Rear fender oil cooler mount details, How I did it Options

[IronHillRestorations]

After I made a post about my alternate location for an auxiliary oil cooler, I thought more details would be helpful.
First let me say that this was a piece of cake for the current project, as the right rear quarter panel was removed for rust repair and chassis stiffening. Due to the difficulty in properly locating the forward mounting holes, I don’t know how feasible this is for a car with the engine installed. When I put a (slightly smaller) cooler in this same area 25 years ago, I made no notes or kept any of the measurements, I just made it work, but at that time it was done with the engine out of the car.
After trial and error fitting of a cardboard mockup, I picked a Mocal 34 row, 235 matrix cooler, which measures 260mm by 280mm, or roughly 10 5/16” x 11 1/8” which doesn’t include the -12AN fittings. This is what I think to be the largest cooler you could get in that area ahead of the right rear wheel. This cooler has a capacity of .75 quarts, which is .20 of a quart more than the kit BAT offers to upgrade a 911 front oil cooler. This is a case where bigger is definitely better.
Since airflow in the rear quarter panels isn’t as good as the front fender , I added a 7” Spal puller fan that will be mounted directly to the oil cooler with a plastic mounting tie kit, which are very sturdy round zip tie fasteners that make it easy. The fan will be wired with a relay to a switch on the dash or an automatic inline switch (to be determined later). On my old install I tried to make the fan automatically switched, but it ran too much and the fan died. A testament to this set up is that I never knew the fan died, and oil temps never got over 220* even in the hot Tennessee summers. Since this is going to be a widebody hot-rod with flared rockers, I’m toying with the idea of incorporating a scoop in the rocker flare, but that too is undetermined.
Here’s a hardware list, that doesn’t include any oil lines, thermostat, or relay wiring for the fan.
1 Mocal A34A12 34 row -12AN 235 oil cooler
2 Mocal/Setrab ABKT-235 oil cooler bracket for 235mm core
1 BAT ABKT1 cooler/fan mounting tie kit
1 M8 x 1.25 x 60mm fully threaded cap screw (13mm hex)
2 M8 x 1.25 x 50mm fully threaded cap screw (13mm hex)
12 M8 washers
8 M8 x 1.25 nylon insert nuts
1 M8 x 1.25 weld nut

Even with the fender off it took more than one attempt to get it in the optimum location, which is as far forward as possible without interfering with the outer suspension console. Using the suspension console as the baseline level plane, the cooler is tilted down at the back about 5* give or take a degree.


Just for reference

Here's what the cooler looks like mounted. It's pretty big.


I wanted to make sure the cooler could be installed and removed with the fender on, I made sure there was no interference. I had the fender on and off several times during the test fitting process.
With the fender off it was easy to use the bracket as a reference where to mark and drill the 5/16” front mounting holes, which are 70mm apart.

[IronHillRestorations]

So it’s all mounted nice and tidy, but how can I pass this on for future use? I used the vertical surface upper cross member on the firewall as a reference point, and butted my ruler up against the lip of the side panel. This is where you’ll measure from to make your reference marks to drill your mounting holes. Flush against the vertical edge of the firewall and the upper stop is the lip of the side panel.



From the upper reference point measure down 176mm and forward 61mm. This is where it’s a little tricky as I wanted a repeatable method that you could use. Keep the ruler flush against the vertical side of that panel and hold it against the inner wall, and set the sliding square at 176mm, this is your down measurement for the top hole. Then I used a shorter scale (ruler) measure a perpendicular straight line from the edge of the vertical ruler 61mm toward the front of the car. I didn’t bend the scale. This is the spot for your top hole. I must confess that this was easy with the battery tray not yet installed.
Continue down that same vertical line to 345mm, and then another perpendicular line 75mm forward for the lower mounting hole. Before drilling any holes measure between your two marks and make sure you’ve got 70mm. You can enlarge the holes a bit if you have to, and in a worst case scenario, you could employ some oversize washers.


The rear mount is very straight forward, which I’m not going to detail. The pictures tell all. You have much more access to install this mounting point.
After it’s all installed I’ll make a stone shield from some black plastic inner fender material, and make a follow up post.

This is how it measured out on this 914-6 chassis, I can’t promise that there isn’t a difference in a later style chassis, or some variance in your chassis. Double check and measure, check and measure again.

I’m not going to get into the front mounted cooler, or rear mounted cooler discussion. This is just how I decided to go. I know this might not be the best choice for a track car, and it’s not “GT correct”. My own opinion is that the trunk space a 914 provides is one of the more practical aspects these cars have to offer. I also am a fan of a full size, fully inflated spare tire. This approach preserves both.

You might get halfway through doing this and decide I’ve caused you more grief than help. Clearly, your results may vary.