OK to put temp senor in waterpump bypass line?

[Apex_speed]

I have a Roush 427R with an Edlebrock dual plane intake. The intake only has 2 ports to the coolant passage and there is nothing on the heads. I'm doing fuel injection so I need the left front port for the FI coolant temp seder and the right port is my heater return. This will displace the temp sender for my coolant temp gauge.

I was just eying the water pump bypass hose that goes from the water pump housing to the fitting on the front of the block under the surge tank. Would it be OK to put an inline fitting in that hose so I can put the temp sender for the gauge there?

It is out of the way so it wouldn't be very obvious and looks like it is 1/2-3/4". I assume there is coolant flowing through this all the time that is reasonably close to engine temperature.

Thanks!

[bingo2]

You can use a Street Tee (Google if you are not familiar with them) of the appropriate size, probably 3/8 NPT.

[Apex_speed]

Originally Posted by bingo2

You can use a Street Tee (Google if you are not familiar with them) of the appropriate size, probably 3/8 NPT.

Yes. Mine is a bit larger so I was just going to use a tee that was gauge specific and flanged on either end as it is a rubber hose. Many of the gauge adaptors I have seen for smaller houses are widened in the point where the adaptor threads in so it doesn't create a restriction. I would probably try to find one of those.

Anyway, I take it that it is OK to tap into the bypass line and that the coolant flow there is constant and representative of engine temp? At least close enough for my dash gauge?

Thanks.

[bingo2]

The Street Tee goes into one of the ports on the intake manifold and allows the use of 2 senders/sensors from the same port.

[Apex_speed]

Originally Posted by bingo2

The Street Tee goes into one of the ports on the intake manifold and allows the use of 2 senders/sensors from the same port.

Ah, got it.

That setup doesn't seem to work well. I have had poor luck with them in the past and someone else on here put one on their Roush 427R and also had an issue. The gauge read much lower than actual temperature unless you turned on the heater so the coolant could flow past it and then it read accurately.

Have you tried one on an intake manifold port with good results?

[cycleguy55]

Originally Posted by Apex_speed

I have a Roush 427R with an Edlebrock dual plane intake. The intake only has 2 ports to the coolant passage and there is nothing on the heads. I'm doing fuel injection so I need the left front port for the FI coolant temp seder and the right port is my heater return. This will displace the temp sender for my coolant temp gauge.

I was just eying the water pump bypass hose that goes from the water pump housing to the fitting on the front of the block under the surge tank. Would it be OK to put an inline fitting in that hose so I can put the temp sender for the gauge there?

It is out of the way so it wouldn't be very obvious and looks like it is 1/2-3/4". I assume there is coolant flowing through this all the time that is reasonably close to engine temperature.

Thanks!

IMO the question is somewhat irrelevant. If you're going EFI you should be running a single plane intake anyway, so ditch that dual-plane and get the proper intake.

[Apex_speed]

Originally Posted by cycleguy55

IMO the question is somewhat irrelevant. If you're going EFI you should be running a single plane intake anyway, so ditch that dual-plane and get the proper intake.

It is a Holley throttle body injection system and both Roush and Holley claim the dual plane intake I have is best suited for the motor and system. Believe me, that was the first question I asked both of them!

[cycleguy55]

Originally Posted by Apex_speed

It is a Holley throttle body injection system and both Roush and Holley claim the dual plane intake I have is best suited for the motor and system. Believe me, that was the first question I asked both of them!

Definitely wise to ask the question. I know some have had success with dual plane intakes, while others have had no end of grief. Best of luck whichever way you go!

[Apex_speed]

Originally Posted by cycleguy55

Definitely wise to ask the question. I know some have had success with dual plane intakes, while others have had no end of grief. Best of luck whichever way you go!

Any idea of what the specific running issues were for the unlucky ones? I’m told that it’s no issue on a big or small block Ford but a disaster on an LS variant. Those have to be single plane.

[bingo2]

I'm not certain what having a heater has to do with this. Put the tee in the other port on the intake manifold.

I have the Holley Sniper atop an Edelbrock Air Gap intake, which is a dual plane, and haven't experienced any issues.

[Apex_speed]

Originally Posted by bingo2

I'm not certain what having a heater has to do with this. Put the tee in the other port on the intake manifold.

I have the Holley Sniper atop an Edelbrock Air Gap intake, which is a dual plane, and haven't experienced any issues.

Glad to hear it's running well for you.

The heater return hose IS IN THE RIGHT PORT of the manifold. If you put a street tee there, you can still attache the heater return to the top of the tee. BUT, I have had an issue where running the temp sender in an adaptor block (street tee) lifted it far enough away from the coolant flow that it didn't read accurately. This was not on a V8 though but a guy on here had a similar issue on a 427R. The heater comment is that when you turn the heater on, it circulates coolant THROUGH the street tee with the sender mounted in it and then would read more accurately (heater core does cool down the return temp a bit if the heater is on).

Anyway, I'm going to pick up a tee at the hydraulic supply house tomorrow when I'm there and try it. I suppose it's worth a shot and I can compare the dash gauge to the data in the Holley system to see if it reads reasonably accurately.

I suppose it's possible that the guy that had the issue had air in his system as that's about where it would end up as it's the highpoint.

[bingo2]

I get all that but, you have two ports, the tee doesn't need to be in the same port as the heater fitting.

[xb-60]

Originally Posted by Apex_speed

....I have had an issue where running the temp sender in an adaptor block (street tee) lifted it far enough away from the coolant flow that it didn't read accurately.....

I agree. I also had the same issue on my Alfa, using a tee to to be able to fit an oil temp sender.
The result of the sender being out in the air flow rather than in direct contact with the block or head was that it read way too low.

Cheers,
Glen

[Apex_speed]

Originally Posted by bingo2

I'm not certain what having a heater has to do with this. Put the tee in the other port on the intake manifold.

I have the Holley Sniper atop an Edelbrock Air Gap intake, which is a dual plane, and haven't experienced any issues.

Ok, how about we try this if you don't mind....where are the following located in your car?

1. Holley Sniper coolant temp sender?

2. Dash gauge coolant temp sender?

3. Heater return line?

[bingo2]

No heater. The CTS is located in the passenger side port where the heater valve would be located and the sender for the analog temperature gauge is in the driver side port. I originally had them installed opposite of their current location but, I changed to more efficiently route the wiring; readings were identical from either location. If I did have a heater, I would try the tee in the driver side port and if it didn't function to my satisfaction I would drill and tap another port as others have suggested.

[Apex_speed]

Originally Posted by bingo2

No heater. The CTS is located in the passenger side port where the heater valve would be located and the sender for the analog temperature gauge is in the driver side port. I originally had them installed opposite of their current location but, I changed to more efficiently route the wiring; readings were identical from either location. If I did have a heater, I would try the tee in the driver side port and if it didn't function to my satisfaction I would drill and tap another port as others have suggested.

Ok, thanks.

I'm going the path of least resistance for now. Holley sender on the right side and gauge sender on the left side as the Edlebreock Performance RPM manifold is drilled correctly for that.

I think I will look into an extension for the t-stat housing that is threaded for a sender as that would likely work well. I'm just not sure if it's physically possible in an SPF Cobra with a 351W block and the surge tank mounted at the top front of the engine.

[Gaz64]

Is there no room in the front water crossover to add a temp sender?

I would drill a hole, tap it 1/8 npt, and fit the sender.
That way you can see the engine warming up on all gauges.
Adding a sender after the thermostat, the gauge will barely work at all, then rise up, showing the thermostat operation.
Unless you want to see it that way.

Gary

[cycleguy55]

Originally Posted by Apex_speed

Ok, how about we try this if you don't mind....where are the following located in your car?

1. Holley Sniper coolant temp sender?

2. Dash gauge coolant temp sender?

3. Heater return line?

BTW, the fitting on the intake manifold is the hot coolant to the heater, and the heater return goes to the water pump.

[Gaz64]

Originally Posted by cycleguy55

BTW, the fitting on the intake manifold is the hot coolant to the heater, and the heater return goes to the water pump.

If you must use a heater hose, this is correct.

Using the return hose would be like placing it in the bottom hose, as the return from the radiator.

[Dumpling]

Isn't there a gauge package for the Holley efi? Can't you mount that or wire in from the feed for the package?