Upgrade to CDI Ignition on 5.7L

[edbriden]

I had an ignition coil go bad on my Sea Ray 26 foot express cruiser. The engine is a carbureted 5.7 L, 325 HP Vortec which was new about 10 years ago. I would like to dump the standard coil/point and upgrade to a newer, hotter ignition. Has anyone done a marine-grade upgrade like this.
Things I am considering.

a. Add CDI ignition package and keep standard point arrangement.
b. Change points to an optical or inductive arrangement with CDI package.

Would appreciate any guidance you can give.

Ed

 

[rodbolt]

Re: Upgrade to CDI Ignition on 5.7L

you simply cannot go wrong changing to the DELCO EST system.
sierra,and a few others, offer kit packages.

 

[bomar76]

Re: Upgrade to CDI Ignition on 5.7L

I would avoid the MSD Marine systems like the plague.

Evidently they were never designed to be used anywhere near water. Rust and corrosion are epidemic in the MSD systems.

I'd go with rodbolts suggestion.

 

[Glastron_V210]

Re: Upgrade to CDI Ignition on 5.7L

I have a delco hei and it's the best thing on the boat.

It's not CDI though. It's a coil based (Inductive discharge) system with an ignition module in the distributor replacing the points.

If you do the change, make sure to get a dist which is NOT computer controlled (An early model)

Google hei and you'll find lots of info on the different models and required connections.

Chay

 

[edbriden]

Re: Upgrade to CDI Ignition on 5.7L

Thanks for the input on the Delco system. I'll check it out and let you know which way I go.
When you made the changes what were the results?

Easier starting?

Improved gas mileage?

Faster?

Ed

 

[wca_tim]

Re: Upgrade to CDI Ignition on 5.7L

what is wrong with a merc thunderbolt iv? of all the toys I've had with many ignition systems, it's probably one of the most bullet proof ignitions I've ever dealt with and really needs no upgrade for all around use. the only advantage i gained when I added the crane cd box was a smoother idle with the fairly long duration cam I'm running and a built in rev limiter I could set.

I would say there is NO speed increase to be gained with any other ignition.

what do you have in it now?

 

[edbriden]

Re: Upgrade to CDI Ignition on 5.7L

Currently it has a stock Mercruiser Distributor and coil. The coil got hot was bubbling oil out of it and it quit working. I don't know if it was suppossed to have a ballast resistor or resistor wire with it but when I turn the ignition switch on now with the coil in place, I get full battery voltage across it. And, since I will have to replace the coil anyway, I thought I might look at an upgrade.

I wish it were the Thunderbolt ignition. I wouldn't be considering an upgrade.

Ed

 

[Bondo]

Re: Upgrade to CDI Ignition on 5.7L

I wish it were the Thunderbolt ignition. I wouldn't be considering an upgrade.
Currently it has a stock Mercruiser Distributor and coil.

Ayuh,... So what is it,... Merc.s been using the T-Bolt for Years....

 

[bomar76]

Re: Upgrade to CDI Ignition on 5.7L

I consider the Mercuiser Thunderbolt IV ignition system to be the best ever offered.

 

[edbriden]

Re: Upgrade to CDI Ignition on 5.7L

Thanks for the many comments. I picked up a used Thunderbolt IV and should have it installed this weekend. I still need to pick up a coil, though. I plan to get the standard Merc coil for this unit (P/N 805570A2) unless someone has a better idea.
Thanks again for all your suggestions.

ed

 

[wca_tim]

Re: Upgrade to CDI Ignition on 5.7L

crap, had you posted this yesterday, I'd have given you one. I have several "spares" and was in the triangle area today... either way, hope it works out well for you. Cheers (and maybe see you on Jordan, we get up that way a few times every summer...)