I have an issue with the RX8 that involves some melting/cracking coolant lines. It jsut so happens that my downpipe runs right next to where all of my coolant lines attach to the block. i have had a few isses with the coolant lines melting and causing leaks, or cracking from the heat cycle of getting hot and cold from the engine getting hot and cool. Its Impossible to re route a couple of the lines to get them away from the downpipe so the only thing i can think of is to run some type of hardline.

My question is, What do you guys suggest i use for the hardline. Its a steel body that the lines connect to. I was thinking find some steel pipe the correct sizes for the lines, bend them to fit the routing that i choose, weld them on to extend them past the downpipe. Once the fitting piece is complete, paint it with high temp engine paint, or have it powdercoated. Are there any other options or ideas that i am not thinking of? Let me know some thoughts.

Here is an older pic to give you an idea of what i am talking about. Setup is a little differnt now, but you can see a mess of coolant lines near the Downpipe.

 

Hard lines would work and there are many coating options that would work and you could use sheet metal to created a heat barrier between the downpipe and pipe (highly recommended). Have you tried a heat shield?

 

I wish i had a better picture on the computer. I have both the downpipe and the coolant lines wrapped in exhaust wrap. One of the nipples the line connects to is so close to the downpipe it practically touches it. Infact, it does slightly with all the wrap on both line and DP. There would be no room to get a heat shield in there. If i were to make/ add hardline, i could cut the small nipple back and have it change directions sooner - before the downpipe.

 

Hmmm. I would think a separate independent heat shield would work much better than wrap but if it is so close that would be tough. I would try and reroute them with hardlines and try and incorporate a heat shield somehow that maybe attaches from the chassis itself.

 

A heat shield would definately be a good idea. I will see if i can work that into the mix. Currently the motor is coming out for a rebuild, so this is the perfect time to do the hardline work. Also, instead of the heat wrap and turbo blanket (not pictured but its on there), i am getting everything on the hot side ceramic coated.

So would normal steel pipe work for the hardline? any suggestion on material i should use. First thought was conduit, but it seems alittle thin. Also seems like a little "backyard mechanic" to be using conduit onthe car. lol

 

Annealed SS( 304 or 316) tubing, thin wall around .030"

Hard lines are standard on our turbo kits...

 

We usually just have custom aluminum piping added to the thermostat housing to extend to the rad and such.

 

Is the t-stat housing aluminum? Have not gotten that far to check it out. Assumed it was steel for some reason.

 

Aluminum would be the way to go fer sure, much easier to work with.

 

The t-stat housing is cast aluminum. Very easy to TIG.

 

Awesome. This could be easier then i thought. It bing an aluminum and not steel. May not have to have it powdercoated now either. Any other suggestions about the project?

 

For this very reason.
Phish, you can also look at a much better exhaust heat barrier.
Like something from here. http://turblown.net/store/index.php?categoryID=18

This stuff works WAY better than the diffrent glass/pumice weaved wraps availble.

I guess you can say I'm afiliated with Turblown. Since the 8 is pseudo sponsored by them. However I get no monitary kick-back.

 

I believe if i get it ceramic coated inside and out i should be ok.

In turblown's kit there are hardlines running to and from the turbo for the turbo being water cooled, what other setup do they have for the rest of the coolant lines. Its hard to see from that picture. Looks like some major changes though.

 

I pulled off the coolant lines from the thermostat lats night and grapped my maginate. Turns out that the housing itself is aluminum, but the tubing that is stupped off for the hoses is steel. I believe i am going to try and flare the tubing from the housing and put a tubing nut on it. That way i can still run hardline the same way with an -an fitting connection instead of welding them. Looks as if i can run hardline for most all of my coolant lines that come off that Housing. Whats keeping me from doing all that way would be connecting to the coolant resivor. Wouldnt know how to connect to platic with an -AN type fitting.

 

Turboblown has the best fix for this although the last time I asked about pricing it seemed uber expensive for a so little metal. I had the same thought although I have never actually had problems with the lines breaking. I have exaust wrap also on my top mount and then I used metal hose sleves from heat shield just in the area that the exaust seems to be suspect.

 

I am in the process of fixing this issue. Since i am pulling the motor for a rebuild, i decied to tackle this problem with a few others. I have ordered aluminum fuel line along with all the AN fittings that i will need. I have tapped the stock coolant res to take the fittings. Plan is is to tap and run aluminum hardlines to everything under the hood coolant related. Just came in from working on the car and the only thing left that i can see as being an issue would be the main big lines to and from the Rad. However i believe that if i jsut raise the lower line and extend the upper main coolant hose at the metal coupler i should be ok.

Upon removing alot of componets i also noticed that the lower coolant line, which i had heat wrapped, was actually sitting on the downpipe - which was heat wrapped also. To this point, i have not had an issue with that line, but i can definately see it being an issue int he futue.

I will post up a picture of the coolant lines when i am finnished, but i believe its going to be a great improvement as far as cleaning up my engine bay and takeing care of my problem. Getting anxious to see my own finnished project.

 

So am I.

 

I think i have found where i can get aluminum 1-1/4" pipe/tubeing. I also have a freind with a pipe bender (makes roll cages and what not). I am thinking of making the two main Rad hoses to and from the Rad out of the larger aluminum pipe. This would solve ALL of my coolant line issues since it would all be aluminum hardline. No chance of melting at all.

 

I bet those hard lines will actually help with some cooling to. It is a lot of work, let us know how it comes out and if you would do it again.

 

I have thought of that benifit as well. Hopefully it will help out a bit in that department. I should get soem more work done it this weekend. I will post up some pictures when i get some real progress made in the next day or two

 

Well, had alot going on this weekend but i managed to get a little done on the car. I am now waiting on more fittings that were backordered. Here are a couple pics of the progress i made. Still need to paint the bracket and have alot more line to run.

 

 

nice!

 

looks good. how much flex/vibrational movement does the hardline have. you don't want it to break as your engine moves...

 

Uh, yeah. This is all gonna break.

When you do hard-lines, you have to have a flexible piece at the motor.