FIXX

iTrader: (2)

Daytona sensors and a merc oe hall effect dist..the box is pricy but it wont break!!..http://www.daytona-sensors.com/products_ignition.html

vintage chromoly

iTrader: (3)

I really appreciate all the responses but, can anyone outline the reason to use a capacitive discharge ignition on a marine application?

Trying to determine if I really need a "box" or if I can simplify it with only an electronic breaker less ignition.

Thanks, rob

FIXX

iTrader: (2)

if your running a big cam it really helps burn all the fuel so it dont load up..other then that its the cool factor ..lol

mike tkach

iTrader: (3)

rob,you did not mention what cam you are useing but imo if the tuneup is right and it is not overly rich at idle you could use a merc t bolt 4 dist or any good quality stand alone dist.i recently learned of a way to stop the rust issues inside the msd,or any dist from a very wise man.after you get it all cleaned up spray the metal parts with crc sp400.NO MORE RUST.

vintage chromoly

iTrader: (3)

Thanks mike. Not sure what bob will spec for a cam yet.
I have the flow numbers and compression nailed down but I need to ensure the dry headers I have will fit so I can let bob know if the exhaust will be wet or dry.

Thanks to all for responding.

So to sum it up, the multiple spark ignition is good for low rpm usage so as to not load up plugs.

ThisIsLivin

I've certainly heard a lot of bad about MSD and I have had to replace my 6M after 10 years. I also had to pull my distributor and clean it up, also after 10 years. I used gun blue and treated all the steel components and then a light coat of WD40. That was 5 years ago and everything still looks like it did 5 years ago. Whether or not you need a CD box, depends on a lot of factors. I have a pretty lumpy cam, I'm carbureted and I like to cruise down the inland waterway which is at least an hour of idling. With my current MSD setup I can idle for an hour, get to the lake and stand on it and no signs of spark plug loading. I have also checked the plugs after a long river cruise and they look great. The advantage of the MSD is that it is marine approved so no Coast Guard or Insurance issues. I looked long and hard at the Mallory ignition when I did my rebuild but stuck with the MSD because the Mallory tech recommended against a marine application. I did add a vent tube to my distributor cap and will be connecting it to my air cleaner housing to help pull moisture out of the distributor. The advantage with the MSD is the availability of all types of custom advance bushings, I tried several different types before I settled on locking mine at 34 degrees. Also their HVC 2 coils rock for voltage spark duration and current. I'm just relating my experience, my boat starts as fast or faster than any of my state of the art EFI cars and trucks.

vintage chromoly

iTrader: (3)

Malloy sells a stand alone, electronic breaker less, distributor that is us coastguard rated and carries a "marine" label.

vintage chromoly

iTrader: (3)

Mallory marine is also infinitely adjustable as far as amount and timing of advance.

MILD THUNDER

iTrader: (3)

The rusting issue, like Mike Tkach said, can be solved by coating a new distributor internals, with CRC SP-400. I did mine a few years back, they still look great.

As for "NEEDING" a CD ignition, I say, no you dont "need" it. The multiple sparks at low rpm, isnt a "bonus" so to speak of. Its because it is NEEDED, with a CD style ignition. Most people think, ''Oh, multiple sparks at low rpm, must help for fouling plugs''. Thats really not why they have it. It is an area by design of that particular style ignition, that simply needs help, in that area. A conventional ignition, doesnt need those multiple sparks at low rpm. Its about the duration of the spark. CD ignitions have a short spark duration, where a conventional one will have a longer spark duration. At low engine speeds, the multiple spark, makes up for the loss of spark duration.

vintage chromoly

iTrader: (3)

So, is there really any advantage to a "box" ignition if the notion that the multiple sparks down low don't actually help the plugs from fouling?
Is the idea that the msd improves idle quality and prevents plugs from loading up not true?