914-6 runs HOT - solved? Options

[767driver]

Hi guys,

Lurked here for a number of years and have finally landed a 914-6. It's a 1970 with it's numbers-matching case running a (stock?) 66mm crank and 86mm pistons for a displacement of 2.3L. It runs Solex cams and 40 Webers. It's only got about 600 miles since rebuild. So the engine is somewhat upgraded but nothing too wild.

When I drove it the 45 mostly-highway miles to my house I noticed it was getting a bit warm. The weather was about 60 degrees. The indicator on the factory oil temp gauge was reading about 3/4. The next day I took the car for a nice "getting acquainted" kind of run on mixed highway and country roads. After 25 minutes on the highway at 80 mph and about 3500 rpms it was getting really warm...almost touching the hashed red part of the hot end of the scale. I immediately went over to a buddy's shop and shot an IR thermometer at the rear of the oil cooler. Got temps of 220 or so at top of cooler and 250-260 at bottom. The cooler still has a Stoddard Porsche decal on it. I checked and the cooler is the $1335 German-made part. Oil quantity ok.

Now I know this is not enough motor to overload the factory oil cooling assuming everything is working correctly. I took the thermostat out of the car and performed the pot-of-hot-water-with-thermometer-trick and verified it opens and closes as it should. I guess the in-dash gauge could be wrong, but the IR thermometer seemed to confirm the high reading. All the tins appear to be in place. I have read the cylinder baffles can be installed upside down causing issues. And that the cylinders themselves can be installed upside down. I guess that new-ish oil cooler might be defective...that's an engine drop...right? Ignition timing, cam timing, fuel mixture need to be checked. And none of the cabin heating air tubes are on the car. The 2 supply ducts off either side of the engine cooling fan duct are capped. Is the fact that no fan air is going through the heat exchangers causing the one under the oil cooler to run hot enough to cause the high oil temps? ANSWER: YES

So...what have I forgotten or overlooked here. I had 2 VERY knowledgeable Porschephiles tell me that barring an oil cooler issue it is almost surely a hot bearing (youch!) making that kind of heat.

Any thoughts or ideas are appreciated.

1970 914-6
VIN 9140432125
Engine 6405400

[767driver]

Thanks for all the replies...and keep them coming!

Some of my thoughts and responses...

I hear the calls for a front-mounted oil cooler. I really don't think, based on all I have read/heard/seen over the years, that this particular engine should need another cooler. I could be wrong...but it's just not that much more motor than the stock 2.0

Ignition/distributor and carbs are all on my short list. This car was "dyno-tuned" at a reputable shop before I bought it...probably within the last 12 months. ALL of that should have been set up correctly. Will verify...

I have seen ZERO evidence of rodents. Having said that, the air flow through the fan housing and engine tins/baffles will need to be checked free and clear.

The belt seems properly tightened by deflecting it with my finger. It sounds like it is turning at the proper speeds when driving (based on my "ear" for my 911's engine sounds).

This car already has the replica 916 double-grilled engine lid on it.

Oil pressure was mentioned by user id porschetub. There is an auxiliary gauge pod installed containing an oil pressure gauge. The engine has 60PSI or a bit more when cold at fast idle. It slowly looses pressure as the temp rises. It was showing 30PSI at about 3000rpm when the oil was real hot.

Gauge accuracy... is there a better way to verify that than pointing an IR thermometer directly onto the oil cooler itself?

And finally the firewall engine access hatch mod was discussed. I am not sure I want to cut an original 914-6 for the added convenience...which is significant...of that hatch.

I think my first action will be to perform an oil change and look for rebuild-related swarf in the sump screen and oil filter.