This is not related to Pacemaker but some of the manufacturing practices used by major boat manufacturers are hard to take. My friend owns a 2008 Cruisers 34' Express with twin 8.2L Mercruiser V8s with V drives. He also has the generator in that very crowded engine bay. Both transmissions developed a small leak and the factory authorized warranty rebuild/reseal of the transmissions. While the engines are out the mechanic notices rust at the exhaust manifolds. They pull the manifolds and find excessive exhaust reversion being caused by improper factory installation of the exhaust system. With such a tight engine bay it appears that there is not enough room to properly pipe the exhaust systems. Due to this design salt water has been infiltrating back into the cyclinder heads and that is causing major problems. Now we have 3 year old Mercruiser motors that may have terminal damage. I do not yet know the outcome of this problem but you can imagine how agonized the owner is as this nightmare proceeds. We are talking about a $300.000 thousand dollar boat designed by a well known builder and assembled in a modern plant. To be continued.
I take it the riser's aren't tall enough relative to the waterline? I think that's the usual culprit when it comes to water reversion into the manifolds. I seem to recall a rule of thumb of about 12" minimum. I wonder if this problem could be alleviated somewhat by installing flapper valves on the exhaust outlets? Or maybe it already has them?
Sorry to hear about your design issue, unbelievable. Does a 1970 25 foot single screw 220 crusader power plant need a siphon break ie. loop with valve, even though the risers are above the waterline?
Exhaust Reversion
Posted - 03/01/2010 : 14:54:02
