Mystery brass fitting on 1500 engine

[Tom Sansone]

Guys,

I am in the process of rebuilding my original 1500 normal engine in my 1955 Continental Coupe. I noticed this brass? or bronze? fitting adjacent to the oil cooler base. It has a hex head with a hole in the middle which is threaded. The hole appears to lead to one of the channels under the oil cooler.

I'm not sure what this is and what should connect to the threads in the fitting. I don't see this in later engines. Any help would be appreciated.

Tom Sansone
Elk Grove, Ca.

[Craig Richter]

Oil temp gauge probe.

[Alan Hall]

Craig is correct..for the later Stork temp gage that used a probe at the end of the sense tube rather than the dipstick used on earlier gages. If I recall correctly this fitting location moved a couple of times in '55, not sure I have ever seen it where yours is located.

[Jim Clement]

what are the numbers on the oil cooler stand ??

[Peter Boettcher]

This brass part is available from Don Zing who makes a very nice reproduction.
My 55 Speedster has this and uses the probe that threads into it.

[Vic Skirmants]

Alan; that's the only location I have seen it on those early 3-piece case engines.

[Donald Zingg]

Tom

Here's the brass sleeve out of the crankcase along with the oil temperature sensor.
The sensor bulb is permanently attached to the oil temperature gauge via a miniature capillary tube.
Hopefully you have the original temperature gauge - - - uncut and intact, as shown in the last photo.
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[Tom Sansone]

Gentlemen,

Thanks for the replies. This has been helpful. My Stork temp gauge does in fact have the sensor...it has not been cut off.

The numbers on the oil cooler stand are 6829. I didn't notice the numbers until you asked. Not sure of their significance.

Can you speculate as to why someone would use a chisel to remove the brass fitting? What might cause the fitting to resist removal with a wrench?

Thanks for the photos and the help.

Tom

[Donald Zingg]

Can you speculate as to why someone would use a chisel to remove the brass fitting? What might cause the fitting to resist removal with a wrench?

Someone unfamiliar with the gauge design tried to unscrew the sender sleeve with the engine in the car.
No way to put a socket wrench over the capillary tube, and not much room behind the fan housing to take a good swing with a hammer against a chisel. Fortunately, smarter, cooler heads prevailed when the inexperienced hand picked up the wire cutting pliers. Count your blessings

[Peter Boettcher]

Hi Donald,

Can you comment on the factory`s use of the Stork gauge vs the Moto-Meter gauge?
My 55 has a Stork gauge set up as you have shown in the photo and I have seem other 55`s with the Moto-Meter gauge.
It came with a bunch of spare parts which includes an NOS Moto-Meter gauge with the same capillary tube arrangement.

Thanks,
Peter OpaX2 Boettcher

[Tom Sansone]

Hey Donald,

Those photos of the sensor and sleeve are great. Can you tell me if the sleeve is open on both ends? I see the threads on one end but the end in the case....is it open or is it closed off? I have used a flashlight to look down the sleeve and it appears to be closed off. I poked a stiff wire down the sleeve and it hits bottom. Does the sensor pick up the temp from inside the sleeve without actually touching the oil? Or did someone block off this sleeve so they could move the sensor to the block with the oil pressure sending unit?

Thanks for your help.

Tom Sansone

[Vic Skirmants]

The sleeve is blocked. The sensor does not touch the oil.

[Donald Zingg]

Can you comment on the factory`s use of the Stork gauge vs the Moto-Meter gauge?

Peter

During the pre-A years both instrument makers supplied oil temperature gauges for all P-356 models.
During the first twelve months of pre-A Speedster production Störk seemed to be the predominant OE temp gauge supplier. The MotoMeter gauge seemed more common in the last 300 or so Speedsters built at the end of 1955. At that time the 356 Speedster was the only Porsche body style still using a thermo-mechanical oil temperature gauge. The 356A Coupe and Cabriolet had VDO electric temperature gauges.

[Donald Zingg]

Can you tell me if the sleeve is open on both ends?

As Vic points out the sleeve is closed at the bottom. It functions as a plug for the hole in the crankcase oil passage and as a receptacle for the oil temperature sensor. When installed the coil spring presses on the sensor bulb keeping it in constant contact against the bottom of the sleeve. Hot engine oil heats up the sleeve which in turn heats up the sensor bulb.

[Gary Cox]

The numbers stamped on the cooler stand look like those commonly used by some of the machine shops to track customers jobs, probably added during a rebuild.