Several factors. Pat just wrote one-the surface area of our oil pans. Most Cobra noses are full of holes-the grill, side vents, hood scoops and no belly pans like modern cars. A 60MPH, 50 degree or colder breeze is a very effective heat remover. Plus the length of oil lines running to and from a cooler-even a blocked one- act as fins on a radiator. One year as a test I capped the cooler lines so that all the oil stayed in the motor. NO difference at all, oil temps never got above 140 and the water barely stayed at
thermostat temp.
All the tape, plexiglass, aluminum covers, billet t'stats-it's all BS. Any doubters should do the only litmus test-cap the lines and run on oil in the motor only.
We all 'love to drive our cars' but I think you need to get mature enough to figure that you can cause gradual destruction of your expensive toy. Set your priorities-drive it every day 'cause 'it's only a replica' or have something you worked hard to build for a long, trouble-free time.

So, if "driving it" in the winter really means 2-3 times a month, since it only really means dry weekends, how hard is it on the motor?

I don't think it does much. It's harder on the driver. I can tolerate mid 50's, if the sun is high in the sky. Anything lower than that and she stays in the garage....

Very interesting. So would switching to a synthetic help, since the oil will run cooler and synthetics flow better in the cold? I was thinking about the amzoil one, since they claim high zinc. I am currently running the vr1 20w50, per my engine builder's recommendation.

It helps in the sense that it allows easier cold starting given lower viscosity. But 'better flow in the cold' still means you have cold oil. You want heat in the oil-any oil-to better keep contaminates like fuel, moisture and debris in suspension and not accumulate on bearing surfaces.
One of the worst practices to cause damage in winter is the starting and idling for 10 or 20 minutes then back into the garage. Really helps the moisture content of your oil.
I have found that the best regimen for engine and component life is no driving below 50 ambient and if a lay-up of several weeks or months is needed, rotating the motor by hand to relieve the valve springs and not starting at all is best. Then a spring drain of the oil for fresh and a priming of the system by removing the distributor before cranking.

Don't drive below 50*?? Really?? Last week end the temp was right about freezing when I started out. The Lambo in our group had a little trouble starting, but I don't think any of the Cobra's did.

My oil cooler has a seperate pump. So in normal street driving it's like not having a cooler at all. As the day wore on and the air temp got warmer (like 55-60*F), the water temp stabilized at about 180*, and the oil temp was about the same. We were pushing it a little hard over some of the mountain passes.

Before I started using a seperate pump, on a day like that with the cooler blocked off I the oil would not see temps >140* or so on the street, no matter how hard I pushed it. Not having the cooler and associated lines with oil running through them made a big differance.

Synthetic oil does pour easier at lower temps. But we're talking about temps below 0*F. At 40*, a 20W synthetic pours about the same as a 20W dino. That being said, you're much better off with a 5W oil in the winter - just like in your other cars.

Synthetic oils don't run any cooler than dino oils. It's not a function of the oil. Synthetics just handle high heat better, which is a whole differant issue.

Most engines don't need a 20W-50 oil, especially in the winter. Unless you're racing. In that case, you take pains to pre-warm the oil before starting and racing. For street driving, you need enough viscosity to maintain proper pressure. Thicker/heavier/higher viscosity just wastes energy, and makes the engine more difficult to lubricate.

I run 5W-30 in the winter with no problems at all. In the summer and racing I switch to 10W-40. That works well for my engine.

Really? A separate pump for an oil cooler? I've never seen or heard of that-could you post a picture or link?

Now the first part of your second statement reinforces what I said earlier. The second part is counter to my experience. We both live in East Coast climate.

Doug,
Here are a couple of photos of my SPF engine compartment after I added the Beaumont remote oil filter adapter with the manual flow adjustment to the oil cooler. I also changed from AN10 to AN12 lines for better flow.

http://www.clubcobra.com/photopost/d...0/DSC09231.JPG

http://www.clubcobra.com/photopost/d...0/DSC09232.JPG

http://www.clubcobra.com/photopost/d...0/DSC09235.JPG

With air temps below 40 degrees, you will not get your oil up to full temp. There are some good comments here that go into the reasons in better depth than me, but it will not happen. The Beaumont unit DOES allow me to get my oil up to temp in the cooler Spring and Fall mornings (44 degrees air temp this morning), so there is a big gain for me.

As I said in so many words earlier, to each his own. My SPF is a big investment for me (8 years of payments coming to an end in 2 months :-), just as many of the builds here are huge investments of money AND time. I choose to drive mine pretty much every day, year round. It's a great experience every time I fire it up. Doesn't matter if it is July or December, the thrill of driving my Superformance MKIII is still there just as it was the first day I got it.

My SPF has a hard earned "patina" that some may not choose for their Cobra. Your choice. Just enjoy it while you can!
Jim Kellogg
Breesport, NY

Thanks for the pics. Looks good!

I modified the oil pan by adding two -10 AN fittings. One for pick up out of the sump, and one for return.

http://i13.photobucket.com/albums/a2...Pan05small.jpg

The pump is a pretty standard item. I got it from Summit or Jegs. It is self priming, and will almost empty the system. That's a nice bonus when changing the oil, as I can get most of the oil out of the cooling circuit.

http://i13.photobucket.com/albums/a2...ump04small.jpg

It's not quite as efficient as the engine pump. But I don't have to worry about pressure drop and things like that. Racing on a hot day, I can keep the oil temps down to about 210-220*. That's about perfect for the Royal Purple I use.

Great thread and comments. Seems to appear that very few has any objective data that prooves a oil thermostat does infact work on these cars, with few exceptions.

Thank you Bob. Very creative and nice work. But it just won't keep oil warm under the conditions we discussed-that's the focus of my posts. Your set-up looks effective as backup supply for race conditions.

Actually, it does. I frequently drive this car in temps well under 50*. Oil temps hover right around water temps, regardless of ambient air temps. Last Saturday I was driving through the mountains with temps in the high 30's to low 40's. Water temps were right about 170*, oil temp was right around 180*. It took about 45-60 minues for the temps to get that high, but they did.

I think that's when damage begins, especially if RPM is needed.