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jacktheflyer · 11-03-2018, 22:00

There is an oil feed line that goes from an oil gallery on the block to the injector pump. I have just replaced one of these lines due to the banjo having corroded and leaking oil. The old part was a flexible hose nad the new part a solid pipe. I suspect thte flexible pipe has been fitted as an aftermarket part but i am concerned there may be an issue with the solid pipe I don't know about.

Has anyone on the forum has an issue with this feed pipe?
Scrubby

RaymondR · 11-03-2018, 22:09

These external oil lines are common on a number of the models of Yanmar engines and being steel they are prone to corrosion. I have repaired a couple of them by drilling the stubs of steel tubes out of the banjo fittings and replacing the steel tube with copper tube. Copper tube is prone to work hardening and cracking however as the tube runs are short and it is easily clamped against flexing it has never proved a problem.

charliehows · 12-03-2018, 16:04

my 2qm20 has an external steel oil line feed to the rockers - i dont like the design but i've checked the line a couple of times over the years (i'm guessing its the original which makes it nearly 40 years old) and it seems robust. Priced a factory replacement a few years ago - north of $200 - probably more now, so a copper replacement would be my first choice too.

ggray · 12-03-2018, 19:55

Quote:

Originally Posted by RaymondR

These external oil lines are common on a number of the models of Yanmar engines and being steel they are prone to corrosion. I have repaired a couple of them by drilling the stubs of steel tubes out of the banjo fittings and replacing the steel tube with copper tube. Copper tube is prone to work hardening and cracking however as the tube runs are short and it is easily clamped against flexing it has never proved a problem.

Do you mean you braze the copper tube in the banjo fitting?

**Wotname** · 12-03-2018, 20:49

FWIW, my YSE 8 has a external steel tube across the top of the crankcase delivering oil to the aft main bearing and then external copper tube to the rocker assembly. The centre banjo fitting has steel one one side and copper on the other side; I don't know if this was original or not.

My 2GM20 has a steel tube though out.

RaymondR · 13-03-2018, 07:41

Quote:

Originally Posted by ggray

Do you mean you braze the copper tube in the banjo fitting?

Silver soldered, I don't have enough heat on board to braze.

**roverhi** · 13-03-2018, 21:15

Don't know if this is line is the same as a 3GM30 and probably the whole GM line but the line on those engines is prone to corrosion. The line passes from the left side of the engine as you are facing it around the back of the engine to the right side. It passes right under the exhaust elbow at the back of the heat exchanger so any leak in that fitting drops right onto the steel line. Replaced mine because it was pitted in that location.

The replacement line from Yanmar appeared to be made of some copper containing alloy so it would better withstand any salt water leaking onto it. Replacement was relatively easy with the engine out of the boat. Had to remove the starter to get at the fixing bolt on the right side. Would probably have to do some work by feel on the left side for an in situ replacement.

**sailorchic34** · 13-03-2018, 21:36

Quote:

Originally Posted by ggray

Do you mean you braze the copper tube in the banjo fitting?

Solder is only is the way to go. Brazing copper tubing is never a good idea as the brazed section becomes annealed and thermal expansion will cause the non-annealed copper to push into the annealed section, which will cause it to leak. The firm I was with in Colorado tested this in 1994 with 1" copper.

Brazed tubing will fail rather quickly, months, not years, if exposed to vibration and temperature changes. In a building with 10,000 brazed copper joints (LUXOR vegas) it can be annoying. Luckily our spec, called for soldering. Contractor brazed, which was and is common. But it has issues.

I soldered my Yanmar's replacement copper tubing (3/32" if I recall) in 2013 and it's still going strong with well over 500 hours on it.