***WARNING, VERBOSE WALL-O-TEXT. IMPATIENT POSTERS SKIP TO TL;DR ***
For a little bit of background, I was running a Sapphire 7970 when Dwood started making his brackets, which interested me since I was mining LTC and my temps would break 80c on the stock reference cooler. I ordered a custom lip bracket one right before he stopped taking orders, and threw a lapped H70 on my card with stellar results like shown in this thread : here
. My temps dropped from 84c stock, to 79c with replaced TIM, to 58c with the H70. I then did a few simple mods I never posted - replaced the crappy rigid ribbed tubing to standard clear tubing, added a Phobya tube res, and replaced the stock fans with 80cfm server fans. Now I was running at 55c full load, and was very happy(for a while).
A good deal popped on one of my other forums, which ended with me adding a second 7970 to my rig. Of course I wanted to ditch the same stock cooler, but I had a couple things to think about. Dwood was no longer taking orders on brackets, I didn't want two separate AIO loops crossing ugly lines all over my case, and I didn't trust the terribly weak stock H70 pumps to push two cards and a bigger rad. This of course led me to the logical choice of adding a second custom loop to my rig, but being cheap and a pretty slick modder, I looked at my parts lying around first - specifically the 280mm Aquacomputer Airplex Modular radiator, Enzotech Sapphire CPU block, and extra MCP655 pump top from an old dead pump...***Mod Starts Here!***
The Enzotech Sapphire RevA. is a big, solid copper waterblock popular during the 775 days. Performance wise it is mid pack compared to other blocks of the same timeframe, but it was one of the lowest restriction waterblocks around and was way cheap in price. This made it perfect for beginning watercooling loops - it was only around $45 bucks new at the time, extremely low restriction so didn't need huge pumps, and performed better then a few more expensive blocks. While the low restriction made it perfect for a GPU setup that has to run flow-killing 90* adapters, the size and weight is an issue. I did some rough measurements and think I can get one in-between the two 7970s if I use non-rotating low profile 90* fittings and stick to 1/4" tubing. I have a horizontal mobo so the weight is not nearly as big an issue as with a vertical mobo, and even with dual GTX GenII 480's and dual pumps I have plenty of room in the bottom section of my custom Extended Ascension. I ordered a second identical Enzotech block that I found for sale on this forum, and a third 655 from a different forum, then got to modding what I have.
First thing I did was mod my spare 655 top to accept G1/4" fittings to reduce it to 1/4", since I did not feel like spending $30 on an aftermarket top. I cut off the stock plastic 1/2" barbs with a dremel, then tapped them with a 1/4" NPT tap. Note that G1/4" and NPT are not exactly identical threads, but in plastic it is "close enough" to work. The first few threads screw in perfectly hand tight, then you torque the last couple with a wrench and it corrects the difference between the straight and tapered threads. Now they screw in perfectly by hand, and I used a beveled drill bit to cut a recess for the O-ring. I was surprised to see that even though the 655/D5 pumps have "permanent" 1/2" ID barbs, the inside routing leading to them is noticeably smaller. I would imagine porting the stock top may actually be worth a bit of flow in a 1/2" tubing setup, but don't have the time nor desire to test that since this loop is using tiny 1/4" ID tubing anything. Nothing too exciting here, this is the finished result - awww, aren't those little barbs cute???:
Next step was to mod the block and bracket. This was pretty straight forward...I mocked up the hole spacing using the stock cooler I had lying around from my old card, then drilled it through. I then used a dremel to trim down the edges on the block itself since it will just barely (~1mm)interfere with the bolts I will use to mount it. After that all I will do is bolt it to the card using the stock retaining bracket on the back and some machine screws+bolts. I only pulled the top vanity plate off the card since I want to paint it red, it doesn't need to come off. Here's another boring, crappy pic to show what I needed to trim:
Tomorrow I should have my 90* adapters in, so can mock it up and make sure everything fits while I wait my my pump to come in.***TL;DR***
I am about halfway through putting two Enzotech CPU waterblocks into a crossfire water cooling loop in a custom Mountain Mods Extended Ascension case. Modded my MCP655 to accept G1/4" barbs, and modded the block to bolt through on an AMD GPU. Waiting on pump to arrive to install modded top and finish/test loop.