TIT 200 deg. lower than EGT

[Boilermonkey]

We are in the process of breaking in our new engine.  The TIT seems quite low given the EGTs.

https://apps.savvyaviation.com/my-flights/39032/49ef0b48-acd5-4ef9-a233-9569ded028ab

The flight on July 13th as an example.  The TIT is about 200 deg lower than the EGTs.

We installed a new JPI 930, could the probe be reading too low?   Or is this real?    Part of break-in?

FYI, we had the cowls off last week as a part of the prop issue (different thread).  The engine, turbo, exhaust, etc. all look normal.

Thoughts?

[LANCECASPER]

I believe the TIT is going to be hotter than any one EGT since it's where all of the Exhaust gas collects. I think your probe is bad. (To make matters worse when the probe is burnt up the TIT temp reads low.)

I wouldn't fly it until you get this figured out. This engine needs correction instrumentation.

[carusoam]

+1 for possible instrument / probe error…

The TIT is down stream of the EGTs…. And often sounds like it should read lower because of that…. But….

You have six exhaust streams collecting at the TIT sensor…. So the average temperature being displayed is actually hotter than the single EGTs that only have one exhaust wave going by in the same amount of time….

 

So…. Probe location is important… and # of exhaust streams the sensor is warmed by is also important…

the funky logic of why TIT is hotter than EGT is because none of this is steady state flow of hot Gasses…

Often the exhaust gasses are still burning and getting hotter, on the way past the EGT sensor….

Then nothing goes by until the next flame front… cycles of very hot and not so hot averaged over time….

 

PP thoughts only…

Best regards,

-a-

[kortopates]

Something is wrong, wrong probe type? (J vs K and ungrounded vs grounded)  or probe tip has been burnt off?  

[carusoam]

TIT sensors live in the most hazardous environment… compared to EGT sensors…

It is often the extensive heat of the environment that destroys the tip of the sensor…

 

PP thoughts only,

-a-

[Boilermonkey]

This is only 15hrs after install of the JPI on a new engine.   I'm going to contact JPI.

[LANCECASPER]

8 hours ago, Boilermonkey said:

This is only 15hrs after install of the JPI on a new engine.   I'm going to contact JPI.

Is it a new TIT probe? If it's anything other than a factory reman, it may not have been changed out. Also has been mentioned by @kortopates it may have been changed out, but the wrong probe may have ben used.

[carusoam]

Expect that the old JPI was installed as-is on the new engine…

That is how mine was done a decade ago…

Unless, you are saying it was a new JPI with new sensors being installed on a new engine…. Because that failure would be weird…

Then still follow the advice of the good Kortopates…. He is the most experienced engine monitor whisperer on MS…. 
 

Best regards,

-a-

[Boilermonkey]

Reman engine with new JPI out of the box.

[LANCECASPER]

2 hours ago, Boilermonkey said:

Reman engine with new JPI out of the box.

Are you using the TIT probe that came from Lycoming on the reman? Or a JPI probe that came with the 930?

[carusoam]

Hmmmm…

what does the JPI say the TIT is when in the hangar?

all the EGTs and TIT should be reading within a few degrees of each other…. Whatever the hangar temp is that day…

If the new TIT probe is off by a couple of hundred degrees…. It may be the wrong type…. We usually use K-type thermocouples… often a J-type is used by other people…. They look very similar except their wires are different colors….

Wire coatings are color coded to indicate they type… mixing types causes similar errors…

Pp thoughts only,

-a-

[Boilermonkey]

4 hours ago, carusoam said:

Hmmmm…

what does the JPI say the TIT is when in the hangar?

all the EGTs and TIT should be reading within a few degrees of each other…. Whatever the hangar temp is that day…

If the new TIT probe is off by a couple of hundred degrees…. It may be the wrong type…. We usually use K-type thermocouples… often a J-type is used by other people…. They look very similar except their wires are different colors….

Wire coatings are color coded to indicate they type… mixing types causes similar errors…

Pp thoughts only,

-a-

I'll check it out, thanks!

[Boilermonkey]

All probe temps withing a few degrees in the hangar before starting.

Checked for leaks, none.   Turbo works normally from ground upto 18K... haven't gone higher yet.

 

[Boilermonkey]

Brand new probe installed.  Still can't get above 1600 TIT before the EGTs peek.  Running at 70% to 75% power.  At least the TIT is now reading 50-75 hotter than EGTs.

[LANCECASPER]

34 minutes ago, Boilermonkey said:

Brand new probe installed.  Still can't get above 1600 TIT before the EGTs peek.  Running at 70% to 75% power.  At least the TIT is now reading 50-75 hotter than EGTs.

Don't stop looking for an answer - the Bravo TIT is capable of going well past 1750 if leaned enough (not that you should run it there). But the fact that it won't go past 1600 indicated tells you something is definitely wrong and 1600 indicated is probably a whole lot higher in reality. If the engine install happened at the same time as the JPI 930, the 930 is not displaying correctly. @philiplane works on Bravos and might be able to provide some answers. It wouldn't surprise me if some pins are wrong on your JPI installation.