An exhausting subject

[Pappy Chris]

Hi -- I spent the last few days getting an exhaust education.

It all began with finding a bad exhaust elbow while RnR the heat exchanger for cleaning.<br style="font-family:Georgia;font-size:13px;text-align:left;" />Based on manufacturers suggestion it seems that a properly sized exhaust system*on a 120HP diesel engine should be 3.5"<br style="font-family:Georgia;font-size:13px;text-align:left;" />What size(s) are others finding in their systems with this size engine?<br style="font-family:Georgia;font-size:13px;text-align:left;" /><br style="font-family:Georgia;font-size:13px;text-align:left;" />It seems that a PO had reduced mine to 2 7/8" through the muffler (sized for<br style="font-family:Georgia;font-size:13px;text-align:left;" />80HP) and connected that to the 3.5" that exits the boat. I am in the process of*taking out the hodge-podge of adapters that has been installed to do this.<br style="font-family:Georgia;font-size:13px;text-align:left;" />Correct size muffler, new wet exhaust elbows and hose should top $400.<br style="font-family:Georgia;font-size:13px;text-align:left;" /><br style="font-family:Georgia;font-size:13px;text-align:left;" />Cheers<br style="font-family:Georgia;font-size:13px;text-align:left;" />Pappy Chris<br style="font-family:Georgia;font-size:13px;text-align:left;" />m/y Moonshine

 

[jleonard]

Pappy Chris wrote:
Hi -- I spent the last few days getting an exhaust education.

It all began with finding a bad exhaust elbow while RnR the heat exchanger for cleaning.<br style="font-family:Georgia;font-size:13px;text-align:left;" />Based on manufacturers suggestion it seems that a properly sized exhaust system*on a 120HP diesel engine should be 3.5"<br style="font-family:Georgia;font-size:13px;text-align:left;" />What size(s) are others finding in their systems with this size engine?<br style="font-family:Georgia;font-size:13px;text-align:left;" /><br style="font-family:Georgia;font-size:13px;text-align:left;" />Correct size muffler, new wet exhaust elbows and hose should top $400.<br style="font-family:Georgia;font-size:13px;text-align:left;" /><br style="font-family:Georgia;font-size:13px;text-align:left;" />Cheers<br style="font-family:Georgia;font-size:13px;text-align:left;" />Pappy Chris<br style="font-family:Georgia;font-size:13px;text-align:left;" />m/y Moonshine

*Mine is 3 1/2 inch from elbow to boat outlet. I just changed my elbow...still good but decided it seemed like time after being in salt water for 5 seasons under my ownership. Had one bolt break off. Had to remove the manifold and take it to my son's shop to get the stud out. Other than the manifold being 4000# it was an easy job.

 

[Goya]

My 120 hp Lehman's have an OD on the elbow of 3 1/2 inches. Inside diameter of the exhaust hose is therefor 3 1/2 inch. Just got a replacement as the starboard elbow developed a small drip. I guess these engines are famous for wearing though elbows. A guy I met at a marina in Sweden (Ford mechanic) told me to check them B4 any long trips. Guess he knew what he was talking about.

 

[Pappy Chris]

Can't quite figure out where the elbow that was on the engine came from. It was threaded. Maybe the PO robbed that off the small diesel too and put it on the 120 just because it would bolt on. All my new parts are ordered and should arrive this week except one (back order). The replacement exhaust elbow I bought seems to be what everyone else has on their engine. Maybe I should start shopping for an extra. Hate to get caught having to spring for a brand new one in a pinch. That would never happen at an opportune time.

CB
Moonshine