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Engine Rotation - Start Motor Question

T

tronic72

Member
Hi,

I have a 1985 cruiser with 2 x Mercruiser shaft drive V8 5 litre (230HP) engines. One has ceased. I'm in the process of ordering replacements and am about ready to order. However I'd like to be 100% sure of what rotation each engine rotates. The opposite rotation engine will cost me $1000 more due to the high cost of the roller camshaft so I'd like to be sure. As I understand it, it's usually the starboard engine that is opposite rotation (right-hand) while the port engine turns in the conventional, left-hand direction. Unfortunately the starboard engine was ceased when I purchased the boat so I don't know. However this allowed me to negotiate a very good price.

My question is, which direction should the starter motors spin for a conventional left-hand rotation engine and which way should they rotate for the starboard engine? My thinking is that if I take both starters out and test them I will know with 100% certainty which direction each engine spins.

Thanks in advance, Mark

PS. I tried entering the serial numbers of the engines without success. They are:6720629 AND 6344566
 
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........................

tronic72 said:
Hi,
I have a 1985 cruiser with 2 x Mercruiser shaft drive V8 5 litre (230HP) engines.
Whether flywheel facing AFT (shaft drive) or flywheel facing FWD (V-drive), engine rotation is always determined as though viewed from the flywheel end.
(courtesy of the Internet)
faq-ro5.jpg
.................
faq-ro6.jpg



One has ceased. I'm in the process of ordering replacements and am about ready to order. However I'd like to be 100% sure of what rotation each engine rotates. The opposite rotation engine will cost me $1000 more due to the high cost of the roller camshaft so I'd like to be sure.
A GM SBC roller cam and roller cam followers will typically go 200K mi in an automotive Engine.
They will go the equivilant in a Marine Engine.
Why not re-use your REV RH Rotation cam/followers and save a huge chunk of that $1K?????
However, if you buy or build a 5.7L Engine, that of course is not an option.

BTW, I'm with Chris..... I would go with the 5.7L Engines.
(steer clear of the 5.0L engines)


As I understand it, it's usually the starboard engine that is opposite rotation (right-hand) while the port engine turns in the conventional, left-hand direction. Unfortunately the starboard engine was ceased when I purchased the boat so I don't know. However this allowed me to negotiate a very good price.
This may sometimes depend on engine orientation..... such as flywheel FWD for a V-drive scenario and whether or not the transmission is "opposite of engine rotation" capable.... in which case both Engines may (key word "may") be Std LH Rotation.

My question is, which direction should the starter motors spin for a conventional left-hand rotation engine and which way should they rotate for the starboard engine?
Again, this may not be that cut and dried.
Are these conventional cylinder block mounted starter motors??? or are they Borg Warner flywheel cover mounted starter motors???
This makes a difference in the direction that they would rotate relative to the engine rotation.
(see my image below)


My thinking is that if I take both starters out and test them I will know with 100% certainty which direction each engine spins.

Yes, I agree, and I'll suggest that you mark each starter motor prior to removing them.

You don't even need to power up the motor. Simply look at the pinion teeth. The shinny side will have been the drive side.
Do the forensic work, and you'll know what direction the pinion gear has been turning the flywheel ring gear. This will tell you the Engine rotation.

Or...... apply force to the pinion gear. The pinion gear's Sprague Clutch is designed to slip in the event of Engine Over-Run.
Find out which direction the Spraque Clutch slips in, and this will tell you which direction it has been rotating the flywheel ring gear.
Again..... this will tell you the Engine rotation.
Click to expand...
 

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Unless I missed something ............
 

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what type of transmission are these connected to? the trans could be reversable too.
as for the starter , we need to know if its an engine mounted one or a aft mounted one. if aft mounted like a typical inboard installation, the starters rotation is opposite the engine rotation.
 
Here's a photo of the starter from the Starboard side. The engine is mounted to the bell housing of the top right of the engine. This means .......

IMG_1395.jpg

....That it's an opposite rotation engine turning clockwise from the rear as per the below image. Is this correct?


enginerotationmarine_000 copy.jpg
 
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STBD side meaning the side the helm is on .If you power up the starter and it turns CCW you have a standard rotation starter in a reverse rotation motor with the aft entry.
 
tronic72 said:
Starboard meaning starboard. Helms not always on the right of the boat.
Click to expand...



It does not matter. What maters is what you have!!!!!!!!!!

I would suggest coming clean on your specific boat and how it is laid out.

Otherwise everyone is guessing when answering your questions..........

What side of the boat is YOUR helm?
What year is your boat?

Do you have mercruiser motors or some other brand name ?

Are you sure you have reverse rotation on one of the motors? if so How do you know?

Get the serial numbers and post them.


Maybe some pictures of the bilge area with the motors as installed may help?

Before asking any more questions or when posting any new questions start of with all the specifics about your boat so there is no confusion as to what you have. Otherwise most will stop answering due to wrong answers based on a lack of information from you.
 
Jack,

Do not reply to my posts anymore. If want to talk to someone with a poor attitude and a chip on their shoulder I'll call my ex wife.
 
That was not a chip on a shoulder

You have posted several topics but in every one the specifics on your boat have been lacking.

Several have tried to answer your question and then a new piece of the puzzle is introduced.

Anyone who asks for information is asked to include as much information as possible so anyone try to help can do so understanding what it is you have for a set up.

after many posts most thought you had standard motor design which would have concluded a standard starter mount. Then you show a picture of the starter which is the complete opposite.

That is why it is important to include as much specifics as possible when asking a question. So every one is on the same page.

99% of the posts on this MERCRUISER forum are about I/O's not inboards. Especially twin inboards with a reverse rotation engine.
This is why specifics are most important.
 
Tronic72. Listen to Jack and people like him. The devil is in the details so provide as much info as possible otherwise you will get the wrong advice that will cost you time and money.
 
.....

I think that Mark has made it clear that he would prefer no further disruptions from those who want to use an attitude.
tronic72 said:
Jack, Do not reply to my posts anymore. If I want to talk to someone with a poor attitude and a chip on their shoulder, I'll call my ex wife.
Click to expand...


kghost said:
That was not a chip on a shoulder
Jack, you do appear to have a chip on your shoulder, and I don't know what this comes from.
And as for attitude, yes, you have an attitude that is inappropriate for this or any forum. Your signature certainly makes a statement regarding your awarness of an attitude.


You have posted several topics but in every one the specifics on your boat have been lacking.
Then politely ask for clarification!
People are often not educated in this area.... and that's why they have come here to this forum in the first place.
Don't chastize them.... instead, help them!!!!

Several have tried to answer your question and then a new piece of the puzzle is introduced.
Jack, don't turn a blind eye to your own adding confusion to the thread.
For example, I beleive that the description in your last starter motor rotation image is incorrect.


Anyone who asks for information is asked to include as much information as possible so anyone try to help can do so understanding what it is you have for a set up.

after many posts most thought you had standard motor design which would have concluded a standard starter mount. Then you show a picture of the starter which is the complete opposite. That is why it is important to include as much specifics as possible when asking a question. So every one is on the same page.
Welcome to Internet Forums, whereby inexperienced people come for advice and information from experienced people.


99% of the posts on this MERCRUISER forum are about I/O's not inboards. Especially twin inboards with a reverse rotation engine.
This is why specifics are most important.
And when necessary, we (as the helpful experienced) politely ask for clarification.

Jack, I'm sure that I could speak for several members when I say that I would like to see you over-come this, and work through your differences just like the rest of us do.
Agree to disagree when appropriate....., clarify when appropriate......, present your reasons for disagreeing....., and do all of this in an adult like manner. (there is no need for foul language or the bad attitude)

If you are corrected by a member, respond politely. Acknowledge your error and move on. If the correction is not accurate, clarify as to why and use the same level of detail that you expect from the OP.
Click to expand...


hottoddie said:
Tronic72. Listen to Jack and people like him. The devil is in the details so provide as much info as possible otherwise you will get the wrong advice that will cost you time and money.
I would encourage you to look at the recent responses to Mark's other threads.
While I agree that details are very important, an ill tempered attitude does NOTHING to add to a thread.
Click to expand...


Let's all make an effort to be polite to each other, and to understand that no two of us will agree on an issue in the exact same way, nor do we need to. But let's also be polite when we explain why we disagree with another.
And let's also keep in mind, that we are all here to either offer suggestions to those who are asking, or to seek help and advice from those who know.




.
 
OK.... getting back on task here.......

tronic72 said:
Here's a photo of the starter from the Starboard side. The engine is mounted to the bell housing of the top right of the engine. This means .......

Mark, I beleive that you meant to say:
The starter motor is mounted to the bell housing of the top rear right of the engine.

This is most definitely an I/B starter motor for a B/W style flywheel cover (bellhousing in the automotive world).

View attachment 12627

....That it's an opposite rotation engine turning clockwise from the rear as per the below image. Is this correct?
Mark, I would say YES!
If your white arrows are correct, this starter motor will turn the flywheel in a CW direction.
A flywheel turning in the CW direction indicates a REV RH Rotation Engine.


View attachment 12628
Click to expand...

tronic72 said:
Starboard meaning starboard. Helms not always on the right of the boat.
Correct!
Click to expand...



Bt Doctur said:
If you power up the starter and it turns CCW you have a standard rotation starter in a reverse rotation motor with the aft
entry.
Just the opposite.
A CCW I/B starter motor (viewed from the nose end) will spin the Engine's flywheel in a CCW direction, giving us a Std LH Rotation Engine.
In order for an I/B starter motor to spin a REV RH Rotation Engine, the starter motor would need to be of CW rotation.
(see my previous image in post # 7)
Click to expand...



.
 
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Hopefully the following info may help as well.

From page 83 of the first link,
How to determine starter rotation!
Another way to determine the starter rotation is to inspect the chamfer on the starter drive gear.... The bevel will always be on the trailing edge.
Click to expand...

From page 85,http://www.partman.com/media/wysiwyg/lmscatalog/page 83-92 starters & alternators.pdf
Marine inboards: To determine the correct starter rotation, position the starter as shown, which ever way the gear turns freely, without engaging the armature would determine the rotation needed.
Click to expand...

More good info on this subject,
http://bpi.ebasicpower.com/mm5/graphics/00000001/CW-starter-rotation.png
http://bpi.ebasicpower.com/faq/starterrotate.htm
http://www.bing.com/videos/search?q...79D6B0538D361741459179D6B0538D3617414&fsscr=0

And are there any numbers on the starter itself such as an AC-Delco number? ... http://www.mercruiserparts.com/Show...&inbr=906&bnbr=5&bdesc=STARTER+AND+ALTERNATOR

1 50-808011A05 STARTER MOTOR ASSEMBLY, L.H. ROTATION) 50-76965A3 (DELCO REMY #1109485) $264.75 $238.68 1
1 50-97499R3 STARTER MOTOR ASSEMBLY, R.H. ROTATION 50-79604A3 (DELCO REMY #1109484) $297.92 $268.58 1

Good luck.:)
 
kghost said:
It does not matter. What maters is what you have!!!!!!!!!!

I would suggest coming clean on your specific boat and how it is laid out.

Otherwise everyone is guessing when answering your questions..........

What side of the boat is YOUR helm?
What year is your boat?

Do you have mercruiser motors or some other brand name ?

Are you sure you have reverse rotation on one of the motors? if so How do you know?

Get the serial numbers and post them.



Maybe some pictures of the bilge area with the motors as installed may help?

Before asking any more questions or when posting any new questions start of with all the specifics about your boat so there is no confusion as to what you have. Otherwise most will stop answering due to wrong answers based on a lack of information from you.
Click to expand...


Jack,

1. The serial numbers were in the original post. I'll await my apology. However cash is fine.
2. No I'm not sure that there's a reverse rotation engine. That's the reason for the post.
3. It might pay to read the OP better before you decide to lecture me or anyone else on here.
4. I said starboard because I meant starboard. I corrected the reply post to make sure you were aware that the helm isn't always on the right hand side of the boat.
5. Rick was right, I made a mistake in my reply post. I meant to say "The starter motor is located on the top right of the starboard engine". However I would have thought Blind Freddy would have seen it was a mistake due to the context.
6. I think my original reply still stands, given the rotation of the starter motor and it's location, and the fact that the engine rotates in the opposite direction of the starter motor, the engine appears to be a reverse rotation engine.
 
tronic72 said:
6. I think my original reply still stands, given the rotation of the starter motor and it's location, and the fact that the engine rotates in the opposite direction of the starter motor, the engine appears to be a reverse rotation engine.
Click to expand...

Yes, but is that true when south of the Equator? :D



.
 
tronic72 said:
6. I think my original reply still stands, given the rotation of the starter motor and it's location, and the fact that the engine rotates in the opposite direction of the starter motor, the engine appears to be a reverse rotation engine.
Click to expand...


The starter always rotates the opposite direction of the engine.
 
Chris, in terms of viewing either from the same perspective, I agree with you.
 

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