April 1993 - American Bonanza Society
April 1993 - American Bonanza Society
April 1993 - American Bonanza Society
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I Q I M35 oil filter. My corporalion<br />
is now the proud owner<br />
of 'I9860R, a 1960 M35<br />
<strong>Bonanza</strong>. This is Ill)' first<br />
<strong>Bonanza</strong> so I have several questio ns<br />
for you.<br />
The 10-470 e ngine has an oil<br />
screen. I have seen that there is a kit<br />
available to replace the oil screen with<br />
a fil ter. Do you think this conversion is<br />
wOl1hwhile?<br />
Also. I have noticed a discrepancy in<br />
the Beech owner's manual and the<br />
Continental engine manual. The Beech<br />
manual says to change the o il every 50<br />
hours whjJe the Continental ma nual<br />
says evclY 25 hours. How often should<br />
I change the oil? -David N. Schach,<br />
ABS 28861, San Fmncisco, Calif.<br />
rpm, OAT was 12 C (ISA+ 19); lcanedlo<br />
20 degrees rich of peak, the CHT<br />
sr.,yed pegged al 200 C. Other examples<br />
are, al 4,000 ft., OAT 24 C<br />
(ISM 17) 23/2300, 20 degrees rich, CHT<br />
pushing 225 C, so cowl flaps were<br />
opened, al 9,000 feet OAT 16 C<br />
(ISA + 19) full lhrotlle (20.8 inches) 2400.<br />
20 degrees rich, CHT 200 C cowl flaps<br />
closed .<br />
I am very meticulous in the operation<br />
and service of lhis aircraft, as any<br />
!>afc pilot/owner should be. I alway~<br />
felt that g(xxi maintenance and operation<br />
according to the POH would get<br />
this engine to TBO. Now I am con-<br />
] . Norman Colvin, retired Beech cerned thal excess heat translates to<br />
Project Engineer on <strong>Bonanza</strong>s excess wear.<br />
and Baro ns, AmcriGIn Bo nanza My question is, will a holter operat-<br />
<strong>Society</strong>'s Technical Consulwnt ing engine (e.g. 200 C) wear faster than<br />
It's best to change oil at 25 a n dSe rvi ~e C Ii~k. l ns~LO r and an engine that opemtes in the 150 C to<br />
~ A<br />
hour intervals if the engine autho r of ColL'm s ClJmc. 175 C range or is the difference neglidoes<br />
11.01 have the o il filter gible? Secondly, do you believe the<br />
and 50 hours if it does have a filter.You Can pur- excess oil consumptio n is re lated to the hotter running<br />
chase dle oil filter ada pier for your engine from Warren tempera lures' -john F. SCianillo, _NID.. ABS 19181 , Fort<br />
James, phone 619/ 438-9590.<br />
Lauderdale, Fla.<br />
\Vhen this adapte r is installed, the o il screen can be<br />
removed and whoever installs the adapter must be sure that<br />
four or five thread contact w ith the e ngine is obtained.<br />
When you talk to \Varren James, ask what the lock nut<br />
torque value is.<br />
10.5508 cylinder head temperatures. You have<br />
~ Q<br />
probably seen the Beechcraft SelVice Comlllunicalion<br />
(No. 91, daled May 1992) regarding high<br />
CI-IT's on the 10-550B engine. I own a 1988 A36,<br />
SIN 2421 wilh 770 hours and r would like 10 share my<br />
obsclVations for your conunents or suggestions.<br />
I have noted all along, since acquiring this aircraft, that<br />
the CHT would rise close to the red line on climbout requiring<br />
lowering of the nose. You just can't climb out at Vy and<br />
keep dle CHT below 238 C (Red Line).<br />
1 expressed concern about this to several mechanics and<br />
was led to believe d1at Ihe 10-550B nonllally ran hol. The<br />
only suggestion I received was to usc Mobil AV-I ($8.00/<br />
quart) because it could w ithstand these hotter operating<br />
temperatures.<br />
Along with the honer CHT temperatures, I have been<br />
experiencing increased oil consumption of one quart evelY<br />
3.5 hours. No I",,,k can be found bUllhe breadler lube drips<br />
a few dro ps. I found the oil dipstick had vibrated loose on<br />
one occasio n and re placed the gasket but it hasn't helped.<br />
There is an interesting quirk when leaning this e ngine. If<br />
leaned 10 20 degrees lean of peak EGT. Ihe CHT wi ll cool<br />
down to 175 C, whe reas at 20 degrees rich of f'C'"k the CHT<br />
is pegged at 200 C. Most mechanic') do not have an explanatio<br />
n for this and some don't be lieve it, but my guess is that<br />
unburned air is cooler than unburned fuel.<br />
I fl y in the southeast, based in Fort Lauderdale. On a<br />
typical trip at 11 ,000 feel M.P. of 19" (h,Jlthrottle) and 2400<br />
I AA I The 10 -550B engine had a cooling problem, however,<br />
Ihis problem can be solved b)' calling Turbo<br />
Flight, phone 303/731-2127. These people have<br />
obtained STC approval for new engine baffles that<br />
really correct the problem.<br />
r would suggest that you add a second gaskel lO Ihe oil<br />
dip stick cover. Unless this cover is tight, it will allow air to<br />
enter the crankcase, pressulizing the case, which forces oil<br />
Ollt the engine breather nlbe.<br />
It wouldn't hurt 10 boroscope the c:ylindcrs to check for<br />
their condition. The engine is using more o il than n0 I111al. It<br />
is possible that the cylinder walls have rust spots.<br />
\Vhcn you lean the engine o n the lea n side of best<br />
power, the engine develops less (X>wer. so less heat is generared,<br />
CHT cools down. You are right, excessive hear contributes<br />
to premature wear and shorter engine life.<br />
I would suggest that you get light on the baffle change,<br />
since it definitely wi ll solve your problem.<br />
Fuel mixture problems. I have a 1966 C33A <strong>Bonanza</strong><br />
and I am havi ng trouble with the e ngine<br />
~ Q<br />
running rough when the mixture is enriched on<br />
descent.<br />
\X1he n descending from altitude, me engine begins to run<br />
rough when the mixture is put in too far. At about 2,000 feet<br />
we have to leavc the lnixture about one to one and a half<br />
inches out. Full rich at this altirude causes the engine lO run<br />
rough. \VIe have been leaving the mixture out this far, or<br />
perhaps a little less, all the way to the ground. Then, on rollout,<br />
we have had trouble with the engine dying wh ile it is<br />
at idle. Lately. we have had to increase the throttle until the<br />
rpm is 1000 to prevent rhe motor from dying on roHouL<br />
In servicing the syslem, we decreased the mixture until<br />
•<br />
COLVIN'S CORNER<br />
AMERICAN BONANZA SOCIETY, APRIL <strong>1993</strong><br />
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