1.03.004 Checking Engine Cylinder Compression

This Policy is complete waiting on Field Service, Engineering, and EHSS approval.

Purpose

The purpose of this procedure is to establish the minimum requirements for checking and recording the engine cylinder compression on spark ignited engines as laid out in this procedure to aid in troubleshooting weak or low power from possible low engine power.

Testing the engine compression on spark ignited engines is not difficult but needs to be done correctly. Why is the engine compression test important? Compression test of the engine cylinders will indicate the mechanical condition and/or sealing effectiveness of the piston rings or cylinder head valves, an engine compression test is the only way to ascertain this information. This can also help in troubleshooting and the diagnose of random misfires of the engine.

The idea behind the engine compression test is to find out if any one engine cylinder is not contributing 100% of its power to the overall engine output.

Procedure

This procedure applies to Flogistix skids equipped with spark ignited engine drive units that are currently in service in the Field, Test Loop, at a Repair Shop, or in Storage Yards. Flogistix Service Technicians will perform the procedure of checking engine cylinder compression as outlined in this procedure. This procedure will be performed during scheduled preventative maintenance, or when trying to diagnose low engine power, low cylinder exhaust temperature, or aiding in the decision of replacement of engines with high engine hours.

Before any work is performed a JSA needs to be done according to Flogistix procedure along with any Customer requirements before any work is started.

Checking Cylinder Compression.

With the engine stopped and not running:

There are two types of compression test the first is the 'Dry' compression test and the second is the 'Wet' compression test.

• • It is important to understand the correct individual cylinder numbers by the model type of the engine.

  • The engine needs to be warm, do not run a compression test on a cold engine

• The fuel system has to be disabled so no fuel is able to vent to atmosphere while cranking or testing of the engine

• The ignition system has to be disabled so there are no open sparks

Dry Compression Test

1. Remove all sparkplugs from every engine cylinder, if reusing sparkplugs keep sparkplugs in order so they can reinstalled back in the original cylinder they came out of

2. Thread the engine compression gauge into the sparkplug hole starting at the number one cylinder, Hand tighten the compression gauge into the sparkplug hole only!

3. Crank the engine over using the engine starter. Make sure the cranking RPM is equivalent to the cranking RPM when starting the engine

4. Once the needle on the compression gauge stops climbing discontinue cranking the engine.

5. Record this compression reading with the cylinder number

6. Now repeat steps 2 thru 5 on the remaining engine cylinders

Interpeting Compression Results

The individual cylinder compression readings of each engine cylinder should not vary more than 15%. The following steps will show how to calculate this.

Using a calculator multiply the highest compression reading that you recorded by.15

For example number 4 cylinder of the engine gave you the highest compression reading that was recorded of 170 psig. put 170 into the calculator and multiply X .15 which comes to 25.5 rounded off to 26 psig.

The next step is to subtract the 26 from 170 which was the highest compression reading of the engine which gives a number of 144 psig.

So then 144 psig should be the lowest allowed compression reading that any one of the rest of the engine cylinders can have. Any compression reading below this can cause a miss fire or low horsepower of the engine.

To help this make more sense look at the compression readings of the example below of a 6 cylinder engine

Cylinder #1 175 psig

Cylinder #2 170 psig

Cylinder #3 175 psig

Cylinder #4 155 psig

Cylinder #5 160 psig

Cylinder #6 170 psig

Now put 175 into the calculator and multiply by .15. This equals 26.25 round this out to 26. Now subtract 26 from the highest compression reading of 175 psig equals 149 psig.

The lowest acceptable compression reading would be 149 psig. The lowest compression reading on the sample above was 155 psig which is an acceptable compression reading.

Any compression reading below the acceptable limits using this formula a wet compression test should be performed.

Wet Compression Test

By performing a Wet compression test this will find out if the low compression on a cylinder(s) is due to a bad cylinder head or bad cylinder compression rings.

This involves adding a small amount of oil to the cylinders with the low compression results then repeating steps #2 thru #5 of the Dry compression Test. The results obtained from the Wet Compression test will help determine if the low compression cylinders from the Dry Compression test is caused by worn piston rings or worn cylinder head valves leaking by.

1. Add a small amount of engine oil to the cylinder that recorded the low compression reading in the Dry compression test. **The amount of oil should be about 1 to 2 tablespoons for the size engines Flogistix is using.

2. Thread the engine compression gauge into the sparkplug hole starting at the number one cylinder, Hand tighten the compression gauge into the sparkplug hole only!

3. Crank the engine over using the engine starter. Make sure the cranking RPM is equivalent to the cranking RPM when starting the engine

4. Once the needle on the compression gauge stops climbing discontinue cranking the engine.

5. Record this compression reading with the cylinder number

There should one of two results, either the compression value will go up or it will stay the same.

Case 1: The compression value increased. This indicates that the piston compression rings are worn out thus the problem is in the bottom end (cylinders) of the engine. Here is why the engine oil helped the piston rings seal better, thus bringing up the compression value almost back to the other higher compression cylinders.

Case 2: The compression value stayed the same. This confirms that the problem is in the cylinder head valves. If the cylinder head valves and their seats are worn out due to valve recession, bent, broken, or burnt no amount of engine oil is going to help seal the compression of the cylinder within the cylinder chamber. If the compression value that is being tested did not go up after the engine oil was added then this is a determining factor that the cylinder head valves have damage and the cylinder head will need to be replaced. If the compression value does not increase the Flogistix Area Manager needs to be notified.will

After the previous steps have been completed with the cylinder compression being acceptable by the guidelines listed in the previous steps, the engine can be deemed acceptable to be continued to run.

Install the sparkplugs, if installing on GM 5.7 install according to policy 1.3.11 GM 5.7 (350) Sparkplugs Installing/removing

If installing sparkplugs on engine other than the GM 5.7 install according to that engines guidlines.

Responsibilities

Management - Management is responsible for implementing, supporting, and enforcing the requirements of this procedure to their respective locations/area.

EHSS - Responsible to assist in the implementation of this procedure and to review for effectiveness.

Employees, Contractors, Vendors, ETC. - Are responsible to follow the follow the requirements outlined in this procedure and ask for assistance

Scope

This procedure applies to all spark ignited engines and is applicable to all Flogistix employees, contractors, and temporary employees.

Hazards

Employees need to be aware of the possibility of extremely hot exhaust pipe surfaces, potential exposure and the inhalation of engine exhaust. Employees should be aware that units could contain flammable and toxic gasses. Potential for the possible hazards of gas ignition or fire, hot surfaces & fluids, rotating equipment. Risk of possible concentration of H2S. Hazardous gases could be in the units pressure vessels, cooler, or associated piping and risk of inhalation of hazardous gas fumes.

Safety

All Personal Protective Equipment (PPE) for normal Field Mechanical duties apply for this procedure.

Four Gas Monitor, which is outlined in the Flogistix EHSS Manual, PPE Section 8, Procedure 8.3

This procedure applies to all units in service in the field, at a service shop, or in any storage yard.

Insure Flogistix personnel have proper safety certification or site orientation if required by the Flogistix Customer.

Insure Flogistix personnel adhere to all Customers safety practices.

Proper use of required tools

Training

All employees shall be initially trained on the following topics:

• Employee Personal Protective Equipment (PPE)

• Lock Out Tag Out (LOTO) procedure according to Flogistix policy

• Methods and Observations that may be used to detect the presence or release of a hazardous chemicals or gas in the work place

Tools & Equipment Required

All employees performing this procedure shall be required to have the listed tools to perform job tasks:

• All required PPE according to Flogistix Safety Policy

• Lock Out Tag Out LOTO items to properly perform LOTO procedure according to Flogistix policy

• Basic tools

• Sparkplug socket

• Compression Tester capable of cylinder compression up to 300 psig

• Remote engine starter button

Approvals

Field Service approved by:

Date:

Engineering approved by:

Date:

EHSS approved by:

Date: