1977 Warrior

Home Pictures Links Specs CTH solved Tips Other Aircraft CTH solved Feb 2008 CHT Solved!!! increased the space between the baffling and front of #2 cylinder to about 3/32 of an inch. On climb, full fuel, one pilot 10F, climb out at 89K, max CHT for #2 was 384F. In cruise #2 was actually cooler than #3 http://www.avweb.com/news/columns/188945-1.html ... Engin Baffling... http://www.piperowner.org/viewforumtopic.asp?id=22280 ...Another Warrior with high CHT... http://www.beechaeroclub.org/modules.php?op=modload&name=News&file=article&sid=2&mode=thread&order=0&thold=0 ...Source Found... http://piperchat.com/forum/viewtopic.php?t=67&postdays=0&postorder=asc&highlight=cht&start=20 ...Mag issue?... am not a mechanic so don't pin me down on my terminology and specifics; read for my intent. The Left (?) mag has two sets of points, one of which works with a vibrator to create a hotter (or more?) spark for starting. These 'starting' points are supposed to be timed differently than the second ('running') set of points. What this fellow found was the the 'starting' points were timed the same as the 'running' points were supposed to be (I don't recall how the 'running points were timed - I think they were timed at the correct interval from the 'starting' points so they weren't contributing anything.) Long story short, both sets of points in the L mag were timed properly and guess what? It starts! Normally. Hot or cold. And yes, both engines were set up the same. My point? OSXUSR, is it possible that the Lou's mags could be set up incorrectly identically (timed) to a setting that would seem to check out as correctly timed to someone checking them out - but not with an eye for critical detail - ; this possible setting being one that would explain Lou's high CHT's?? I've been battling High Chat's for the past 9 months. My #2 will go to 460 on climb (summer), and 405 Leaned in cruise 2500 RPM, the other three are typically within 10 degress of each other 370 climb, 320 cruise. 2 Cylinder runs at 450 on climb out, 405 at 2500 cruise (leaned) All other 3 cylinders average about 350 in climb and 320 in cruise What has been tried to fix/diagnose the problem: Check for induction leak (none) Fixed baffling (no change) Removed excess flashing on number # 2 cylinder fins near the spark plug (no help) Changed CHT system from an old Alcor with ring spark plug probes to a digital Aerospace logic with Bayonet probes (Cylinder Ring probes gave colder readings about 30 degrees colder on each cylinder) Checked Dry Tappet Clearance on #2 & #4 cylinders (both within tolerances) Checked Valve Lift Clearance on #2 & #4 cylinders (both within tolerances) Ran a test in flight with the primer only hooked up to #2, ran at 2500 rpm, leaned, then opened the primer to allow excess fuel into #2 (no change in CHT) Pumped the primer slowly CHT dropped from 404 to 400 Blocked off 1/2 of the right side air intake with duct tape (to see if it had too much air). Added an 30 x 2 in strip of aluminum on the bottom of the cowling to help increase suction of the cooling air. I did find a problem with a leaky #2 primer line, but that did not help the CHT issue. Beefed up engin baffles.. no help. Made an air deflector to channel air directly to #2... #3 went up about 10 degrees (as expected), #2 did not change. Expensive changes..... Nov 2005: Annual inspection found 0 compression on #2, pulled the jugs and found cracked exhaust valve guides in #2 and #4 Looking at the spark plugs, #2 looked much cleaner (cylinder was running leaner) Cylinders were overhauled, new intake guides were installed. Grind seats, valves, lap and and assemble rebush-bore-reface rocker arms Carburetor was in bad shape, had it overhauled as well. Put the plane back together, installed new AutoLite plugs Note: Rings were not replaced Test flew the plane, out side air temp was about 5 degrees C, 40 gals fuel, 2 pilots... Climb: #1 366, #2 430, #3 385, #4 310 2500 L: #1 352, #2 398, #3 370, #4 302 Since the new carb and cylinders, the temps have changed as follows: #1 +30 degrees #2 -10 degrees #3 +40 degrees #4 - 20 degrees June 2006 Well I still have a problem. Summer time temps, #2 will still go up to 440 in climb. In full power cruise I can keep #2 under 400. Jan 2007 Put a 1/16 space between the front #2 baffling place and the clyinder, #2 dropped by 10 degrees, would still go up to 420 in the summer, but if I would back off the throttle by 150 RPM, I could keep it under 400 degrees Feb 2008 CHT Solved!!! increased the space between the baffling and front of #2 cylinder to about 3/32 of an inch. On climb, full fuel, one pilot 10F, climb out at 89K, max CHT for #2 was 384F. In cruise #2 was actually cooler than #3 -andy Website Technology by Bangsberg Software Engineering