Jabiru Engine mod

[The Agent]

JABIRU AIRCRAFT PTY LTD
P.O. Box 5186 Phone: +61 7 4155 1778
Bundaberg West Fax: +61 7 4155 2669
Queensland, Australia. Email: info@jabiru.net.au
SERVICE BULLETIN: JSB 013-1
Issue: 1
Date: 8th August 2006
Subject: Jabiru 2200 Engine Rocker Chamber Vent
1 Table of Contents
1 TABLE OF CONTENTS................... 1
2 APPLICABILITY.............................. 1
3 BACKGROUND ................................ 2
4 RECOMMENDATIONS:.................. 3
4.1 MODIFICATION PER SECTION 6:... 3
4.2 OPERATIONS UNTIL MODIFIED:... 3
4.3 OPERATIONS AFTER MODIFIED: .. 3
5 COMPLIANCE:................................. 3
6 PROCEDURE – VENT ROCKER CAVITIES............................................................................................................... 3
7 AIRWORTHINESS NOTE:.............. 5
2 Applicability
Jabiru 2200 engines (all models) in the following Serial Number ranges:
2200A – S/No. 2068 – 2439
2200B – S/No. 2 – 28
Jabiru Service Bulletin: Jabiru 2200 Engine Rocker Chamber Vent
JSB 013-1 8th August 2006
JSB013-1.doc Page 2 of 5
3 Background
The upper valve train of Jabiru engines is lubricated by means of a low-pressure feed which
supplies oil to the valve guides and rockers, then flows back into the sump via the pushrod
tubes.
In the engines listed above the flow of oil back into the sump can be reduced by internal airflow
and pressures inside the crankcase. This effect is magnified by a build up of negative pressure
inside the rocker cavity (as air is drawn out of the rocker cavity by the normal leakage past the
intake valve guide) and by the additional oil flow from the hydraulic lifters.
This restriction in the amount of oil flowing back into the sump leads to the rocker cavity filling
with oil. As the rocker cavity is at a high temperature (typically over 130° Celsius) the oil is
overheated, becoming very thin and gradually loosing it’s lubricating properties. This leads to
increased upper valve train wear (valve guides, rocker bushes etc) and elevated oil
consumption as the thin oil is sucked down the intake valve guides and burnt in the engine. In
some cases oil may also be found in the induction manifold.
This phenomenon varies from engine to engine due to differences in operating regimes,
different average oil levels in the sump, different engine vent outlet pipe positions and different
levels of blow-by past the piston rings. Jabiru 3300 and 5100 engines (including 3300 engines
with hydraulic lifters) do not suffer from this problem due to the larger airspace volumes in their
crankcases and oil sumps.
Drilling a small vent hole inside the rocker cavity removes the negative pressure inside the
rocker cavity and allows the oil to drain normally into the sump (Note that as the pressure inside
the cavities is generally less than ambient, air is sucked in through the vents – only negligible
amounts of oil flow out). The following Service Bulletin details the installation of the rocker
cavity vent and ways to manage oil consumption before and after the vent is added.
Jabiru Service Bulletin: Jabiru 2200 Engine Rocker Chamber Vent
JSB 013-1 8th August 2006
JSB013-1.doc Page 3 of 5
4 Recommendations:
4.1 Modification per Section 6:
Jabiru Aircraft recommend that all engines in the range noted be modified as detailed in Section
6 during their next scheduled 50-hourly maintenance.
Notes:
· it will take some time for the engine’s oil use to stabilise due to the new oil level operating
regime or the modification. Generally at least one hour of circuits will be required to
stabilise consumption by de-glazing the cylinder bores and burning clean the combustion
chamber, though it will vary from engine to engine.
· Some oil consumption is normal. The engine’s Instruction & Maintenance Manual provides
specifications for normal oil usage.
4.2 Operations Until Modified:
In the time between issue of this Service Bulletin and incorporation of the modification detailed
below, follow these guidelines:
a) Fill the oil sump no higher than the lower mark of the dipstick. Note that oil level is read
by screwing the dipstick fully in – just inserting the dipstick without screwing it fully in will
give an inaccurate oil reading and result in higher oil usage.
b) Check the position of the crankcase vent outlet to ensure that the crankcase vent is
being exposed to pressure equal or less than the air pressure inside the cowls. Venting
into the cowl space (as with factory Jabiru installations where the oil overflow bottle is
vented to cowl pressure) is acceptable, but installations where the vent line is exposed
to ram-air pressure or other elevated pressures should be modified accordingly.
c) Do not fill the sump above the lower mark before flying longer legs – the excess oil will
quickly be burnt or blown out the vent. Oil consumption when filled below the lower
mark should be monitored and known to be acceptable before carrying out flights of
over 3.5 hours duration.
4.3 Operations After Modified:
b) Continue to fill the oil sump no higher than the lower mark of the dipstick.
c) Oil consumption when filled below the lower mark should be monitored and known to be
acceptable before carrying out flights of over 3.5 hours duration.
5 Compliance:
· Jabiru Aircraft recommend changing oil level operating regimes immediately (Ref details
above).
· Jabiru Aircraft recommend modifying the engine in accordance with Section 6 below
during the engine’s next scheduled 50-hourly maintenance.
6 Procedure – Vent Rocker Cavities
Jabiru Service Bulletin: Jabiru 2200 Engine Rocker Chamber Vent
JSB 013-1 8th August 2006
JSB013-1.doc Page 4 of 5
i) With reference to the engine’s Instruction & Maintenance Manual, remove the aircraft
cowls and engine ram-air ducts.
ii) Remove the rocker covers from the engine.
iii) Locate the position shown in Figure 2 below and use a small centre punch to mark the
hole position.
iv) Using a 3/32” drill bit, drill a hole in the head as shown. The hole must angle upwards to
encourage oil to flow back into the rocker cavity instead of out into the engine bay.
Before drilling, coat the tip of the drill bit with grease to catch the aluminium shavings
from the hole. Drill in stages, cleaning and re-greasing the drill every second or two.
Ensure that no loose shavings escape into the rocker cavity.
v) Replace the rocker covers re-assemble the aircraft.
Figure 1. Vent Position – View Looking Parallel to Valves
Vent hole
located midway
between valves
at the top of the
rocker cavity.
Jabiru Service Bulletin: Jabiru 2200 Engine Rocker Chamber Vent
JSB 013-1 8th August 2006
JSB013-1.doc Page 5 of 5
Figure 2. Sectioned View of Head Assembly – Hole Shown.
7 Airworthiness Note:
Where required, work called for by this Bulletin must be carried out by authorised personnel
only. In Australia this generally means the original builder of an Experimental-category aircraft
(either RAAus or VH registered), an RAAus Level 2 holder for other RAAus aircraft or a
Licensed Aircraft Maintenance Engineer (LAME).
On completion of the work, the authorised person must note the completion of the actions
required by this bulletin in the aircraft’s maintenance logbook. As a minimum, this note should
refer to the completion of maintenance requirements of this Service Bulletin, indicate the date of
the work and the identity (including licence number where appropriate) of the person carrying
out the work.
Vent hole running upwards
from rocker cavity into
external finning. Note: hole
may be angled further
upwards if required.

[The Agent]

There are two drawimgs that I am unable to show so please look at the website to get these.

[Rudix]

Hi Agent !

Thanks for the info, will have a look to see if I need to do this.

Here is the link to the document from Jabiru with the drawings:

http://www.jabiru.net.au/news/technical ... B013-1.pdf

Safe flying,
Rudi

[Tjoek]

Hi Guys,

I am planning to fit Jabiru 85 hp in my Whisper kit. I have been cautioned about the Jabiru's reliability by a number of persons, but I am of opinion that these warnings are mainly based upon hear-say.

I would appreciate any views/advice from owners on the issue.

Thanks
Tjoek

[The Agent]

TJOEK MAKE SURE OF ONE THING AND ONE THING ONLY.


Make sure that enough air for cooling gets to the engine and have enough vent space for the hot air to get out.

Routing.

[Rudix]

Hi Guys,

I am planning to fit Jabiru 85 hp in my Whisper kit. I have been cautioned about the Jabiru's reliability by a number of persons, but I am of opinion that these warnings are mainly based upon hear-say.

I would appreciate any views/advice from owners on the issue.

Thanks
Tjoek

Hi Tjoek !

It is a lot of BS I know of 2200A's that have more than 2000 hours without a single problem ! Not many Ratax 2 strokes that can say that !

85HP for the same weight of a 582, much lower consumption, TBO's of up to 2000 hours (USA), 4 stoke "quietness", No melted pistons, having to change jets between the coast and GP, it is an easy choice for me.....

The older 1600 motors had some problems, mostly valve problems, the later 2200's, and the 2200A's or upgraded 2200's are a different story, the TBO's are getting higher and higher and remember they are flying in certified planes as well !

It is true that the ungeared Jabiru performs better in faster than slower planes...

So, I would rather have a Jabi than many others......

Regards,
Rudi

[Duck Rogers]

I have been cautioned about the Jabiru's reliability by a number of persons, but I am of opinion that these warnings are mainly based upon hear-say.

It's worse than hear-say. It's a downright lie!!

[Boet]

:D .....Mmmmmm........All this BS looks very time consuming and complicated. Much easier to gooi in a new 912S.












ROTAX rules!!

[Duck Rogers]

Boet..lyk my jy krap nou weer waar dit nie jeuk nie, nê :D :D

[ZULU1]

Jica..DWN from Ballito our Chairman, blew a hole in the piston at 120 hrs, (85 hp hydraulic lifters) he flew it on Unleaded as advised. Its now fixed but he has to fly on Avgas/Unleaded 50/50 now he said last night it flys like "marvellous" so Jabiru; like all engineers obviously fixed it.

HKS had many problems also in the early series engines, now they seem fixed. I am sure that Rotax did in the beginning with the 912.

eish Zulu1

[FAWGie]

There are several folk out there who sow seeds of doubt regarding the Jabiru engine....Before I bought my J400, I spoke to some of them and was seriously concerned.....

I did my homework...these stories are absoluterly rubbish....and founded by folk that have a personal axe to grind with Jabiru, etc......

The Jabiru engine product is well refined and flying in thousands of aircraft all around the world.....

It is my personal preference anyday over the Rotax and any other type (and I own aircraft with both types....)

[Tjoek]

Thanks guys. You confirmed it. Nothing wrong with the Jabiru. And its such a simple and clean installation.

What is the situation with Mogas vs Avgas on the Jabiru? Are there anyone out there that runs on Mogas?

[jabirusk]

I have only run my Jab on Avgas. I think to use anything else is asking for trouble. It was designed to run on Avgas so why mess with the thing??

[DieselFan]

What about on trikes? Price same as 582?

[ZULU1]

Eric at Cato Ridge has a Streak Shadow with a Jabiru in the back. He has many air vents feeding ram air into the motor. He watches the temps but seems to be very satisfied. Running Avgas will make the motor run cooler in any event but they do require plenty air. So somebody has to make the decision and put on a trike, trouble is Avgas is not cheap.

eish Zulu1