I am appealing to the very wide range of experience and knowledge here.

I am installing a EGT ( Exhaust Gas temp ) gauge on my diesel pickup. I want to turn up the pump to make more power, but don't want to melt things---like pistons. 1200 degrees is pretty much the agreed on max EGT (pre-turbo) on a Ford/International IDI engine.
How confident can I be that 1000 degrees on my new gauge is really 1000 degrees? Boiling water as a reference point gets me on 212. I was wondering if lead or solder brought just to the melting point would be a reliable reference point.
Any ideas?

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags

There should be a spec from the maker of the probe part that provides the resistance value for various temperatures for testing purposes.

resistance if its an RTD or mV if its a thermocouple - you might have to dig for this info. (I didnt think that they made RTD's that read up to 1200F, but I could be wrong...)

edit- there are actually standardized values and wire colors for thermocouples....we can go into this further if you dont like my cooler idea below...



Cooler idea? get the $30- laser thermometer at Harbor Freight (or whatever tool store you like better). It might be off by 5 or 10 degrees, and I'm not sure how high the laser thermometer goes (800F ?) But you could at least track the EGT meter on the way up and see if it is consistent.

...and you can use it to diagnose home HVAC issues or if your baby has a fever (gonna try this one when baby #4 arrives soon

(Just kidding about the fever thing - It would not be accurate and that laser is too close to baby eyes for me...but It'd be funny if it worked )

-John

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2009 Kia Sedona
2009 Honda Odyssey EX-L
12006 Jetta Pumpe Duse
(insert Mercedes here)

Husband, Father, sometimes friend =)

Really? Thought it can run at 1200 or even 1250 but you cannot keep it in indefinitely past that?

A way to check is to put 2 of them. One after the other. Only other way I know of is to infra red scan it on a dyno.

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01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

I think it might be lower on the outside by more than a few degrees, but only a test will tell.

I like the fever idea-you can check up on everybody without getting up from your seat

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$60 OM617 Blank Exhaust Flanges
$110 OM606 Blank Exhaust Flanges
No merc at the moment

1200 seems low for cast block/cast heads...

Gm says you can run all day at 1375*F.... And I have aluminum alloy heads!

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-Justin

91 560 SEC AMG - other dogs dd
01 Honda S2000 - dogs dd
07 MB ML320 CDI - dd
16 Lexus IS250 - wifes dd

it's automatic.

What is the melting point of aluminum? somewhere around 1220 F. While the bottom of the pistons get a cooling jet of oil aimed to carry away some of the heat, we can't measure at the pistons, either, so 1200 is a good safe max. Some guys say 1250 for a short burst is OK.

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags

True but my under, which is standing, is that the pistons are NOT aluminum or at least not pure aluminum and is going to melt at higher than 1221F. Further to that, with the intake charge and oil cooling, I don't think 1250 is going to be the temperature of the piston itself.

__________________
01 Ford Excursion Powerstroke
99 E300 Turbodiesel
91 Vette with 383 motor
05 Polaris Sportsman 800 EFI
06 Polaris Sportsman 500 EFI
03 SeaDoo GTX SC Red
03 SeaDoo GTX SC Yellow
04 Tailgator 21 ft Toy Hauler
11 Harley Davidson 883 SuperLow

Isn't the relevant melting point that of the aluminum alloy?

True, except the relevant point is how do we know the gauge reads correctly?

Perhaps the softening point of the alloy would be good, too.

All I know is that from the many people on the IDI website, people who have rebuilt these engines at various miles and conditions pretty much agree that 1200/ 1250 is a good safe max. Some guys do report a higher temp. Also its important to know these are pre-turbo--as close to the exhaust port as possible.

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags

i am impressed !!
a diesel technical thread in OD!
I am sure there is plenty of info in DD on EGT.
Have seen over 1300 for short time when working hard ( earth moving gear).

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Grumpy Old Diesel Owners Club group

I no longer question authority, I annoy authority. More effect, less effort....

1967 230-6 auto parts car. rust bucket.
1980 300D now parts car 800k miles
1984 300D 500k miles
1987 250td 160k miles English import
2001 jeep turbo diesel 130k miles
1998 jeep tdi ~ followed me home. Needs a turbo.
1968 Ford F750 truck. 6-354 diesel conversion.
Other toys ~J.D.,Cat & GM ~ mainly earth moving

My Duramax EGTs will spike to 1700-1800*F during a quarter mile pull.

__________________
-Justin

91 560 SEC AMG - other dogs dd
01 Honda S2000 - dogs dd
07 MB ML320 CDI - dd
16 Lexus IS250 - wifes dd

it's automatic.

The 1200 number sounds like what I remember also.... and if anything is a bit conservative - which would be good for engine life.

If you still want to *measure* temperature - there are also these options:
Craftsman Multimeter With Thermocouple from Sears.com

You plug the thermocouple into the multimeter, and set the MM to *F or *C and it reads the temperature at the tip of the thermocouple.

the challenge here would be to find a way to hold the tip of the thermocouple against the exhaust manifold while it heats up to 1200F long handled screwdriver ? It'd be tough to do this under load (a big c-clamp?) but I maintain that if the two measuring devices track from 0 to 400*F (can you get here idling in your driveway ?, then the same probe should be good at 1200*F

I agree with the above that says give yourself 100*F of 'fluff' based on the fact that the outside of the manifold will be cooler than the inside. This should still tell you if the installed EGT reads reality or not.

If this were a refinery or power plant, there'd be a 2nd tap/hole in the manifold for a 2nd measurement device - and you'd use that for a 2nd opinion. Or you'd send the EGT probe and meter into the Instrument shop to be calibrated... dont ask how much that costs

-John

__________________
2009 Kia Sedona
2009 Honda Odyssey EX-L
12006 Jetta Pumpe Duse
(insert Mercedes here)

Husband, Father, sometimes friend =)

How about using something like a "Markal" Thermomelt Heatstick? they are a sort of crayon that melt at specific temperatures, you could attach your sensor to a chunk of steel, mark the steel with a specific crayon and then heat the steel from below making note of the registered temp at the moment the marking melts. They make crayons that indicate from 100F to 2000F and about every 50F in the range around 1200F. They claim certified accuracy to plus or minus 1% of rated temp. If you had a couple ranging up to the max temp it would give you a good idea of your sensor/readout performance. I've used them in the past heat treating metals.

Temperature Indicators | Markal

Here's one 850F for $8 plus shipping

http://www.waresdirect.com/products/Commercial-Products/Markal/Thermomelt-Heat227944?trackURL=froogle&gclid=CMSk4NXZkLwCFaxr7AodZycATw


eBay's got many of them for $5 free shipping here's a 1200 F one

http://www.ebay.com/itm/NOS-Markal-THERMOMELT-TEMPERATURE-INDICATOR-STIK-1200-F-649-C-/400333846958?pt=LH_DefaultDomain_0&hash=item5d35c1b9ae#ht_1678wt_900

This is a good idea!

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1982 300SD " Wotan" ..On the road as of Jan 8, 2007 with Historic Tags