distributor question

[Twolane]

Have a 250 Chevy inline six that's a Mercruiser 165. Generally unmolested original drive train in an old 79 model boat.

It has an old points type distributor. I can visually see the differences between the marine alternator and starter from what their automotive counterparts would be. Can't immediately see what's different about the distributor though?

Ask because I have a couple of old HEI distributors setting around. Is there a reason not to lose the points type OE setup and swap in the HEI distributor? Thanks.

 

[markheck1]

Re: distributor question

The marine distributor will be sealed so no fuel vapor can get inside the distributor and ignite.
Simply put Auto distributor + Enclosed engine compartment = BOOM

 

[Twolane]

Re: distributor question

So it's a difference in the distributor cap somehow not venting? Some difference in the housing? Lack of a vacuum advance so no intrusion around where the advance enters the housing?

"Simply put" is a nice simple explanation. But it doesn't explain how the difference is achieved.

Sign me,

Just Curious


Now on the same note.... If a common HEI distributor isn't an option are there aftermarket electronic ignition kits to replace the points within the distributor for the marine aftermarket as there is in the automotive aftermarket? And do these kits have a good reputation?

 

[cr2k]

Re: distributor question

The advance curve will be different also for a little more performance for an UN smogged engine.

 

[thumpar]

Re: distributor question

Look at getting a Pertronix ignition. It will convert it to electronic ignition. I would recommend the Ignitor II or III. My dad has been running one on his 66 mustang for probably 10 years and I converted my Mercruiser to the Ignitor II a couple years ago. I gained a couple hundred RPM and easier starting. When I did mine I also got one of their coils with internal balast to make it easier.

 

[Oshkosh1]

Re: distributor question

The marine dizzy will have a sticker on it saying it's for marine use...

Also...

I thought of coverting to a Pertronix...but didn't. Set the dwell/timing correctly, ensure plugs, wires etc are all in good working order and I can't see where there would be much difference in starting/performance in THIS motor...in a marine enviroment over OEM. My motor starts within 1 rev cold, holds a rock solid idle, and from what I can tell...performs to the limit of the fuel system/carbuerator.

Obvioiusly it's "no maintenance" so that whole 15 minutes it takes to check/adjust/replace in need be the points on a yearly basis will be saved, and you MAY(but I doubt it's even measureable in a boat) see a very small increase in fuel efficiency due to the larger plug gap/hotter spark,...but it would take a MASSIVE amount of fuel consumption over YEARS(decades in my case)to see the return on the price of the coil/module etc,...but hey...I do think the coil has a cool flame on it!

Just my take! Good luck!

 

[Twolane]

Re: distributor question

Look at getting a Pertronix ignition. It will convert it to electronic ignition. I would recommend the Ignitor II or III. My dad has been running one on his 66 mustang for probably 10 years and I converted my Mercruiser to the Ignitor II a couple years ago. I gained a couple hundred RPM and easier starting. When I did mine I also got one of their coils with internal balast to make it easier.

That's good to know. If wanted to do a conversion and lose the points can use the same Pertronix kits that come from the automotive aftermarket. Just need to stay with the marine distributor and cap to avoid the aforementioned "boom." "Boom," of course, being a bad thing....

 

[Twolane]

Re: distributor question

The marine dizzy will have a sticker on it saying it's for marine use...

Also...

I thought of coverting to a Pertronix...but didn't. Set the dwell/timing correctly, ensure plugs, wires etc are all in good working order and I can't see where there would be much difference in starting/performance in THIS motor...in a marine enviroment over OEM. My motor starts within 1 rev cold, holds a rock solid idle, and from what I can tell...performs to the limit of the fuel system/carbuerator.

Obvioiusly it's "no maintenance" so that whole 15 minutes it takes to check/adjust/replace in need be the points on a yearly basis will be saved, and you MAY(but I doubt it's even measureable in a boat) see a very small increase in fuel efficiency due to the larger plug gap/hotter spark,...but it would take a MASSIVE amount of fuel consumption over YEARS(decades in my case)to see the return on the price of the coil/module etc,...but hey...I do think the coil has a cool flame on it!

Just my take! Good luck!

Don't disagree with a thing you're saying. The slight difference might be measurable on an engine dyno. But I don't expect to feel it in the seat of my pants. This is just about doing a few things to a new-to-me old rig because I want to. Need isn't figuring in. Just want to make sure nothing that's done causes problem rather than reduces them.

 

[stonyloam]

Re: distributor question

That's good to know. If wanted to do a conversion and lose the points can use the same Pertronix kits that come from the automotive aftermarket. Just need to stay with the marine distributor and cap to avoid the aforementioned "boom." "Boom," of course, being a bad thing....

Actually you keep your old distributor, just replace the plate inside with the Petronix conversion. Put in the Ignitor II module, the Flamethrower II coil and lose the resistor and you are good to go.

 

[generator12]

Re: distributor question

Look at getting a Pertronix ignition. It will convert it to electronic ignition. I would recommend the Ignitor II or III. My dad has been running one on his 66 mustang for probably 10 years and I converted my Mercruiser to the Ignitor II a couple years ago. I gained a couple hundred RPM and easier starting. When I did mine I also got one of their coils with internal balast to make it easier.

+1 - My Merc starts and runs so much more smoothly with the Pertronix.....

 

[Twolane]

Re: distributor question

Actually you keep your old distributor, just replace the plate inside with the Petronix conversion. Put in the Ignitor II module, the Flamethrower II coil and lose the resistor and you are good to go.

Familiar with the Pertronix products. Have used them in street rods or classics for years. Knock on the proverbial wood have yet to have one fail. A nice little install-and-forget-it upgrade.

 

[thumpar]

Re: distributor question

One thing to remember about the Pertronix units. If you get the original Ignitor don't leave the key on without the engine running. It will burn the unit out. In the later models they put in protection for that.

 

[Twolane]

Re: distributor question

One thing to remember about the Pertronix units. If you get the original Ignitor don't leave the key on without the engine running. It will burn the unit out. In the later models they put in protection for that.

Thanks for the flashback. Had forgotten about that but made exactly that mistake once at a cruise in with an old 56 T-bird. Not always the smartest tool in the box....

 

[dukebrown]

Re: distributor question

Don't disagree with a thing you're saying. The slight difference might be measurable on an engine dyno. But I don't expect to feel it in the seat of my pants. This is just about doing a few things to a new-to-me old rig because I want to. Need isn't figuring in. Just want to make sure nothing that's done causes problem rather than reduces them.

I switched from points to electronic ignition on my Mercruiser 888 and was amazed. The boat ran great before the switch but runs much, much better with hotter spark. Picked up 5mph top speed and seems to drink less fuel.