Temps for CHTS JPI 700

K, that sounds about right for 180hp. Back to them baffles, have a hard look for hard seals and gaps.
 
I do have a tuned exhaust that claims it makes an extra 20hp. Not sure if it's true or not, or if that would have any bearing on it.
 
DavidWhite said:
I do have a tuned exhaust that claims it makes an extra 20hp. Not sure if it's true or not, or if that would have any bearing on it.
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Yep, it sure would, it does that by allowing an increased fuel flow which will cause an increase in temps.
 
Skylane81E said:
These suckers run pig rich at takeoff
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Bingo.

180 HP @ 17 GPH = 0.57 BSFC, which sounds about right for full rich takeoff power (best power is about 0.50).

Remember if that exhaust "adds" 20 HP, it probably means that the restrictive exhaust that was on the plane took 20 HP away.
 
Ted DuPuis said:
Bingo.

180 HP @ 17 GPH = 0.57 BSFC, which sounds about right for full rich takeoff power (best power is about 0.50).

Remember if that exhaust "adds" 20 HP, it probably means that the restrictive exhaust that was on the plane took 20 HP away.
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Part of why I have to clean my cowl flap!
 
DavidWhite said:
I tried running it LOP today. It seemed to do alot better, how many degrees LOP should I run it?
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5 for best power WOT LOP back to as far as you can until rough, should get you to 70* or so LOP on the coldest. Did you try setting 8.7-9 gph WOT @ 2000' and seeing where it fell?
 
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DavidWhite said:
I tried running it LOP today. It seemed to do alot better, how many degrees LOP should I run it?
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Lean until rough, rich until smooth. :)

In your case I'd be looking more at CHTs than anything, and try to keep all off them below 380 if possible. You will quickly determine how possible that is. If 400 is the number, then go to keep below 400.
 
Ted DuPuis said:
Lean until rough, rich until smooth. :)

In your case I'd be looking more at CHTs than anything, and try to keep all off them below 380 if possible. You will quickly determine how possible that is. If 400 is the number, then go to keep below 400.
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I struggle keeping #3 below 420 in cruise, and below 450 in climb. It hit 446 today.
 
Henning said:
5 for best power WOT LOP back to as far as you can until rough, should get you to 70* or so LOP on the coldest. Did you try setting 8.7-9 gph WOT @ 2000' and seeing where it fell?
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5 degrees LOP? It seemed like between 5 and 20 degrees LOP was the smoothest. It still isnt as smooth as ROP, but the CHTs are lower and I burn alot less gas.
 
DavidWhite said:
I struggle keeping #3 below 420 in cruise, and below 450 in climb. It hit 446 today.
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Then pretty much on the edge of roughness is what you want.

I suspect that the cooling in your plane isn't as good as on the ones with the O-320s or O-360s from the factory. This is just a side effect of your conversion, and it is what it is. Although the baffles shoudl be examined.
 
DavidWhite said:
5 degrees LOP? It seemed like between 5 and 20 degrees LOP was the smoothest. It still isnt as smooth as ROP, but the CHTs are lower and I burn alot less gas.
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Yep, it'll never be every bit as smooth until you do some plenum work and get everything to flow match, get used to it, it's fine.
 
Im about 2.5 hours away from doing oil change number 2 (@40hrsSTOH) since the top overhaul on the 180 Conversion O-360. CHT's are settling down in the 360-380 range in leaned out cruise, but I also see about 445 on the warmest cylinder (#3) and around 405-415 on the others in climbout only. Lower the nose, and the CHT's do drop some. I'm still running straight non AD mineral oil. I plan to change out to my usual X/C 20-50 and Camguard at the oil change. Will using this oil make any significant difference in the CHT's?

I'm really pleased with the break-in so far. Used a quart of oil in the 27.5 hours since the first O-C @10hrs and the color of the oil has gone just to a darker honey gold, rather than that dark greeninsh-brown that oil used to be on the old jugs. I'm told that's due to the new cylinders being much tighter than the old ones, and that the non AD oil does not suspend byproducts of combustion in the oil itself as compared to AD oil.
 
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Do they all have the same sort of probe? My #3 reads lower solely because it uses the spark plug gasket probe rather than the threaded plug style probe because the probe hole on that cylinder is used by the standalone CHT gauge.
 
flyingron said:
Do they all have the same sort of probe? My #3 reads lower solely because it uses the spark plug gasket probe rather than the threaded plug style probe because the probe hole on that cylinder is used by the standalone CHT gauge.
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Yes the monitor system was installed new with the overhaul.
 
I have been dealing with the same hot CHT's in my Beech Sundowner. I have the washers sensors and the 1 and 2 cylinders run near 400-420 on cruise climb. The no. 3 cylinder, only one with a probe, is running 375-380 during the same cruise climb. I am going to try leaning more and note the temps.

I just ordered 3 more bayonet probes to replace the washers....also giving the baffles another inspection. I hope this takes care of the problem.

FYI
The JPI page noted in FAQ section that the Alcor bayonet probe (@$60 ea) can replace the 5050T bayonet probe by JPI (@$120 ea).
 
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In a 90 knot cruise climb my CHTs were all above 400,
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I fly a TB20 (IO540-C4D5D) and no way would I climb it at 90kt. Way too slow.

Vx or Vy until clear of obstacles and then trim to 120kt. That just keeps the CHTs to 400F-410F (ISA conditions).

In cruise, say 360F at low altitude, 65% power (23" / 2400 / 11.5 USG/hr).

I climb using the constant-EGT method, described here. No "cruise climb", therefore.
 
peter-h said:
I fly a TB20 (IO540-C4D5D) and no way would I climb it at 90kt. Way too slow.

Vx or Vy until clear of obstacles and then trim to 120kt. That just keeps the CHTs to 400F-410F (ISA conditions).

In cruise, say 360F at low altitude, 65% power (23" / 2400 / 11.5 USG/hr).

I climb using the constant-EGT method, described here. No "cruise climb", therefore.
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I don't think white lighting is going to be climbing much at 120...
 
Just want to confirm we're talking about a 180 HP converted 172 here. Those CHT's are high.

I agree with Ted, get the baffling checked and/or re-done, and maybe modify the cowl a bit (legally) to get better cooling.

I have a JPI EDM 700, and watch my CHT's, pretty much just in climb as that's when the #4 cyl. will approach 400F. I usually drop the nose a bit after 2,000 ft. to a cruise cilmb of 100 - 105 KIAS in my Tiger. Vy is 90. That helps cooling a bit, and then I lean once over 5,000 ft.

While 446F is below redline, it's not helping cylinder/valve life.
 
peter-h said:
I fly a TB20 (IO540-C4D5D) and no way would I climb it at 90kt. Way too slow.

Vx or Vy until clear of obstacles and then trim to 120kt. That just keeps the CHTs to 400F-410F (ISA conditions).

In cruise, say 360F at low altitude, 65% power (23" / 2400 / 11.5 USG/hr).

I climb using the constant-EGT method, described here. No "cruise climb", therefore.
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Lycoming O-360 in a C172 or cherokee/archer POH is T/O climb is 80 kts. and cruise climb is 90 kts. Comments should always refer to same type of aircraft, otherwise it's apples and grapefruit.
 
Want to lower the temps the seeing on your JPI? Pull it out and put an EI unit in. I've had both in mine and the EI will consistantly read 30-40 degrees lower on climb and cruise. The probes are different and I think that's what causes the difference, apparently Lycomming used the EI bayonet style probes for their certification. Mine had to have the EI unit for FAA certification of my cowl. I now have a AuRacle unit with JPI probes and see the same temps as I saw on my JPI.
 
I've always wondered how these cheap probes were calibrated. I don't see many shops dunking them in hot oil prior to installation...

I've long suspected cheap Chinese electronic sensors mated with bar graphs and displays that are more precise than the possible error of the sensor published on the manufacturer's data sheet.

Just sayin'... How does one know the temperature being displayed is even accurate? Too many years building electronics to trust them without verification.
 
denverpilot said:
I've always wondered how these cheap probes were calibrated. I don't see many shops dunking them in hot oil prior to installation...

I've long suspected cheap Chinese electronic sensors mated with bar graphs and displays that are more precise than the possible error of the sensor published on the manufacturer's data sheet.

Just sayin'... How does one know the temperature being displayed is even accurate? Too many years building electronics to trust them without verification.
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http://www.tempil.com/products/thermax/10-level-strips

I've been sticking these things on engines for years.
 
denverpilot said:
Right, I know about those. (And the "pencils"...) The question is, do most installers use them?

Also, maybe a dumb question, but where would you stick those on a cylinder? Fins everywhere.
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On the fins, no worries. Do installers use them, I doubt it.
 
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Anthony said:
Just want to confirm we're talking about a 180 HP converted 172 here. Those CHT's are high.

I agree with Ted, get the baffling checked and/or re-done, and maybe modify the cowl a bit (legally) to get better cooling.
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The question is what can be changed. He could get a 337 to try to put cowlings from a 180 HP 172 on (which might be better, I'd suspect so).

The plane was designed to cool a 145 HP engine. Now it's got to cool a 180 HP engine, and I'm betting not much was done to improve cooling. Plus it's summer. I'm not sure how much he can really do without making significant changes.
 
Ted DuPuis said:
The question is what can be changed. He could get a 337 to try to put cowlings from a 180 HP 172 on (which might be better, I'd suspect so).

The plane was designed to cool a 145 HP engine. Now it's got to cool a 180 HP engine, and I'm betting not much was done to improve cooling. Plus it's summer. I'm not sure how much he can really do without making significant changes.
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Put a 1.5" air dam under the back opening of the lower cowling. It'll increase the airflow significantly.
 
Henning said:
Put a 1.5" air dam under the back opening of the lower cowling. It'll increase the airflow significantly.
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I'd consider that a "significant change", since it's a modification to the cowling. While I'm not an A&P, I'd suspect that would need approval to do.
 
Ted DuPuis said:
I'd consider that a "significant change", since it's a modification to the cowling. While I'm not an A&P, I'd suspect that would need approval to do.
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I'd agree, but I would hope you could find a FSDO willing to work with you on it.
 
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