Indeed, that's what what I'm seeing. I'd think that head has to have been swapped at some point, as a '77 US would've been emissions spec...?
Water temp sensor in block (1 Viewer)
- Thread starter Aircooled1
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- Thread starter
- #22
Agreed. Will see if anyone else has another idea. But if i have no other options could use the head-based sensor for my sniper and the block based sensor for gauge.
I know a few have used the block port for the Sniper install on here from reading other threads. I think Holley prefers the head, but it should also work.
- Thread starter
- #24
Right. I guess the head could have been swapped. It had all emissions equipment present when i got it. Is there a way to branch the existing head based sensor connection so that I can attach two leads to it? I figured that was not possible But it would solve my problem.
There is another possible location for a water temp sender that i have used in the past.
I had a water pump that was made to be used on a 2F with an oil cooler. I do not run an oil cooler. I used that extra port to mount my sender. I just cut a length of coolant hose maybe 2.5 or 3 Inches long, slid one end over the extra port and pushed the sender into the other end of the hose. The aftermarket (Autometer) sender is longer than OEM and extended into the water flow. Couple of hose clamps and I had a water temp gauge.
But it looks like you already have a new water pump...
I had a water pump that was made to be used on a 2F with an oil cooler. I do not run an oil cooler. I used that extra port to mount my sender. I just cut a length of coolant hose maybe 2.5 or 3 Inches long, slid one end over the extra port and pushed the sender into the other end of the hose. The aftermarket (Autometer) sender is longer than OEM and extended into the water flow. Couple of hose clamps and I had a water temp gauge.
But it looks like you already have a new water pump...
It is my understanding that there was a threaded port on the thermostat housing for that model year.
It appears from the picture that an earlier housing was used on this build, which doesn't have the port.
It appears from the picture that an earlier housing was used on this build, which doesn't have the port.
EDIT: Was thinking of a different port on the housing - Pighead's has an extra.
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GA Architect
SILVER Star
I run a Sniper on my rig and have for almost two years. One of the best upgrades I've made!
FWIW:
I have my original OEM gauge cluster reading my water temps out of the OEM head, using an OEM temp sensor, so that head tap is taken. The second tap in the head is for my heater line, so that is taken. With that being said, if my head had an extra tap for an additional sensor, I would have located my Sniper's water temp sensor there. Also, if I wasn't using my OEM gauge to read the water temps, then I'd run the Sniper's temp sensor there. And, if I wasn't running a heater, then I'd use that tap.
THUS, my Sniper's temp sender is located in the block drain as you wish to do. I've had no issues with this location!!!!!
Sniper Sensor: Sure, it may take a few additional seconds for the block drain location to get to 160 degrees, but it does get there and that is all that matters. If you go the block drain route, go ahead and install the Sniper sensor. It will be a plug and play when you install the Sniper EFI unit.
And if you need to use the block drain, SIMPLE, take the Sniper sensor out. Drain the block, then reinstall the sensor.
I have a March 78 FJ40 and there is a additional sensor port next to #4 intake port. Hard to see behind the carburetor. The plug has a big head. Also my thermostat housing has those additional ports that Pighead was referring to. This information will not help Aircooled1 but maybe someone else down the road.
- Thread starter
- #31
Thanks all for the help.
StinkyPig
SILVER Star
Yes there is! But... Taken from the Sniper installation instructions:
"Must be installed in a coolant passage in either the intake manifold or cylinder head. Do not install in thermostat housing."
I have to believe that the fluid in thermostat housing sees greater temperature swings as the cooling juice and thermostat do their work.
If there is no additional port in the head (my 78 has an extra port) than the block would be the next best location with the most consistent coolant temp.
I believe that Holley is making a generalization for all brands of engines when they say “do not install in the thermostat housing” since some engines may have ports downstream of the T-stat.
On the F or 2F, I believe that the t-stat housing port would be an ideal place for the Sniper sensor.
Here are my thoughts. The coolant that has been cooled by the radiator, enters the block first via the water pump. It then moves from the block up into the head where most of the engine heat is generated. It then exits the head into the lower t-stat housing where the port that “73FJ40” has pointed out is located. That port is below the t-stat and the coolant temperature at that point would be un-affected by the t-stat position whether it is open or recirculating. I have not ever measured, but I would bet that temperature in the t-stat housing would get to the 160 deg F temperature that the Sniper is looking for, quicker than the temperature at the block drain.
I am not saying the sensor in the block drain will not work fine, but I do believe the t-stat housing would work fine also and may even be more accurate and quicker to respond to engine temperature.
On the F or 2F, I believe that the t-stat housing port would be an ideal place for the Sniper sensor.
Here are my thoughts. The coolant that has been cooled by the radiator, enters the block first via the water pump. It then moves from the block up into the head where most of the engine heat is generated. It then exits the head into the lower t-stat housing where the port that “73FJ40” has pointed out is located. That port is below the t-stat and the coolant temperature at that point would be un-affected by the t-stat position whether it is open or recirculating. I have not ever measured, but I would bet that temperature in the t-stat housing would get to the 160 deg F temperature that the Sniper is looking for, quicker than the temperature at the block drain.
I am not saying the sensor in the block drain will not work fine, but I do believe the t-stat housing would work fine also and may even be more accurate and quicker to respond to engine temperature.
StinkyPig
SILVER Star
I After pulling the plug next to the #4 intake port, and noting that this hole is not only very shallow on my head but also mostly obscured by steel casting...
I expect that coolant flow around the temp probe might be minimal once an adapter is installed.
And after reading Steamers explanation and noting that the T-Stat housing is rather large and the fact that there was a temp sensor there when the machine had smog...
I think Steamer is correct. I'm going for the TStat housing.
I expect that coolant flow around the temp probe might be minimal once an adapter is installed.
And after reading Steamers explanation and noting that the T-Stat housing is rather large and the fact that there was a temp sensor there when the machine had smog...
I think Steamer is correct. I'm going for the TStat housing.
StinkyPig
SILVER Star
Sure am!
Well, when you get the Sniper up and running, you will be able to monitor the temperature at that location with the Sniper’s display and check for stability or fluctuations.
As far as the head port goes, you need to run an adapter, which pushes the thermocouple up a bit. That makes more room for fluid to flow around it despite the shallow port... similar to the OEM sensor had.
It does also seem like the lower thermostat housing is more like an extension of the head on the 2f, so I don't see any issues there myself. Only real difference is that it's at the end of the line vs more centered so there might be a slight delta, but I doubt it's enough to matter. The head port is likely a bit easier to hide the wiring, though.
It does also seem like the lower thermostat housing is more like an extension of the head on the 2f, so I don't see any issues there myself. Only real difference is that it's at the end of the line vs more centered so there might be a slight delta, but I doubt it's enough to matter. The head port is likely a bit easier to hide the wiring, though.
What does this sensor do for the Sniper? Just tell it to start learning? Cant this setting be adjusted to compensate? How accurately are we trying to measure temps on these old tractor motors?
I am going to be in the same boat as @GA Architect when I eventually get to this mod.
I am going to be in the same boat as @GA Architect when I eventually get to this mod.
There's a few compensation tables to adjust the base fueling map - doesn't need to be accurate to the degree by any means. "If the coolant is 50*, richen up by 30%. At 80*, 20%...etc". As long as it's not gated by the thermostat, I'm sure it'll be happy enough, and those tables are tuneable. The main thing is that it's aware of the engine temp in that period between startup and the thermostat opening, which is why they have that warning in the install.
They do similar things with air temp to drive adjustment factors.
Oddly enough, that's the tuning mine needs now - it's a little cranky with this cold weather until the coolant temp hits 125* or so in the head.
They do similar things with air temp to drive adjustment factors.
Oddly enough, that's the tuning mine needs now - it's a little cranky with this cold weather until the coolant temp hits 125* or so in the head.
