Izusu 6BD1 engine part identification

[rockycoastcruises]

I am hoping that somebody knows what this is on the port side of the engine. For some reason the photos are on their side but the part is located under the heat exchange. It seems like it also has an adjustment that can be made but not sure what this is about. I have looked at a schematic and it appears that this is the top portion of the oil pressure pump but not sure. Any information would be appreciated.
Thanks,
Joe

[SSJera58]

I believe that to be an old mechanical tachometer drive. Like older speedometers in automobiles a cable would have run to the back of the Tach.

[rockycoastcruises]

Thank you SSJera58. I have worked hard to find an answer and very much appreciate your feedback and detailed information in your email. Today I had Sound Diesel Marine located in Connecticut contact me in response to an email that I had sent. Joe, the owner was very helpful. He explained the same thing about this part/tach drive unit, and explained a bunch of other things to me. I've never had any dealings with this company before but based on his feedback and willingness to assist I am sure that I'll be working with him in the future for any parts and assistance that I might need. It's great to actually find a mechanic that knows the Isuzu 6BD1 engine.

[rockycoastcruises]

I should also say that Bill, from Casco Bay Diesel Repair responded to my email stating that this is a tach drive unit. It's nice to have people that are willing to take the time to share their expertise. Sometimes it takes a village to keep an old boat going.