Oil Cooler speculation

I'm in the final stages of my 1973 911's 3.6 liter engine conversion, and I'm wondering what to do about oil cooling. The car used to have flexible lines running to a fender-mounted radiator style cooler. It kept the old 2.2 engine nice and cool.

But the new engine doesn't have an internal cooler (to make room for the power steering unit, apparently), so I've upgraded to a Carrera cooler with the hard (and also wider) turbo lines running to it. My plan was to mount a fan onto the Carrera cooler, but there isn't room for one in the wheel well.

My question: will the larger cooler with the larger supply and return lines be sufficient to keep the engine cool? Has anybody tried this? Do all 964s have fans, and do they run a significant percentage of the time?

As I see it, the only way to get enough room for a fan down there would be to chop into the battery box, and then do an Optima battery conversion, replacing my (just-installed) stock double battery set-up. I don't want to do this pre-emptively, unless someone who's been down a similar road assures me that it's the only sensible option.

Ideas? Opinions?



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Jack Olsen
1973 911 T sunroof coupe

Jack , a number of months ago there was an article in Excellance about a person who put a 3.6 in his early Targa. He was having some cooling problems after the swap. On the advice of Patrick Motorsports he installed
the 993 oil cooler unit from them, around $400. You might want to contact them.

Hope this helps.

Jack,

To answer one of your questions, I'm pretty sure all the 964 oil coolers have fans. I put one(w/ hardlines) in my '70 because of the crazy eat here in South Florida and it had the fan attached to the grill. If you need any part numbers off the setup, let me know.

I can't wait to hear your report after completion and some driving.

Rich

Jack - one very important issue is to completely inclose the radiator with a shroud and make sure fresh air can get in and out. I don't know what bodywork (valence) or ducting you have available, but getting air volume through the radiator will help tremendously. You shouldn't have to rely on a fan to pull air from somewhere while the car is moving. It should only be needed when at rest. Sorry if this is an obvious point, many people overlook it.

One other question. What type induction and exhaust are you using? I have been looking for a street (heat exchanger type) header system for a large bore ingine. SSI is too small and B&B are substandard in quality.

Jack,

Another solution might be to put your 'old' cooler , or a Mocal, or Earl's unit in the left fender, and plumb it in series with the one in the right fender, having two up front like all of the 550's and 356's with the four-cam Carrera engines! More work, but more cooling for the beast! And, none of the fender-mounted fan setups provided forced air for more than about 40% of the area of the cooler, anyway ... presumably for bumper-to-bumper traffic jams, and waiting in line at the bank ... you may not even need to worry about those contengencies, at all!

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Warren Hall
1973 911S Targa

Warren - I am doing the same setup with my car. The washer tank and overflow have to be removed on the left side. This is no biggy for me because these tanks aren't being used. I didn't mention this because most folks use these tanks. I thought I was the only one that had no use for windshield wipers, radios, power windows, and A/C condensers. HA!!

Jack, and Rarly,

I believe on a '73, the only thing that would have to be removed or moved would be horns and the charcoal fuel vapor canister ... horns could be put almost anywhere up front, and the charcoal monstrosity could be put back with the fuel pump beside the trans with longer lines!

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Warren Hall
1973 911S Targa

Thanks, guys. My concern had been that I would get this last part of the job put together, take it out on the street, see the gauge spike into the 260 range, and immediately have to turn it around and go back to work. It sounds like I'll be able to enjoy it a little before tearing it apart again.

Which works fine, since there's now a 'stage 2' to the conversion. Getting stuck with a later-model LSD has meant ordering new stub axles and a spacer to go where the electronic speedo sender goes. And the air conditioning project -- mating the 964 compressor to a (rear?) wheel well based condenser, a front 1973 condenser, with all-new, custom cut hoses has also been relegated to the second extended pit stop.

Once I map out the limitations of the passive oil cooling set-up, I'll either drop in a second radiator cooler, like Warren suggests, on the other side of the car, or I'll get creative with the sawzall and strap in a fan -- and maybe even some ducting from one of the otherwise-useless horn grills.

I'll keep you all posted. Thanks again for the answers.

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Jack Olsen
1973 911 T sunroof coupe

I couldn't tell from your pictures, what kind of front spoiler you have? I've heard that the best cooling upgrade for our system was a "ruf" type cooler for the front spoiler. I've seen them run in series with the fender mounted coolers also.
I looked into it when I was putting a front cooler on my 70T, but my aftermarket C2 type spoiler doesn't leave much room for mounting anything there. I think you would have to add a RSR type spoiler with the large cut-out for the radiator.
My mechanic said that I should look into getting a newer, high capacity oil tank. He said that that would definitely help keeping the oil temps low. But your project is a bit more of a leap than mine was, going to the 3.0. Ed

I have the early S type spoiler, not the RS one, which has the cut out area for a front-mounted cooler. I may be jumping through a lot of hoops for something that's only about aesthetics, but I personally don't like the look of the front oil cooler.

If a larger oil tank helps keep temperatures down, then I'm in luck. I've got a later-style tank going into the thing. We'll see how it all holds together.

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Jack Olsen
1973 911 T sunroof coupe

Yes RarlyL8, you are the only "Survivor" I know. But, I have contimplated a reorganiztion of the left front fender to accomidate an additional cooler. I also wondered about a different option. Mount an additional cooler behind the front a/c cooler, just below the fuel cell. Spend some time at a machine shop and I bet you could make a cover/scoop that would have minimal visual impact yet funnel air over the a/c unit and to the oil unit. To really enhance flow, the scoop could be made to dump all incoming air through the oil cooler.

You are also making the assumption that the heat needs to be transfered to the air. I can also be diffused. Put a pony keg in the bonnet, fill it with oil, and attach the lines. You could probably drive for a month without using the same oil drop twice. Of course, you'll need a pay advance everytime you changed the oil.

Rich