7S3161 Valve Lifter Has Three Different Designs
3300 Family Of Engines
There are three different designs for the 7S3161 Valve Lifter. See the illustration. All three designs are interchangeable and all three designs can be mixed or matched in the same engine.
Three different designs of 7S3161 Valve Lifter.
New Fuel Nozzles Resist Adapter Cracking And Leaking
Caterpillar Machines Powered By 3304 And 3306 Machine Engines
Description of Change: New part numbers have been released for the fuel nozzles in these machine engines. The adapter portion of the fuel nozzle was changed back in November of 1998 in order to provide a stronger adapter. The stronger adapter is more resistant to cracking and leaking. The adapter portion of the fuel nozzle is the threaded piece that the fuel line attaches too. The part number changes were necessary in order to better facilitate parts replacement and reliability tracking.
Adaptable To: The chart identifies the new and former fuel nozzle part numbers.
The new fuel nozzle part numbers became effective with 3304 (07Z34711) and 3306 (6NC13156) Machine Engines. The former fuel nozzles have been canceled.
Later Pre-Chamber Cylinder Heads On Early 3304 Engines Without Drilled Rocker Stands Are Used
Publication Date -11/10/2012
Engine:
•3300
Machine Engines:
•3304
On early pre-chamber cylinder heads that are used on 3304 engines, passages were not drilled into the cylinder head to supply engine oil to the valve train. The part number is 2P-6484 Cylinder Head Gp. This remanufactured head casting is no longer available.
A new rocker stand and rocker shaft must be used with 0R-2674 and 0R-2675 cylinder heads with drilled rocker lube holes. A 7N-8015 Bracket and a 8N-3312 Rocker Arm Shaft must be ordered along with the cylinder head. The combination of parts allows the engine valve train components to receive adequate lubrication.
View of non-drilled rocker stand and drilled head with uncovered oil supply passage
Valve Spring Retainers Now Have Thicker Flanges
All 3208 Industrial, Marine, Generator Set Engines
Reference: “Larger Valve Springs,” May 20, 1981 Engine News, page 5.
Description of Change: The flange thickness has been increased on the valve spring retainers for all 3208 Industrial, Marine and Generator Set Engines. See the reference article. The thickness was increased from 2.8 ± 0.5 mm (.11 ± .02″) to 4.5 ± 0.5 mm (.18 ± .02″). The thickness change was the result of a manufacturing change at the factory.
The increased thickness of the flange has no effect on the operation and use of the retainers.
Adaptable As: The new parts are direct replacements for the former parts. The part numbers for the valve spring retainers were not changed.
Illustration 1 shows a comparison of the new and former 9N5497 Valve Spring Retainers (double spring) used in turbocharged 3208 Engines. Illustration 2 shows a comparison of the new and former 1W4260 Valve Spring Retainers (single spring) used in naturally-aspirated 3208 Engines. The cup-shaped 9L9425 Retainer used on earlier engines was not changed.
Illustration 1.
Illustration 2.
Publication Date -27/04/1983
Remanufactured Cylinder Head Groups
3208, 3306, 3406 And 3408 Engines
An article on this same subject was published in Engine News, February 22, 1984. The earlier article did not have complete information. Put a mark through the earlier article and make reference to this article.
Remanufactured cylinder head groups are now available in the United States and Canada for the above engines. These remanufactured cylinder heads include all the components of a standard cylinder head group. The cylinder heads which are shown in the chart can be returned for core credit. For additional information, on these remanufactured cylinder head groups see IRM REMFGD 84-9.
Publication Date -12/12/1984
Valve Lash Adjustment Not A Warranty Item
All Caterpillar Engines
Valve lash adjustment is a normal part of engine maintenance and should not be claimed as a warranty item. If the valve train must be removed or disturbed to do warranty work on other engine components, then valve lash adjustment can also be listed on the claim.
The rate of valve train component wear does not stay the same throughout the life of the engine. Valve train wear is greatest during the first few hours of operation. After this, the components wear only a small amount and valve lash needs only minor periodic adjustment.
Valve lash measurements made on the engine are sometimes greater than the plus/minus specifications. This is not necessarily an indication of defective material or workmanship. It does not mean that a failure of the valve train will happen soon.
The specified valve lash setting simply allows the valve train components to have a satisfactory service life. Always make valve lash adjustments when the engine is completely cool.
Date Updated -16/01/1985
Visual Inspection Can Detect Chrome Plated Engine Valves
Rebuilt engine valves can sometimes be mistaken for new Caterpillar engine valves. Some engine component rebuilders supply used Caterpillar engine valves that have had their stem diameters built up by a chrome plating process. Close visual inspection of a valve stem near the valve retainer grooves can show an indication of the chrome plating process. This area can have an uneven appearance where the chrome plating ends, see Illustration 1. Valve stems that are not chrome plated will have a smooth appearance as shown in Illustration 2.
Illustration 1. Chrome plated valve stem.
Illustration 2. Valve stem without chrome plating.
Use Care When Handling Water Seals For Cylinder Head Spacer Plates
All 3400 Series Engines
Petroleum products can damage the rubber used in spacer plate water seals (4W1055 Seal). This damage can be caused by the use of a water soluble oil in the cooling system or by contamination during maintenance or assembly.
When petroleum products come into contact with these seals they cause the rubber to swell. This can result in extruding and eroding of the inside diameter of the seal lip.
Location of seal.
Reusability of Exhaust Valves in All Caterpillar Engines
Several questions have surfaced regarding the reusability of exhaust valves in cylinder heads reconditioned by dealers and Caterpillar Remanufacturing. The biggest contributor to the confusion, regarding exhaust valve reuse, are product problems. These product problems have a direct effect on customer perception of exhaust valve life. When dealers have problems with customer perception, they become “guy shy” and sometimes “over-repair”.
Engine Division Engineering agrees that the life of an exhaust valve, under normal operating conditions, should be two engine life cycles. However, when an engine is operated with high exhaust temperatures, the life of the exhaust valve can be drastically reduced. In most cases, when a dealer reconditions a cylinder head for a customer in his territory, the dealer has some idea of the type of operating conditions the engine experienced and customer maintenance practices. Along with this information and the Reference material, the dealer can make a confident reuse decision. Under normal or typical operating conditions, where exhaust temperatures are not beyond the upper limit, exhaust valves should be reusable if they meet the current “Reference” specifications.
The Caterpillar Remanufactured Products Group started replacing exhaust valves, in remanufactured cylinder heads, across the board in September 1990. This was a decision based on dealer/customer concerns, regarding exhaust valve failures and that Remanufacturing didn’t know the head history. Various dealers were replacing exhaust valves on all in house cylinder head rebuilds. Dealers also reported customers were requesting new exhaust valves be installed in reconditioned heads because of poor experience with exhaust valve life in reconditioned cylinder heads.
3500 Series Engineering recommends that all exhaust valves be replaced at rebuild, because operating temperatures can not be accurately identified by visual inspection. High exhaust temperatures may be related to aftercooler housing gasket leaks, loose turbocharger center housing band clamps, turbocharger failures, etc. Dealers can base exhaust valve reusability on history, customer operating conditions and site location. If the site is in high altitude, which results in higher than normal exhaust temperatures, the dealer should replace the exhaust valves at rebuild. Intake valves are replaced only if they do not meet the guidelines in the Reference material.
When rebuilding engines, the reusability of all of the cylinder head valves is a cost savings, and should be executed whenever possible. Caterpillar’s position, with some exceptions, has always been and will be to recommend reusability of engine valves as per the Reference material.
Dealers have the advantage of the customer’s equipment history. This can take some of the risk out of making reuse decisions. The history of a component, received by the Caterpillar Remanufactured Products Group is not known, so they take the positive quality approach, and replace all exhaust valves to prevent failures.
Date Updated -01/08/1992