Re: Reverse rotation mpi
 

None taken.
Crap, the day I stop learning things or having to be corrected is (hopefully) a long way away!

I'm still trying to figure out why you need reverse rotation on a pulling truck/tractor. Something to do with multi engined units and gearboxes to channel them all together ?? I love tractor pulls. Haven't been to one in forever.

Re: Reverse rotation mpi
 

[QUOTE=mcollinstn]None taken.
Crap, the day I stop learning things or having to be corrected is (hopefully) a long way away!

Something to do with multi engined units and gearboxes to channel them all together ??
Correct

Re: Reverse rotation mpi
 

if the merc mpi is a batch system, does anybody know the order for the batch firing?
also, these engines will be installed on an angle in an inboard boat. will mpi work installed like this?

Re: Reverse rotation mpi
 

Why re-invent the wheel?

Use two standard-rotation engines and do the reversing with the correct transmission the way almost everybody does it today.

Mercruiser stopped building opposite rotation years ago. To properly do one requires complete disassembly and install the pistons backward. Very time-consuming and costly. Easier and cheaper to do it in the tranny.

Re: Reverse rotation mpi
 

Edward
Thats exactly what I had planned until this forum explained that it was possiblr to do a reverse mpi. Cost is the motivator. I already own c/r 454's with c/r borg-warner trannies. My motor mounts are already in position for these trans with no further work.
If the MPI I just purchased will work then the only additional cost is the difference between a standard rotation (5300) and a c/r (5800) No engine bed replacement or realignment probs. I have a source for c/r 502 long block, already built and ready intake,etc.
If I buy new trans they are 2500 each (5000) plus have to redo beds, realign,etc. and labor rates at a boatyard are very high !!!

Re: Reverse rotation mpi
 

Oh yeah, did i mention the cost of new shafts?

Re: Reverse rotation mpi
 

I think the proplem is solved and heres the story for enyone interested:

The Gen VI C/R engines available today are true C/R engines. By this I mean that not only does the crank rotate oppositely but the cam does too !! In my old c/r 454 there was a gear to gear timing arrangement so that evan though the crank turned opposite, the cam (and dist and oil pump turned right).

The proplem to overcome I'm told was not the MPI but the dist. With a reverse rotation dist the cam dist gear exerts downward pressur on the dist shaft (instead of upward pressure normally). Unless corrected, this will cause a dist shaft and bearing failure in short time. The solution was daveloped a few years ago by both Marine Power and Crusader. Instead of a gear to gear C/R they built true C/R engines. To deal with the downward pressure on the dist they had Delco build a dist that had a thrust bearing that could handle the downward force.

Sooooooooo, 2 c/r 502's, 2 merc mpi's, a left and right dist and you have c/r mpi 502/415 and you can save 10000 on trannies ans setup labor !!

Re: Reverse rotation mpi
 

Might check this out..........


If you have a Borg Warner velvet drive transmission......

On the front plate of the transmission there are four bolts going into the transmission (located between tranny and engine must be seperated to locate bolts and plate)
remove bolts from plate,
rotate the plate,
reinstall the bolts,
and you have just changed the output shaft rotation.


What boat and engine package are you working with?

It appears
Edward again is correct
just my two cents worth half priced.
However,
since you are a gambler I would bet on it!
VeeCat in Texas
I will take transmission
for 3 million dollars......................

Re: Reverse rotation mpi
 

Food for thought,
Are you absolutely positive your engines are counter rotating?

Possible your transmission is already doing this for you..........

Tranny for 3 billion dollars........................................... ..........

Re: Reverse rotation mpi
 

Veecat, what you are referring to is the pump indexing on the 71/72 series Velvet Drive. The pump is rotated to match the engine rotation, this has no effect on the output rotation which is still the same as the engine rotation when in forward (mostly always true, except some of the reduction units have an opposite output)

The 71/72 series cannot be run in reverse for any length of time (or at anything much above idle).

We run into this question every day, really only 2 options which have been pointed out above. New trans (along with a re-rig) or reverse rotation engine.