Helpful tips for identifying your exhaust elbow & flanges on your Perkins (Part 1)
Exhaust mixing elbows and flanges are found on all fresh water-cooled marine engines. These parts need to be replaced often because of their location and exposure to salt water. Unfortunately, most are not supplied by the engine manufacturers and so can be difficult to identify. This Tech Tip, one of a series we publish, focuses on identifying mixing elbows and flanges used on 4-cylinder Perkins marine diesel engines.
The illustration below shows the four most common elbows and the two most common flanges used on four-cylinder Perkins diesel engines.
A. PN ELBOW A
This elbow stands 6″ tall, has four bolt holes on the bottom (3.25″ by 2.5″) and is common on 4108’s. It is sometimes identified as PN 3776713.
B. PN ELBOW B
This elbow is 7″ in overall diagonal length, male threaded (2.25″ OD) on one end, no threads (1.75″ID) and is used on 4108’s and 4154’s. Used with Flange A (see G.).
C. PN ELBOW C
This elbow is 7″ in diagonal overall length, similar in dimension (2.25″ OD by 1.75″ ID) to ELBO B but is unthreaded at one end and female threaded at the other. It typically uses a five-bolt mounting flange. It is found on 4107.
D. PN ELBOW D
This elbow is 9″ in overall diagonal length, one end is female threaded and 2.75″ ID, the other end 3″ OD, unthreaded and found on 4236’s.
E. PN ELBOW E
This elbow (sometimes referred to as a 15017 elbow), not pictured above, is large, dome-shaped, and resembles a deepsea diver’s helmet. It is usually found only on Navy Whaleboats with Perkins 4107’s.
F. PN ELBOW F
This elbow, also not pictured above, is 6.5″ tall, female threaded (1.875″ ID) on one end for a four bolt flange to the manifold, and unthreaded (1.5″ID) at the muffler end. This is commonly found on 4107’s or Westerbeke 40’s. The Westerbeke PN is 33067.
G. PN FLNG A
This four-bolt flange (2.5″ by 3″) with a 2.5″ OD bolts to the late style 4108 heat exchanger/exhaust manifold (PN PE 180) and accepts ELBO B. It is sometimes identified as PN 37426472. This can sometimes be found in stainless steel for lifetime service.
H. PN FLNG B
This five-bolt flange, (2″ by 2″) with 1.75″ OD bolts to early style 4107/8 exhaust manifolds and accepts several elbows including ELBO E. It is sometimes identified as PN 0380203.
We hope that the above chart is useful and if you are able to identify other Perkins elbows and flanges please feel free to share your suggestions by e-mailing drdiesel@foleyengines.com.
