904 Combo Gauges Sender Question

[CHAFF]

Hi everyone,

I'm a 914 guy but I have a 911 question for eveyone over here. I'm building a 904 combo gauge and the numbered gauges came out of a 911....I thought they would have part numbers on them but they didn't. Anyway, I was wondering if anyone on this board could help me match up the proper senders...unfortunately I don't know the year of 911 that these guages came out of. What is strange is that temp max = 280???/press max = 140??? this seems odd as all the other pics I've seen are like 300 and 180.

Any help is much appreciated

thx
-L[img]

[Grady Clay]

Chaff,

Welcome to the 911 Forum.
You will find lots of help here.

First, what 100 mm instrument housing are you going to use that accepts three gauges?

My choice for the temperature sender and gauge would be the “early” 911 which goes from 140F to 280F. This gives the most needle deflection per degree of any of the Porsche temperature gauges. Porsche “dumbd-down” the gauges so owners wouldn’t complain about too high engine temperatures. They even took off the numbers. In fact a 911’s gauge reads the coolest temperatures in the engine.

The temperature sender is ’65-’68 and has the push-on terminal axial to the sender body. Porsche P/N 901.741.632.00. The suitable gauge (black background, white numbers, and orange pointer) is from a ’68 only 911S/L combination instrument.

An even more clever solution can be the ’68 911S/L Sportomatic gauge. It is calibrated for the early sender and additionally has a socket for an over-temperature warning light. The face of the gauge wasn’t calibrated with numbers but any of the instrument rebuilders can add the calibrated markings.


The oil pressure is a little easier. I think there are only two choices; pre ’74 and ’74 and later 911. My choice would be the earlier version although it is prone to indicate “zero” at idle on a 911. I think its range is 0-140 psi. There are VDO sending units available that also incorporate a pressure switch for a low oil pressure warning light.

For competetion there is an oil pressure switch that is adjustable in the range of 5-60 psi. I have mine set about 35 psi. It comes on below about 4500 rpm when the engine is hot. Since the engine is only running in the 6-8300 range, it never comes on during competetion. It has a 917 part number.

The fuel gauge should be standard 914 at the bottom of the instrument. It gas an integral low fuel warning light socket.

A challenge is going to be the placement of the necessary warning lights. You will also need to make a decision on the angular position of the calibration numbers for the temperature and pressure gauges.


The 100 mm three-gauge 904 instrument has oil temperature using the above sender, a mechanical oil pressure gauge (complete with copper pipe from the engine), and a regular VDO fuel level gauge.


Another (easier) solution is to mark the tach with speeds in various gears and replace the speedometer with a 911 combination instrument. This gives you a spare for any other gauge you want (voltmeter, transmission temperature, boost, etc.) I have done this and left the functioning speedometer under the cowl (so the odometer kept working).

Porsche solved this issue with the center console. The problem is the important gauges aren’t in the easy view of the driver.


You obviously have been researching this. Can you post links to other discussions about this subject? If this can be easily done, there is wider application.

Best,
Grady

[CHAFF]

Thanks Grady, I'm sourcing all the senders I'm needing now and I'll give you an update when its all done.

What I'm building is basically this:

904 guage

but I would prefer to use the numbered gauges.

Cheers
-L

[Grady Clay]

I’m impressed. I need one of those for my street 914-6 2.8S MFI. That way I can re-install my spedometer in the instrument cluster. Who sells the kit? I have both of those gauges in my hand.

Best,
Grady
gradyclay@hotmail.com
I leave my PM box full so e-mail me or post.

[Early_S_Man]

Well, it looks like the Pelican kit is discontinued:

904-Style Combo Gauge Kit

Put that all important oil pressure reading right on your dash. Designed after the gauge used in the 904 race cars, this kit is the perfect addition for the 914-6 owner. Kit comes with faceplate and rear mounting plate. Requires gauge body and modules to complete. Sold ONLY as a kit.

904-Style Combo Gauge Kit [Photo]
pel-9146-013 No Longer Available

http://www.pelicanparts.com/cgi-bin/ksearch/PEL_search.cgi?command=show_part_page&please_wait=N&make=POR&model=9144&section=CONsix&page=5&bookmark=3&part_number=pel-9146-013

[CHAFF]

There is a very long history behind these kits. However, currently you can get a simple kit from johnman

http://www.914club.com/bbs2/index.php?showtopic=58970&st=0&gopid=754790&#entry754790

BTW: those senders for the early 911 are very very expensive at PP I have the right ones here right?


-L

[CHAFF]