Marine HEI Distributor

As most of you know I am not an advocate of using automotive parts on a marine engine. However after recent talk about HEI conversions it got me doing some research.
What I found is the automotive distributors sell far below 100.00 some as low as 40.00 as for the marine version more like 300-400. So I ask the question exactly what is the difference between automotive and marine distributors. This is almost impossible to find out, lots of info on fuel pumps,carbs,alts and starters but almost nothing about distributors. So besides vacuum advance and venting I see no difference between the two . If anyone has any facts about marinizing a automotive dist let me know.

My understanding is that a Marine distributor is sealed to protect the spark from getting to possible gasoline fumes in the engine/doghouse area. This is not necessary on a automobiles due to the fact that the fumes will vacate the engine compartment on their own. On a boat they have nowhere to go unless your blower is activated...

That is somewhat true however there are 3/8 holes covered by fine brass screen in the bottom of the stock dist. Gas fumes are heaver than air so im pretty sure they are there to vent the cap.

A reverse rotation engine will have a different gear.

Yes it will they are available too my 89 is standard rotation.

AFAIK the difference is in the venting. That fine mesh screen on the ventilation holes is to prevent spark from escaping the unit, hitting the fuel vapors in the bilge and causing an explosion. The marine dizzys have those screens in place but other than that use the same caps, rotors and assembly.

I've got a friend that has big dollars into his drag cars. When he showed me the $50 ebay distributors that he runs, I was a convert. I've run them in everything since then and have never had a problem.

Now, why don't they add the screens and market them as "marine?" Demand. They can crank out a container load of automobile dizzys and sell through them relatively quickly. The market for the marine unit is much, much smaller.

So here is where I am . I bought the dist and 8mm wires . I then removed the vac advance and installed a aluminum bracket to prevent the pick up coil from moving. Then I filled the hole in the base where the vac advance went through. I then drilled 2- 3/8 holes in the bottom of the unit and epoxied fine brass screens to the inside. I installed the dist and wires and checked the timing. The total advance of the original dist was 15 degrees it was the same on the HEI unit so no modification was required. Engine starts immediately and runs great . I will keep you posted as time goes on.

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I just did this conversion on my 87 Comp. I went with the DUI HEI distributor from Performance Distributors. They build the distributors specifically for your application so as to have the proper timing curve and advance. What is your total timing above 3000 rpm's? You should see between 30-35 degrees. If you only get 15 degrees total advance from the distributor and then you base timing will need to be at least 15 degrees and that's a bit much according to most opinions. My DUI distributor was calibrated to have 24 degrees of total advance so when I set my base timing to 10 degrees like we all seem to do then I get 34 degrees total timing above 3500 rpms. Most all of the automotive distributors rely on the vacuum advance to get the total time to where it needs to be at the higher rpm's so I would be interested to see how much total advance you get with your base time at 10 degrees.

Thanks for the info I just ordered a advance curve kit from summit . I will play with it next week. So you are saying total advance including base timing should be about 34 degrees.

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Originally Posted by michael hunter

Thanks for the info I just ordered a advance curve kit from summit . I will play with it next week. So you are saying total advance including base timing should be about 34 degrees.

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You didn't have any fitment issues with the thermostat housing and body of Dizzy ? What setup are you using any links !!?


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I'm really interested In your findings , and how did you fit the distributor in next to thermostat housing ? I wanna use a HEI on my engine build to clean up the wires and ballast resistor . Did you just pick one up of eBay ?


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its a tight fit but doable . I got it on ebay. I set the advance weights to 30 degrees max advance . It runs great time will tell how it will all work out.

Hello Michael,
I just receive my HEI + 8.5mm ACCEL wires, and will do the swap soon.

What spark plug do you use behind of your HEI ?

Thanks

Same plugs just open the gap to 45.