It’s been along time since a Monster tower owned the spotlight. You can’t escape seeing Corsair’s 800D case featured in magazine ads for Gaming PC boutiques. In only 6 months, the case has become one of the most sought after full tower cases in the market. Hardware reviewers praised the 800D for it’s spacious interior and built in features. Corsair invested a lot of time into R&D, and it shows. The research involved watching and listening to the community. “Why don’t manufacturers pre-fit cases for radiators?” Corsair was lurking and taking notes. The 800D fits a 360 size radiator without any modification. This was a nice gesture, but there will always be people who want to squeeze more performance out of this chassis. This illustrated guide shows you how to modify the 800D to fit a 420 size radiator.

Products:
1x Hardware Labs “Black Ice” 420 GTX Radiator or any 3x 140mm radiator.
1x 420 Radiator Grill from performance-pcs
12x M4 x 30mm size socket head machine screws
3x 140mm cooling fans (model of your own choice)

Tools & Supplies:
Painter’s Masking Tape.
Pen or pencil.
Rotary tool.
1x 1.5″ cutting wheel attachment for Rotary Tool
Jigsaw with 18 TPI or higher metal cutting blade.
Rounded side hand file.
Center punch.
Power Drill with 3/16″ drill bit.
12″ Measuring Square.

Hardware Labs “Black Ice” 420 GTX Radiator (3x 140mm cooling fans)

Link to diagram of Hardware Labs “Black Ice” 420 GTX Radiator

The Obsidian requires altering the 5.25 Optical drive bay to fit the 420 radiator. You must remove the 5.25 bay by drilling out all of the pop rivets on the front of the Obsidian chassis.

Yellow line illustrates the rear portion of the top of 5.25 bay you need to remove. (left access panel side)

Using Rotary tool with 1.5″ reinforced cutting wheel attachment to remove the section from the 5.25 bay.

Jigsaw with 18 TPI or higher metal cutting blade.

The top panel of the Obsidian case is pre-fitted for 360 radiator (3x 120mm). We’re going to remove this to fit the 420 radiator (3x 140mm).

Cover the top panel with masking tape. Then position the 420 radiator grill on the top panel. Use a 12″ Measuring square to center the grill.

Trace the inside of each fan opening.

Using Rotary tool with 1.5″ reinforced cutting wheel attachment to make the initial cut in the panel before using the Jigsaw.

Using Jigsaw with 18 TPI or higher metal cutting blade to cut the fan openings.

Use a rounded side hand file to clean up any jagged edges caused by the Jigsaw.

Using the Center Punch to mark the mounting screw holes.

Using 3/16″ drill bit to make mounting screw holes.

This is how my initial cut out for the radiator looked.

I attempted to install the grill/rad/fans, but the remaining “recessed” material of the top panel wouldn’t allow everything to fit flush without using different size screws. I decided to modify the panel further by removing the remaining honeycomb perforation and flatten the lip.

Flattening the fold was done by turning the chassis upside down on the bench, and flattening the folds with a rubber mallet. Now I could use M4 x 30mm length machine screws to attach everything together.

The edges of the radiator opening after being flattened.

Now the grill/rad/fans will now fit flush together.

I used the stock 140mm cooling fans included with the 800D for fitting the radiator.

Black aluminum 420 Radiator Grill installed.

I used twelve M4 x 30mm size socket head machine screws to install the grill/fans/radiator.

This approach to the 420 radiator installation worked out great. You may discover your own approach. This guide is to inspire you to mod your 800D however you want. The recessed center portion of the top panel helps reinforce rigidity. However, the chassis is steel, so I don’t believe it was detrimental for Corsair to have it designed it this way.. I think it would have been fine if was made flat in future versions. I would like to see Corsair revise the Obsidian to fit both 360 or 420 size radiators.

You can follow more progress of my Obsidian 800D case mod for Hardware Canucks HERE

Before modifying the case, I placed the 360 version of Mnpctech rad grill on the 800D. You can purchase the 360 radiator grill from performance-pcs, HERE

- Bill Owen