Normal Engine Temperature?

[merbesfield]

Kenik that is good stuff. I have read this type of info before, but if you do not use it every day you tend to forget how it works. Has anyone installed Oxygen Sensors into the exchangers on our early cars? In talking to the PO, he is an engineer, he suggested the idea, which would allow for greater adjustability etc. Acquiring more info and being able to drive the car after small adjustments were made would be cool. Sort of like a modern car  or having a rolling dyno test.

[Flieger]

My MFI does not put fuel in the oil (well, enough to smell or feel it anyway) and I do not have a thermostat- it is fixed in the warm position with a screw. I would be skeptical of any mechanic that accepted fuel in the oil and said simply that "they all do that".

[edmayo]

My feeling here is that if he is talking C/O numbers he is probably only checking the idle mixture, as most C/O machines are stationary units. Only idle is checked at "no load", the rack adjustment for the main running circuit must be checked under load. It is possible that the idle setting is correct, but the load setting is still too rich. Currently we use an "Innovate" A/F ratio tester that allows for on the road "load" testing. It gives the readings in air/fuel ratio not C/O. It is important that your thermostat housing reach approximately 100 degrees F. to properly lean out the pump which is why I keep asking about this. You might consider finding a chassis dyno where the MFI can be tested under load. They've become fairly common now.

[Tom F.]

Ed, how do you rig up the oxygen sensor on an MFI car?

[edmayo]

The tester has a bracket that will clamp it (sensor) temporarily in the tail pipe. If you wanted to have a permanent installation you'd have to weld a bung in the exhaust pipe.

[304065]

Ed, how do you rig up the oxygen sensor on an MFI car?

Here is how I did it seven years ago (!)
http://forums.pelicanparts.com/porsc...y-911-mfi.html

These days you would use an LM-2 with two sensors so you can measure each bank and compare the AFRs- a nice way to verify you have side-to-side correlation correct!

[Chuck Miller]

Mark,

I've been going through both of your threads hoping to find some mileage and past mechanical history on you '73 with no luck......

I was hoping by now an obvious problem and fix would have been found.....

I've owned my '73S for 22 years here in sunny SoCal. The first two years without an external cooler, and the first 14 years with the stock 2.4S engine. The ONLY time I've experienced high temps, over 220, have been on the track in the summer.

The 'normal' running temps should be between 180 and 210, as RPM goes up so will the temp but nominally. Other then summer, when I drive my car (even the first 2 years without the front cooler) at a constant normal RPM it hardly ever gets off 180.

I even heard that back in the day that stock Early S's had the rep of being 'cold blooded little bastards'....

I hope your temp issue is a combination of few little things that you are sneaking up on ....... however.... please remind us of how many actual miles this engine has on it.
Has it been rebuilt?

Most all these cars have had work done to them.
When new these car's weak point was their top end.... Old mechanics said their top end were 'soft'. My records show my car's guides and valves were done at about 50,000 miles......

I'm hoping not, but it might be your temp problem is a little 'deeper' then we've been thinking.

Ed M., am I being way off base here???

[merbesfield]

Here is how I did it seven years ago (!)
http://forums.pelicanparts.com/porsc...y-911-mfi.html

These days you would use an LM-2 with two sensors so you can measure each bank and compare the AFRs- a nice way to verify you have side-to-side correlation correct!

John, This is exactly what I was talking about. Where do you get these LM-2's?

Chuck, My car has 135K miles on it. Though I have a ton of history, I do not have any history about when if the motor was opened up. I know it has been gone into bc you can see the sealant at the joints. I have attempted to contact the original PO, but have not had success yet. The guy I bought it from, said he was told the top end was worked on and the engine re-sealed. It was definitely re-sealed bc it is fairly dry. So, the car has 135K, but not sure on the engine. I to remember my old 73S not running too hot without an oil cooler. So based on most of the posts, my car is too hot. I too hope that it is not deeper.

I like the idea of being able to take readings and making adjustments using the knowledge from a sensor.

[304065]

Mark,

Innovate Motorsports is the manufacturer. They have great support and Klaus Lattinger, the founder, is a big German car enthusiast.

http://www.innovatemotorsports.com/products/lm2.php

Not cheap but you should consider it an investment that will last for many years. I still have my LM-1 and have used it on many cars.

To Chuck's point: excessive engine temperatures are often attributable to internal issues.

In my case I had multiple broken rings, an ignition advance that was off the charts due to a worn-out distributor, and a host of other internal problems.

[RSTarga]

When my car was new, and had no front oil cooler, it ran hot in traffic with a/c on creeping up towards 230. On the highway at speeds of 110 120 it would start to creep up to the same 230. Once I got the loop cooler on these temperatures reduced by about 10 degrees, and when I put the 28 tube cooler they dropped another 10 degrees. This is in Texas 90+ temps. I would put the oil cooler on and see what the results are.
He might still have an overheating issue but then you could compare apples to apples, since most of us have done the upgrade.