catmandoo
Well-Known Member
Last Month saw the commisioning of a replacement 42 HP Mercedes OM 636 engine after my old one died somewhere in the Messina Straight . Making an executive decision I bit the bullet and ordered a refurbished basic unit on an exchange basis from Westfield 4x4 . It took about 6 weeks overall to get and install.
I saw it being tested on the test bed in Westfield's well equipped machine shop near Lancaster and it ultimately arrived in Sicily in a nice packing case with all necessary gaskets and bits for connecting the existing ancillaries on the old engine such as Bowman heat exchanger , starter , alternators and inlet manifolds .Also included
was the test info for the 9 hours run in Westfield's insulated test booth .
The Yard at Marina del Etna did a good job of transferring and connecting up and allowed me to live on the boat and work on it at the same time . Great set of Guys. Good professionals too
One or two points to note for other Mercedes users
1 New parallel wired glow plugs were provided but we found that
previous owners had not removed the resistance coil for the less
efficient series type . No wonder I had difficult starting previously
. I bypassed it and now get 12 volts at each plug . Great! starts
like a motor car !!!!
2 It was worth geting new CW hoses and copper return pipe . the old
ones I will keep as emergency spares but they look quite grotty .
3 The support for the throttle cables and manual oil extraction pump on the old engine was at the back on a bracket attached to the block using the head compression bolts . Not a very good location as the compression of the head gasket is compromised by making the bolt gripping length shorter. Used supplier's alternative which attaches to the inlet manifold bolts .
Enzo at the Marina del Etna yard made me a separate bracket for the oil pump which
attaches to non critical bolting
4 With a the new oil cooler attached I now get a constant oil pressure
of 8 bar even after several hours of operation at a constant 82 degrees CW
temperature and 29 degrees sea water inlet temperature ( CW circuit includes hydraulic oil cooler as well as engine oil cooler and Bowman closed circuit CW cooler. Note it is worth checking the tubes in these small in series heat exchangers periodically as fouling up can seriously restrict total CW flow )
For those people with Hydraulic drives ( in my case Volvo bent axis pumps) attached to the flywheel end of the engine look out for external corrosion on the reservoir tank. Discovered the reason for a continuous hydraulic oil leak on the Volvo drives . The reservoir tank was leaking at the back . On taking it out, the back facing the stern which was hard up against a bulkhead was pock marked and rusty as were the welds . It was not economically repairable and as it could only be removed with the engine out or by substantially dismantling the chart table the gas locker and the back end of the wheel house the Marina del Etna made me an exact copy in 316 SS all in in one day fitted and air tested too !!
6 I also got a new fresh water cooling pump although I could have
reused the existing one which was substantially new but decided on
the basis of keeping the new basic unit totally new and virgo intacta . An extravagance since I also had a spare but I dont regret it .
7 Actual removal and installation of the engine was no problem . Most of the remaining time was taken up with disconnecting and connecting hoses, pipes, and cables . its however easy if you list and colour tag all items and work out the sequence or removal of each bit before starting making sketches of cable positions on items like alternators , starters and instrumentation etc.
d
Trust this info will be useful to Catfisher owners and others with Mercedes OEM636 engines
When I left Riposto with the new engine throbbing away nicely Etna signalled my departure with a small eruption /forums/images/graemlins/grin.gif
I saw it being tested on the test bed in Westfield's well equipped machine shop near Lancaster and it ultimately arrived in Sicily in a nice packing case with all necessary gaskets and bits for connecting the existing ancillaries on the old engine such as Bowman heat exchanger , starter , alternators and inlet manifolds .Also included
was the test info for the 9 hours run in Westfield's insulated test booth .
The Yard at Marina del Etna did a good job of transferring and connecting up and allowed me to live on the boat and work on it at the same time . Great set of Guys. Good professionals too
One or two points to note for other Mercedes users
1 New parallel wired glow plugs were provided but we found that
previous owners had not removed the resistance coil for the less
efficient series type . No wonder I had difficult starting previously
. I bypassed it and now get 12 volts at each plug . Great! starts
like a motor car !!!!
2 It was worth geting new CW hoses and copper return pipe . the old
ones I will keep as emergency spares but they look quite grotty .
3 The support for the throttle cables and manual oil extraction pump on the old engine was at the back on a bracket attached to the block using the head compression bolts . Not a very good location as the compression of the head gasket is compromised by making the bolt gripping length shorter. Used supplier's alternative which attaches to the inlet manifold bolts .
Enzo at the Marina del Etna yard made me a separate bracket for the oil pump which
attaches to non critical bolting
4 With a the new oil cooler attached I now get a constant oil pressure
of 8 bar even after several hours of operation at a constant 82 degrees CW
temperature and 29 degrees sea water inlet temperature ( CW circuit includes hydraulic oil cooler as well as engine oil cooler and Bowman closed circuit CW cooler. Note it is worth checking the tubes in these small in series heat exchangers periodically as fouling up can seriously restrict total CW flow )
For those people with Hydraulic drives ( in my case Volvo bent axis pumps) attached to the flywheel end of the engine look out for external corrosion on the reservoir tank. Discovered the reason for a continuous hydraulic oil leak on the Volvo drives . The reservoir tank was leaking at the back . On taking it out, the back facing the stern which was hard up against a bulkhead was pock marked and rusty as were the welds . It was not economically repairable and as it could only be removed with the engine out or by substantially dismantling the chart table the gas locker and the back end of the wheel house the Marina del Etna made me an exact copy in 316 SS all in in one day fitted and air tested too !!
6 I also got a new fresh water cooling pump although I could have
reused the existing one which was substantially new but decided on
the basis of keeping the new basic unit totally new and virgo intacta . An extravagance since I also had a spare but I dont regret it .
7 Actual removal and installation of the engine was no problem . Most of the remaining time was taken up with disconnecting and connecting hoses, pipes, and cables . its however easy if you list and colour tag all items and work out the sequence or removal of each bit before starting making sketches of cable positions on items like alternators , starters and instrumentation etc.
d
Trust this info will be useful to Catfisher owners and others with Mercedes OEM636 engines
When I left Riposto with the new engine throbbing away nicely Etna signalled my departure with a small eruption /forums/images/graemlins/grin.gif
