41 replies to this topic

[Cnj]

Sorry to hear that Craig.

thnx. Totally our fault. We built and installed the motor in my garage and then did not do a careful test run to make sure all was good - plus I kept on driving as the engine slowed down cause it felt like an electrical fault. I now know what a seizing motor feels like and won't forget it. Sometimes you have to pay to learn.

Cnj.

[fotostars]

Here is the noob question:

I installed one of those on the upper radiator hose, I thought it was working alright. Let the car warm-up, eventually the light goes off. All good. Let it warm to the point where the fan switches goes on to test my other warning light (high temp) conveniently wired to the fan... Still good.

Then start driving, the high temp light turns off (it's a really cool day out there) and the warning pressure light comes back on.

Oh, last piece of info, I have a thermostat.

 

So here is my stupid question: When the thermostat closes to "keep the engine warm", does it drop the pressure in the upper hose to the point that the warning light would come back on? It would seem like so, or I have another problem to chase.

 

If that's the case, where would you install the sender to avoid this (short of removing the thermostat? (I was thinking in the bypass of the heater core)

 

Comments?

[Randy Thieme]

My first guess is yes, downstream from the thermostat the h2o pressure would drop. Before moving it ask yourself if you'll have a thermostat installed on the track? And if so, is it going to get hot enough on grid before going out to create the same scenario?

[Bench Racer]

MotorSportsHeaven shows through parts the location to be in the heater hose.http://www.motorspor...cost_p_683.html

[fotostars]

My first guess is yes, downstream from the thermostat the h2o pressure would drop. Before moving it ask yourself if you'll have a thermostat installed on the track? And if so, is it going to get hot enough on grid before going out to create the same scenario?

Yes, I have been running with a thermostat installed. Not planning on removing it.
I was in that situation at the track over the WE (after my winter work in the garage). This is when I noticed the issue.
I'm still trying to understand if it makes sense that the pressure is dropping in the upper hose when the thermostat closes.
The fact is, it's a closed system, thermostat open or not. So I'm assuming the pressure is even throughout the system. Right?

So is it just because the temp was not high enough that it didn't build enough heat hence not enough pressure?
The needle barely made it to 180 that session after I started moving (1st morning warm-up, it was ~40 outside temp)...
So I disconnected the sender to not have that warning light all the time for the rest of the WE. I should have experimented more during the day when it got warmer... Darn...

[RussMcB]

MotorSportsHeaven shows through parts the location to be in the heater hose. http://www.motorspor...cost_p_683.html

 

The description on the web page is a little confusing.  I'm not sure if the "optional" T-fitting is really "included".  My hunch is, for an extra cost, you can choose one of the two location options.

 

Pasted from the site:

 

Includes:

• Relay
• Relay Harness
• Pressure Sensor
• Optional 5/8 Heater Hose T-fitting or 1-1/4" Radiator hose T-Fitting (Includes 2 Clamps, Ground Harness)
• Green LED (System GOOD)
• Red LED (Warning/Pressure Low)
• Miscellaneous Connectors

[suck fumes]

See below.

[Randy Thieme]

Yes, I have been running with a thermostat installed. Not planning on removing it.
I was in that situation at the track over the WE (after my winter work in the garage). This is when I noticed the issue.
I'm still trying to understand if it makes sense that the pressure is dropping in the upper hose when the thermostat closes.
The fact is, it's a closed system, thermostat open or not. So I'm assuming the pressure is even throughout the system. Right?

So is it just because the temp was not high enough that it didn't build enough heat hence not enough pressure?
The needle barely made it to 180 that session after I started moving (1st morning warm-up, it was ~40 outside temp)...
So I disconnected the sender to not have that warning light all the time for the rest of the WE. I should have experimented more during the day when it got warmer... Darn...

 

The thermostat is a a type of valve, when it closes the water pressure downstream from it should drop.  If the sensor is between the thermostat and the radiator the pressure reading should drop.  It may not drop all the way down to atmospheric pressure since there may be some overall pressure build-up due to heat, but it will change. 

[Blake Thompson]

I lost a brilliantly fast motor to just this problem.  I wince at how much time/money I've spent trying to get that little bastard back, which I could have saved for $70...

[suck fumes]

Ok let me go into more detail about how to calibrate our kits.
1. If you mount it in the heater hose, MAKE SURE you mount it in the hose that goes into the cylinder head. So if your looking at the motor and the two hoses in the back, it will be the one closest to the passenger side going into the head. You will not get the proper pressure reading if you install it into the right hose closer to the driver.

2. You can also mount it into the front radiator hose and have it be just as accurate.

3. The proper way to calibrate the kit after install is to start the car, let it warm up over 165deg. Then adjust the sensor till you just see the red light go out. Then rev the engine, if the red light flickers on and off, adjust it out a little more. The idea is to keep it consistent at wide open throttle.

4. Adjustment turns: Most of the time it will take anywhere from 1/2 a turn to 3 turns out to adjust properly, not every car is exactly the same.

[Jim Drago]

We use this system, works great and hard to beat for $25.00.  

 

http://www.longacrer...d=1094&catid=11

 

We use a different light as we wire it up into our cluster, but works great if you want to do it yourself, this is another option.

Jim.

[Bench Racer]

Please note:


When Longacrer and MotorSportHeaven units are compared, MotorSportHeaven is a fail safe unit per say. No red or green light on is an indicator the unit is not functioning. With the Longacrer unit at the same level one dosen't have a clue if the unit is functioning or not.

[fotostars]

We use this system, works great and hard to beat for $25.00.  

 

http://www.longacrer...d=1094&catid=11

 

We use a different light as we wire it up into our cluster, but works great if you want to do it yourself, this is another option.

Jim.

 

This is what I installed. I don't believe it's adjustable...

 

Jim, where did you install it? Upper Radiator hose or heater bypass? Do you have issues on cold days?

[Jim Drago]

This is what I installed. I don't believe it's adjustable...

 

Jim, where did you install it? Upper Radiator hose or heater bypass? Do you have issues on cold days?

We install ours in the back of the head.  No issues in cold. No thermostat either though

Jim

[Rob Burgoon]

Please note:


When Longacrer and MotorSportHeaven units are compared, MotorSportHeaven is a fail safe unit per say. No red or green light on is an indicator the unit is not functioning. With the Longacrer unit at the same level one dosen't have a clue if the unit is functioning or not.

 

You're certainly right, but you're not completely boned with the Longacre unit.  You can test it by simply by turning the ignition on before starting the engine.  Ignition on & engine off should light the warning light.  No warm fuzzies while on track though.

[fishguyaz]

perhaps putting in an actual gauge an addition to the light might be worthy.

this way if the light does go on, you can glance at the gauge to verify before deciding to shut down.

[Duncan]

You're certainly right, but you're not completely boned with the Longacre unit.  You can test it by simply by turning the ignition on before starting the engine.  Ignition on & engine off should light the warning light.  No warm fuzzies while on track though.

 

You can easily add a relay and second light to the Longacre unit and get exactly the same behaviour.  Green light when the system is pressurised, and a red light when it's not.  If people are interested, I'd be more than happy to post a wiring diagram.  It's very simple.

 

Duncan

[RussMcB]

You can easily add a relay and second light to the Longacre unit and get exactly the same behaviour.  Green light when the system is pressurised, and a red light when it's not.  If people are interested, I'd be more than happy to post a wiring diagram.  It's very simple.

 

Duncan

Sure, I'd like to see it, if it's easy.  Thanks for offering.

[Duncan]

Here's one way to do it.

 

WaterPressure by duncanrellis, on Flickr

[Jim Drago]

You're certainly right, but you're not completely boned with the Longacre unit.  You can test it by simply by turning the ignition on before starting the engine.  Ignition on & engine off should light the warning light.  No warm fuzzies while on track though.

 

 

Not sure what confidence the green light gives?   green light = no light in longacre?

As you said, if you turn the key on the light will illuminate. It will also illuminate when car is cold until it builds pressure and shuts off. 

 

So the real question is... What do you do when your green light goes out and red light does not illuminate? Do you shut it off and pull over?  

 

Green light is a nice feature if you need that light staring in your face saying all systems are a go for you to be confident in the system. I have confidence knowing the warning light is working every time I start the car.   

Jim