engine tin removal Options

[pda914]

Is it at all possible to remove the engine tin over the oil cooler and temp sensor without dropping the engine? I need to get at both the oil cooler top and I need to replace the temperare sensor.

If so what should I look out for?

[stugray]

Why would you :

be replacing it with a type K themocouple together with a themocouple amp with offset correction and some op-amps to make it act like an thermister with a negative temp curve that the megasquirt expects.

why wouldnt you just replace it with a new thermistor "that meagasquirt expects" that is not grounded to the engine case like the stock version?

Sounds like a lot less work.

Take a stock CHT, and drill out the core and replace it with a two wire (or 4-wire if you are really anal) and hook it up.

Converting from thermocouple back to thermistor-like thing sounds like an experiment that isnt required.

Stu

[pda914]

I will be replacing it with a type K themocouple together with a themocouple amp with offset correction and some op-amps to make it act like an thermister with a negative temp curve that the megasquirt expects. This will isolate the temp sensor from the engine ground that electrically noisy.

Thermisters are qustionable above 300F i think . A thermocouple is a nice linear sensor but the only issue is making something with a postive thermnal coefficent to be negative.

Why would you :

be replacing it with a type K themocouple together with a themocouple amp with offset correction and some op-amps to make it act like an thermister with a negative temp curve that the megasquirt expects.

why wouldnt you just replace it with a new thermistor "that meagasquirt expects" that is not grounded to the engine case like the stock version?

Sounds like a lot less work.

Take a stock CHT, and drill out the core and replace it with a two wire (or 4-wire if you are really anal) and hook it up.

Converting from thermocouple back to thermistor-like thing sounds like an experiment that isnt required.

Stu

[pda914]

I thnk drilling out an old thermister and tring to glue it back together with some sort of epoxy that can transfer heat in order to get an isolated ground sensor is questionable in its final performance. I'd go the electronics route and take a sensor that is primarly linear from 0 to 500/deg C where a silicon based sensor is questionable after 300 def F.

The megasqiurit has a 0-5 volt AD in it Just take two op-amps with the first being non-inverting and add a gain of two after the termocouple controler giving it a postive temp coeffecient of 20mv/deg C followed by a unity gain inverting amp. Thus getting the same negative themo co-efficient as the thermister ( but linear). I don't care about lower temps so the layout is good from 40 def F to 420 deg F. The themocouple is the isolated ground type so it does not couple the engine ground to the sensor ground.

I will be replacing it with a type K themocouple together with a themocouple amp with offset correction and some op-amps to make it act like an thermister with a negative temp curve that the megasquirt expects. This will isolate the temp sensor from the engine ground that electrically noisy.

Thermisters are qustionable above 300F i think . A thermocouple is a nice linear sensor but the only issue is making something with a postive thermnal coefficent to be negative.

Why would you :

be replacing it with a type K themocouple together with a themocouple amp with offset correction and some op-amps to make it act like an thermister with a negative temp curve that the megasquirt expects.

why wouldnt you just replace it with a new thermistor "that meagasquirt expects" that is not grounded to the engine case like the stock version?

Sounds like a lot less work.

Take a stock CHT, and drill out the core and replace it with a two wire (or 4-wire if you are really anal) and hook it up.

Converting from thermocouple back to thermistor-like thing sounds like an experiment that isnt required.

Stu