engine rotation

I have a trawler with 2 perkins 354s

which one rotates normal and which one reverse

(im new to twin engines sorry if its a silly question

In many twin set ups the engines are identical and the props are reversed and the rotation change is in the transmission gear. Start the engines and look at the engine rotation. Put them in gear and look at the shaft rotation. You will get the picture.

Remember that the rotation, whether or not it's clockwise or anti-clockwise, is noted by viewing from the REAR of the engine looking forward.

I have a single Perkins 6.354 that is anti-clockwise. Which to me, seems weird.

Didn't know that Tom.

Tom.B said:

I have a single Perkins 6.354 that is anti-clockwise. Which to me, seems weird.

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Not at all weird. "It's left handed" and I'll bet that most single engines on this Forum are the same. Mine is!

Your boat backs to starboard?

Mine's left-handed too.

Unless there is a twin set up, my guess is that Lehmans are left handed, or as I look at it, we dock to starboard because in reverse that is the way the boat pulls. (Ignoring my wing engine which purposely pulls to port.)

Marty

You guys are not staying focused. The thread starter asked which of his two engines rotates normal and which rotates the reverse? I do not have Perkins 354s so I do not know. But I would like to know.

davesail said:

I have a trawler with 2 perkins 354s

which one rotates normal and which one reverse

(im new to twin engines sorry if its a silly question

Click to expand...

Dave I own a single so take this with a grain of salt but have been told by many who should know that most twin engines rotate the same direction. The rotation reversal for the prop shaft normally happens in the marine gear (transmission). Hope this helps.

There is an echo in the room. That was my answer.

davesail said:

I have a trawler with 2 perkins 354s

which one rotates normal and which one reverse

(im new to twin engines sorry if its a silly question

Click to expand...

Davesail,

Typically, when viewed from the rear of the boat:

The Port engine should be a "Left Hand Engine" and the flywheel should rotate Counter-clockwise. This is the "Normal" engine.

The Starboard engine should be a "Right Hand Engine" and the flywheel should rotate Clockwise. This is the "Reverse" engine.



You can also confirm this by finding the engine identification code. Perkins "Right Hand Engines" are identified by the letter "X" stamped immediately after the manufacturing location code letter (e.g. 354UX252T). The first three numbers are the cubic inch size, the next character is the manufacturing location. The "X" will be the next character if the engine is "Reverse Rotation". This identification is located on the Fuel Injection Pump Mounting Flange on the Left Side of the Engine.

Hope this helps.

LarryM
m/v Boomarang

obthomas said:

There is an echo in the room. That was my answer.

Click to expand...

Oops. Read no further than the OP on my iPhone. Shoulda read the rest of the thread first

most all engines today are left handed,years ago they had left and right engines by changing the camshaft,so that the props swung outboard, years ago chris craft used to turn one engine around the othe way and drive the tranny off othe front of the engine, when they changed the cam they also reversed the firing order,had right hand starters , anmd a lot of other things,now days they turn the direction of the props with the tranny,in velvet drives the switch the pump around so it goes the other way worked on many of them many years ago.

My "ex" a 78 Mainship 34 came originally with a "anti-clockwise" or backwards rotation Perkins (T6.354). Some parts like the coolant circulation pump were obsolete, some others were a pia to source unless the distributor had the manual for the backwards engine.
That was one of the reasons I repowered.

Capt Jerry, you triggered a memory I had long forgot. I remember those motors well. Crusader also did this by using timing "gears" on one engine and timing "chain" on the other. The firing order, distributor and timing were reverse of each other. I remember many years ago doing a full tuneup and setting the timing on both engines one day. Following the tuneup I was pleased with myself because they ran smooth as silk when tested (idling) at the dock. Next day during sea trial I found my port engine would bog out when applying any throttle and for the next two days I tore the engine apart looking for the problem. Embarrassingly after much hair pulling I found I had set the timing on both to 10 deg BTDC and of course the Port should have been ATDC. (maybe vice-versa I forget). I am still amazed at how well it ran at idle being so far out of time.

Sorry Davesail for transgressing slightly off topic.

LarryM said:

Davesail,

Typically, when viewed from the rear of the boat:

The Port engine should be a "Left Hand Engine" and the flywheel should rotate Counter-clockwise. This is the "Normal" engine.

The Starboard engine should be a "Right Hand Engine" and the flywheel should rotate Clockwise. This is the "Reverse" engine.

You can also confirm this by finding the engine identification code. Perkins "Right Hand Engines" are identified by the letter "X" stamped immediately after the manufacturing location code letter (e.g. 354UX252T). The first three numbers are the cubic inch size, the next character is the manufacturing location. The "X" will be the next character if the engine is "Reverse Rotation". This identification is located on the Fuel Injection Pump Mounting Flange on the Left Side of the Engine.

Hope this helps.

LarryM
m/v Boomarang

Click to expand...

This^^

My twin Perkins rotate as described. 6.354 NA

LarryM said:

Hell, now I'm confused

Click to expand...

Uh....thanks, Larry....that really clears it up. ==========================>:lol:

SeaHorse II said:

Uh....thanks, Larry....that really clears it up. ==========================>:lol:

Click to expand...

Walt,

Maybe too much coffee

Larry

Take a good look the next time your boat is hoisted.

Here is my left-handed, counter-clockwise, prop-walk-to-starboard propeller: