Overheating, Engine / Cooling Options

[ash00]

Hi All,

After a month and a half of business trips, I finally got to drive my the 1970 914 that I'm still learning about.

One thing is clear, that the restoration was half-assed, and rather than blaming the PO, I have to figure things out the hard way. Hopefully before the fact. I'm trying to not let this leave a bad taste in my mouth of the 914 experience.

The recent issue is overheating. This is my first car in the aircooled world, and the car was equipped with a rebuilt 2.0L with the weber downdraft setup in place of the FI. It runs well when warmed up, but during driving, I can't drive it for more than 10 minutes without the gauge being pegged to the red. I'm hearing things of "false air" and such.

Pardon my ignorance, but I need a place to start looking for info. Is there any documentation or info out there on how the air cooling is managed, and what hardware is there for me to test / check? Any tips are appreciated.

Thanks,
Ash

[Porschef]

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Hey Ash,

You might want to check the gauge for accuracy first, then make sure there's no mouse nests/ obstructions in the cooling fins and that the flaps are operating properly. Also, that the oil cooler has air flow.

I have a kitchen thermometer with a long probe; something like that might be able to tell you how hot your oil is by putting it down the dipstick tube.

If you're over say, 220-230, then there's other issues at stake.

Good luck.

[ash00]

Great Idea. i have a fluke with a TC. I'll try that out. I'll first check at startup, idle for a few minutes, then driving for a bit and seeing what it is at halfway, then 3/4 then at red.

[injunmort]

after checking what joe suggested, i would first check the timing. then check jetting in the carbs. i would not drive it until you get a handle on this problem, if the gauge is right and timing and jetting is off, you can easily hole a piston.

[ash00]

Definitely.

What should timing be set at?

[injunmort]

34 degreess btdc fully advanced. good tech article on pelican parts site on the procedure.

[SirAndy]

Also make sure your cooling flaps are installed and operating correctly.

There is a LOT of misinformation about those floating around and i have even seen "rebuild" engines where they had been removed completely.
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[injunmort]

i had a rebuilt engine in my dd that had the flaps removed. needless to say i replaced it over the winter.

[brant]

top of my head.... I thought factory timing was supposed to be 27degree's

usually on a carb'd car with any cam in it... slightly higher than stock is good for power
especially at altitude
but sea level, maybe not so much

[injunmort]

i think 27 degrees is for stock distributor advance fi. i did mine according pelican with stock cam and new dist. at 34, weber 40's and it runs about as well as it can with the cam/carb combo. did not like 27 degrees at all.

[era vulgaris]

Since this is your first air cooled car, let me ask what RPM do you typically cruise at?
If the answer isn't between 3k and 4k rpm, then you're doing it wrong. The cooling fan is bolted to the crankshaft, so in order to get enough cooling air moving, you need to cruise at higher rpm than a water-cooled car.

Also, there's a valve (can't remember what it's called - oil pressure relief/oil pressure release...something like that) that allows oil to bypass the oil cooler when cold to aid in warm up. Over time it can get worn out and not allow enough flow to the oil cooler when the engine is warm.

Also, just FYI, the temp gauge only measures oil temp. Not sure what you mean by "false air".

[ash00]

I appreciate all the help guys! Looks like I'll have to do some digging. I have to find what the flaps look like and see if I do have them.

I'll have to run the temp test on the oil. If that is the oil temp I'm reading, then I have to see what is restricting or causing it to get hot quicker than normal.

Any links or pictures as to what the cooling flaps are supposed to look like so I can compare?

[SirAndy]

I have to find what the flaps look like and see if I do have them.

This should help:
http://www.914world.com/bbs2/index.php?s=&...t&p=1732173
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[era vulgaris]

You won't be able to see the actual flaps as they're under the cooling tin. But you will be able to see the bar that links both flaps together. It'll run across the engine behind the oil filler tower. You can see it in the pics SirAndy linked to.
If you do have the cooling flaps installed, then you should also check to see if you have the thermostatic bellows that operates them. The thermostat is kind of below the pushrod tubes on the drivers side, it looks like a set of bellows, and there should be a wire that runs from it up through the cooling tins and connects to that crossbar that the flaps are attached to.

[ash00]

Awesome- that helps.

I assume that the flaps are actuated from red lever by the shifter?

[ChrisFoley]

Awesome- that helps.

I assume that the flaps are actuated from red lever by the shifter?

No, the flaps are automatic.
The red lever opens the flappers on the heat exchangers to move heat into the cabin.

[era vulgaris]

Awesome- that helps.

I assume that the flaps are actuated from red lever by the shifter?

No, as I mentioned, the flaps are actuated by the thermostatic bellows, which is attached to the lower part of the engine on the driver's side, kind of below the pushrod tubes. The bellows open and close with the heat of the engine, closing the flaps when the engine is cold and opening them when it is warm. This process is completely autonomous of any input from you.
If your thermostat is missing or broken, or if the cable from the thermostat to the flaps is broken, the flaps automatically default to the open position to prevent overheating of both the cylinder heads and the oil, as the flaps deflect cooling air to the cylinder heads and the oil cooler. That's why it's necessary that you have flaps if you have the stock oil cooler, because without them cooling air will not be directed toward your oil cooler.

[Elliot Cannon]

Also make sure your cooling flaps are installed and operating correctly.

There is a LOT of misinformation about those floating around and i have even seen "rebuild" engines where they had been removed completely.
(IMG:style_emoticons/default/wacko.gif)

My flaps aren't removed but are locked in the full cool position. It just takes a little longer to warm the engine up. "Full cool". I like that. (IMG:style_emoticons/default/biggrin.gif)

[r_towle]

Also make sure your cooling flaps are installed and operating correctly.

There is a LOT of misinformation about those floating around and i have even seen "rebuild" engines where they had been removed completely.
(IMG:style_emoticons/default/wacko.gif)

My flaps aren't removed but are locked in the full cool position. It just takes a little longer to warm the engine up. "Full cool". I like that. (IMG:style_emoticons/default/biggrin.gif)

Super cool

[boxsterfan]

Also make sure your cooling flaps are installed and operating correctly.

There is a LOT of misinformation about those floating around and i have even seen "rebuild" engines where they had been removed completely.
(IMG:style_emoticons/default/wacko.gif)

My flaps aren't removed but are locked in the full cool position. It just takes a little longer to warm the engine up. "Full cool". I like that. (IMG:style_emoticons/default/biggrin.gif)

Yep, my understanding is that it is better to have them in the default open "cool" position then none at all. Just a little longer warm-up time as you mention...