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ignition.. ditributor marine VS automotive

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I need a new distributor for my engine.

Mercruiser 350 magnum ski tournament.

5.7 v8

In my opinion it is just a regular (chevy) gm 350 automotive motor with some marine Parts. Now I want to place a Hei ignition distributor (2 wire) that you also can buy at an autoshop.

My dealer said that i need an special marine distributor,because a distributor for an chevy 5.7 v8 (same engine) will give troubles.

Can Some body give me some info.

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Marine electrical components are designed to operate in an engine compartment with poor ventilation and the high potential for fuel vapor. As was mentioned there is extra spark arresting protection and some additional measures to combat corrosion due to the wet environment.

Even aftermarket companies like MSD and Mallory have marine specific distributors (housing and cap are different for sure).

Get the right parts just to be safe. Skidim is a good source of you feel the dealer is over priced.

  • Like 2
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What part of the distributor is bad? I have one I removed from my engine which is same as yours but I removed the shaft. One thing to look at are the kits on Michigan motorZ website they get rid of the mercruiser ignition module which is expensive

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Also, an automotive distributor is a vacuum advance distributor and a ma4ine distributor is not. A marine distributor is weighted for full advance as boats go up hill all day long...

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My 95 has the exact same distributor as yours. Same as the car version. Mine corroded badly, but still useable. I replaced most of the parts, but in the long run, a 3rd party designed for marine use would wear and work better. I'd change the coil to match too.

You'll be glad you did, nice hotter spark to the plugs, easier starting, etc.

Steve B.

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My stock Vortec distributors' advance is controlled be the engine controller (MEFI). It has no advance built in.

Also, the original cap and rotor appeared to be automotive grade, they had aluminum contacts which had substantial corrosion on them. I replaced them with Accel parts that were brass.

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Thnx for the info.

So there is not much difference, only the price, alu or brass, vent capsules.

For an marine distributor you pay twice as much.

I think I order a msd pro billet automotive distributor (hei)

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Um, spark arresting is a big deal. I've seen the results of an automotive starter used on a boat. The fumes lit off and sent the engine cover in the air when the engine was cranked. The only thing that put out the ensuing fire was the fact the boat was in the water and started to sink.

An automotive part "may" not cause an issue but why risk it.

  • Like 3
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An unusually big gasoline engine under a boxcover.... even with a blower, it's serious stuff. You pay for insurance, you should pay for the right marine equipment and ensure you keep you and your pasengers safe and sound and happy. Piece of mind is also worth much, knowing you did all you could to do it right. Save $$ somewhere else ;-)

Edited by malibuparadise
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PS I use mallory marine (magnetic) distributors on both my boats (carbed).They look cool too.

Looking cool and not going BOOM are both very cool IMO!

Edited by Rednucleus
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There are a lot non-marine parts I would use in an engine (I built the engine in my boat with mainly non-marine components) but anything dangerous, that can cause an explosion, is all marine.

And that's coming from someone calling themselves "Madman"!

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@timalibu: are you planning on changing plug type and gap for the HEI upgrade or run the engine at a higher speed and need to compensate for the smaller dwell time. The thunderbolt IV Merc system is pretty darn reliable and you can get different advance modules if you want to alter the ignition curve. The thunderbolt IV has no problem at 10:1 compression and if yours is stock, it is only 9.4:1 so not near the working limit of the system.

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Certainly I change the gap.

I fixed an automotive distributor from a chevy 350 tbi. And compare it with my marine distributor. The only diference is that the marine version got some holes in the botomplate!!!! For a automotive Hei ignition distributor I pay 100 .

the marine version is 380,-....

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