3.6 conversion and oil temp problems

Joeaksa · 08:38 PM

I have Bill Verburgs old 3.6 964 engine in my 1985 911. Runs like there is no tomorrow and has more power than my license has points. Jeez does that thing put a smile on your face when you kick the throttle in!

Problem is that when the engine came to me I believe that the oil temp sender may had been changed when it was removed from Bill's car. What was in it who knows but its doing the same thing now again so something is not right. When I turn the ign key on the needle moves off of the peg but thats it. Stays about 4 mm below the bottom white line on the gauge.

Talked with Bill a while back and he felt that the sender was not correct and that I needed to put a different one in. That still may be the case. I ordered a new sender for my car from Pelican, the same one that should have been in my 1985 3.2 engine, thinking that it would interface with the harness and gauge fine and work.

Just drove it about 20 miles in 110 degree heat and the needle did not even get into the bottom white "cool" marks. In other words, it comes off of the peg and then just sits there the entire time you drive.

Anyone have any ideas what is going on here and how in the world do I get some sort of oil temp indication in the cockpit? I felt the external oil lines running to the cooler and they are hot as hell, so the temp is up there...

TIA,

JoeA

Bill Verburg · Bill Verburg's Garage

what coolers do you have?
what gauge, numeric or stock Carrera?

You can double check the oil temp w/ a laser thermometer or even a meat thermometer w/ a long probe.

There are several different guages and senders, all '65 - '89 temp senders were on the right hand side of the fan housing, They measure the oil temp. at the aft end of the main oil gallery. These cars are reading hotter oil and generally measure 5 - 10&deg F warmer than the 964/993 cars which moved the temp sender to the top of the c/c and measure oil after the cooler and before entering the main oil gallery.

early cars - '76 (like mine oem) had the numeric guage.

In '77 they used the same gauge and sender but w/o the numbers, then in '82 they changed the gauge and the sender.

The '82 up gauge scale is compresssed and has a different sender. The compression of the scale means that 210&deg F (normal) is lower on the scale than previously. The red line on these scales is 300&deg F

When I had the engine in my car I had the early sender to match my guage, I asked Steve to put the early sender on the new 993 and put the late 993 sender on your 964. That should have been the correct sender for your guage, I looked it up the '97 ROW993 and your car use exactly the same temp sensor, just in 2 different locations measuring slightly different oil states.

Joeaksa · 07-01-2005, 04:05 AM

Bill,

I have the stock 1985 gauge, no numbers, just the colored markings. Have thought about going to the numbered gauge but if you look closely even the stock gauge has numbers on it. Not sure how calibrated it is though.

At this time only the stock front fender cooler. I know it needs more but the last six months at work has been a bear and right now its driven only early in the day or early evening when there is no chance of getting stuck in a traffic jam. Do not feel that its overheating but I have no idea just how hot its getting without a valid reading on my gauge.

Had thought of doing a temp check with the IR device, but do not have one and its a moot point now, the gauge is not giving a valid reading and need to get that corrected.

Now I am baffled as its pointing to possibly having a wiring harness or other issue with the gauge. Its giving the same indications (coming off of the peg when the key is turned on, but stays there no matter how hot the engine oil is) with two different sender units.

Will keep checking, thanks for the help!

Joe A

johnsjmc · 07-01-2005, 05:03 AM

I think you can test that the guage wiring is at least hooked up. You disconnect the sender wire at the sender and ground it( with the ignition on engine off). That should send the guage reading to full hot end of the scale. Most guages senders work by providing a variable resistance to ground. I assume Porsche does as well.If the guage end works you can see with an ohm meter if the sender is changing with temp. Still doesn,t address the calibration issue but may help you determine if your problem is guage/sender/or wiring.