Usage:
All 3208 Naturally Aspirated Truck Engines
- SUPPLEMENT: 10/05/83
TRUCK ENGINE NEWS, APRIL 13, 1983, PAGE 1. In the article "Improved Valve Springs Available" four more cylinder head part numbers which must have the valve spring seats machined for the improved valve spring must be added to the paragraph after the "Notice" on page 1. These are 9L7230, 9L9145, 9L9270 and 9N2362 Cylinder Heads. The information in Special Instruction, Form SMHS8131 and SMHS8167, can be used for the installation of new parts in these cylinder heads.
Also, add these four additional cylinder head numbers to Special Instructions, Form SMHS8131 and SMHS8167.
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Reference: Truck Engine News: May 12, 1981, "Larger Valve Springs "; August 18,1981, "Larger Spacers Used With Larger Valve Springs "; January 26, 1983, "Spring Seat Enlarger Available For Use On Cylinder Heads ".
The reference articles tell about the use of the larger valve springs in the above engines. A summary of the information in these articles, new reconditioning recommendations, and the engines to which these changes are adaptable to can now be found in this article.
Description of Change: The reference articles tell about the use of new valve springs, retainers, spacers, and nozzle clamp assemblies. The new valve springs have the same spring rate as the former valve springs. The new springs are made of a larger diameter wire and also have a larger coil diameter than the former springs. This results in lower stress in the spring and longer service life. The larger coil diameter makes it necessary to use new spacers and retainers. Also, new fuel injection nozzle clamp assemblies are used to give the clearance needed with the larger valve springs.
Adaptable As: The new parts, when used together, are direct replacements for the former parts as shown in Chart A. The former parts are still available for parts service use in all 1100 Series Engines. Chart B has the in effect and adaptable to serial numbers, and the models that the new valve springs are used in.
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All the new parts must be used together when a replacement is made of the former parts. Also, the recommendation is to change all the former retainers, valve springs, fuel nozzle clamp assemblies, washers and spacers on a cylinder head or engine at the same time. Do not mix the former and new parts on the same cylinder head or engine.
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Special Instruction, Form SMHS8167, has complete information for the installation of the new parts in 3208 NA Engines. To install the new parts in earlier 3208 Engines with 9N1107 Cylinder Heads, the cylinder head valve seat area must be machined for the larger diameter of the new valve springs. Special Instruction, Form SMHS8131, has complete information for installation of the new parts in engines with 9N1107 Cylinder Heads.
Cylinder Head Reconditioning Recommendations:
Caterpillar now recommends that only the new valve spring parts be used when reconditioning cylinder heads for earlier 3208 Naturally Aspirated Engines. The new springs will give longer service life than the former springs and are a product improvement that was not available when the earlier engines were built.
Identification:
The outside diameter of the new spring is 39.6 mm (1.56" ). The outside diameter of the former springs is 36.6 mm (1.44" ). A tool can be fabricated to easily check which valve springs are in an engine. The tool shown in the illustration will fit (go) over the outside diameter of the former springs. It will not fit over the outside diameter of the new valve springs. The tool can be made from wood, plastic or aluminum according to the dimensions in the illustration.
Tool which can be used to check valve springs.