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Posted by: 98101 Nov 19 2017, 04:01 AM

I just bought a 914-4 from California with a carbureted 2.4 motor and a Patrick Motorsports front oil cooler. Here in Seattle it doesn't run well at part throttle when it's cold. It seems to take a long time to warm up, and even then the highest I've gotten the oil temperature is 80C. The oil pressure gauge reading also takes a long time to come down. Complicating matters, it's a new engine and the previous owner hadn't dialed in the carbs to his satisfaction.

The car has the bellows air thermostat installed and I observed it in the cold "do women know about shrinkage?" position. Is there a way to tell if the flaps are working properly without taking off all the engine tin?

The Patrick Motorsports front oil cooler kit includes an oil thermostat. Per the previous owner it's installed where the oil lines return to the engine. I'm not sure how this works exactly, but I would have expected it to take the front oil cooler completely out of the loop until it's needed. Is this a correct assumption? Is there an easy way to test the oil thermostat?

Posted by: campbellcj Nov 19 2017, 08:21 AM

I have the same issue. In colder temps I often block-off much of the front intake for the aux oil cooler with gaff/racers tape to keep more heat in the engine! I still have the standard 911 engine-mounted oil cooler also, and the front is really not needed or wanted in certain conditions; however, mine is a racecar typically running 7500rpm for 20mins at a time, in hot SoCal weather. Thus it is 'open' and active a lot of the time. My original builder used a Troutman thermostat which is in the front fuel filler vicinity. It's kind of a strange location but he swore he'd used it successfully many times and I've had no issues with heat or reliability of this whole setup.

You should be able to tell by feel or perhaps an infrared thermometer whether oil is flowing past the t-stat and thru the cooler and returns. In my car it's very noticeable with braided stainless lines and a metal-shrouded oil cooler - you're talking roughly 200F fluid inside metal when right now I see 41F ambient outside.

Sorry, I'm not sure about the cooling flaps question.

Posted by: Edward Blume Nov 19 2017, 08:24 AM

QUOTE(98101 @ Nov 19 2017, 02:01 AM)

Posted by: rhodyguy Nov 19 2017, 08:40 AM

Show us detailed pictures of the carb linkage. Does the cooler have a fan?

Posted by: GregAmy Nov 19 2017, 09:17 AM

A quick way to check the bellows is with a propane pipe torch. Start with it cold and it should be shrunken. CAREFULLY wave the torch back and forth across the bellows - don't try to weld the damn thing, just heat it up - and you should see it extend. If it doesn't then obviously it's not working.

Do you have something in the oil lines that looks kinda like the below? That's an oil thermostat. It internally bypasses oil flow away from the cooler and back to the engine until it reaches a set temperature (180F-ish?) You verify it's working by touch, feeling of there's heat before it, and the cooler is still cool/cold.





Edit: just caught this topic below on the bellows:

http://www.914world.com/bbs2/index.php?showtopic=311795

Posted by: Mark Henry Nov 19 2017, 10:13 AM

No front cooler T-stat completely shuts off the cooler loop, when cold it will close about 90%.

Do you still have the stock cooler?
If you do you could block the front cooler off a bit or completely in cold weather.

Posted by: GregAmy Nov 19 2017, 11:33 AM

Mark, from experience with the Summit t-stat above, there's a decisive and obvious difference in the touch-temperature of the lines before and after the bypass when the engine is warming up. It's a fair basic test to check general operation.

Posted by: 98101 Nov 19 2017, 02:18 PM

QUOTE(rhodyguy @ Nov 19 2017, 07:40 AM)

Posted by: 98101 Nov 19 2017, 02:50 PM

QUOTE(Mark Henry @ Nov 19 2017, 09:13 AM)

QUOTE(GregAmy @ Nov 19 2017, 08:17 AM)