflow-powered car, which used the same expansion tank and thermostat housing as the water rail, and it appears it was plumbed the same way.

 

http://home.comcast.net/~cobar/webphotos/duratec_cooling_layout_revised_3.jpg

 

To add a heater, tap into the side of the water rail and T in the return to either the lower radiator hose or the expansion tank return line.

 

-John

[bsimon]

John,

 

The WSCC drawing looks right to me. I can't remember what the Cosworth drawings had for the heater source, but I do recall it returned to the water pump inlet housing.

 

I'll send the Cosworth drawings to you PM so there's no copyright issues with posting them here. You can adjust your drawings to reflect what's shown for public consumption.

 

Be aware that Cosworth intends that you use the original electric override thermostat installed in the water pump inlet housing (USA style) and not the Ford Mondeo style rear thermostat.

[Alaskossie]

Bob,

 

The Pierats comment about coolant flows through the overflow tank under full throttle that you quoted involves Tom Jones's Duratec, so apparently it "does apply to Duratec."

 

Tom

[JohnCh]

I'll send the Cosworth drawings to you PM so there's no copyright issues with posting them here. You can adjust your drawings to reflect what's shown for public consumption.

 

Thanks Bob.

 

Be aware that Cosworth intends that you use the original electric override thermostat installed in the water pump inlet housing (USA style) and not the Ford Mondeo style rear thermostat.

 

Did the later Mondeos move the thermostat to the back? I have a 2.0L Mondeo and it came with the thermostat fitted to the waterpump. BTW for those who don't want to use the electric thermostat, you can substitute the mechanical version Mazda (the car company, not the guy with the HP fetish ) used in their Duratec installation.

 

-John

[bsimon]

Early, late, front, back, Mondeo, Mazda, Ranger...not really sure. These new fangled engines change around so much I can't keep track.

 

I'm old school. Small block Fords came two ways; water pump inlet right on cars and inlet left for trucks. Everything else was the same for 40 GD years.:yawn:

 

The Mazda thermostat is interesting. I'll have to look at the Cosworth wiring diagram to see if they are actually controlling the stat with the ECU or have substituted the Mazda mechanical replacement for their application.

[Sean]

Cosworth recommended coolant flow diagrams? That would be useful!

[bsimon]

Guys, send me PM and I'll fwd the .pdfs. Monday.

[Sean]

Bob - Did you get my PM?

[bsimon]

Sean,

 

I haven't received a PM from you yet. Give it another go.