High CHT on #5

[GeneS]

Hello all. I'm stumped. I've got an '05 Ovation 2 DX. #5 cylinder head temp runs about 40-60° hotter than the others. The EGT on this cyclinder is lower than the others. LOP or ROP same situation. The shop replaced the original injectors with the tuned injectors and no change.

Any ideas would be greatly appreciated.

 

[carusoam]

Gene,

Just to get started....

What device are you using for EGT / CGT?

I was not able to open the links.  Sorry if I missed some details.

Best regards,

-a-

 

[GeneS]

[carusoam]

Now I see the photo of the G1000.

 

Sharing some initial thoughts...

You have already checked the fuel flow to that cylinder, compared to others.

Check for induction leaks?  ROP this would make more of a difference. Lop, not so much.

Temporarily swap leads for cht and EGT with other cylinder. To see if this is a real temperature difference or a measurement error.

Calibrate the temperature sensors?

Baffling?  The air flow, not the question.....

Best regards,

-a-

[KSMooniac]

I'd check the baffling carefully first, especially the seals to the cowl.  Then I'd run a GAMI lean test and record the data.  While LOP I'd then do a mag check too.

[fantom]

Make sure the baffling isn't folding over when you put the top cowl on.

I thought Ovation 2 DX production ended in 2004, and the DX doesn't have the G1000 panel. I suspect you have the more expensive Ovation 2 GX.

[Cruiser]

Is the sensor different on the #5 cylinder? I don't know the setup for the DX or G1000.

You don't say if this is a new problem or it has always been that way. The EGT value is not so important unless there is an ignition (plugs) or fuel restriction problem that causes the value to change.  How does the CHT track to the EGT when leaning? It should show a normal increase to peak and then decrease LOP as you reduce fuel flow.

[Becca]

Quote: GeneS

Hello all. I'm stumped. I've got an '05 Ovation 2 DX. #5 cylinder head temp runs about 40-60° hotter than the others. The EGT on this cyclinder is lower than the others. LOP or ROP same situation. The shop replaced the original injectors with the tuned injectors and no change.

Any ideas would be greatly appreciated.

 

[N513ZM]

Quote: Becca

Gene - YMMV but most Ovation drivers find that pixies often cut some 1" diameter holes in the baffling in front of #5 - behind the alternator which is the source of the problem to begin with. Now go find some pixies...

Umm... my apologies to Becca, but somehow I was logged in as you and didn't notice until after the post. Not sure why but I believe this is a long time bug in MooneySpace code.

Anyway, from one Ovation driver to another - hie ye forth in search of said pixies (or at least a mechanic that will do this for you. The little people tell me it works like magic.

As for model year and DX, GX etc - I have a 2000 Ovation 2 (DX before they called it DX) that is registered as a model year 1999 - completed and certified airworthy in 12/1999 but sold as a 2000 model year (Ovation 2 not available until 2000).

Mike

 

 

[Cris]

Would you be able to post a picture of what that pixie hole look like?  Thanks

[Jvancecpa]

Please on the picture of the holes.  Just bought 2008 Ovation but had a 2005 Ovation2GX and I remember #5 always running hot and sometimes in the 425-450 range.  Thanks for the help.

[GeneS]

Pixie hole has been drilled per instructions from a helpful member.  I haven't seen it yet but I'm leaving for a 3 hr flight tomorrow at 4am.  I'll take pictures of the hole and the results.  Pictures of pixies are not likely.

Gene

[Piloto]

It appears that you may have a hot CHT probe. Try swapping it with #6 cylinder.

 

José

[MooneyMitch]

My 2 cents here please.  Yes indeed, #5 on the IO-550 runs hotter because it is behind the alternator.  It also appears to me, based on the CHT temps I'm seeing, you are running ROP.  Possibly the 393 reading is not that out of line in your particular ROP setting. 

And yes, ROP or LOP, given #5 is behind the alternator, it will be hotter that the others.

[GeneS]

I couldn't get a photo of the hole without taking the cowl off but here's the result.  I is definately an improvement and probably good enough.  In the photo, I'm at 9000 ft and 50F ROP.

 

 

[Shadrach]

50 ROP would be the best way to test it... I'm guessing you're ~70% power and at 50ROP you're running CHTs about as hot as is possible, so it seems that the fairy has solved your problem.

[KSMooniac]

(now go educate yourself why 50 ROP is about the hottest setting you can possible run, along with the the highest internal cylinder pressure!  There are much better settings.... )

[GeneS]

Quote: KSMooniac

(now go educate yourself why 50 ROP is about the hottest setting you can possible run, along with the the highest internal cylinder pressure!  There are much better settings.... )

[jetdriven]

if you count extending your range 30% and skipping a fuel stop slower too....

[jlunseth]

Slower to damage the engine yes.  50 ROP and over 65% is just about the maximum stress you can put on the engine.  You can, and for a cruise setting should, go further ROP without changing %HP materially.  You can go LOP also, my experience with that is that it does slow you down.  But 50 ROP is about dead center in the "red box" where your internal cylinder head pressures will be greatest.

[Shadrach]

Quote: GeneS

I understand that there are cooler power settings but they are all slower right?

[KSMooniac]

Flying at something other than 50 ROP will also increase the chances of making TBO without requiring a top O/H, unless you got some of the TCM jugs with off-center valves, in which case you'll have to do one no matter what.  

[GeneS]

I've got a 2.5 hr trip this afternoon.  I'll run at different power settings and record temps and TAS. I'll report back. 

[danb35]

Quote: GeneS

I understand that there are cooler power settings but they are all slower right?

[GeneS]