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MAINTENANCE MANUAL
BRP-Powertrain
Effectivity: 912 i Series
Edition 1/Rev. 0
12-20-00
page 9
January 01/2012
4) Checking the compression
General note
.
Special tools
To measure the compression pressure the following special tools and
equipment are necessary.
Instruction
Testing is carried out using the
differential pressure test procedure
.
Value
The maximum permissible pressure drop is 25 %, e.g. from 6 to 4.5 bar
(600 kPa to 450 kPa) (
D
).
If the pressure loss is less than 25% then the valve seats and piston rings
are working properly. The spark plug has to be installed according to
chapt. 12-20-00 section:
.
If the value is over 25% inspection, repair or overhaul must be carried out
in accordance with the BRP-Powertrain instructions for continued airwor-
thiness.
- Detailed inspection of affected engine components.
WARNUNG
WARNING
Risk of electric shock!
Ignition “
OFF
“ and system grounded!
Part number
Description
n.a.
Compressed air approx. 6 bar (600 kPa).
n.a.
2 pressure gauges.
n.a.
Orifice jet*, of 1mm (0.04 in) inner diameter and 3 mm (0.12 in)
length.
* or equivalent e.g. orifice diameter 0.040 in., long 0.0250 in.,
60° degree approach angle according to AC43.13, latest issue.
n.a.
Adapter to spark plug thread.
n.a.
Connect line.
Step
Procedure
1
Operate the engine until the temperatures have stabilized for a period of 5 min
(engine oil temperature between 50 to 70 °C (122 - 160 °F).
2
Starting with cylinder head 1 move piston to TDC position.
3
Remove the upper spark plugs. Prevent dirt or other foreigner particles from
penetrating the engine (
A
).
4
Screw adaptor (1) into the spark plug thread and connect up the two pressure
gauges (2) with the orifice jet (3) between them (
B
).
5
Now put constant pressure, between 5.5-6 bar (550-600 kPa) on the line and
take readings at pressure gauge (
C
).
6
Repeat this proceeding at all 4 cylinder heads.
Summary of Contents for 912 iS Sport
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