Comments requested on Lyc. O320-H2D (C172M)
ADSavarese
Brian Mellor wrote:
>
> (This message posted to rec.aviation.marketplace, rec.aviation.misc)
>
> I am thinking about buying a 1979 C172, with the above engine. I am told
> that they are NOT good engines - need additives every 50 hours, and are
> prone to bits breaking, e.g. cam followers.
>
> Anyone have any real experience with these engines (good or bad)?
>
> Would appreciate any info. Brian Mellor
Try contacting the Cessna Pilots Association at 1-805-922-2580, or by
FAX at 1-805-922-7249. Their technical folks are excellent and will
give you an unbiased and thorough technical explanation of the "H"
engine.
Hope this helps.
ADSavarese
C172 N9859V AKH
Gastonia, NC
a...@vnet.net
Brian Mellor
Anthony Steller
Yes everything you have heard is true. It is a bear to work on, most people
I know have abandoned
that engine in favor of something else. The camshaft is one of the few
weaknesses of Lyc engines
that are otherwise perhaps the best engines in the industry. The camshaft
is on top. The camlobes are
very small and when you shut down the oil drains off the cam. so when you
start again you get metal to metal contact cousing the failure of the
camfollowers that are hardened steel. The H series was by far the worst.
good luck and best wishes.
Tony Steller CP MEL SES. CFI A&P. GI.
Brian Mellor <br...@aviation.demon.co.uk> wrote in article
<022cada8$6e25b280$b945...@aviation.aviation.demon.co.uk>...
BJ Nash
Definately old info, as was the case when they first came out 20 years
ago. I ran my 172 to 2863 SMOH before I sold it and have another with
2200 on it SMOH. We will use them in our Cessna 170B conversion
becuase they are cheap and bullet-proof. For more info, send email to
lyc...@pdsig.com for a auto response email file.. bill nash
(Our aviation directory is also available by email:
inf...@pdsig.com).
On Mon, 14 Jul 1997 07:34:36 GMT, "Brian Mellor"
<br...@aviation.demon.co.uk> wrote:
>>(This message posted to rec.aviation.marketplace, rec.aviation.misc)
>>
>>I am thinking about buying a 1979 C172, with the above engine. I am told
>>that they are NOT good engines - need additives every 50 hours, and are
>>prone to bits breaking, e.g. cam followers.
>>
>>Anyone have any real experience with these engines (good or bad)?
>>
>>Would appreciate any info. Brian Mellor
AIRCRAFT REMANUFACTURING
1291 E.Vista Way, #150
VISTA, CA. 92084 (760) 749 0239 FAX: 749 6384
Aviation Parts Sales Directory: Inf...@pdsig.com
ADSavarese
This is a multi-part message in MIME format.
--------------480C5CBFF39
Content-Type: text/plain; charset=us-ascii
Content-Transfer-Encoding: 7bit
Brian Mellor wrote:
>
> (This message posted to rec.aviation.marketplace, rec.aviation.misc)
>
> I am thinking about buying a 1979 C172, with the above engine. I am told
> that they are NOT good engines - need additives every 50 hours, and are
> prone to bits breaking, e.g. cam followers.
>
> Anyone have any real experience with these engines (good or bad)?
>
> Would appreciate any info. Brian Mellor
Brian,
Attached is another piece of info I found related to Cessna 172 engines.
The "H" engines are discussed on pages 5 and 6. I found it interesting
reading. Hope it helps.
ADSavarese
C172 N9859V AKH
Gastonia, NC
a...@vnet.net
--------------480C5CBFF39
Content-Type: text/plain; charset=us-ascii; name="172ENG2.TXT"
Content-Transfer-Encoding: 7bit
Content-Disposition: inline; filename="172ENG2.TXT"
Copyright (C) 1994 Gregory R. Travis
The author makes absolutely no claims regarding the accuracy of the material presented herein.
The author reserves the right to revise this material as the real facts come in...
------------------------------------
Nomenclatura
Lycoming's specific convention for post-WWII aircraft piston engine designation is as follows. Note that this convention is fairly standard and applicable to many other manufacturers.
C-D-M
Where:
C Letters indicating the engine's configuration:
I Fuel injected
O Opposed type (pancake-style)
X X-type engine
R Radial type engine
G Engine is geared
T[S] Engine is turbocharged
S Engine is supercharged, EXCEPT for most Continental TURBOcharged engines. These
are designated "TS". See below.
L Engine is liquid-cooled or left-turning (ugh!)
A Engine is designed for aerobatics (DRY SUMP)
AE Engine is designed for aerobatics (WET SUMP)
M Engine is designed for unmanned drone (UNCERTIFIED)
H Engine is designed for helicopter installation
V Engine is designed to have the crankshaft in the vertical, not horizontal, plane. Usually implies "H"
D The engine's displacement in cubic inches.
M The manufacturer's "data" - often indicating what types of accessories or engine revisions.
Regarding "L" - it seems that the convention is that if the L is the first thing in the configuration list, then the engine is left-turning. If it's the LAST, then the engine is liquid-cooled.
Lycoming and Continental differ in the "manufacturer's data" portion of the engine designation. For example, a typical Lycoming designation looks like (from the Lycoming Overhaul manual):
Example:
TIO-541-E1B4D
Where:
TIO - The prefix as described above.
541 - The engine's cubic inch displacement, as described
above. A 1 at the end indicates an integral
accessory drive (e.g. TIO-541) except for the
76 series engines (see below).
E - Power section and power rating for the displacement
1 - Nose section (provisions for a prop governor, hollow/solid crankshaft, prop governor location)
B - Accessory section (fuel pump type, accy pad(s), etc.)
4 - Counterweight application (if applicable, see the power section to determine this)
D - Dual magneto (if applicable)
Continental does not try and describe the engine's configuration or options in the engine's designation. Considering how confusing Lycoming's designations can become, this may not be the worst idea!
Instead, Continental lists only what Lycoming considers the "power" section with a 1 or 2 letter designator. Information about what types of accessories, counterweights, revisions, etc. are numerically encoded (and the encoding must be looked up!) on the engine's dataplate.
Example:
IO-360-K
Pancake-style (opposed) engine of 360 cubic inches displacement and fuel injection. Power section
"K"
Glossary:
{Turbo/Super} charging
A method of compressing ambient air via a pump. This pump is almost always a rotating compressor although other types have been used (i.e. a Roots blower). The compressed
air is often used to boost engine output, to pressurize an aircraft's cabin, and to provide pressurized air to magnetos (to prevent high-altitude arcing).
The different names refer to the power source for the compressor. A TURBOcharger is driven by exhaust gas from the engine. A SUPERcharger is driven by a belt or gear directly from the engine's crankshaft.
Continental, confusingly, calls turbocharging "TurboSuper" charging. Hence turbocharged Continental engines typically look like TSIO-XXX-X[X]. I do not know of any recent
Continental engines which incorporate a supercharger - all their boosted engines are turbocharged as far as I know
Lycoming has made both turbo and supercharged engines within the last thirty years. You will not see a TS in a Lycoming engine, instead you will see either:
TIO-540 (turbocharged 540) -or-
IGSO-540 (supercharged 540)
for example.
All supercharged Lycoming engines are also geared. Turbocharged Lycomings are produced in geared and direct-drive models.
"Turbo"normalizing
The turbo-(or super!)charger is limited to producing no more than 29.92 inches (typically) of "pressure" on a turbonormalized engine. Turbonormalizing is used to recover lost power due to altitude gain but is not used to boost the sea level power of an engine. Virtually all after- market (and quite a few factory-installed) turbochargers are turbonormalized. This allows ordinary "off the shelf" engines to be used.
A turbonormalized engine may or may not have a "T" in its designation. For example, the turbonormalizing on the Cessna T182 was performed by the Cessna factory, not Lycoming.
The engine in the T182 is an O-540, not a TO-540.
Geared:
The engine's crankshaft turns at a faster rate than the propeller. Used to boost engine power output, which increases with RPM (within limits) without sacrificing propeller efficiency, which decreases with RPM.
Pancake:
Term used by many gearheads to describe opposed engines.
==========================================================================
Cessna 172s were manufactured with the following engines (in rough chronological order):
Engine Make & Model Power TBO Fuel Yrs C172 Models
-------------------- ----- ------ ------ --- -----------
Continental O-300-A/C/D 145HP 1800Hr 80Oct 1956-67 <Blank>/A->H/T-41A
Continental GO-300-A/C/E 175HP 1200Hr 80Oct 1958-63 C175&Powermatic
Continental IO-360-D 210HP 1500Hr 100Oct 1967-81 R172E&T-41B/C/D
Lycoming O-320-E2D 150HP 2000Hr 80Oct 1968-76 I->M
Lycoming O-320-H2AD 160HP 2000Hr 100Oct 1977-80 N
Continental IO-360-K 195HP 1500Hr 100Oct 1977-78 R172K
Continental IO-360-KB 195HP 2000Hr 100Oct 1979-81 R172K
Lycoming O-360-F1A6 180HP 2000Hr 100Oct 1980-85 C-172RG (Cutlass RG)
Lycoming O-320-D2J 160HP 2000Hr 100Oct 1981-86 P
Lycoming O-360-A4N 180HP 2000Hr 100Oct 1983-86 Q (Cutlass)
Engine breakdown by FIXED GEAR, FIXED PROP model:
(Blank) or models A through H: 145HP, 6 Cyl, 80 Oct Continental O-300-A/C/D
Models I though M: 150HP, 4 Cyl, 80 Oct Lycoming O-320-E
Model N: 160HP, 4 Cyl, 100 Oct Lycoming O-320-H
Model P: 160HP, 4 Cyl, 100 Oct Lycoming O-320-D
Model Q: 180HP, 4 Cyl, 100 Oct Lycoming O-360-A
Military T-41A 145HP, 6 Cyl, 80 Oct Continental O-300-D***
Military T-41C 210HP, 6 Cyl, 100 Oct Continental IO-360-D***
Model 175 A&B: 175HP, 6 Cyl, 80 Oct Continental GO-300-A/C*
Engine breakdown by FIXED GEAR, CONSTANT SPEED PROP model:
Model R172E/H/J: 210HP, 6 Cyl, 100 Oct Continental IO-360-D**
Model R172K: 195HP, 6 Cyl, 100 Oct Continental IO-360-K/KB**
Military T-41B & D 210HP, 6 Cyl, 100 Oct Continental IO-360-D***
Model 175 C & P172D (Powermatic)175HP, 6 Cyl, 80 Oct Continental GO-300-D*
Engine breakdown by RETRACTABLE GEAR, CONSTANT SPEED PROP model:
Model R172RG: 180HP, 4 Cyl, 100 Oct Lycoming O-360-F1A6
===========================================================================
Notes:
* Cessna experienced trouble with the geared engines in the model 175 (also known as the Skylark) and, in 1963, changed the designation to P172D (also known as the Powermatic) in an attempt to remove the
stigma of the engine. The 175 has always been, basically, a 172 airframe with some changes. The P172D is even more so: it's a straight 172D airframe. For more information, see note 1 below.
** The "R" designation (as in R172) is problematic. It sometimes refers to aircraft derived from Reims designs, as in the "Reims Rocket" AKA the R172E AKA FR172E, Models derived from the "Reims Rocket"
included the R172E/R172H/R172I/R172J which were all 210HP, and the R172K which was derated to 195HP. Reims was Cessna's French subsidiary (now independent). The "R" designation is also applied to the R172RG, for no apparent reason.
The R172H/R172I/R172J were never produced in any quantity. The most numerous example of all is the 195HP R172K which is known by the marketing name "Hawk XP"
*** The T-41-B/C/D models are just militarized R172E airframes (although the T-41C has a fixed-pitch prop).
The T-41A is a two-seat militarized version of the original (145HP) C172. It was a training plane designed to lower the cost of "weeding out" those who just didn't have what it takes to be a pilot. The Air Force decided that this little bit of learning was too expensive in the T-37 (Cessna twin jet trainer) and sought out the lower-cost T-41A as a device to accomplish that goal.
The T-41B was produced for the Army, to train its fixed-wing pilots and for other (liaison/scouting) duties. It differs from the standard 172 airframe in that it has no baggage door, has a strengthened firewall, jettisonable doors, and long-range (52 gallon) fuel tanks.
The T-41C was produced, again, for the Air Force and is almost identical to the T-41B except that it has a fixed-pitch prop. It was used as a cadet motivational (pilot indoctrination) tool. Many T-41Cs were later modified to T-41D standards by the addition of a constant-speed prop.
The T-41D most resembles the T-41B. It, too, has a constant-speed prop. It was intended as an "export" T-41 and one that was not just to be used as a trainer (options included rocket hardpoints!).
**** There are no "J" or "O" model 172s. C172J was intended to be the designation of what is now known as the Cessna 177 (Cardinal). When the designation changed to C177, the "J" was retired.
Comments:
1. The geared Continental engines used in the C175 Skylark and P172D Powermatic have a history of upper-end (cylinder) distress ostensibily caused by the higher RPMs. It is supposedly becoming very difficult to overhaul these engines as parts are in short supply, especially for the gearboxes. Major $$$$$ for gearbox parts.
2. There is also doubt about about continued ability to economically overhaul "plain" Continental O-300s. Like their smaller O-200 brothers, the low-compression/output Continentals suffer badly from valve sticking when run on 100 Octane fuel.
3. Cessna switched to the Lycoming O-320-E2D IN THE 172 after it became apparent that these engines were NOT going to be powerful enough (even by Cessna's standards!) for the C177 Cardinal. Unfortunately, Cessna had pre-bought literally thousands of Lycoming O-320-E2Ds in anticipation of using them in the C177 (which they also anticipated would replace the C172 line). Thus they were forced" to find an alternate use for the -E2Ds; they put them in 172 airframes, creating the C172I.
Cessna test pilots complained that the 4-cylinder Lycoming was not as "smooth" as the 6-cylinder Continental engines. Nevertheless, they liked the 2000 hour TBO and ability to run at higher RPMs (up to 2700 continuous) at altitude.
The O-320-E2D powered 172s are considered very desirable. The engine is one of the most reliable Lycoming has produced and has few problems except that it suffers when run on 100 Octane fuel.
4. The 195HP Continental IO-360 powered C172s (C172XP) use a derated version of the IO-360-D engine. This deration was necessary to meet certain noise requirements, to keep the plane in the "low performance" category, and to keep from competing too much with the 230HP C182 line. It is possible to convert a 195HP C172 into a 210HP C172 at overhaul time.
5. The 1973 172 model M introduced the "Camber-Lift" wing and numerous aerodynamic improvements. The M and subsequent airframes are thus considered the "most desirable" with the overwhelming bias going to the M and N airframes. The P airframe is not as desirable as it was weakened at the doorposts and other areas in an attempt to reduce weight and increase interior room. The P airframe is also restricted to 30 degrees of flaps (as opposed to 40 in all other models). This reduction in flap travel
allowed a 100LBS increase in gross weight (up to 2400LBS). This gross weight increase is available as a retrofit to the N airframe via an STC which involves some paperwork and a physical restriction against
more than 30 degrees of flap.
6. The -D2J version of the Lycoming O-320 was introduced to replace the -H2AD series. It is not considered AS reliable as the -E2D for no apparent reason. It occasionally suffers from valve sticking.
Switching to the O-320-D2J engine, in the 1981 model year, was an attempt by Cessna to revive lagging C172 sales. They believed that these sales lagged because of the growing reputation of the O-320-H2AD
engine (partially true) and that, by "introducing" what is, essentially, a retrograde design (the -D2J engine) that they could recover their lost market share. Alas, this was not to be as the early eighties
were actually the beginning of the entire industry's decline. This development, at least, could not be blamed on the O-320-H2AD!
Note that this was not the first, nor the last time, that Cessna had felt it necessary to "shake off" a bad reputation. Several examples of that come to mind including the Skylark->Powermatic name change and the Cardinal->Cardinal "Classic" name change.
************************************************************************
The O-320-H2AD story:
There is a tremendous amount of hype surrounding the O-320-H2AD engine, some of it valid, and some of it pure parroting of what one has heard from others.
For reasons unknown, Aviation Consumer seems to be on a vendetta against the engine, although I've noticed that even they seem to be mellowing on the issue. For example, their latest "Used Plane
Buyer's Guide" states that it's a tossup between an O-300 powered 172 and a O-320-H2AD powered one, at this point. They also, reluctantly, concede that the engine has proven reliable in service.
In the mid 1970s, AVCO Lycoming purchased several million dollars worth of automated milling machinery. Operational considerations of this equipment, as well as a desire to improve both the production AND serviceablity of their engines led to a major crankcase and head redesign.
Engines resulting from this redesign were designated "76" series engines. Some of them still have "76" stamped on the valve covers. All of them have "76" as part of the engine serial number (except
for the O-360-E series, which have 77 as part of the serial number. Nevertheless, the O-360-E engines are generally called "76" series engines).
Lycoming made a deal with Cessna to purchase the O-320-H2AD variant as well as with Piper to use the {L}{T}O-360-E engines (in the Piper Seminole). The "new design" engines were supposed to be much cheaper to build and buy, as well as being easier for a mechanic to service. For 172 applications, the O-320-H2AD also offered 10 more horsepower as well as the ability to burn 100 octane gasoline.
Other variants of the -H engine are the -H1AD, H1BD, H2BD, and H3AD.
Current "76" series engines include:
O-320-H and {T}O-360-E series engines. Lycoming considers these engines different enough from all their other engines that they publish completely separate ("76" series) engine operating handbooks for them. As far as I know, these engines are still in PRODUCTION (i.e. one can buy one NEW).
Practically, the "76" series differ in that they:
1. Have removable (non-mushroom style) tappets
2. Have no separate accessory case - the case is cast with the block
3. Use automotive-style "canoe" rockers on studs, as opposed to rocker shafts and arms.
4. All use Bendix dual magnetos as opposed to two separate mags.
Points 1 & 2 are shared with other Lycoming engines, in particular the 541 series. They're also a major feature of MOST Continental engines.
Point 4 is common in many Lycomings.
Point 3 is a characteristic of the 76 series only.
Unfortunately, the early life of the engines was not rosy. Both the engines and the magnetos suffered from some serious teething problems.
Briefly, serious early problems with the "76" series engines included:
Crankshaft assembly. The gear retaining design was inadequate. An AD came out necessitating replacement of the crankshaft.
Oil pump problems. This necessitated replacement of much of the oil pump (note this problem has afflicted MANY Lycomings)
Valve rocker, retainment, and spring seat problems.
Virtually all of these problems were taken care of early on and later engines were manufactured with the fixes in place. They can be considered evolutionary teething pains, as might happen to any new design.
Then, the big one, problems with camshaft and tappet spalling began to occur:
One theory:
The "76" series was introduced just as GA began to decline. The result was a lot of aircraft spending a lot less time in the air. Camshafts dried out and tappets spalled. Especially on the "76" series where, in order to allow removable tappets, tappet face diameter was reduced.
Lycoming worked on several fixes to this, including progressively larger and larger tappets. The final fix is the so-called "T" mod, which was incorporated in all 1980 and later engines during production as well as being a field retrofit. This mod improves top end lubrication and involves even larger tappets.
(As an aside: Apparently both Lycoming and Cessna had difficulty reproducing the camshaft failures in-house. I imagine that's because they probably RAN the engines, looking for failure, as opposed to letting them sit around)
The FAA went ahead and promulgated an AD as well, requiring use of the Lycoming TCP oil additive or a lubricating oil containing the additive (such as AeroShell 15W-50) in ALL "76" series engines. This additive is highly effective and the key to ensuring that your O-320-H2AD delivers a long and productive life.
-------------------------------------------------------------------------
Questions one might ask about the O-320-H2AD:
1. Is it a safe engine?
Absolutely. The O-320-H and O-360-E engines are certificated aircraft engines with a long history of very reliable operation, often in commercial (pipeline-patrol) or training role.
Operationally, there are several engines that come to mind that I consider more "dangerous". For instance, I might feel a bit uneasy flying behind a non-K model, non-VAR crank Continental TSIO-360 at
night. The same thing goes for the overstressed TSIO-520-BE used in the early Piper Malibus.
Anecdote time:
One flying school down in Florida ran their O-320-H2AD to 3400 hours before they overhauled it. I have personally witnessed several O-320-H2AD engines with over 6,000 hours (total, not SMOH) of trouble-free flying time (pipeline patrol).
In terms of trouble, there are many, many other engines that are likely to give more trouble. Just about ANY geared engine, for example. Most turbocharged engines, if not operated properly, for another.
Yet the HYPE behind the O-320-H2AD is (arguably) much higher.
2. Why don't I hear about problems with the {L}{T}O-360-E engines?
Beats me. It is, essentially, the same engine as the O-320-H2AD, although the displacement is larger and it has provisions for a constant speed prop.
All of the problems attributed to the O-320-H engines are present in the {L}{T}O-360-E engines, including the AD for TCP additive. Yet no one cautions (at least not usually) against buying a Seminole because of the ENGINES. And there is no a rash of SDRs about the Seminole's engines. We also don't hear about Seminoles losing engines and augering in.
Why? See the next section...
3. What about continued SDRs on tappet spalling in O-320-H engines?
The O-320-H engine, with T mod and additive, continues to generate SDRs detailing tappet spalling problems in numbers slightly ahead of other Lycoming O-320 engines.
My thoughts (which are worth what you paid) on this are twofold:
a. There are not enough to statistically demonstrate a trend, therefore the conclusions are invalid.
b. They're finding them BECAUSE people are looking for them:
Removing tappets and inspecting same and camlobes is fairly trivial in "76" series engines. Unlike most other Lycoming designs, it does not require cylinder removal. Add to this that people REGULARLY inspect their cams on these engines both during use and during a prebuy, along with the predisposition for mechanics to find such problems and it's possible to account for the "blip."
If you're a mechanic, and you find, say, a spalled O-320-E2D, you might not write up an SDR. But say you find a spalled O-320-H2AD? You'll probably want to add it to the statistical database. Thus mechanics are more INCLINED to report spalled O-320-H2AD engines. Just my opinion, of course.
4. What about sudden in-flight stoppage (i.e catastrophic engine failure)?
This was a concern before the AD came out on the crankshaft gears (1978 I believe). The post-AD crank, indeed the whole bottom-end, of the -H2AD is as stout as any other O-320 series engine. As long
as the engine was manufactured after the cranks were changed, or has had its crank changed (as required by law) there is no problem.
Tappet spalling, while still a potential problem (see below), does not result in sudden engine failure unless the spalling has gone on so long that metal clogs vital oil passages. Note that this is possible on just about ANY engine, especially Lycomings.
4a. But, what about the dual magnetos?
They are, electrically, two separate magnetos. However, it is possible for the drive gear to fail, which would result in sudden engine stoppage. Some people feel uncomfortable about this. Note that the same condition can occur INSIDE a "traditional" engine's accessory case, obviating the advantage of two physically separate magnetos.
Note that the "76" series is also not the only engine to incorporate dual mags, they are (were, actually, until Continental bought the Bendix magneto business) quite popular in Lycoming engines.
When looking at an engine with the dual mag (any engine), you should be wary of the 2000 series. The 3000 series is MUCH improved over the 2000. The equivalent 3000 series mags can directly replace an older 2000 series. If you find one with a 2000 series, think about replacing it with a 3000 series (rebuilt 3000 series mags run about $600-700 with a core refund).
5. Is spalling still a problem?
Yes and no. One must understand that, eventually, ALL Lycoming engines will spall. Therefore, one should be aware of several ways of avoiding it as long as possible (hopefully beyond TBO!):
1. Use Lycoming's additive or AeroShell 15W-50 in ALL Lycoming engines.
2. Pre-heat ALL Lycoming engines whenever the temperature is below freezing.
3. FLY all Lycoming engines often, preferably at least once a week.
4. Change oil often. I recommend every 25 hours.
5. INSPECT the tappets regularly - every 500 hours. Removing and inspecting the tappets on a "76" engine is trivial (about an hour of shop time total). Inspection of the tappets should be considered a mandatory prebuy step.
If you follow the above advice, you can seriously limit your chances of having camshaft troubles. I'll go even farther and say that, if you have a T-modded O-320-H2AD engine and if you follow the above advice, your chances of making it to TBO and beyond are extremely good.
Likewise, if you take an O-320-H2AD, leave it in a barn and come out in -30 degree weather the NEXT YEAR and start it, well, I can pretty much guarantee that you've just turned the engine into garbage.
Probably more than you ever wanted to know, again,
greg
--------------480C5CBFF39--
Ryan R. Healy
Brian Mellor wrote:
> I am thinking about buying a 1979 C172, with the above engine. I am told
> that they are NOT good engines - need additives every 50 hours, and are
> prone to bits breaking, e.g. cam followers.
>
> Anyone have any real experience with these engines (good or bad)?
Brian...
You are right, the "H" series Lycoming engines in Skyhawks were not the
best engines in the world. They are notorious for camshaft problems
primarily because of poor lubrication. Actually, the camshaft was just
a bad one in general on that engine and I suppose that an argument could
be made that it was put in a bad spot as well.
Fortunately, there were some mods available for that engine where you
could install an improved camshaft with lobes of a superior design, and
that solved the problems for the most part. A lot of H2D owners opted to
put the D2J engine in Skyhawks at overhaul time. Someone owns the STC to
that mod, and it is just a matter of obtaining the STC and dropping the
improved D2J engine in. No change in performance though. Skyhawks that
have had this done usually sport two oil access doors...one at the top
of the cowling (which is no longer used) where the H2D oil
filler/dipstick was, and one on the right side for the D2J's oil
filler/dipstick.
I wouldn't turn down a perfectly good Skyhawk just because it has the
H2D engine on it. A lot of mechanics think that the H2D engine is
superior to the D2J in terms of working on the engine. The camshaft
problems can be eliminated with the camshaft retrofit. If you still are
really uncomfortable with having the H2D engine, wait until overhaul
time, get the STC for the D2J, and the problem is solved.
One other thing as I am thinking about this engine thing....the H2D
engines have quite a problem with moisture corrosion. Just like any
engine, they need to be run regularly to eliminate as much engine
moisture as possible, but the H2D engine is famous for corrosion
problems. The easiest way of solving that dilemma is to just operate
the aircraft regularly. The majority of corrosion problems result from
disuse rather than excessive use.
--
Blue Skies,
***********************************************************
* Ryan R. Healy, C-ASMEL-I, CFI-ASMEL-I, AGI, IGI *
* E-Mail: mailto:rhea...@sprynet.com *
* Web Page: http://home.sprynet.com/sprynet/rhealy707 *
***********************************************************
bill...@geocities.com
Brian Mellor wrote:
>
> (This message posted to rec.aviation.marketplace, rec.aviation.misc)
>
> that they are NOT good engines - need additives every 50 hours, and are
> prone to bits breaking, e.g. cam followers.
>
> Anyone have any real experience with these engines (good or bad)?
In late 1978 I purchased a brand new Cessna 172N with 0320-H2AD engine.
Shortly after purchase, I sorta forget details - the valve train was
re-worked per an AD. The reqs of the AD specified that a "mouse milk"
additive was required at each oil change thereafter. You can easily
find that requirement.
I owned that Cessna for about 7 years and put over 1300 hours on its
engine without any problems, whatsoever. It was the first year that
Cessna upgraded its engine from 150 to 160 HP. In spite of all the
horror stories about the infamous H2AD engine - most are not true.
Would I buy another late 70's Cessna?? Not on your life!!
Not because of the engine - but rather the filiform corrosion problems
that plagued all late model 70's Cesssna's. It was a dumb cost saving
technique that Cessna made to go to a wash primer.
Hence, most Cessna's during the latter 70's, in humid conditions - were
laden with filiform corrosion. I've seen models including 310's that
were affected.. Whats filiform corrosion?? Well, you can readidly see
it cause it looks like a cancer of worms spreading under the paint.
I imagine most late 70's Cessna's are now repainted.
However, I remember very well - flying into Long Beach & meeting with
the Cessna zone representative just one year after I bought that
turkey.. Just a few days after the warranty expired.. He laughed at me
& was the rudest asshole one could encounter. For that reason - I'll
never again own a Cessna. Not because of the H2AD engine - but
corrosion.
If you want quality - buy a Beechcraft.