0540 B4B5 acceptable cylinder head Temp

mikenizicmikenizic
in General Discussion
Hi All,

Seems that my 235 runs a little on the warm side and has for quite some time. The engine runs great, excellent compressions, good oil temp and oil pressure. Does anyone else have the same experience with the 0540 and if so what are your CHT's and what is an acceptable temp?

Thanks,

Mike

Comments

  • CaptPeteCaptPete
    What CHTs are you seeing and under what conditions?
  • mikenizicmikenizic
    Capt Pete,

    I usually Cruise around 22 to 23 squared between 6500 and 9500 and see CHT's anywhere from 375 to 390. I lean until the engine runs rough and than advance to where the engine runs smoothly and than advance just a touch more and I see around 13 to 13.5 gph on my JPI 450.

    Mike
  • flyguydonflyguydon
    Is that all cylinders? It is a little hot, but not way too hot. Is that cruise? What do you see on an extended climb?

    Make sure your timing is correct. Advanced timing will raise temps. Ask PK.
  • mikenizicmikenizic
    I only have a single probe CHT, I always do a conservative cruise climb and the temp rarely goes much over 400 but it really likes 390 in cruise. I think it's a little hot as well. I will check the timing tomorrow. This is the original engine to the plane and it has 1150 hours on it since new (1971). I bought this plane about a year and half ago and have put about 125 hours on it. It has alot of power and I have had no major problems, I have also had three acceptable oil analysis's over that time.

    Mike
  • PilotKrisPilotKris
    The Cherokee 235 was not even produced with a CHT gage. To do that, during certification, Piper had to demonstrate that no matter what the combination of airspeed, power, mixture and OAT, it was not possible to exceed maximum allowable CHTs.

    It must have worked as the O-540-B4B5 in the 235 has a reputation of not only easily making it to TBO, but exceeding it by 30-50% without problems, even without the "help" of multi-probe graphic engine monitors.

    In short, it pretty much doesn't matter how ham-fisted the operator is, it's unlikely, short of some mechanical problem, to hurt that engine.

    390 in cruise isn't especially hot and I doubt that you'll have any longevity issues because of it. Check your baffles and go aviate. Any issues you have will most likely come as a result of lack of use (1150hrs in 39 years).

    PilotKris
  • flyguydonflyguydon
    PK,

    It is hot here in Florida right now! Since you pointed my temp problem to timing, I have had no troubles at all with my IO360CIC. In an extended climb with it 100 out, I might see 360 on the hottest. In cruise, 2 and 4 go for about 270ish and 1 and 2 are about 300. I have over 70 hours on it since the issue...
  • PilotKrisPilotKris
    Hey, you're welcome Don.

    Although now, your temps seam almost too low (especially in FL). Perhaps you're not leaning aggressive enough?...

    PilotKris
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