Keeping my air-cooled engine "cool"

[kamaro]

I have a nice 1976 911 with the stock 2.7 engine without the external oil cooler, and since I'm using this car in a very hot climate (temp will be 105F or more for two months or more in a row!) I'm obliged to add an external oil cooler, I need to choose between collecting all the bits and pieces of a factory oil cooler and lines/hoses .. etc, or just slapping in some AN lines and an aftermarket oil cooler. What do you guys think about my best bit in terms of cost and effectiveness?

execuse my "so newbie" questions. I've been working with american muscle cars all of my life and all of sudden I got my self a German car!

[Uwon]

BAT Inc. has all you need and more.
British American Transfer
Others will chime in, I’m sure.
Cheers,
Johan

[Jack Stands]

When I had a ‘75 2.7 (also with no external cooler), I bought a Turbotrol cooler that worked fine. I think any of the aftermarket systems will help, though if you’d be able to source the factory lines, thermostat, and cooler from a Carrera, that might be the cleanest install. Any of the oil cooler options should be adequate for a stock 2.7.

[chrismorse]

Stock lines, clamps, thermostat, cooler, mounts and stone guard, fan FIT, with very little work and really get the job done.
I sourced a used set of hard lines from Elephant at a great price, new thermostat, Carrera cooler kit and flex lines. It went together quickly and worked very well.
The stock 74 now has sane oil temps and pressure.

A few years ago my 77 308 oil cooler sprang a leak and I went with BAT/Mocal for the cooler, lines and importantly, a 180 degree thermostat - the stock system had NO thermostat and took forever to come up to temp. It took a "few" hours to fab up all the -12 stainless lines, mounts and get things clearanced. It works well.

On the Porsche, the thermostat has a high pressure bypass to protect the cooler and engine. I don't have a good sense of how frequently non bypass systems suffer problems, but the factory felt it important enough to go to the expense of doing it.

It looks like the internal passages and fittings on the stock parts are larger diameter than the -12 Mocal equipment, important for an oil cooled engine.

From the few pictures of the Mocal coolers I have seen, it looks like the thickness of the cooler body is thinner than the Carrera cooler, perhaps not as much surface area/cooling ability?

Finally, I believe it is prudent to have more cooling ability than you currently need, to provide a safety margine against the eye watering cost of a overheating/engine failure.

Let the thermostat, not the cooler size control the critical oil temp, (like the old Ferrari did).
Chris

[dfhtrhjn]

I have a '77 2.7 liter. I put an IROC bumper up front and a Setrab oil cooler in it. I ran stainless braided lines the whole way with a Mocal external thermostat where the stock Porsche thermostat would have been.

It works really well in 105 degree weather, no external fan needed.

That being said, you can use Porsche hard oil lines, or run your own like I did. There's no benefit to either, and both are equally easy to install.

You can use the stock Porsche external thermostat, or a Mocal, again no benefit to either. Both operate at the same oil temps.

You can also do front fender mounted oil coolers like stock with no bumper mods. The only caveat is that you *may* need a second oil cooler in the driver's size fender for the weather you're talking about. You may also need to mount thermostatically controlled fans on the fender coolers.

[ischmitz]

The first thing to consider is whether you want a radiator style cooler like the Porsche brass 28-line or a forced-air style cooler. The key difference is that the latter relies on air flow for efficiency. A forced-air cooler does next to nothing with no air flow (e.g. stalled in traffic) but works once there is sufficient air flow through its core. When Porsche went to the forced-air coolers on the Carrera they had to add a fan for that very reason. The brass 28-line cooler is radiating heat off its surface. It's probably not as efficient but works without air flow.

The next question is whether to go stock, reproduction, or AN-lines. If you can pick up a nice set of fixed oil lines I'd go for that. Or if you have the funds look at Elephant Racing's finned oil lines. AN lines is an option but I personally don't like the looks. Plumbing from the engine to the external thermostat can be done with AN lines if you don't run wide tires. However, stock Porsche lines are better as they hug the inner fender and there is less chance of interference between lines and tires. One more thing to consider is that the hard oil lines itself act as a radiator and help cooling while AN lines don't do that.

When I did the cooling for my car (narrow-bodied '74) I went with Porsche hard lines and a stock brass 28-line cooler in series with a center-mounted forced-air cooler. I had the front tub modified to create air flow through that cooler and it hides behind the stock valance. In traffic I take advantage of the brass cooler's ability to keep things in check and once I get up to speed the center-mounted cooler kicks in.

[sp_cs]

How about carrying more oil?

https://www.eb-motorsport.co.uk/productinfo.asp?id=322

[Jdub]

I would encourage you to use stock Porsche parts to do this because the path is well laid out, and the resale value may be more favorable having use Porsche parts. The Carrera forced air setup would probably be ideal for the heat you describe, maybe placing a switch to manually turn on the fan as well. You will find a wealth of information about this on this BBS but use Google to search for more hits and returns.

My experience for a '78 was to remove the "trombone" loop cooler and install a 28-tube cooler given the cooler temps I run in and rare 90+ days we might encounter. This was just insurance and I like to fiddle with my car.

EDIT: Feel around the right side headlight for a cooler mount. Your year might have a welded mount in place for the cooler (see this: Carrera Oil Cooler Install Question).

Link that might be helpful: https://www.pelicanparts.com/techarticles/911_carrera_oil_cooler/911_carrera_oil_cooler.htm

[Targalid]

Check the classifieds on this forum for oil lines, coolers and thermostats. I bought my hard lines, cooler and thermostat from the classifieds. The used hard lines may have some dents but you can easily fix them for $5 and a beer. The 76 has the mounting bracket as part of the inner fender/tub.
Fixed my Crushed Oil line for $5 and a beer.

[911pcars]

Oil is great for absorbing heat; not too good at rejecting it without assistance. Increasing oil volume merely increases the time to bring up to operating temperature.

The later tube and fin-type coolers are more efficient at transferring heat to the atmosphere. All coolers need air flow to maximize heat transfer. The space under the fender isn't an ideal location, thus a fan is recommended.

You could follow the history of 911 external oil cooler upgrades over the past 50-60 years and arrive at a consensus as to materials and components. Be cautious about supposed whiz bang products claiming superior cooling. They usually compromise cooling and/or oil flow.

Sherwood

[GH85Carrera]

Resale is not your concern right now, but it will be someday. The OEM Carrera setup works fairly well. I would check the Elephant Racing prices, not cheap, but high quality, know product.

For sure get something with an electric fan. My 85 had the cooler but no fan. I added a fan myself and it does help a lot. In slow traffic it helps a lot, and on long road trips of many hours of driving in 100+ degree heat the fan helps at highway speeds as well. I have driven from Savannah, GA towards Oklahoma City in August and it was triple digit every day and of course I was going west looking at the blazing sun shining on my chest and hands on the steering wheel.
The AC kept us (my wife was with me) cool and the engine never got above 210. I have a oil temp gauge with numbers on it.

[86 911 Targa]

Originally Posted by kamaro

I have a nice 1976 911 with the stock 2.7 engine without the external oil cooler, and since I'm using this car in a very hot climate (temp will be 105F or more for two months or more in a row!) I'm obliged to add an external oil cooler, I need to choose between collecting all the bits and pieces of a factory oil cooler and lines/hoses .. etc, or just slapping in some AN lines and an aftermarket oil cooler. What do you guys think about my best bit in terms of cost and effectiveness?

execuse my "so newbie" questions. I've been working with american muscle cars all of my life and all of sudden I got my self a German car!

As installed on our M/Y 1986 Targa.

On temp: 210f

Off temp: 197f

Gerry

[kamaro]

You guys are amazing! , I couldn't be happier with all these valuable information. Thank you guys so much!

So my final verdict is to get a complete OEM oil cooling system from a newer Carrera. I posted a WTB thread in the classified section.

Thanks again.

[Jdub]

Good move I think. Lots of information on this BBS especially concerning installing the lower bracket and relocating the horns (not hard).

Be absolutely sure the lines, thermo., and cooler have not been involved in an engine meltdown that would mean shards in the assemblies (ask the seller). You will be flushing all of these anyways but you want to start out fairly clean.

[kalinsd]

Send the cooler to Pacific Oil Coolers. oilcoolers.com They check for leaks under pressure, ultrasonic clean/flush and recoat the cooler for protection from the elements. All work completed to aircraft standards. About $130. for the work included shipping to my location. You won't be sorry to have this work completed.

[SoxFan82]

Not that I'm saying to go rebuild everything as a solution...but anecdotally, we had our engine rebuilt on our 84 911 3.2 last fall, and replaced some things like the oil pump, lines, etc. It used to run about halfway up or a little higher on the temp gauge, even in cool weather. Now even in hot weather it barely goes over the 1/4 mark on the temp gauge.

[lvporschepilot]

A 44 row Setrab with 12an lines and Mocal tstat works very well. If you are extra-paranoid, go 50 row. Install a 6" puller fan with a heat switch and you're good to go.

[grant lyon]

If originally a California car, make sure to swap the 5 blade blower fan to the 11 blade, and lose the thermactors.

[manbridge 74]

Even with a cooler consider inspecting your engine tin to body seal, the foam pieces behind the shock towers, spark plug wire seals at valve covers and any extra gaps around the crank pulley. A clean fan will help too.

[kamaro]

I found that if I go with the OEM route (using mostly used parts) I will end up paying $1500 or even more. So I decided to build my own using AN hoses and fittings and a 50 row Setrab cooler. way more efficient and WAAAAAY cheaper than a new OEM system.

Thanks guys for all the valuable info.