merc 470 alternator mod

[408camaross]

hey guys i havent posted here in awhile but i recently traded my camaro for a 1985 sea ray 270 sundancer with twin merc 470 4 cylinders. im planning on doin the alternator mod, 4 in heat exchangers, and convert over to hei ignition. but my question is do i need to put alternators on both engines or will 1 105 amp alternator do the job? i dont know enough about these yet to know if i need an alternator on both engines. any help is appreciated
thanks Jason

 

[Jeepers]

Are they currently running? If so, just go. If you have plans on fixing one or both then......good luck. Parts and good prices are hard to come by. Not dogging those motors, if they are good then good for you. Sorry, no comment on the alternator question.

 

[cpt. sundancer]

Did not think that you could have an HEI dist. on a boat....safely

 

[408camaross]

the starboard motor only has 135hrs while the port motor only has 335hrs and they do run excellent, just from what ive read so far to get the reliability out of them is to get away from the stator charging system, which i dont know if one or both motors have the charging system. and as far as the hei set-up what i meant to say was convert them over to the pertronix ignition and get away from the points.

 

[blackbeard]

I have a 21ft.Galaxy with that 470 engine with the alternator conversion . I had trouble with the bracket that holds the alternator.It was made of some kind of alloy that kind of wraped around the alternator.Ended up making my own mount.I think the kit mount was around 120.00 .Hopefully it has been updated to a better grade of metal.

 

[berth control]

I did the alternator on only one of my motors. It works fine, but it's not really ideal. The reason I did that was because the other motor has a power steering pump on it that goes where I put the alternator.

The single alternator puts out enough power, It's just tough to get the single alternator to charge three different batteries without combining the banks and without using the battery switch. I needed to buy a box that combines the different banks when the voltage goes above 13.5 volts and keeps them separate when the voltage drops, so it combines them during charging and then keeps them separate during use.

About the petronix conversion, I don't think it's really that big of a deal or worth it to upgrade. Just buy new points, condenser, ect. and have someone who knows what they are doing set it up. They aren't bad if they are set up properly.

About the heat exchangers, I would run the ones you have and see if the motors overheat. They most likely won't under normal conditions. If you keep them clean and keep the water pumps in the outdrives good, you should be fine.

These motors are not THAT bad, but they do suck. They are loud, idle rough, and shake a lot. No matter what. They are also quite finicky, requiring lots of tune ups. With older boats like ours though, it's best to just run 'em and deal with it. I actually have two working spares for parts, ect. Haven't needed much though.

Good luck!

 

[408camaross]

thanks for your input bud i really appreciate it, i like these motors, seem pretty easy to work on and with the wide beam on our boats theres really alot of room to be able to work on these motors, now since i read your post im wondering if we could run the low profile alternator on the motor with the power steering?? i dont see why not, on our boat there seems to be quite a bit of room down there. but i was lookin at our starboard motor and it has a msd super blaster coil so im wondering if that motor already has the pertronix conversion or not? as far as the heat exchangers go when we took the boat on the sea trial the owner had it up on plane and wide open for roughly 25-30 min and they were running great, oil pressures were great, temps were great, and the boat was suprisingly fast it topped out at 38 according to the lowrance, now this was with 3 big guys, half a tank of fuel, and maybe another 400lbs of gear on board. so im thinkin with full gear, 6 people, full tank of fuel itll be slower but im so far very pleased with the 4 cylinders

I did the alternator on only one of my motors. It works fine, but it's not really ideal. The reason I did that was because the other motor has a power steering pump on it that goes where I put the alternator.

The single alternator puts out enough power, It's just tough to get the single alternator to charge three different batteries without combining the banks and without using the battery switch. I needed to buy a box that combines the different banks when the voltage goes above 13.5 volts and keeps them separate when the voltage drops, so it combines them during charging and then keeps them separate during use.

About the petronix conversion, I don't think it's really that big of a deal or worth it to upgrade. Just buy new points, condenser, ect. and have someone who knows what they are doing set it up. They aren't bad if they are set up properly.

About the heat exchangers, I would run the ones you have and see if the motors overheat. They most likely won't under normal conditions. If you keep them clean and keep the water pumps in the outdrives good, you should be fine.

These motors are not THAT bad, but they do suck. They are loud, idle rough, and shake a lot. No matter what. They are also quite finicky, requiring lots of tune ups. With older boats like ours though, it's best to just run 'em and deal with it. I actually have two working spares for parts, ect. Haven't needed much though.

Good luck!