Running Hot on the Highway Options

[NJ914Guy]

My car is a 1973 914 2.0 running dual Weber 40 carbs, an Aircooled.net SVDA vac advance distributor (vac port connected to dual carbs) and a Pertronix electronic ignition module.

Here in NJ, on a 80-90 degree day, the car runs great on the back roads ranging from 30-45 MPH. Using the dip stick temp gauge, she runs around 180-195 for oil temp. If I take her up ont the highway and run the car at 65-80 MPH for 10-20 minutes, the temp will run up to 220-240, based on the outside air temps, which seems too hot.

I assume that since I am fine on the back roads, my flaps and fan are clear and working fine? I do have 100% of the factory tins in place, and from 180-240 degrees, the car runs strong at all temps.

I am thinking that I have a problem and would like to rule out some things. Here's my list of things to try. Please feel free to comment or make additional suggestions.

1. Change oil. I am running 10W-30 now. Have some fresh Brad Penn 20W-50 on hand. Could an oil change help?
2. Drop the oil screen and check for any sludge or blockage which may be impacting oil flow.
3. Check timing on the SVDA dizzy. I am wondering if it's advancing a little too much on the highway? Per John's instruction, when we installed the dizzy we set timing to: 38-45 Total Advance (hose connected) @ 3500 RPM.
4. Pull spark plugs and check for lean conditions.
5. Check carbs and idle jets. Not sure what's in there, but I hear that I want idle jets of 50.

[ape914]

One other thing that can be added to the tunning tool box is an automatically adjustable fuel regulator. Upon senseing the manifold vacuum change when the accelerator is floored from a lean cruise, the fuel pressure can be bumped up, maybe from the leaner end of 27 psi to the richer end 34 psi or what ever. Some Vanagons have a regulator like this, maybe can be adjusted to needs, some other cars should have simular regulators, so there should be plenty of choices.

so we got these things we can tweek on an engine, hopefully finding a nice combo of good mpg, good sporty performance, and cool running.........

spark timing, Use an electronic adjustable unit, knob or switch(es) on dash for adjust lean or sporty performance.

mixture via MPS, Use two differently adjusted MPS one for lean cruise, one for power, switch on dash.


mixture via fuel pressure, Use automatic regulator to boost pressure when power required.



for carbs you need carbs that allow a cruise in idle circuit,
and ...

Adjustable or adjusted dizzie for spark timing to allow the greater advance need for lean cruise.