Best place to measure temp? And what thermometer to get?

[stormchaser]

I want to get an IR thermometer. Any suggestions? I'd rather NOT spend a fortune, but also don't want junk. Also, when measuring engine temps...trying to compare to the water temp gauge...where should I take the readings? Engines are 8v71TIs...

[Passages]

I got one on eBay for around $25. Picked up a phototach for about the same price too.

They were obviously from China but not junk and work fine.

[stormchaser]

The photo-tach...what are they and how do you use one? lol

[Avenger]

how do you sue one? lol

First, you need a good attorney, of which there is no such thing.

A photo-tach is an optical tachometer. You paste a reflective strip on some rotating component, in this case the damper or flywheel, and aim the unit at it to measure RPM.

Raytech is a good brand of IR temp gun.

[stormchaser]

The phototachs...do they come with multiple strips so I can use one for both engines? Are they accurate?

[stormchaser]

Also, where should I aim the thermometer to get the best readings?

[Pascal]

for coolant, i usually look for the warmest spot, usually near the temp sensor or near the tstat.

when taking measuremnt, try to do it fairly close since the further you are the wider the cone, and keep it consistent.

also, keep in mind that the surface color/material/reflectiveness can affect reading.

[Avenger]

The phototachs...do they come with multiple strips so I can use one for both engines? Are they accurate?

They should come with multiple pieces of reflective tape. You should be able to use any reflective tape available in auto part or hardware stores. You may even be able to get away with a clean, sharp stripe of white paint.

These are digital units and should be accurate to +/- 1 RPM or better. Much more accurate than the analog tachs on your instrument panel.

Re: IR temps. Remember you are measuring surface emissivity, not actual coolant temperature. However, you can usually get a reasonably close number by reading the thermostat housing if it's accessible. You should check multiple locations i.e. exhaust manifolds, cylinder heads, turbocharger, transmission housings etc. The important part to to consistenly hit the same spots and compare engine to engine. This way you'll have a baseline to compare to if something gets out of range so you can catch trouble early.

[GJH]

I bought my IR Thermometer at Radio Shack, maybe 40 bucks? Works well. In addition to above, I shoot the oil filters, transmissiion and the turbos, the alternators, ambient temp of the ER and the stuffing box. I have some baseline readings that I remembered, so I can note any variance. DD has some of these temp guidelines in their manual.


This is a handy device for a variety of other stuff too, such as various pumps and oneself..

[bobk]

An annual IR temperature check of the electrical connections on the panels while under full loads is also a good preventative measure. Poor connections will begin to heat up and can be corrected before a problem starts.

Bob