Thursday, September 12, 2013

Cooling... Part 1

 So tonight I started to sort out the cooling system. From the factory, the E21 radiator overflow bottle (pictured bottom left) is located adjacent to the strut tower, above the exhaust manifold.

The exhaust manifold did not in itself present any issues as I have heaps of clearance in terms of height back there however the normal hose path goes to the radiator which is accessible from the inner side of the brake assembly. In my case (as you will see in photos further down the page if you are new to the build) the radiator supply hose has to be accessed from the outer side of the brake booster so I cannot use the standard location. 

In a standard application of "measure twice, cut once" I made sure there was enough clearance for the bonnet using the unscientific "put it in there and close it" method; then made a bracket to hold the supply bottle. I had to remove the rear mount as it did not allow the bottle to sit flat. I may JB weld a new bracket to the bottle if it moves too much once filled. The bracket was made from 40x40 angle aluminium

The new location means a relatively simple path for the hoses, and also means the reservoir is located higher than the rest of the system and still "flat" as per its original location - this is vital to ensure the system can self-bleed. Note that the standard falcon item doesn't appear to be an easy fit in this location; thankfully the BMW unit seems intact and uses the same size hoses. The only thing missing is a second bleed hose nipple, however I will just fit a T piece to work around this.

Here you can see the main bleed hose nipples - both on the reservoir and the radiator - I will have to drill two holes to allow the hose for this bleed to pass through. I will most likely fit the T peice at the top of the system right next to the reservoir and feed the other bleed hose along the top of the radiator and along the path you can currently see the headlight wiring following.

Side profile showing bonnet pin location and reservoir/coolant cap - here you can see how far proud the setup sits.

With the bonnet fitted, inside you can see clearance is very tight - less than 1cm on both the cap and the un-tapped bulge at the front of the reservoir (This bulge appears to be intended for a sensor perhaps?)

A wider shot showing the hose outlet, you can also see level with the top of the bumper the hose outlet from the radiator. Some major cutting will be required both in the area around the bottom headlight and surround mount, as well as most likely the headlight bucket itself to clear the hose. Sometimes I think it would be much easier to simply opt for a single headlamp front. Despite feelings of the opposite from some E21 fans, I feel the twin light front "makes" the car, so will continue to work to preserve that look.

A shot showing the bonnet pin so you can see roughly where the bonnet sits in comparison to the reservoir. It's close!

I can't fire up the compressor to use the die grinder to modify the headlight brackets tonight so instead I've moved on to looking at making a thermofan fit. I have no room for a clutch fan (and there is no provision for one anyway on the EF-AU belt setup) so have to make a thermofan fit. I have removed the brackets from an EF-AU fan (single unit) - normally these are configured with dual speeds and have two fans (one comes on with A/C) - since I don't have A/C I shall only need one fan however I am going to struggle to get it to fit - hence removing all plastics/guards etc.

Here's the back of the fan - you can see there are three locating bolts - if I can make a bracket that holds this and modify the top center of the metal front bumper (and possibly the plastic grille/headlight surrounds/their mounting locations) then I should be able to make do with this fan. The alternative is an A/C assist thermofan from a Holden Commodore - these appear thinner however one can only assume that their flow capacity is also reduced. I will look into this further before hacking into the bumper as I do have a commodore unit available to me.

The overall airflow may not matter massively as the thermofan will most likely only be needed while idling or cooling down after driving (when the engine is no longer under load) - I have no intention of performing stand-still burnouts (where a clutch fan is traditionally far more advantageous)

The core is around 3" thick (apologies for the mix & match of metric and imperial sizes - I find it far easier to be precise in mm, and approximate in inches!)

Measurement is 1.5-2" from the bracket/base to the fins

The core would clear at the very center, but will require clearancing either side - this may impact how the headlight bracket sits. One of the main reasons I'm considering the commodore unit.

At the outside edge (both sides here are symmetrical) - the headlight bracket to the left would have to be trimmed (see black line) and clearanced slightly.

I've also sorted out a top hose - this is taken from a commodore (I believe VQ V8) although V6's have the same 90 degree bend that lends itself to our requirements. You can also see the Blue Bosch injectors from a BA per my last update, and the ford Belt cover. Note also minimal clearance this side of the radiator - there's certainly no "moving it back a touch" to gain clearance at the front.

A closer shot.

The video above shows how I install and remove the bonnet on my own - this certainly helps when trying to get small pockets of progress achieved late at night on my own!

Anyway, I still have to grind out the clearance I need for the side hose, and the bottom hose may require an adaptor and a cut-n-shut from an existing hose as it's a couple of compound bends from one to the next. I'll also be looking into the commodore fan further to assess it's flow capabilities. If nothing else it might prove sufficient to allow the car to run/idle and check timing etc.

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