PIN-SPRING 2D6403 - Caterpillar

Caterpillar Products:Machine Engines All 3500 SeriesCaterpillar Products: 3500 Family Generator Sets and Power ModulesEngine: All 3500 EnginesIntroduction
Do not perform any procedure in this Special Instruction until you have read and understood the information.Using these instructions can help detect a single cylinder with excessive pressure blowing past the piston rings.The blowby can be due to piston rings that are worn or broken. The blowby can also be due to worn or damaged cylinder liners.The common materials that are needed for the testing can be obtained in most shops.This test uses the crankcase breathers or T-hoses, where all venting locations are fitted with caps or plugs.One plug is drilled to provide restriction and amplification of the pressure signal.One is fitted with a 1/8 inch hose barb fitting and a hose that is routed to a manometer.All other breathers are capped off.A manometer is used with the cylinder cutout function of Caterpillar Electronic Technician (ET) to determine crankcase pressure changes associated with individual cylinders.A torque converter load is maintained on the engine during the test in order to maintain a small load on the engine. The load enables all the injectors to have similar injection duration so that failed cylinder can be found more easily.Ensure that there are no other leak paths for exhaust gas to escape the crankcase in order to perform the test.Note: Oil filter differential pressure typically runs between 2 and 4 PSI at coolant temperatures above 77° C (170° F). Excessive blowby is suspected If oil filter differential pressure alarms are present or the filter differential pressure exceeds 5 PS.
Do not operate or work on this machine unless you have read and understand the instructions and warnings in the Operation and Maintenance Manual. Failure to follow the instructions or heed the warnings could result in injury or death. Contact your Caterpillar dealer for replacement manuals. Proper care is your responsibility.
Required Test Materials
Illustration 1 g03251500
(1) 1/8 inch hose (2) Hose clamp (3) 1/8 inch hose barb fitting in a plug or cap (4) Plug or cap with drilled hole for restriction and amplification (5) Manometer
Table 1
Required Materials    
Material     Comment    
3 ABS plastic plugs 1-1/2 inch inner diameter and 2-1/4 inch outer diameter
Or
Six similar caps     The plugs or caps are used to seal off the breathers.
Install a threaded fitting into one plug or cap, enabling installation of a 1/8 inch hose barb fitting (3) .
Drill a 1/2 inch hole into one plug or cap (4). A 1/2 inch hole is a good starting place.
Having a few different caps with 3/8, 1/2, and 3/4 inch orifices will allow the restriction to be varied as necessary. Different sizes can help produce 4 to 10 inches H2O at the beginning of the test.
The holes in the plugs or caps provide restriction and amplify the signal to the manometer. A smaller hole increases the restriction (pressure) and therefore increases the amplification. Too little or too much amplification will make cylinders with more blowby difficult to find.
A variable sized orifice can