78SC ROW - OIL Cooling Gauge Upgrade Question

acapella8 · acapella8's Garage

I have a 78SC ROW with a standard oil temp and press gauge. I wish to upgrade to one that reads actual temp in degrees.

This is the one I'm planning to install, Part NO 911 641 104 29:

My question -- I think I read that my existing sender will not work with this type of guage -- what is the correct sender Part number that I will need for this???

DeutschMark · 07-23-2006, 06:19 AM

Our host sells the gauge with the correct sender as a kit.

acapella8 · acapella8's Garage

I know, but I just need the sender...do you know that part number?

DeutschMark · 07-23-2006, 06:25 AM

The sender is listed as 901-641-632-00-M100.

acapella8 · acapella8's Garage

Thanks -- But Will that work with my 78??

It looks like that sender is for earlier years -- but I could be wrong...

DeutschMark · 07-23-2006, 06:41 AM

"Adding this gauge half to your combo gauge is a simple process, but also requires you to replace your temp sender with the earlier style one."

rattlsnak · rattlsnak's Garage

yes, it will work, Youre using an early style gauge, so you need the early style sending unit.

William Miller · 07-25-2006, 11:43 AM

I have a simular, but related question.
I did an engine swop a few weeks ago.
My 83 3.0 Euro engine went into my brother's 73.5 with the style of gauge shown at the top. We had no problem swoping the temp sender from the 2.4 to the 3.0, but couldn't swop the oil pressure sender because the nipple on the bottom of the senders were different. The 73.5 sender had what I've seen as a typical sized sender, but the SC sender had a huge nipple.

Because we were stuck we just swopped out the oil pressure half of the gauge.

Does someone make an adapter to reduce the bigger hole for the smaller nipple on the old style? Do they make a sender that will fit in the big SC hole that matches the early style gauge?
Thanks.
I'm bringing this up because you need to make sure the nipples match too!

john d 81SC · 07-25-2006, 12:35 PM

What I found that adds to the confusion of the oil temp sender retrofit is when you look up the part (#901-641-632-00-M100) for the pre-1977 unit, and then click on both pictures, two different senders are shown - one with a round disc top, the other with a tab. When I called for clarification as to which is the correct one, the Pelican person checked with the vendor and told me the picture on the left. However, when you click on the picture for the gauge and sender sold as a package, the picture of the sender is that found on the right - the sender with the tab.

emcon5 · emcon5's Garage

Just curious, but how is this an upgrade?

Tom

john d 81SC · 07-25-2006, 01:09 PM

Tom,

In 78, Porsche switched oil temp gauges, going from a numbered gauge to one that has white and red ranges. There are numbers with this gauge, but they are hidden - you have to look at an angle at the very edge of the gauge to see the numbers. If you want a numbered gauge, it requires a retrofit of both the gauge and the sender. If you leave the original sender with the numbered gauge, your temp readings will be inaccurate.

emcon5 · emcon5's Garage

Quote:

Originally posted by john d 81SC
In 78, Porsche switched oil temp gauges, going from a numbered gauge to one that has white and red ranges. There are numbers with this gauge, but they are hidden - you have to look at an angle at the very edge of the gauge to see the numbers.

Kind of my point. If his is a 78, it should be this one:

But even if it is this one:

In either case, if you know where normal operating temp is, and where you-better-pull-over-and-let-things-cool-down is, what difference does it make that it doesn't have (easy to see) numbers on it?

Tom

acapella8 · acapella8's Garage

Thanks for all the help guys.

I was looking for earlier style with numbers. mine only has the range.

Also, I am upgrading from trombone to carerra style radiator cooler, I want to see the diffference in the cooling by using the guage while I still have trombone, then when I move to cooler.

Sorry that I'm a bit confused -- but what sender (part no) do I need with the top most pictured guage?

john d 81SC · 07-25-2006, 02:31 PM

Tom,

The PO of my car had the retrofit done. I prefer the numbers for when on the track - looking for some "wiggle room" before I absolutely have to come off. And I'm lazy and don't want to have to remember the Celsius - Farenenheit conversions.

Great seeing Calvin - I miss Watterson's column!

Doug Steinel · Doug Steinel's Garage

John d 81 SC, at what temp do you come off the track?

Doug

john d 81SC · 07-25-2006, 06:30 PM

Doug,

Approximately 230 -235 degrees. I use Mobil 1 which supposedly holds up better at higher temps. I think Bruce Anderson is quoted in his Performance Handbook as saying that 240 degrees is hot and 250 degrees is too hot.

acapella8 · acapella8's Garage

250 is too hot. Dodn't want to be in that range, I like the numbers -- people have been giving me flack -- but I like to see real numbers!!

emcon5 · emcon5's Garage

Quote:

Originally posted by john d 81SC
The PO of my car had the retrofit done. I prefer the numbers for when on the track - looking for some "wiggle room" before I absolutely have to come off. And I'm lazy and don't want to have to remember the Celsius - Farenenheit conversions.

Nothing to remember. The top white line is 248�F. Don't let it get there.

Quote:

Great seeing Calvin - I miss Watterson's column!

You can still read the back strips on line every day:

http://www.gocomics.com/calvinandhobbes/

Tom

Doug Steinel · Doug Steinel's Garage

If I parked my 911 at 235 degrees, I wouldn't even be able to drive it home at 70 mph from downtown Washington to my house on these hot summer days (40 mi, mostly freeway). And I have removed the AC and have a trombone filter. My oil temperature really rises as ambient temp hits the 90s. The manual that came with my '77 from Porsche says park the car when it hits 300 degrees. Usually the members of this board place respect what the factory says about our cars... how about this case?

Doug

john d 81SC · 07-26-2006, 07:43 AM

Doug,

FWIW, I didn't have concerns about my oil temps until I began DE. Over 2 years I replaced the trombone oil cooler with the European 28 tube brass cooler, added the "Cool Scoop" which I bought thru Pelican (removed the side marker light - this device funnels air into oil cooler area), added Elephant Racing finned oil lines, and use Mobil 1. I was advised halfway through these changes that the best solution was a front oil cooler, but since I do only 10-12 track days a year, I didn't want to alter the front of the car. All these mods have helped. Was highway driving last week in temps of high 80's, and oil temp stayed at about 195 degrees. In stop & go, the temps climbed to 210.