Sky High CHT in Cruise

[Oscar Avalle]

  On 3/4/2013 at 3:12 AM, Taracka said:

This sounds to me like an instrument issue although I'd want to determine that ASAP. My 63 C model with a JPI installed when I'm real careful will see CHT's around 400 in climb and around 350-370 in cruise. If I'm not careful temps will climb 430-440 in climb. I went through all the usual suspects such as baffle leaks, mixture issues, etc. and concluded these models run hot. In fact after extensive research I couldn't find anyone with a similar model and JPI equipped Mooney who saw significantly lower temps. This is unfortunate since 400+ isn't good for cylinders and can contribute to shortened life although this Mooney has always had high temps and has made it to TBO twice now.

Anyway, I'd check probe connections to rule that out and maybe substitute another probe to see if that helps. I know how frustrating this can be. Hope you get it figured out.

 

Yes, indeed. I have been trying hard to reduce the CHTs. I looked at baffles, timing (I have a LASAR ignition which already puts me in a negative territory) cowl flaps, climb profiles and the latest now I decided to change the spark plugs... and I called PennYan Aero who did my overhaul (they said it is normal to have CHT in the low 400s in a newly overhauled engine (my engine has now 50 SMOH).

 

After all this effort, my CHTs stay  at climb out between 400 and 440 and in cruise they go down to 360 with CHT 2 and 3 staying at 390 to 400.  So it seems that the M20C do like to run hot.

[jetdriven]

you can disable that LASAR timing advance

[Oscar Avalle]

  On 3/4/2013 at 5:32 PM, jetdriven said:

you can disable that LASAR timing advance

Byron,

 

How could I do that?

[jetdriven]

I think by just unplugging or disabling the power to that control box.  Have a search, VAF is a good source.