VansAirForceForums  
Home > VansAirForceForums

- POSTING RULES
- Donate yearly (please).
- Advertise in here!

- Today's Posts | Insert Pics

  #1  
Old 10-08-2017, 03:36 PM
LeMar LeMar is online now
 
Join Date: Dec 2008
Location: Sioux Falls, SD
Posts: 39
Default O-360 #2 and #4 high CHT

Backround:
O-360A1A, 1,000 Hrs since new, RV-7, 1,000 Hrs
Never had high CHTs until about 50 hours ago when #2 and #4 became higher on climb out. Now, at 120 kts cht on those two cylinders climbs to 420 fast and would go higher if I didn't back off power.
Ignition: EFII on bottom plugs, slick mag on top

So far I've changed intake couplings and gaskets, checked the carb for looseness, changed mag and harness. Nothing has had any real effect. Baffle seals aren't perfect but are pretty good and I can't see much change from several years ago. Checked #2 cht probe in hot oil and it tracks with a digital cooking thermometer.

Something has changed but I don't know what. I've read through high CHT posts here on the forums but haven't seen any describing symptoms like this.

Ideas?

Thanks,

LeMar
Reply With Quote
  #2  
Old 10-08-2017, 04:03 PM
mr.sun mr.sun is offline
 
Join Date: Aug 2006
Location: Wet, Western Washington
Posts: 74
Default o-360 #2 and #4 high CHT

Double Check timing
__________________
Greg RV-7 flyer
Reply With Quote
  #3  
Old 10-09-2017, 06:10 AM
Bob Martin's Avatar
Bob Martin Bob Martin is offline
 
Join Date: Jan 2005
Location: Richmond, Virginia
Posts: 1,004
Default Primer

You don't mention a primer system?
If you have one, check that too.
Also check that the primer ports and injector ports are there and not leaking too.
__________________
Bob Martin
RV-6, 0-360 Hartzell C/S, Tip up, 1150+TT
James extended cowl/plenum, induction, -8VS and Rudder. TSFlightline hoses. Oregon Aero leather seats.
D100-KMD150-660-TT ADI2- AS air/oil seperator. Vetterman exhaust with turndown tips.
Louisa, Virginia KLKU N94TB
Reply With Quote
  #4  
Old 10-09-2017, 06:14 AM
snopercod's Avatar
snopercod snopercod is offline
 
Join Date: Aug 2016
Location: Asheville, NC
Posts: 867
Default Timing?

Quote:
Originally Posted by mr.sun View Post
Double Check timing
Why would timing only effect two cylinders, please?
__________________
(2017 dues paid)
Reply With Quote
  #5  
Old 10-09-2017, 07:28 AM
John Myers's Avatar
John Myers John Myers is offline
 
Join Date: Feb 2006
Location: Newalla, OK
Posts: 22
Default High CHT on 2&4

I would check one of the double duty coil packs on the ignition system. One dead coil pack would leave two cyl's only getting fire from the mag and the cht's on them would go up.
Reply With Quote
  #6  
Old 10-09-2017, 08:20 AM
N941WR's Avatar
N941WR N941WR is offline
 
Join Date: Jan 2005
Location: SC
Posts: 10,960
Default

Quote:
Originally Posted by John Myers View Post
I would check one of the double duty coil packs on the ignition system. One dead coil pack would leave two cyl's only getting fire from the mag and the cht's on them would go up.
That would cause cylinder temps to drop, not rise, and then only if both ignitions stopped firing on those two cylinders.

Check you baffles, you might have a crack that is letting the cooling air out. Look around the corner of #4.
__________________
Bill R.
RV-9 (Yes, it's a dragon tail)
O-360 w/ dual P-mags
Build the plane you want, not the plane others want you to build!
SC86 - Easley, SC
www.repucci.com/bill/baf.html

Last edited by N941WR : 10-09-2017 at 08:23 AM.
Reply With Quote
  #7  
Old 10-09-2017, 03:22 PM
N363RV's Avatar
N363RV N363RV is offline
 
Join Date: Nov 2009
Location: Arlington, tx
Posts: 200
Default Maybe john is on to something..

I know the other guy mentioned chts... but maybe you should look at the exhaust temps.
Exhaust gas temps do go up when you run on only one mag or one side of a dual ignition system. You haven't mentioned your exhaust gas temps.
Did you change your aviation style plugs to new ones or at least confirm the gap? Don't forget to check the resistance too. 1k to 5k is acceptable.

I would also stick a light in the cowling at night and try to observe any egregious air leaks. That side of the cowling gets the least amount of air in it during a climb on a normal day... but 120kt should overcome even the worse leaks.

If the carb got some junk on one side it might alter the performance of the jet negatively.

I hope you get it worked out. Please post what the final resolution is.
__________________
Builders: John & Amanda
Model: RV 6A
Airworthiness issued Aug 2010
Based - GPM
Reply With Quote
  #8  
Old 10-09-2017, 03:49 PM
Raymo's Avatar
Raymo Raymo is online now
 
Join Date: Nov 2014
Location: Richmond Hill, GA (KLHW)
Posts: 1,370
Default

Is your oil cooler mounted on the back of #4 and did you remove a winterization plate about 50 hrs ago? (sorry to state the obvious).
__________________
Ray
RV-7A - Slider - N495KL - First flt 27 Jan 17
O-360-A4M w/ Catto 3 blade NLE, AFP FM-150 FI, 1 PMag, Vetterman Trombone Exh, SkyTech starter,
PlanePower Alt, FlightLines Interior, James cowl & plenum
All lines by TSFlightLines
NSDQ

"The object of the game, gentlemen, is not to cheat death: the object is not to let him play."
Patrick Poteen, Sgt. U.S. Army
Reply With Quote
  #9  
Old 10-10-2017, 12:12 PM
LeMar LeMar is online now
 
Join Date: Dec 2008
Location: Sioux Falls, SD
Posts: 39
Default

Some good ideas here. I think the next thing to check is CHT vs EGT as I don't remember what the EGTs were doing. Nothing that would have alarmed the system or me but still, maybe something is happening.
The other thought is to remove the primer lines from #2 and #4 and plug the holes. The primer system is the solenoid type and I never actually use it but rather use the accelerator pump for starting. Perhaps there is a leak on that side of the engine allowing air to be sucked in. I have checked for fuel leaks on the primer system but maybe air will leak in where fuel won't leak out. I'll post my findings.

LeMar
Reply With Quote
  #10  
Old 10-10-2017, 12:45 PM
Bob Martin's Avatar
Bob Martin Bob Martin is offline
 
Join Date: Jan 2005
Location: Richmond, Virginia
Posts: 1,004
Default Primer

Quote:
Originally Posted by LeMar View Post
Some good ideas here. I think the next thing to check is CHT vs EGT as I don't remember what the EGTs were doing. Nothing that would have alarmed the system or me but still, maybe something is happening.
The other thought is to remove the primer lines from #2 and #4 and plug the holes. The primer system is the solenoid type and I never actually use it but rather use the accelerator pump for starting. Perhaps there is a leak on that side of the engine allowing air to be sucked in. I have checked for fuel leaks on the primer system but maybe air will leak in where fuel won't leak out. I'll post my findings.

LeMar
The solenoid has a "in" and "out"....marked with a 1 and 2....(not sure of the order), if it is reversed it can leak fuel though. The solenoid can go bad as well. The install manual says it can be mounted in any direction but recommended vertical, I think. All things to consider.
The above conditions usually contribute to rich running or stumbling at idle, not lean or higher CHT's....that most likely is a leak in the induction or primer line systems.
Bypassing for troubleshooting seems like a good idea.
__________________
Bob Martin
RV-6, 0-360 Hartzell C/S, Tip up, 1150+TT
James extended cowl/plenum, induction, -8VS and Rudder. TSFlightline hoses. Oregon Aero leather seats.
D100-KMD150-660-TT ADI2- AS air/oil seperator. Vetterman exhaust with turndown tips.
Louisa, Virginia KLKU N94TB
Reply With Quote
Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump


All times are GMT -6. The time now is 12:54 PM.


The VAFForums come to you courtesy Delta Romeo, LLC. By viewing and participating in them you agree to build your plane using standardized methods and practices and to fly it safely and in accordance with the laws governing the country you are located in.