May 31, 2012

Coolant Junction Pipe

An elaborate solution for a simple problem, all because I didn’t want a coolant bypass hose touching the intake.

When I first mocked up the turbocharger, with my new manifold, it was clear that its position was going to interfere with the original route of the passenger side hoses. The lower radiator hose was modified first, being shortened somewhat, while the thermostat housing was cut up and welded back together. The hose right below it (the one that connects the block to the hardline on the passenger frame rail) was initially shortened so that it ran a little closer to the motor, meeting my original need of clearing the turbo (it can be seen in a picture in this post). Later on while fabricating my intake, it became an issue again, rubbing against the tubing. Being that it wasn’t the best solution in the first place (the molded hose ended up a bit kinked) I started playing with alternatives. Because the hose was trying to make a 45 degree turn off of a straight fitting (on the block) I first tried replacing the stock fitting an Earl’s 45 degree swivel fitting (this required an XRP metric to AN adapter).

This was a step in the right direction, but the length of the passenger side hardline was still pushing the hose too far forward. So I started eyeing the hardline itself. I wanted to simply shorten it, but the hardline was too out of round for a tube cutter and there was no pulling the whole assembly (for alternate cutting methods) with the motor in the car. So instead I cut the line in the next closest round spot, right behind the hose that connects to the coolant reservoir. Now my solution would also need to include this junction. Since I was going to be fabricating a new piece I decided to make something really nice. Starting with a 3/4" aluminum elbow, I opted to add a -12AN bung to host another Earl’s fitting. With these fittings at each of the hose, removal is a matter of unthreading, as opposed to hose clamps, and the 45 degrees gave me additional intake clearance for. The bead rolled hose joiner for the reservoir hose actually came from the piece of original hardline I cut off.

I discovered it after cutting off the crimp to remove the soft hose. It was a little grimy but it cleaned up alright. I did all of the cutting, prep, and dry assembly but sourced the TIG welding to Scott at Ballistic Motorsports. Dad has since switched jobs and no longer has access to a TIG. Scott came highly recommended through the NEMotorsport group and did an outstanding job. Before dropping everything off I worked up through 400 grit sandpaper then, after bringing the welded piece home, I gave it a once over with 600 before taking it to the buffing wheel. To mate the new coolant junction to the original hardline I purchased a silicone reducer from HPS and installed it with some leftover hose clamps from Forge Motorsport. With everything installed my clearances are REALLY tight, but everything fits!

I do have mixed feelings on the outcome of the final routing of the bypass hose. Again, it clears everything, but it is awfully close to the water pump pulley. I modified a cushioned hose clamp for extra security against the hose rubbing against anything. The narrow diameter of the clamp couldn't be drilled out for the larger M10 hole, so I purchased some EZ-Lock threaded inserts from McMaster-Carr that stepped the hole down to an M6. Ideally in the future I'd like to replace the soft-line with a better-routed hardline, I just don't have a feasible way of fabricating something like that right now. Plus, I'm more focused on getting the car running. There is always room for improvement later.

This has actually been finished for about a week, save for an elbow to connect the hardline to the coolant reservoir. Instead of getting another rubber piece I went through the HPS catalog and found a compatible silicone piece. With all of this buttoned up my intake is finally in, although the filter I purchased is just a hair too big (I've got another on order).

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