Originally Posted by Eleanor's Nemesis
A couple of things I have heard over the years about marine engines.
Yes, I know this can get me in trouble. But maybe John can shed some light here and tell me if this is fact or fiction.
Some marine applications turn in the opposite direction, used if there are dual engines. ...
I was thinking about an opposite rotation example also. It must be to balance the torque. I imagine it requires a different cam and dist than a normal clockwise rotation engine, correct?
Well, in the words of the late-great Mr. John Wayne - 'Now that ain't exactly true'
Yes, counter-rotational engine assemblies can be common in some marine applications.
It is done for several reasons;
* to counter the rotational torque of the other engine(s) used in the unit
* change the reactionary rotation of the hull from the propeller design
* match the design of the final-drive system on the prop. rotation
* just because ... I've worked on a few older boats with CCR and really couldn't figure out why they used it
CCR can be used to counter 'another' engine - but then it again it is common to find a single engined boat with a CCR (LH) engine. Again done to change effect on handling of the craft for most applications.
I can only think of one manufacturer that was still using a CCR unit from the factory on their ski boats - that would be "Correct Craft".
If you've driven a boat much you would be used to the fact they turn (and back) much better one direction than the other - no use trying to back a vessel out of slip the opposite direction of the prop rotation, you won't get far - or at least where you wanted to be ...
With modern final-drive system the rotation of the prop(s) can be set-up in the gear box - so there's no reason to modify or change anything in an engine system to turn a different way from CWR (RH).
And a CCR engine does not take a special cam, distributor, oil pump or other rotational part for 90% of the applications.
All that is done to get the desired rotation is to drive the cam from the crank via a 'reversing' system - such as a direct gear set driving the cam vs. a chain on a standard chevy engine.
If a stock design cam is used, the firing order is changed to fire the engine in reverse order vs. the 'normal' GM 1-8-4-3-6-5-7-2.
It is also common to find the cam design 'reversed' to allow the desired rotation - depends on the manufacturer and needs of the power plant.
The starter also is of course 'reversed' so it turns the engine in the correct direction
But, in many applications, it's easier on performance units to just turn the engine around and drive from the front of the crank - does the same thing without all the extra hassles
Originally Posted by Eleanor's Nemesis
Supposedly the salt is very difficult to get out of the engine. True or not so true?
Not necessarily true ...
Most modern dedicated 'Salt' water applications now use a "Closed" circulation system with 'anti-freeze', just like and automotive application.
These system involve a water-to-water intercooler and circulate 'raw' water through the cooler to exchange heat from the closed system coolant.
This makes adapting modern EFI and aluminum component engines much easier, without the fear of corrosion eating the system in a few years ...
It's important to understand that dedicated Aluminum components made for 'marine' applications are usually "Hard Anodized" internally, so any contact with a corrosive medium (salt water) will have minimal effect on degrading the internal aluminum surfaces.
There have even been attempts to use PTFE ('Teflon') based coatings on internal passages and parts to retard corrosion effects - expensive and easily damaged if not careful, but very effective in many cases.
I don't know 'Jack' - should I
Is he into boats, engines or marine builds?
I don't race anymore, so I'm not up with some of the folks that still do
I do know the guy that built this thing -
Gotta luv a 10qt marine oil pan
I still haven't seen pictures of the boat it went into though