Running hot, need advice please

[Sevenfold]

New owner 914/4, 2.0, 1973, 50k miles.
I am a weekend driver. Not racing.
Getting familiar with her and making efforts to have a cooler running engine which I suspect may be running hot.

Symptoms:
Starts up great. Idles fine. A little rough running/missing until warm at 5 minutes into the drive. After 5 minutes it runs more smoothly with less missing. During acceleration there is no miss, it pulls fine. Once back on steady pace, it starts to miss.

Engine temp seems fine for 20 minutes and then climbs after 40 minutes when it can stall when idling at a stop light. When hot, the gears begin to grind when shifting as well. Seems an unrelated combo of symptoms???

Status, questions and remedies I am working on:

1] What is the normal running temperature?
Where should my temperature gauge reside? Mine goes to above halfway, maybe to 5/8s when 40 minutes into a drive. No numbers on gauge.

2] Currently there are no plug boots, which allow air to pass around the plug wires. I plan to install those plug boots, to get it to run cooler, to reduce escaped air. Does this seem right? >
a) There are two mystery holes on top right tin. One between two spark plugs and another small one on top > Should these be plugged/sealed? (see images)

3] Fixing broken cable to original german temperature bellows which is contracted when cold - so I believe it will be functional (see image)

4] Mounting 2 airflow flaps under car.

5] Engine cooling fan shroud/housing is clear and engine oil cooler appears to be new and free of any external debris.

6] On-engine oil cooler is newish, clean, silver, and dirt free. Don't see any other oil coolers.

7] Engine oil level fine.
Oil preference? (Brad Penn 20w50 partial synthetic or Castrol 20w50 with Zinc ZDDP)

8] Transmission fluid level needs checking, getting 17mm male allen socket.
Does anyone recommend flushing the transmission fluid? if so, how often?
Fluid preference? (80/90w GL5 Dino non synthetic gear oil; Coastal GL-5 85/140W; or full synthetic)

9] Gasoline
(Premium 90-91 octane) to run cooler.

10] Timing/Valve adjustments > Have not been done since I bought the car 6 months ago. How often > Once a year / every ?k miles?

Thanks for patience with my "jumping off point" here. Feedback is invaluable.
Cheers

[Dave at Pelican Parts]

Originally Posted by Sevenfold

When hot, the gears begin to grind when shifting as well. Seems an unrelated combo of symptoms???

My car began to do that when the transmission was pretty worn. I also had Red Line MTF in it at the time; my mechanic chewed me up one side and down the other for that.

1] What is the normal running temperature?
Where should my temperature gauge reside? Mine goes to above halfway, maybe to 5/8s when 40 minutes into a drive. No numbers on gauge.

The gauges weren't numbered. The best idea is to know where it usually runs and then pay attention if that changes. I know that isn't much help here.

There were different gauges and senders used through the years, and aftermarket senders and gauges have sometimes been swapped in. So the readings may not be all that consistent with other 914s.

2] Currently there are no plug boots, which allow air to pass around the plug wires. I plan to install those plug boots, to get it to run cooler, to reduce escaped air. Does this seem right? >

Yes, you want to make sure there aren't holes for cooling air to escape. (Which is one reason I really hate the dealer-installed A/C on a 914!)

The biggest potential leak is the plug on top of the fan shroud that you look through when setting the engine timing. If that is missing, it can be a problem. Smaller leaks like the spark plug holes are usually not as much of a problem, but it's still good to have the holes plugged.

Also make sure the seal around the edge of the engine bay is still there.

a) There are two mystery holes on top right tin. One between two spark plugs and another small one on top > Should these be plugged/sealed? (see images)

One is for the CHT sensor, AKA Temp Sensor II. This is used by the FI's "brain" to tell when the engine is warming up. There is a factory grommet for that hole, but I don't know if it's currently available.

The other for a plastic clip that either holds fuel hoses or ignition wires, I don't remember which any more!

3] Fixing broken cable to original german temperature bellows which is contracted when cold - so I believe it will be functional (see image)

Make certain that the moving flaps are there under the sheet metal. There are a number of people who figure that "no flaps == more cooling", and they will sometimes discard those flaps. Which is a problem, because the one on the oil cooler side actually ducts air into the cooler, and it cools much worse without that flap in place!!

4] Mounting 2 airflow flaps under car.

I thin those should already be present on a 73. Look under the car at the leading edge of the engine compartment.

8] Transmission fluid level needs checking, getting 17mm male allen socket.
Does anyone recommend flushing the transmission fluid? if so, how often?
Fluid preference? (80/90w GL5 Dino non synthetic gear oil; Coastal GL-5 85/140W; or full synthetic)

Not full synthetic. It seems to be too slipper for our synchros to really work well. Plain dino 80/90 is just fine; remember to change it annually. Some folks really like Swepco (including the mechanic I mention above) which is more expensive.

9] Gasoline
(Premium 90-91 octane) to run cooler.

Probably won't make any difference, but if you feel better about it then go for it!

10] Timing/Valve adjustments > Have not been done since I bought the car 6 months ago. How often > Once a year / every ?k miles?

Oil change every 3000 miles. Valve clearances checked either every 3000 or every 6000 miles. If you have stock-type points and condenser ignition, check probably every 6000 miles. If you don't drive much, do all of them every year.

--DD

[Sevenfold]

Great thorough tips and observations.
Now I can get my hands dirty. Thanks

[930cabman]

How did these issues end up? all resolved?