Coolant Pipe retro help

CnC79X19

CnC79X19

True Classic
Wondering if anybody has tried the 1" copper "slide thru" the original in coolant pipes under the car with good results? I've seen it done here on the forum and just wanted some feedback with regards to success rate? Removing the box and fab'ing new stainless pipes at this point isn't even an option for us. Rad hoses, water pump and aluminum rad (with dual 10" fans) will be new and installed but I'm just curious if the lesser reduction in the diameter of the new copper coolant pipes will cause it to overheat? I'm guessing the originals are 1 1/4" so 1" is a considerable drop in size? This would be a more reasonable task for us compared to drilling out all the spot welds. I'm aware that this isn't textbook but I'm finding that I'm more and more impressed with a lot of the things guys do here that many in the automotive world would feel is less than ideal anyway? Some of this stuff is ingenious.
 
A bunch of folks here have and there's a bunch of threads. I just searched for "copper" and did a manual filter:

* https://xwebforums.com/forum/index.php?threads/re-pipe-diagram-tools-materials-and-method-s.32484/
this one even has PDF instructions on first post by Tony. It's basically a PDF of the instructions on the XWeb Wiki: http://xwebforums.com/wiki/index.php/CoolantPipeReplacement

* http://trazia.com/x19/coolant.html
Ricardo has a nice site with his own step-by-step instructions.

There are others too, not necessarily copper:
* https://xwebforums.com/forum/index.php?threads/coolant-tube-replacement-begins.32460/
* https://xwebforums.com/forum/index.php?threads/another-coolant-pipe-saga.32218/
* https://xwebforums.com/forum/index.php?threads/coolant-tube-replacement-begins.32460/
 
Cliff, others will likely have differing opinions. But to me dropping to 1" diameter tube is too significant of a reduction. Do the math and review some physics, it is a HUGE decrease in flow and volume. Given the length of the pipes, the small size of the water pump (originally designed for a front engine car with no pipes), and the unusually hot engine compartment of it's mid-engine design, the system is pretty much at its limits already. This seems to be supported by the numerous problems that crop up when any component of the system is not up to full potential. And blowing a head gasket isn't worth the risk of overheating (especially after everything you've gone through to build this engine). But I'm sure some of the people that have done the 1" technique have not had any problems. So it might depend on the climate that you will be running in, how you drive it, what other mods have been done, etc, etc.

I agree that removing the box is a pain, but there is another option. A couple guys managed to remove the old tubes WITHOUT removing the box. They cut off the ends of the old tubes and twisted them out. I did not review the links Darin provided (sorry, short on time), but look for the recent threads on doing it this way. It allows the use of larger (stock size) tubes to be built up in the box; 1-1/4" copper with fittings sweated on the ends. This is how I will approach it (but many other things are ahead of it on the list first). Hope this makes sense, message me if any questions.
 
I did this just recently. Slide out the old, slide in the new stock size piping. Quite easy actually.
I haven't even done anything to the ends of the tubes, just use good clamps, not regular hose clamps:
418WZSL53oL.jpg
 
To get around the potential issues with undersizing of the pipes you could add a helper electric pump on the return line near the radiator. Bob Brown did this on the ‘Queen’ to serve as an assist. I suspect the images are gone from that thread but basically one of the Bosch pumps used as a secondary pump on various German cars. They run 60-90 bucks on eBay.
 
kmead said:
To get around the potential issues with undersizing of the pipes you could add a helper electric pump on the return line near the radiator. Bob Brown did this on the ‘Queen’ to serve as an assist. I suspect the images are gone from that thread but basically one of the Bosch pumps used as a secondary pump on various German cars. They run 60-90 bucks on eBay.
Click to expand...

Going off on the tangent - The 'problem' I have even with increased impeller speed, oversize rad, original model T/stat, baffled expansion tank, etc., etc., is that coming to a stop after a period of at least 15min highway speed results in a estimated 10-20ºF increase in engine temp (based on gauge deflection) when ambient temps are 70 or above. Drops back immediately when moving. SInce it never actually goes over 'normal" that's not really an issue, however, it shouldn't do that - I feel my butt clench anytime that needle tips the 190º mark :D

Based on the evidence, I'd say it has to be rapid heat soak from the lack of air circulation that the cooling system just can't respond to, given the overall design, distance of rad from motor, etc.. I added the engine bay vent fan(in lid) to suck out that heat soak, but haven't resolved the automated engagement satisfactorily. I need to add a manual switch to confirm that engaging the fan immediately when coming to a standstill resolves the issue.
 
when I got my car years ago, the box was already butchered...they cut a slit right down the middle, and bent it open to "repair" the pipe. So when I replaced mine with 1-1/4" copper, I just simply used a cutting wheel, and cut along the 2 corners running all the way from front to back, leaving the 2 sides in place, and the bottom open...I then found a local sheet metal fabrication shop that made a "lid" with overlapping edges. I then used short sheet metal screws along the sides to attach it... It was very cheap, think the guy made it for like 50 bucks. I was elated when the guy asked if I wanted it in stainless for the same price, also made it out off thicker metal in case of bottoming out to protect the hard copper which will crack if it is impacted hard. I agree with others that 1" would probably be too small. BTW it your cooling pipes are rotted, you can bet the heater lines are too, I used copper for those also. My car ran hot for years until my 2nd "tear the whole car apart" episode, which at that time I removed the heater line in the hump...never saw a drip under the car, but that line was riddled with tiny corrosion spots that were obviously "steaming" out the pressure
 
Kevin Cozzo said:
I just simply used a cutting wheel, and cut along the 2 corners running all the way from front to back, leaving the 2 sides in place
Click to expand...
I hesitated to say it on the forum publicly, but that is how I intend to approach mine. In fact I discussed this with Cliff (original poster) off line. There seems to be a STRONG aversion to modifying the box on this forum, claiming it destroys the structural integrity/chassis stiffness, etc but I don't agree. Hope this doesn't start that whole discussion again. I'll leave it at saying I agree with Kevin's approach (except I might use 'nut-certs' and bolts instead of sheet metal screws).

I will also need to replace the heater tube, as Kevin did. So the box will need to be opened...not going to get away with pulling the cooling tubes out the end like Ulix did unfortunately.
 
Hey Doc,
I've decided to start by carefully removing the lower ends of the box with the cradles where the pipes rest (with a body saw to make a precise and cosmetic cut leaving a hollow channel channel) and hopefully twisting the pipes free before making any other cuts. If it works out, I'll cut them on one end, then bend and create replica's before sliding them back in. That should leave me with only two points requiring a solder joint. I can easily fab up new end cradles and add a saddle on each contact to secure them. Because I'll be able to jockey them side to side a bit I'm in hopes that will allow them to break free. If they won't then I'll really only be out my time I think? If I'm not successful then I'll chalk lines, score them and make two full length cuts to remove everything out the bottom.
 
I run with no box bottom and I wonder if this has an appreciable effect on the pipes acting as long radiators since they are now open to cooling air instead of cooking in the box. If you really wanted to get funky you could weld on longitudinal cooling fins!
 
I'm liking your idea Carl. Maybe a few deflector style spoilers along the length of the channel might aid in cooling with a moving car? Has anyone got a definitive answer as to whether or not the box actually does act as a structural component?
 
carl said:
I run with no box bottom and I wonder if this has an appreciable effect on the pipes acting as long radiators since they are now open to cooling air instead of cooking in the box. If you really wanted to get funky you could weld on longitudinal cooling fins!
Click to expand...
I'm liking your idea Carl. Maybe a few deflector style spoilers along the length of the channel might aid in cooling with a moving car? Has anyone got a definitive answer as to whether or not the box actually does act as a structural component?
 
CnC79X19 said:
Has anyone got a definitive answer as to whether or not the box actually does act as a structural component?
Click to expand...
Cliff, unfortunately this has been one of those age-old debates with rather strong opinions behind it. Rather than starting another word war on it, perhaps you can review some of the older discussions on the topic. Try a search but let us know if that doesn't bring anything (I don't have great luck with searching this forum). I'm not trying to put you off but I can already hear the LONG dissertations about how Fiat has the best engineering in the world and how the X is perfect and how bad it would be to change anything, etc, etc, etc. [Sorry]
 
No worries Doc. I'm going to go way out there and try something with a metal cage that will leave it open for air flow and heat dissipation but add an increased amount of integrity. Also more protection if anything happens to make it's way under the car.
 
That sounds really interesting. Please keep us posted how you decide to approach it. I'd like to explore other options when the time comes to do mine.
 
I am firmly in the camp of those who believe the coolant pipe box offers a notable amount of structure to the car. Having spent a fair portion of my life working closely with engineers, every possible inch apart you can put two coupled structures apart has a huge effect on the beam strength of the object in question.

That all the structures in the floor of an X are stressed can be borne out by the fact that we sometimes see stress cracks in the structure that the shifter passes through.
 
Noted, and thanks for the info. I will see to it that the cage’s construction (if I do go that route that is?) will take that into account. I’m confident that a framed, open box will be equally and most likely stronger than the original set up. I’ll make sure to take pictures
 
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CnC79X19 said:
Has anyone got a definitive answer as to whether or not the box actually does act as a structural component?
Click to expand...

Yes, it definitely does if only based on the cracked spot welds owners observe when servicing these. The important questions are:
* how much strength does the box section add
* does it really need it

The first question is answerable by testing and observation: you take an exxe chassis and hook it up to a torsional rigidity measurement device. Something like this:
main-qimg-5b345ee5abda31f80a1f102742e71715-c.jpg
For an exxe, I'd think the best way would be to somehow seize or fix the struts into place (or make a solid strut) so you are mounted to both the suspension arm pickups as well as the strut tower top. then attach the rear hubs to the floor. the front gets the balance bar with a deflection gauge. If I remember correctly, someone here did this with their exxe - or at least linked to it.

Anyways, test it with the cover then remove it and test without. It'll twist more, but how much is what matters. Actually, how much you care about torsional rigidity is what matters.
 
Dr.Jeff said:
I hesitated to say it on the forum publicly, but that is how I intend to approach mine. In fact I discussed this with Cliff (original poster) off line. There seems to be a STRONG aversion to modifying the box on this forum, claiming it destroys the structural integrity/chassis stiffness, etc but I don't agree. Hope this doesn't start that whole discussion again. I'll leave it at saying I agree with Kevin's approach (except I might use 'nut-certs' and bolts instead of sheet metal screws).

I will also need to replace the heater tube, as Kevin did. So the box will need to be opened...not going to get away with pulling the cooling tubes out the end like Ulix did unfortunately.
Click to expand...


yeah, wasn't till later I found my friend had a "blind nut" setting tool...if I ever tear that apart down there again I'm gonna do that, and seal the whole thing up...put some kinda body caulk down the seams, and at each end seal where the tubes come in and out with some kinda expandable foam
 
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