clpbs

has any body seen a Merc EFI run C/R with luck.It's always been in the trans

VeeCat

I don't think Mercury has ever built a counter rotation engine. I have never seen one. Of course I have only sold them since 1978.
Wait anything over 25 years old is considered an antique.

jerosejr

I'm with Edward. Anybody ever actually seen a reverse MPI engine !!
I personally own a carb c/r and I've seen lots of other carb c/r motors but never an injected engine.

VeeCat

Was looking at your notes of your conversation with Borg Warner,
My guess is that Mercruiser found another tranny builder like Paragon or some other and Borg Warner no longer builds the switchable (indexing) version.
Wonder what transmission Crusader and others are using these days? Maybe you could find a pair of the older used Borgs. I still think they are reversable at the output. I will try to give Mercruiser a call and get another opinion for you. Maybe I'm wrong but I do not believe there is any vast amount of left hand rotation (C/R) motors out there. Even in the carb versions at least not Mercruiser. Will get you Mercruisers take on it and post it asap.

NOBODY

I doubt anyone has ever seen one, but as for would it work I see no problem.

jerosejr

Hey VeeCat
I think what Mbam was trying to say was that back in the day of twin inboards (maybe before I/O) the only way to get c/r in the props was thru engine rotation. It was really simple. All you got to do is grind a new cam !!

To implement this thru a trans, Borg decided to make ONE model of tran, but make it indexible. Mbam is saying that you only had to buy two Model 72 borgs Then index them to whichever engine you mated it to.

If you mated tran #1 to your port engine (standard rotation) then you did nothing. The tran came from the factory to accept standard and output standard.

However, if you mated it to your starboard engine (counter) then you rotated the bolts, and, voila!!, your tran now accepts counter and outputs counter. This way borg only built one model

Mbams point is that indexing does change rotation but indexing does not alter the manufacturers purpose of building a tran that wil output ONLY WHATEVER input it receives.

VeeCat

Very good description
I looked at the Mercrury Dealers Electronic parts catalog today. I looked back at the older mid 80's stuff with inboards that had borg's trying to clarify in my mind if they did or didn't build Counter Rotating 454's. I fold in the list some engine numbers with LH in the model description. I was looking for something that said counter rotation. Couldn't find for sure and was going to call Merc and discuss and got sidetracked with work. The LH that I found may very well be Counter Rotation. The mechanic that I talked to said rotation description depends on if you are at the front or back of the engine. Left is right, Right is wrong his way of remembering it. In a car you look from the front of the engine. I believe he was telling me Mercury engine run counter clockwise as thier standard rotation. What he also told me which I never thought of on your inboard,
That it is possible to run both props the same direction. I have sold thru the years and you have probably seen or driven a twin I/O with 260's and alpha drives that rotate the same direction(props and motors). You get a twist effect that you can compensate (somewhat) with drive trim and tab trim. Not you best option but only requires changing one prop. Your cheapest way out. Again not the best way to fly, but cheap way for now. Those Borgs are real high from Merc.
Did you get to check your E-bay motors out before buying? Good luck with the project! Let you know if I come up with anymore brilliant idea's.
VeeCat

Edward R. Cozzi

Mercruiser has built many small and big block Chevys and small block Fords that are counter-rotating. It's a very expensive proposition. The pistons are installed backwards, the cam is a different grind, but still turns clockwise so the oil pumps works. This is done with two bigger gears and no timing chain. Also the starter motor is wound differently with a reverse-rotation starter drive.
The Mercruiser Thunderbolt 4-screw distributor cap has both firing orders on it.
Remember the boat manufacturer Penn-Yann?
In their single engine applications they used the opposite rotation engine all the time.
Hard to believe you've been around boat engines since 1978 and you could say that.

mcollinstn

<<Originally Posted by VeeCat
I don't think Mercury has ever built a counter rotation engine. .>>

This thread ORIGINATED from a guy who ALREADY HAS a set of CR Mercruiser engines. This was made clear from the onset. He's just wanting to figure out his best option for doing CR with brand new motors...

Mbam

I gave up 20 posts ago