Bore scope Exhaust Valves

[JohnInReno]

I welcome comments or suggestions on these 4 exhaust valves. The engine is a Superior IO-320 with roller tappets, dual Pmags, and 400 hours since new.

Please pay special attention to #3 which is exhibiting erratic EGT at idle only. Possible sticky valve? Cylinder #2 also has a half moon mark on the edge that I can't explain.

Obviously, I am new at this.

Cylinder #1


Cylinder #2:


Cylinder #3


Cylinder #4

[BillL]

The edges on #2 and #3 look suspicious. You might get a picture with the valves open and get a look at the seating band. A leak down test listening at the exhaust pipe is another diagnostic to be done. All together maybe a picture emerges.

[tim2542]

Symmetry and the look of burned pizza is good.
I agree with Bill, leakdown test is in order, and if nothing definitive is found let it develop and look again in 25~50 hrs.
Check this out:
https://www.aopa.org/training-and-sa...e/valve-safety
Be sure to download the poster.
Tim Andres

[pa38112]

They look good to me. 400 hrs is time for a valve wobble test. That is the only way you would find a sticking valve.
What do you mean by erratic EGT at idle?

[Aggie78]

Engine monitor with download capability?

You might consider signing up for their pay service, they have an analytics program called "failing exhaust valve analysis" or FEVA that has a very good probability of predicting whether you have a problem.

Their website has more info on the subject.

https://savvyanalysis.com/content/feva/

[JohnInReno]

Originally Posted by pa38112

They look good to me. 400 hrs is time for a valve wobble test. That is the only way you would find a sticking valve.
What do you mean by erratic EGT at idle?

I am a subscriber to SavvyAnalysis. This link should work:

https://www.savvyanalysis.com/flight...7-06e555a43bd2

[JohnInReno]

Originally Posted by BillL

The edges on #2 and #3 look suspicious. You might get a picture with the valves open and get a look at the seating band. A leak down test listening at the exhaust pipe is another diagnostic to be done. All together maybe a picture emerges.

I will try to get pictures with the valve open. A leak down test is also on the list.

Thanks,
john

[tim2542]

You can also watch the valve open and close, I've spotted a worn guide doing that. You can see the valve slip sideways just as it closes. Obviously, don't squish your gadget with the piston.
Tim Andres

[scard]

That pattern at 11 o'clock on #2 would have me looking in there often.

[pa38112]

Originally Posted by scard

That pattern at 11 o'clock on #2 would have me looking in there often.

Isn't that just a section of lead flaking off? There is no discoloration.