Tach Sending Unit Location on 3208 Cat Diesel

[JC80]

I have a 1989 390 EC. Does anyone have a picture or diagram or any descriptive information on where I can find the tachometer sending unit on the Caterpillar 3208 diesels? I've heard they are on the front of the engine so I was crawling around trying to see but the engine bulkhead compartment was too close for me to get a good look past all the belts. I need to be able to find these guys to see if there's room for me to work on them to swap the senders (if not, my ideal gauge replacements won't be a viable option).

Any advice is greatly appreciated. Thanks! :smt038

 

[fwebster]

The tachs on Caterpillar powered boats use a tooth counter sender. It is on the bell housing right above the flywheel and counts the teeth as they pass. You are looking for a cylindrical looking thing threaded into the bell housing on one end with wires coming out of the other end.

 

[Boatingnut]

On mine, the tach cable comes out of the front of the engine, right under the expansion tank. Some of the senders are mounted right there. On my boat, the senders are mounted on the Glendinning synchro unit, just follow the cable if you are not sure what it looks like. Good luck!

It is good to know about these tach cables, as they fail regularly on the 3208. Design flaw.

 

[JC80]

Thank you for the responses. I just did google searches on the terms "flywheel", "bell housing", "expansion tank" and "glendinning" and I'm slightly more knowledgeable than before For the record, it's not that I'm lacking all mechanical knowledge, but I've always worked on motorcycle engines as opposed to beasts like this.

So by summarizing the above posts, I should be looking on the top of the front of the very engine (just aft of the belt)?

Time to start trying to figure out how this synchro unit works now....

Thanks again!

 

[Boatingnut]

That is correct, right above the top pulley (circulating pump) and set further back. Once you see the black cable, you cannot miss it!

Send me a PM with an email address and I will send a couple of pictures.

 

[fwebster]

I think the type of sender is dependent upon the type of tach the boat is fitted with. A mechanical tach is as Boatingnut describes; an electronic one is as in my earlier post.