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-   -   vortec head coolant sensor '71 Chevelle (http://www.hotrodders.com/forum/vortec-head-coolant-sensor-71-chevelle-146245.html)

307malibu 10-07-2008 11:59 AM

vortec head coolant sensor '71 Chevelle
 
I'm trying to get my motor filled with fluid and started. I can hardly wait! But . . . I'm hung up on my coolant temp. sending unit right now. I replaced the 307 in my '71 Chevelle with a 1997 vortec roller block. Problem is, the coolant temperature sending unit from the '71 is too big for the hole in the vortec heads! What do I do from here?

Thanks!

techinspector1 10-07-2008 12:19 PM

Ace Hardware in the plumbing department. Male/female reducer with threads on the male end to screw into the head and female on the other end to accept the sender.

lg1969 10-07-2008 12:22 PM

The adapter that screw into the standard 307 heads. Did you removed it and transfer to the new heads you got?

carsavvycook 10-07-2008 01:22 PM

You do have a perplexing problem. :D

The best solution would be, to relocate the temp sender to the intake manifold. If there is not a large enough, or any threaded pipe holes in the intake water runners, drill and tap one.

If you try to reduce the sender down in size with fittings, the sender would not be submerged in the hot coolant flow. Thus, you would get a very false reading. Reading much cooler then the actual coolant temp. Temp senders don't read steam.

406 bug 10-07-2008 02:14 PM

Get the reducer, it will read just fine. I would not muck-up the water neck with a fitting- plus, it looks much cleaner not having senders and wires on top of your motor.

SSedan64 10-07-2008 02:49 PM

I agree with Carsavvy, relocate or get a sender that will fit the smaller hole. You do want the probe in the coolant flow, not back in a reducer.

tomslik 10-07-2008 05:10 PM

drill it out and tap it for 1/2" pipe threads....

carsavvycook 10-07-2008 05:38 PM

I don't believe there is enough 'boss' in the area of the head, to drill and tap it that large. This is why I recommend moving it to the intake manifold area.

307malibu 10-07-2008 06:33 PM

or . . .
 
Would it be possible to just get a sensor for a '97 silverado, like where the vortec motor was originally from? Or wouldn't that match up with the factory wiring (I'm fine with splicing in a different fitting, but I do want it to actually work good).

By the way, all I'm talking about is an "idiot light" setup. I don't have a fancy temp gauge in my base malibu.

Thanks for the help so far, guys!

carsavvycook 10-07-2008 07:47 PM

Quote:

Originally Posted by 307malibu
Would it be possible to just get a sensor for a '97 silverado, like where the vortec motor was originally from? Or wouldn't that match up with the factory wiring (I'm fine with splicing in a different fitting, but I do want it to actually work good).

By the way, all I'm talking about is an "idiot light" setup. I don't have a fancy temp gauge in my base malibu.

Thanks for the help so far, guys!

Resistance values from a 1997, are way different from a 1971.

You need to use the stock sender from the 1971 application. This will work correctly with your dash 'light'/gauges.

schatzy 10-07-2008 08:15 PM

I had the same problem when I put vortec heads on my 72 Chevy pick-up. I went to Napa and tried to find a sender that would fit the head but have the same resistance as the original. No luck, ended up putting it in the intake in the hole just under the upper radiator hose.

307malibu 10-08-2008 10:36 AM

Routing the sensor into the intake could've been a good idea, but on the chevelle setup the thermostat housing comes out almost right on top of the 1/2" plug on my intake (edelbrock performer EPS)! There isn't room for the sensor AND the radiator hose. Other ideas? I gotta think this problem has come up with many guys, considering how popular vortec heads are!

Thanks for the help!

carsavvycook 10-08-2008 11:18 AM

Can you post a picture of your intake, around the thermostat housing?

I have installed mechanical gauges in 2 intakes before. I know it can be done, even with a factory sender.

The water port runners had a 1/4" wall thickness, and with thread sealant, it will hold, and will not crack. A torque of 18-20 Foot pounds is enough.

They also make thermostat housings that "rotate", (time to improvise) but you may need to get a different upper radiator hose, to make it work without putting a 'kink' in your hose.

In a case like this, you need to be able to 'think outside of the box' to make it work.

Disregard what is the 'given', step back, look, and think 'how can I make this work'. :welcome: to Hot-roding 101. :D

406 bug 10-08-2008 11:21 AM

Quote:

Originally Posted by 307malibu
Routing the sensor into the intake could've been a good idea, but on the chevelle setup the thermostat housing comes out almost right on top of the 1/2" plug on my intake (edelbrock performer EPS)! There isn't room for the sensor AND the radiator hose. Other ideas? I gotta think this problem has come up with many guys, considering how popular vortec heads are!

Thanks for the help!

Your right, the problem has come up before. When you purchase an AutoMeter temp gauge, the package contains, adapters/ reducers so it will fit most applications (such as yours). If you feel usure of using a reducer based on what others have indicated, call the Autometer folks and obtain direction from them. I think you will find that its ok.

carsavvycook 10-08-2008 11:46 AM

Quote:

Originally Posted by 406 bug
Your right, the problem has come up before. When you purchase an AutoMeter temp gauge, the package contains, adapters/ reducers so it will fit most applications (such as yours). If you feel usure of using a reducer based on what others have indicated, call the Autometer folks and obtain direction from them. I think you will find that its ok.

What I have seen, the 'threaded' hole in a Vortec head is 1/4NPT.

I have "adapters" in stock, and from what I see, by the time you 'drill' them out to fit the stock "temp sender probe" they will 'break if you sneeze'.............

There is no way this will work!

rant over.

waiting for a 'pic'.


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