Technical Bulletin

The Cat® 3500 Series diesel valvetrain has had multiple updates. Using compatible valvetrain components is critical to the service life of the engine.

Floating Bridges:

• The update from the “doweled” valve bridge to the “float” bridge is common.
• On older-style assemblies, the valve bridges rode on a dowel that was pressed into the cylinder head.
• Newer style floating bridges no longer require a dowel to ride on and eliminate the bridge adjustment. This update also introduced ½” diameter stem exhaust valves and required different valve seats, valve springs, valve guides, rotators, spring washers, and valve stem seals.
• Since the release of the “floating” valve bridges there have been additional updates depending on specific applications.

NOTES:

There have been multiple component updates in these valvetrain components. Some of the changes have been global changes that updated parts everywhere they were used, while others have been specific to select machines or applications. IPD deals with rebuilders and parts suppliers around the world, some are very technical and make their own decisions as to which updates or combinations of components work best in their situations. Others consistently want only the latest designs. And still, there are those that have had good experiences with what they’ve been using and want to continue using what works best for them.

This tech bulletin is not intended to be your only resource for parts reference, but rather to help explain some of the changes and make you aware of possible incompatibility issues. Please contact IPD for more specific application information, or reference IPDNet.

To help illustrate the complexity of the parts compatibility for the 3500 valvetrain, attached are lists of some compatible parts groups that we have found.

These lists are for reference only! They are not intended to replace actual part number research or updates for your specific application.