temp senders

[toolsinbox]

454 with alpha.

I need to get the temp guage working so I am going through everything before I fire up this engine. I seem to have two sending units on the thurmastat housing. Should there be two? On the one on the right the pin where the wire connects just pulled out when I checked the connection. Just as a note, when I put the teather clip on to get power, the temp guage goes to max.
While I am working on guages should I be putting any temp senders anywhere else on the block, or manifolds?

 

[J. Mark]

Re: temp senders

You may have a second sender for an alarm.

Don't use teflon tape on the senders- Senders act by opening and closing a ground through the engine block-teflon tape may prevent a ground signal. Senders are brass so that when tightened into steel they make a nice seal since the softer brass can distort-also the threads are tapered. The intake may have a position for a sender (typically on a small block chevy it is on the front left hand side of the intake-I am not sure on a Big Block)

 

[ken_23434]

Re: temp senders

The second one is probably a Temperature SWITCH. The switch (if used) probably goes to the warning system to let you know the motor is overheating. If you check the resistance of it, you will see either an open or a short depending if you are above or below the setpoint for the alarm. I believe at "normal" temperatures the switch is open, and it closes (shorts) when the engine is too hot.

The temperature sending unit is basically a variable resistor. It will have a resistance that depends on it's temperature. At ambient temperatures, I think you will be seeing about 100 ohms.

As stated earier, do not use teflon tape. Both types need to be grounded to the engine block to work properly.

 

[mkast]

Re: temp senders

should I be putting any temp senders anywhere else on the block, or manifolds?

Usually each temperature sender has it's own gauge.
How many temperature gauges were you planning on installing?

 

[180shabah]

Re: temp senders

Usually each temperature sender has it's own gauge.
How many temperature gauges were you planning on installing?

I was wondering the same thing...

 

[toolsinbox]

Re: temp senders

Thanks for your input. With this info I can determine what is what.

As far as how many temp guages. two out of the 7 guages I have on my instrument pannel work and I want temp guage working before I start this engine for the first time. As I was reading here I noticed a few guys were monitoring manifold temps ( Not sur intake or exaust) I just want to make sure I am taking all precausions.

I intend on re-doing the guage pannels and replacing all of the guages and switches, so I was looking into the best approach. I have been boating a long time but this is my first i/o. I have been boating long enough to have blown a friends i/o engine not having a funtional guage.

Of cource when I re-do the guage cluster it will be all matching, so pre planning is a must. Is it necessary to monitor temps elswhere than at the thermastat ?



Thanks