Reverse rotation mpi
03-13-2005, 10:20 PM
#51
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Re: Reverse rotation mpi
Everyone listen to Marc. If you got LH and a RH motors, use 1.91:1,1.88:1 trannys.RH goes on Port side and LH goes on STRD. side, those trannys have an opposite rotation output (EX: LH motor,RH output ). If you got 2 LH motors, use a 1.91:1 0n STRD. side to use a RH prop. The PORT side will use a 2.10:1 LH model (make sure to get LH model, 2 are made and the RH model has a different cut rear planetary assm. for RH motors). The 2.10:1 on the PORT side will give you same rotation as engine, LH prop. Have used that 2 LH combo alot, no problems, no complaints.
03-14-2005, 09:15 AM
#52
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Re: Reverse rotation mpi
Marinetrans
Agree completely, EXCEPT, that doesn't solve MY problem. I currently own 1.5 borgs. If I'm gonna have to buy two new trans (1-2.11 and 1-1.88) I might as well get two new borg 5000's, buy 2 new standard 502's, and pay out the wazzoo to have my engine beds rerigged !!
(Oh!! almost forgot ..... doing it your way I also have to pay for new props!!)
800runsnew and others already have c/r long blocks (pan to head) available. These are matched 415hp to the standard rot 415hp. OK. Now that thats done how about MPI.
Each injector on the Merc MPI has a red wire AND either a blue or green wire. If you inspect your MPI you'll notice that the Green wire is connected to number 1, 7, 4, and 6 cylinders. The blue wire is connected to number 3, 5, 2, and 8. For purposes of this discussion we'll call these the Green Batch and the Blue Batch. Every 90 degrees of crank rotation (4 times per revolution), one of these batches (and I mean all four in the batch) injects or fires fuel. This is called Batch Firing.
Heres what happens:
G= Green Batch or 1746
B= Blue Batch or 3528
Standard Rot Firing Order
| Rev #1 ................| | Rev #2 ...............|
1 8 4 3 6 5 7 2
G B G B G B G B
1 2 7 5 6 3 4 8
Reverse Rot Firing Order
The Merc computer is already programmed to deliver a dose of fuel, even if you rotate the engine backwards.
Agree completely, EXCEPT, that doesn't solve MY problem. I currently own 1.5 borgs. If I'm gonna have to buy two new trans (1-2.11 and 1-1.88) I might as well get two new borg 5000's, buy 2 new standard 502's, and pay out the wazzoo to have my engine beds rerigged !!
(Oh!! almost forgot ..... doing it your way I also have to pay for new props!!)
800runsnew and others already have c/r long blocks (pan to head) available. These are matched 415hp to the standard rot 415hp. OK. Now that thats done how about MPI.
Each injector on the Merc MPI has a red wire AND either a blue or green wire. If you inspect your MPI you'll notice that the Green wire is connected to number 1, 7, 4, and 6 cylinders. The blue wire is connected to number 3, 5, 2, and 8. For purposes of this discussion we'll call these the Green Batch and the Blue Batch. Every 90 degrees of crank rotation (4 times per revolution), one of these batches (and I mean all four in the batch) injects or fires fuel. This is called Batch Firing.
Heres what happens:
G= Green Batch or 1746
B= Blue Batch or 3528
Standard Rot Firing Order
| Rev #1 ................| | Rev #2 ...............|
1 8 4 3 6 5 7 2
G B G B G B G B
1 2 7 5 6 3 4 8
Reverse Rot Firing Order
The Merc computer is already programmed to deliver a dose of fuel, even if you rotate the engine backwards.
03-14-2005, 09:23 AM
#53
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Re: Reverse rotation mpi
So all you got to do is match the distributor gear and distributor to the cam.
If the cam spins backwards, you gotta have a reverse thrust distributor.
And it's gotta have a different gear (cause it will still spin the normal direction for the benefit of the oil pump).
If the cam spins backwards, you gotta have a reverse thrust distributor.
And it's gotta have a different gear (cause it will still spin the normal direction for the benefit of the oil pump).
03-14-2005, 09:34 AM
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Re: Reverse rotation mpi
Hey I wish you guys would take a look at my other post "Electric or seawater driven fuel pump".
The late mpi's came with electric fuel pump (I'm talking regular fuel pump not the high pressure pump)
Mine came with the most gawldarned contraption I've ever seen. Sinced the Gen 6 didn't have a pump boss Merc altered their old seawater pump with a boss and cam to drive a fuel pump attached to the seawater pump. This looks stupid and a nitemare to repair.
Any problems using the old style seawater pump and installing an accessible electric fuel pump?
The late mpi's came with electric fuel pump (I'm talking regular fuel pump not the high pressure pump)
Mine came with the most gawldarned contraption I've ever seen. Sinced the Gen 6 didn't have a pump boss Merc altered their old seawater pump with a boss and cam to drive a fuel pump attached to the seawater pump. This looks stupid and a nitemare to repair.
Any problems using the old style seawater pump and installing an accessible electric fuel pump?
03-14-2005, 02:00 PM
#56
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Re: Reverse rotation mpi
Have taken out 1.52:1s and put in a 2.10:1 on Port side and a 1.91:1 on STRD. side.We increased the diameter of prop and a small increase in pitch.Customer says boat plains faster,more cruise speed, little faster on top end.Backs up great and manuvers better too.
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