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AERA Technical Bulletins – September 12, 2022




Engine Surface Finish and Flatness Recommendations


The AERA Technical Committee offers the following information on the proper surface finish and flatness for cylinder block and cylinder head decks. This information should be considered and referenced anytime the decks of blocks and heads are being worked on.


The following are general specifications that cover both diesel and spark ignition engines and are expressed in English units. It should be understood that the bolt spacing, location of oil and water holes, pressures, etc. will vary … engine to engine … and there will be exceptions where closer tolerances might well have to be observed to properly seal an engine.



Revised Spacer Plate Installation Procedure on Caterpillar C15, C18, C-15 and C-18 Diesel Engines


The AERA Technical Committee offers the following information on a revised installation procedure for the Caterpillar C15, C18, C-15 and C-18 diesel engines. This modification is now used to better seal the joint between the block and spacer plate on these engines. The repair is also adaptable back to previously built engines.


It is now recommended to use a gasket sealant while installing the spacer plate and gasket Part #4C-9505. This sealant includes an applicator that is to be used to apply the sealant evenly to the cylinder block side of the spacer plate gasket. As an alternative to the above 4C-9505 sealant, Loctite 5923 or Permatex Aviation Form-A-Gasket #3 may also be used. 




Is it really the Water Ferrule’s fault?


By Steve Scott


Over the years there have been several updates to the water ferrules in Caterpillar® 3406 and C15 engines (see sidebar “Background” further in this article). While a leaking ferrule

may not cause a major failure, it’s not uncommon to remove the cylinder head and find rusted head bolts from a ferrule that was no longer sealing. A rough list of the updates and changes to these ferrules is outlined in the sidebar. However, that’s not the main point of this article. Our hope is to give you a short explanation of the two different water ferrules you may encounter, and a condition you might not expect to find.



Subscribe to the AERA YouTube Channel


The AERA YouTube channel features Prosis Pro tutorials, AERA webinars and membership information. We invite you to check out the wide selection of videos and subscribe! New content is added regularly.



Podcast Episode 19

Compression Ratio


In this episode, Steve and Chuck introduce a new segment of the podcast called “Ask The Tech” where they take questions received on the AERA techline and explain the answers. This episode is on compression ratio, understanding what it is and how a machining process can change the compression ratio. Our history segment covers an invention that we all probably like in our vehicles – the cruise control!




Engine Professional Magazine


Engine professionals worldwide receive this full-color publication four times per year. Each issue is filled with highly technical and application-driven articles from our staff of writers, as well as feature contributions from industry professionals. In addition to the print version, you can also read our digital version online.





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