Engine Overheating Help (High CHTs)

[Will.iam]

Ok let’s apply some logic here. The OP said #1 and #3 are hot so I’m presuming #2 and #4 are not and if this is the case then it can not be timing as that effects all 4 cylinders so we can drop the timing issue as not the problem . Now there could be a weak spark plug that’s not firing well or fouled but to have that in 2 cylinders is highly unlikely but definitely more possible than timing that could only effect 2 cylinders, besides that’s and easy test to verify, just swap all the spark plugs on the odd cylinders with the even cylinders and see if the problem moves or stays that will rule out or confirm and issue with the sparkplugs. 
It maybe in fuel flow. A gami sweep test would quickly check that as well. When i was on the hunt to fly deeper lop i also had different cht by alot. When i got my fuel flows even  my cht also became closer together. With his fuel flows already on the low side of 18 gph  it wouldn’t take much unbalanced fuel flow for a cylinder to be running not rich enough to cool at T/O power. And induction leak on NA engine at wot doesn’t matter where the cylinder is getting its air from as the throttle is not reducing any of the cylinders. Induction leaks start showing themselves as you restrict airflow to the cylinders and are greatest at idle power. (Note do not apply this logic to turbo charged models as induction leaks will certainly show as overly rich and cool cht on a cyl that is leaking air in a turbo system)

baffling also a prime suspect since 1 & 3 are on the same side and both started running hotter at the same time. Just one small leak somewhere on that side can cause both cylinders to rise thus a single point of failure could have effect on both cylinders where as even the fuel flow requires 2 failures one for each cylinder to happen at the same time. Maybe if the partial blockage is in the spider fuel flow divider but again to only effect one side and not all 4 is less likely than air escaping somewhere on that side of the cowling. 

[hazek]

1 hour ago, Will.iam said:

The OP said #1 and #3 are hot so I’m presuming #2 and #4 are not and if this is the case

Never mind what they say, just look at the data:

15 hours ago, Jarerh said:

This is the flight in which I had some engine roughness and CHT #3 tended to have a mind of its own, pulled the cylinder after this flight: https://apps.savvyaviation.com/flights/shared/flight/9962458/5b23d3f3-71e9-4feb-ac34-01b25341f1dd

This is a break-in flight where CHT 3 rapidly reaches 440: https://apps.savvyaviation.com/flights/shared/flight/10132193/0238ab27-4e50-41be-a418-cc720035a6eb

[Ragsf15e]

Dumb question… have you made sure the cowl flaps are working and opening all the way?  I believe there are measurements in the mx manual.

On my F, 3 was always hottest but not nearly as hot as yours. It seems like all 4 of yours are hotter than they should be.  It’s got to be timing or airflow (baffling/cowl flaps).