EGT variations of greater than 100deg

[Schllc]

The engine recently underwent a tear down after a gear up. 
everything in the engine was replaced except for the crank and the turbos, and magnetos were also overhauled. So new cylinders, pistons, cam, lifters etc. 
the engine only had about 300 hours at the time of the gear up. 
I bought it with about 10 hours after the tear down. 
it runs very well both LOP and ROP but I notices this today and I’m not sure why or if it’s something to be concerned about. 
it’s fairly consistent in cruise. 

[carusoam]

Start with the basics…

1) could be instrumentation…

2) could be fuel distribution…

3) if it is real… the CHTs will also follow the EGTs…  CHT 2 is a touch high, along with EGT2, but there is no visible connection between the colder EGTs and their paired CHTs….

4) Have you run a Gami spread calculation?

This will identify if the hot EGTs are leaner than the cold EGTs…

5) If all the CHTs are close together… this is a hint that something is a bit weird with the EGTs and how they are being sensed…

6) Start with getting data out of the machine, and loading the data up to Savvy…

7) Then the usual, click share at Savvy, and post the link here…

8) Many people would be interested in seeing the Acclaim data… a few are engineers… the rest are engine knowledgable…

9) If not so lucky… the data on the G1000 is for current display only, and none saved to be downloadable…

10) This looks more like EGT sensor issues…  a quick test is done by swapping sensors to see if the low EGTs follow the sensor, or if they stay behind…  it could be the result of lousy sensor location….

Modern Mooney manufacturing had the EGT sensors accurately placed…. Something may have changed if the exhaust system got swapped out…

 

NA PP thoughts only, not a mechanic..

Best regards,

-a-

[ArtVandelay]

I would check the gami spread, this shows how balanced your fuel flow is.

[Schllc]

Don’t have gami’s yet but going to send the data log to JP soon. 
fuel flow is a bit high as well so it could be a fuel setup. 
I just dont think I’ve seen any of my engines have this big a difference in EGT’s with such ideal cht’s. 
tried swapping out the probes and it didn’t change the readings. It could be their placement , or fuel flow spread between. Injectors. 
I don’t think it’s cause for alarm or “airworthy action”. 
just wanted to check with the brain trust here
I will follow up when it’s resolved. 

[carusoam]

Gami spread…

A test that can be run with existing FIs, No Gamis required…

For the procedure… Savvy does a nice job of explaining it…

Check what the costs are for having Savvy review your data and make recommendations…

Doing the Gami spread is important… when it shows a tight spread, as expected….  Then instrument placement is suspect…

With the turbo, the exhaust system is confined flow… so the sensor placement won’t be as critical as a NA exhaust.   NA systems have large temperature changes over short distances as the pressure is relieved quickly in the open ended exhaust pipe… PV=nRT…

PP thoughts only…

-a-

[jlunseth]

I am told that the JPI probes need to be installed in a specific way with a specific set of washers in a specific order. Now, your panel is a G1000 I presume so don’t know if anything like that applies to your probes, I just know that probe installation needs to be done exactly correctly or the readings will be in error. If the readings are correct then the likely issue is unbalanced fuel flows, although you say you have swapped injectors and nothing changed. It just seems like a couple of the cylinders are running richer than the others. I have GAMI’s. I can tell you that mechanics who had worked on my plane before I got it had done a pretty good job of putting the wrong injectors on the wrong cylinders, and the injectors are supposed to be tagged with the cyl number and all the tagging was gone. My A&P had to re-arrange the injector order, and tag the injectors, then it has worked fine. Like GAMIs should. The CHT’s seem so well in line with each other it is hard to conclude there is something wrong with the fuel flows, more likely an instrument problem.