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AFR 180 Eliminators are tapped for a 3/8 NPT sending unit. The OEM sending unit is 1/2 NPT. Ask me how I found out?
Had the bottom end builder for my L-82 rebuild tap the new aluminum heads for the OEM 1/2 sending unit. Willcox also sells OEM type sending units for 3/8 NPT heads-pricey though.
BTW-It's totally ridiculous that these aluminum head manufacturers are selling heads for Gen 1 SBC that do not offer heads with the 1/2 NPT. On my list to call AFR and give them some jive.
You cannot adapt a 1/2 NPT sending unit to fit a 3/8 tap-its to big for adapters. It would work the other way around. I tried.
AFR 180 Eliminators are tapped for a 3/8 NPT sending unit. The OEM sending unit is 1/2 NPT. Ask me how I found out?
Had the bottom end builder for my L-82 rebuild tap the new aluminum heads for the OEM 1/2 sending unit. Willcox also sells OEM type sending units for 3/8 NPT heads-pricey though.
BTW-It's totally ridiculous that these aluminum head manufacturers are selling heads for Gen 1 SBC that do not offer heads with the 1/2 NPT. On my list to call AFR and give them some jive.
You cannot adapt a 1/2 NPT sending unit to fit a 3/8 tap-its to big for adapters. It would work the other way around. I tried.
With these new aluminum heads, the OEM temp sensor is too big.
Does anyone have a part # for a water temperature sensor that fits & functions correctly?
(3/8" pipe threads).
TIA.
Steve
Some folks here will nay-say this solution, but it works just fine: Use one of the 1/2" threaded holes on the intake manifold.
Think about it, the coolant is moving throughout the engine pretty quickly, so isn't going to change temp. from the head to the intake manifold coolant passage.
Pete
From: Las Vegas - Just stop perpetuating myths please.
Not really. That will move the sensor out of the circulating coolant pool and it will measure a stagnant water temperature. Also the sensor may now hit the exhaust header/manifold.
Not really. That will move the sensor out of the circulating coolant pool and it will measure a stagnant water temperature. Also the sensor may now hit the exhaust header/manifold.
I looked at using adapters on my AFR's and came to the same conclusion: The actual sending unit of the 1/2 OEM unit will not be in the coolant flow and I assumed would not read accurately using a 1/2 to 3/8 inch adapter. The sending unit in the manifold would work fine but I wanted the OEM location so I had my AFR head tapped for 1/2NPT threads.
Not really. That will move the sensor out of the circulating coolant pool and it will measure a stagnant water temperature. Also the sensor may now hit the exhaust header/manifold.
Not correct sir! The temp sender is partially hidden below the fuel line, but you can see it is in the coolant passage going from the right head to the thermostat area. Hardly stagnant coolant, but high speed flow.
This is a Chevrolet Bow Tie intake BTW. Like I said in my original post, some folks will put this solution down (I know you guys) but it works and works well.
From: Las Vegas - Just stop perpetuating myths please.
Flow only when t-stat open. And the OP wanted to use it in the head near the exhaust manifold/header which i recall a fairly tight space. But how much circulation the sensor will see with that extension i agree i dont really know - could well be adequate i have to admit. But what we dont know is what we dont know. Why make it an experiment Pete?
The intake location works or you can take the correct unit to a machine chop and have the threads re-cut to fit your new heads. That been mentioned many times on the forum. I need to do it for my '77 with an '87 engine.
Flow only when t-stat open. And the OP wanted to use it in the head near the exhaust manifold/header which i recall a fairly tight space. But how much circulation the sensor will see with that extension i agree i dont really know - could well be adequate i have to admit. But what we dont know is what we dont know. Why make it an experiment Pete?
It's not an experiment, it's something that works. I've run the same sender in the original head, and in the new intake with new heads. Temp gauge reads the same either way. Also, the bypass is internal in the right side of the block, allowing some coolant movement when the t-stat is closed.
And even if flow is only when the t-stat is open, unless then engine is in real trouble, the temp gauge won't register much until the engine warms and flow starts in any case, no matter where you're sensing the temp.
IDK what all the excitement is about. It seems whenever a workable solution is offered, some people get their dander up and put it down.
OR, they love to spend the OP's money on wild solutions way beyond what the OP originally asked. Not so much in this case, but it's all over this forum, and not just the C3 sections.
Here is yet another option. I was in your boat too, I opted for an $11 replacement water neck. My car did not have any ports on the water neck before but a 1982 was perfect for what I needed.
It tells me when and if the thermostat opens. I have a 180 tstat , the gauge reads 180 most of the time and its relatively unobtrusive.
I looked at using adapters on my AFR's and came to the same conclusion: The actual sending unit of the 1/2 OEM unit will not be in the coolant flow and I assumed would not read accurately using a 1/2 to 3/8 inch adapter. The sending unit in the manifold would work fine but I wanted the OEM location so I had my AFR head tapped for 1/2NPT threads.
You make a couple of good points! Surely the 1/2" to 3/8" adapter would not position the sensor in good, active coolant flow past it.
For me, the Forum didn't exist, or at least I didn't know about it, when I built my engine. My engine was fully assembled and in the car before I realized the temp sensor wouldn't fit the new aluminum heads. At first I used a L98 sensor, but the gauge read way too low. After an exhaustive unsuccessful search for a compatible 3/8" sensor, I chose the inlet manifold location. I was loath to remove a head to have it machined for the 1/2" sensor. Had I known before I had the heads installed, I probably would have had the coolant sensor hole enlarged and threaded for the 1/2" sensor.
In the end. It's all good. We can all learn from one another.
Pete
You make a couple of good points! Surely the 1/2" to 3/8" adapter would not position the sensor in good, active coolant flow past it.
For me, the Forum didn't exist, or at least I didn't know about it, when I built my engine. My engine was fully assembled and in the car before I realized the temp sensor wouldn't fit the new aluminum heads. At first I used a L98 sensor, but the gauge read way too low. After an exhaustive unsuccessful search for a compatible 3/8" sensor, I chose the inlet manifold location. I was loath to remove a head to have it machined for the 1/2" sensor. Had I known before I had the heads installed, I probably would have had the coolant sensor hole enlarged and threaded for the 1/2" sensor.
In the end. It's all good. We can all learn from one another.
Pete
With these new aluminum heads, the OEM temp sensor is too big.
Does anyone have a part # for a water temperature sensor that fits & functions correctly?
(3/8" pipe threads).
TIA.
Steve
I used one like this on my 79....works just fine. I had the same problem with my new Dart heads....I spent way to much time finding this solution.....anyway, here it is:
this one is from an 81 corvette - should work just fine:
Temp Sender
