Electronic Ignition Conversion Question

[Gilded_Splinters]

I plan to change over to Pertronix kits in the spring and have a question:

I have heard and it's stated on the Pertronix web site that there are "special instructions" pertaining to some circuitry that needs to be made in order to have this work in an OMC situation, and this is fine.

On the Sierra site, they have what appears to be the identical kits that they even call "Ignitor", "Ignitor II", etc., but they say that they will not work with electric shift assist modules.

Now if you're wondering why I don't just buy from Pertronix, it's because I have a friend that works for a marine parts wholesaler and I get a massive discount on anything that I buy as long as it's from a brand that they carry. They carry all Sierra products, but not Pertronix.

So...the question is (finally) - Can I assume that these are the same kits and that the same adaptive electronic junk will work?

Also, what are the particulars of the resistors and such that are needed to pull this off.

Thanks.

 

[bruceb58]

You can buy a CDI ESA that is compatible with the Pertronix and not need the diode circuit.

Personally, I would just keep the points.

 

[Gilded_Splinters]

I'm curious...

Why would you keep the points??

In my case, I'd deal with them, but the distributors are in an impossible position and closely obstructed from above. It's a hassle just to get the cap off. Setting the points in the shadows with a mirror is a bummer.

The CDI units are $112.00 each.

$224.00 makes the diodes seem a much better choice.

 

[bruceb58]

A way better choice would be to switch to a Delco Voyager distributor.You have twin OMC Cobras?

I think points are more reliable that the Pertronix ignitors.

 

[Gilded_Splinters]

Yes, twin OMC Cobras. Double trouble.

I mentioned that the distributors are hard to work on.

They're not removable without removing the engines. I know that sounds crazy, but there it is anyway. You might be thinking: "Cut hatches in the deck." No soap there either. Right above the distributors is a large, glassed in structural member, which is really the root of the problem.

Points when accessible are inconvenient. Reliable, but inconvenient. Points that you can't see are a big pain in the ass that I'm not dealing with any more.

So...back to the original question. Anyone know if the Sierra and Pertronix are the same?

 

[bruceb58]

I see your issue.

Just so you know, OMC came out with a revised ESA after your engine came out. It uses a timer rather then the overstroke switch. It;s a way better design and the newer CDI ESA incorporates the same design. Kill 2 birds with one stone.

Yes, twin OMC Cobras. Double trouble.

Funny, I was thinking that would be the perfect name for your boat.

 

[Lou C]

Interesting, I knew that CDI made an ESA for the electronic distributors . They also make one for the old points systems which I just used to replace my OE one that just quit working ; but this one still uses the over stroke switch. The new ones from OMC/BRP for sure use the timer because the wiring is different . On the CDI one I just installed the wiring is the same as the original one.

 

[HT32BSX115]

Personally, I would just keep the points.

I agree.

My last boat had points ignition for 39 years (1966 Mercruiser). Very reliable. My last engine in my current boat (The OMG 460 King Kobra) also had points ignition from 1987 until I removed it in 2006 (19 years) VERY RELIABLE.

Yes, twin OMC Cobras. Double trouble.

It would really be Double TROUBLE if it was twin 460's!!

 

[bruceb58]

On the CDI one I just installed the wiring is the same as the original one.

Would still use existing wiring. You don't need to rewire. As a test, hold down your overstroke switch and then the shift switch and see if the engine stumbles. The CDIs have not been using the overstroke switch for a long time. Part number?

 

[Offrddrver]

No Title

[FONT=&quot]G.S.[/FONT]​

[FONT=&quot]I'm responding to your original post questions and comments.[/FONT]

[FONT=&quot]1. I recently upgraded to the Pertronix Ignitor II sensor and Flamethrower II coil (oil filled) from the original Prestolite BID sensor (not points) and original oil filled coil. (see attached picture 3)[/FONT]​

[FONT=&quot]A. Long term reliability - ? I don't know as I have only had three outings with it (no issues so far)[/FONT]​

[FONT=&quot]B. Performance - (after original tuning and 1 additional fine tuning) - Much better then before install. Holeshot is great, and ramp up to W.O.T. feels very strong. Top end speed on my "power prop" stayed the same, (42 mph), but that may just be the dynamics of the prop Vs my boat size/shape. I haven't tried my other "speed prop" with this setup yet as top end speed it not my goal. My goal is pulling a 265 lbs slalom skier out of the water without dragging/submerging him, and this setup helped/cured that problem.[/FONT]​

[FONT=&quot]C. Install - ? Very easy on my boat, required simple wiring change due to the Diode & Resistor circuit install. Also required timing adjustment/calibration after install, and spark plug gap increased from .035 to .040. (Timing light, rotate distributor to get 10deg BTDC, check advance ....simple stuff.)[/FONT]​

2. The circuit is shown in attachment 1 and my version of it is in attachment 2.

[FONT=&quot]A. Diodes 400 PRV, 3Amp Rectifier= Fry's Elecronics #: 1808711 or NTE: 5804[/FONT]
[FONT=&quot]B. Resistors 47k ohm ? Watt 2% Tolerance= Fry's Electronics #: 999316 or NTE: HW347[/FONT]​

[FONT=&quot]C. I used water resistant AMP connectors to modify the boat connectors, they are the sealed version to prevent spark or water problems. (they are used in the semiconductor industry on liquid chemical systems) Sorry I don't know the part number as I obtained these years ago.[/FONT]​

[FONT=&quot]D. I used AMP pins to connect the wires within the connectors.[/FONT]​

[FONT=&quot]E. I used a small solder joint circuit board to solder the components together. (see attached picture 2)[/FONT]
[FONT=&quot]F. I used a 4x AA battery box (modified) as the mount to make it look clean. (see attached picture 4)[/FONT]​

[FONT=&quot]3. Ignitor and Flamethrower or (II (2) Versions)[/FONT]​

[FONT=&quot]A. The SIERRA Flamethrower II (18-5472) picture and listings match what I purchased from Summit racing (Pertronix Flamethrower II).[/FONT]​

[FONT=&quot]B. The SIERRA Ignitor II catalog listings are an unknown for me. Here is why.... [/FONT][FONT=&quot]The picture for Sierra Ignitor II units are shown in black, but my direct contact from Pertronix states all Ignitor II units are RED. [/FONT][FONT=&quot]However, the Sierra catalog states it is an Ignitor II unit, and it also states to use with the Flamethrower II coil. My Pertronix contact stated to use the Ignitor and Flamethrower together, and to use the Ignitor II and Flamethrower II together, but does not recommend mixing one to the other.[/FONT]​

[FONT=&quot]C. I have the Pertronix contacts name, number, and e-mail if you are interested in talking with him. He may be able to tell you that they sell to Sierra directly. Direct mail me (however that works within the Iboat site) and I'll give you his information.[/FONT]​

[FONT=&quot]D. "they say they won't work with the ESA" - That is correct as directly stated. These units, senor and coil only, will not work directly with the OMC Cobra ESA modules alone. However, with the Diode & Resistor circuit installed between the coil and the ESA then it will work, just as mine and many other's do.[/FONT]​

[FONT=&quot]4. I did not buy direct from Pertronix either, as it was cheaper through Summit Racing, but Pertronix rep Bill has been great to work with and answered all of my questions even though I didn't buy from them direct.[/FONT]​

[FONT=&quot]A. Sierra: $200.00+ for Ignitor II (Summit Racing: I only paid $130.00)[/FONT]​

[FONT=&quot]B. Sierra: $50.00+ for Flamethrower II (Summit Racing: I only paid $37.00)[/FONT]​

[FONT=&quot]C. I know your buddy can get you a great discount, but can his discount beat others Non-Sierra Versions of these same parts? You may still want to price compare.[/FONT]​

[FONT=&quot]I hope this helps you in some way. I can only say the Ignitor II, Flamethrower II, and circuit install is working for me at this time.[/FONT]​

[FONT=&quot]I am looking into the CDI ESA module also, but at this time I can't drop the cash on it considering the upgrade circuit is working for me. [/FONT]​

[FONT=&quot]Also, one more benefit I just remembered; I noticed that my shifting feels and sounds much smoother now that everything is installed. That was just kind of a bonus.[/FONT]​

[FONT=&quot]Best of luck on whatever you decide.[/FONT]​

[FONT=&quot]Offrddrver[/FONT]​

 

[bruceb58]

If you get a performance improvement, your points were not adjusted properly. In your case, you did not have a points distributor but a failing electronic distributor!

There should be no performance difference between points and a Pertronix ignitor.

Shifting should definitely not be different.

Offrdrver, why are you using 47K ohm resistors when you are supposed to be using 4.7K ohm resistors?

 

[cionjay]

the igniter from sierra is the same one from pertronix. I would suggest to purchase the ignitor (original. Not ver. 2 or 3) Use the flame thrower 3 ohm (original. not ver. 2 or 3). CDI makes a new heavy duty ESA for OMC. Even if you buy the sierra product, pertronix will honor the warranty for 2 years (keep your receipt). It is easy and straight forward install. Good Luck

 

[Offrddrver]

Sorry G.S

4.7k ohm resistors is what I used, not 47k ohms.
I looked up the part number again for you: Fry's Electronics #: 999266 or NTE: HW247 = 4.7k ohms 2% Flameproof resistors.
I clicked on the wrong part when I was researching, sorry about that.
Just follow the diagram as it is from the Pertronix site, (my attachment) and it will be correct.
Make sure your diodes are in the correct orientation if you choose to use this circuit.

Bruce, I only state my findings as they worked for me. I don't try to guess how they will or won't work for others.
Yes, my shifting did improve, and no I made no additional adjustments other then adding this setup.
Maybe rough shifting prior to install was part of the failing/shorted Prestolite unit or maybe not..... I don't know how that effected my shifting. All I know is it is better with this setup.

And my Prestolite wasn't always bad, and yes my boat feels like it performs better than ever before and I know the holeshot is better than every before, because I'm the skier that is being pulled in my comments.

Best regards C.S., again sorry for my 4.7k Vs 47k ohm writing/research mistake.

Offrddrver

 

[Gilded_Splinters]

Loads of good info here.

Thank you all very much. I will update as conversions are made.