Topic: 2 temp sender ports or 1 in 81T-6049 head?


chrismac    -- 01-31-2010 @ 7:10 AM
  I am rebuilding a 1940 Mercury V8 and have a selection of 81T heads. One 81T-6049 head has a threaded hole on both sides of the water inlet. The other has a single hole. The 81T-6050 head has a single hole. I think these holes are where the water temp sending units go. If a head has a second port was it used for sending units or heater plumbing?
Thanks,
Chris


trjford8    -- 01-31-2010 @ 8:14 AM
  Heater plumbing.


Stroker    -- 01-31-2010 @ 8:25 AM
  In many truck and industrial applications, a second "probe" was installed in the head, which consisted of a sealed brass bulb filled with tar. When an unattended motor overheated, the tar would melt, opening an electrical contact,which would break the primary voltage supply to the ignition, thereby shutting off the engine.

These could be easily "re-set" by inverting the probe in boiling water to allow the contact to be reestablished.


TomO    -- 01-31-2010 @ 9:06 AM
  If you are building the engine for a car that will be judged, use the head with one hole. The second or high temperature sending unit (01A-10990) was used on the 1942-1948 cars, and the p/n does not appear in the 1940 parts catalogs.

The sending unit with one terminal (99A-10884) should go in the left hand head an the heater connection would go in the front hole of the right hand head.

Tom


kubes40    -- 01-31-2010 @ 9:57 AM
  Tom is correct. All 1940 Ford's and Mercury's intended for public consumption had a singular hole in each head. In that hole of the left head, the temperature sending unit was installed.
On the right head, if there was no heater, this hole had a large hex head (brass) plug. If there was a heater, the plug was removed and the heater control valve installed in its place.
As an easy way to determine which side the respective head goes on... find the part number cast in to the head. That part number should be closest to the the cowl when the head is installed.
Mike Kubarth


chrismac    -- 01-31-2010 @ 10:04 AM
  Thank you! I really like this club! A guy can ask detailed questions and knowledgeable members respond with excellent information. Membership makes restoring an old Ford much more enjoyable.

Appreciatively,
Chris


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