Ignition coil

[cc lancer]

Re: Ignition coil

I have never seen or heard of an internal coil resistor on a automotive base marine engine.<br />Resistance on the older engines Ford and Chrysler used the ceramic ballast resistor, Chevy used the resistant wire.<br />Coils that I have seen and used come in different voltage output, from a low of 35,000 up to the MSD Blaster Coil which is rated at 45,000 volts.<br />All coils are not created equal, there are differences in quality and the ability to suppress moisture from entering the coil.<br />Boats owners should check the coil tower periodically for cracks and carbon traces going to the primary or negative terminal. If found the coil and wire should be replaced. The MSD Blaster which is used in marine and racing applications is the highest quality out there. I have been putting them on boats for over 10 years, and not a single failure. Sure they cost more, but I don't want a coil failure 25 miles off shore.

 

[Scaaty]

Re: Ignition coil

Most electronics just whiz by me, and I stick to mechanical stuff. But just to second a point DonS made, AND to answer Luckypenny's original question -why do some (Rabidfish and Buttanic excluded, as I always seem to understand and learn something from them) here wander so far off subject and screw everything around is beyond me- is a page just looked at from Custom Chrome on Coils for Harley-Davidson. On one page only, there are coils with the following resistance. <br />1.5<br />2.3<br />2.8<br />3.0<br />3.8<br />4.2<br />4.5<br />4.7<br />4.8<br />5.0<br /> And last I looked, Harley don't make a whole bunch of different motors (more like 3). So, I think that shoots to hell the theory of just a couple of coils for for the vast Car/Boat world. Luckypenny, yes there are differences...subtle...but enough to get the correct coil called for. If you would like to upgrade off points to electronic, you can go the "Pertronix" route, but for a few more bucks, go with a new electronic distributor. And any upgrade make sure you do it all, including coil and wires and what ever the new system's calling for in plugs. Hope this helps.

 

[Scaaty]

Re: Ignition coil

Originally posted by cc lancer:<br />[QB. The MSD Blaster which is used in marine and racing applications is the highest quality out there. I have been putting them on boats for over 10 years, [/QB]

BUT, would you put one of those on Luckypennys old 77 350 points ingnition without upgrading anthing else?

 

[Don S]

Re: Ignition coil

Before people that don't understand coils start buying into the misinformation that the only difference between coils is 6 or 12 volts and internal or external resistor, ought to read the information in the link below. <br />In any coil there is both primary and secondary resistance (Also not talked about by those that THINK they know coils).<br />For Mercruiser coils, those values are in the service manual for the engine. How you find that information for a cheaper automotive coil is beyond me, most coil labels don't have that information.<br /> Coil Information <br /><br />Anyone ever hear this quote before?<br /> "If you can't dazzle 'em with brilliance, baffle 'em with bull $---."

 

[rabidfish]

Re: Ignition coil

I think Don has expounded on one or more of the issues I was trying to address. Thanks Don!<br /><br />The point is: There are many factors that go into an ignition coil design. Not just primary voltage, and secondary voltage. <br /><br />I thereby stand behind Don's original statement:<br />(I use the correct parts)to ensure the best chances for the boat to come home safe!

 

[trog100]

Re: Ignition coil

"Coils that I have seen and used come in different voltage output, from a low of 35,000 up to the MSD Blaster Coil which is rated at 45,000 volts."<br /><br />yep and the high voltage output is all governed by the current that goes thru the primary and how cleanly its switched..<br /><br />the blaster u mention needs transistorized ignition to get that 45000 volts.. and takes more current thru its primary than points can manage..<br /><br />45000 volts is total overkill.. "marketing hype" 8000 is enough to fire a plug under normal circumstances..<br /><br />the other governer here is exactly what voltage is required to jump the plug gap.. if it only takes 8000 volts to jump the gap (45000 blaser or not) thats all it gets..<br /><br />in extreme conditions.. weak mixtures.. super high revving engines.. oily two strokes.. a few more volts helps.. but unless its really needed its just wasted.. pretty much like that blaster coil is on the average boat..<br /><br />my 1.5 and 3 ohm figures are rough guides.. for points type engines and only intended to offer a way of telling whether or not a resistor should be in circuit.. <br /><br />there are probably a million slight variations on a theme mainly cos it really aint critical.. and harley might well have a whole gamit tween 1.5 and 5.. but i am quite sure they dont really need em.. he he <br /><br />folks love to complicate things.. but your average coil really aint that complicated nor is the basic principles as to how it works..<br /><br />also.. modern (none boat) engines fitted with electronic ignitions tend to have forty or so thousands volts as opposed to the old points thirty thousand or so fed to the plugs because of economy and emission controls.. modern car engines need all the help they can get to keep lean burn technology firing away happily without nasty misfires.. on an old boat engine it would be totally wasted.. <br /><br />trog100<br /><br />ps.. and don quite wisely avoids all this crap by saying use the part number quoted for your boat.. i make the stupid mistake of trying to explain in simple terms how something works.. i never learn do i.. he he he

 

[rabidfish]

Re: Ignition coil

Still... it's a good discussion to have. Maybe someone will read it that wants to know something about their coil/ignition system.<br /><br />The ignition system (even a basic one) is often misunderstood, it helps to shed a little light sometimes.

 

[rodbolt]

Re: Ignition coil

trog<br /> gotta dissagree with your numbers. after using an instrumentfor many yras that measures secondary voltage in Kv. on most all systems that use a gap of less than .o8" on a side electrode plug you wont find much over about 12 Kv if all is normal. surface gaps tend to run 10 -15Kv. all the hype on the side of the coil indicates is the amount of voltage avalible to spark IF needed. such as a dirty plug abnormal cyl pressures and what have you. lectricity,bass and me are right lazy. lectricity maybe slightly more than me. most auto ,marine and outboards see a typical 5-10 KV on the secondary side. if you see more investigate the problem. man them snapon Kv testers are great. if it dont need 45Kv toarc and only needs seven then 7 is what ya get even though the system is technically capeable of more.<br />but I do agree that its just to simple to purchase the correct part and let it ride <br /> makes life easy

 

[Don S]

Re: Ignition coil

Probably the same thing I have.<br /><br />

 

[rodbolt]

Re: Ignition coil

thats the one.<br /> man is it handy.<br /> hey was that you that was trolling for Orcas with salmon? seems a waste of salmon

 

[trog100]

Re: Ignition coil

yes my secondary voltages were more based on what the system is capable of as opposed to what is actually being used.. my 8000 wasnt far out thow..<br /><br />i can never remember figures anyways.. he he<br /><br />trog100<br /><br />ps... a quote from your totally beyond the comprehension of normal folks link don.. easy aint it.. point to a none understandable link.. i could have done that.. he he<br /><br />####<br /><br />"In typical use the coil is connected in series with a ballast resistor of a few ohms to reduce the voltage, which in turn reduces the current through the coil so it doesn't burn up. The ballast resistor isn't used during cranking (when the battery voltage is usually reduced to around 6-8 volts). A typical DC coil resistance would be around an ohm, and at 12 Volts, the DC current would be 12Amps, dissipating more than a 100 watts"<br /><br />####<br /><br />1.5 ohms aint far of "aound an ohm".. he he.. and a "few ohms" is even nmore accurate.. he he he.. the rest is just gobble-de-gook to most folks.. and of course it fails to mention totally the many coils out there that dont need a balast resistor at all.. these of course would have the magic formula of "around an ohm" and a "few ohms" all in one.. he he he<br /><br />and the 12 amps typical use is total and utter rubbish.. the power transistor on my assisted system is rated at 4 amps nominal.. i dont think it would take kindly to having 12 amps going thru it all the time.. neither would normal points..

 

[Don S]

Re: Ignition coil

Nope, wasn't me...... Darn it. <br />He should have slowed down, and let the orca swallow the bait, then he would have had a battle on his hands for sure <br />Besides, I always heard the bigger the bait the bigger the fish you catch <br /><br />trog, if you can't remember figures, maybe it would be a good thing to not spout figures unless you are sure of them. Some people believe everything they read. <br />The good ole "Garbage in, Garbage out" routine.

 

[trog100]

Re: Ignition coil

u trying to make me insult u don.. he he he<br /><br />i am on probation u know..<br /><br />trog100

 

[Don S]

Re: Ignition coil

u trying to make me insult u don..

No, I'm trying to make you stop giving inaccurate and partial information.<br />A coil has 2 sections, Primary and secondary. You seem to only want to talk about the primary side, when the secondary is just as important.<br />I'm quite sure the ignition designers speced out a 40K volt secondary on some coils, just to tic you off, and it had nothing to do with what the system actually needed under varing conditions.

 

[newport dave]

Re: Ignition coil

There is more required of the coil than just firing the plug. While the firing voltage is important, the more important issue is burn voltage and time. <br /><br />That is the amount of voltage (kv) available to maintain spark (burn). The higher the firing kv and burn kv, the shorter the burn time. <br /><br />All cylinders are using all the energy available to them. What is not used in firing the plug is used in maintaining the spark, the spark ends when the energy available from the coil is depleted. So a better coil will still fire a plug at around 10kv, but it will result in a longer burn time and more complete fuel burn.<br /><br />Below is an example of a burn voltage vs burn time. The upper set of waveforms is primary voltages. The lower set is the secondary voltages.<br /><br />If you look at the secondary ignition waveforms, you will see the second cylinder (#8) in the firing order looks different. There is a problem (bad plug in this case) that is requiring more voltage to fire the plug and maintain the spark. Thus you see a high firing voltage, a high turbulant burn line, and reduced burn time.<br /><br />Dave<br /><br />

 

[rodbolt]

Re: Ignition coil

wow<br /> been a while since I ran an ign analyzer. dont miss it much though <br />in the marine world we usually cant access the machine to the boat and most dealers arent going to buy one . however with my CD-77 and my Kv tetser and a good timing light I can usually find it fairly rapidly. trons is trons and we really dont care what its used on. the key is understanding what the ign system does and how it works. after that its just another thing to inspect and eliminate or repair

 

[tommays]

Re: Ignition coil

this is much better than and oil post i am learning some good stuff<br /><br />tommays

 

[cc lancer]

Re: Ignition coil

Robby6950 asks:<br />BUT, would you put one of those on Luckypennys old 77 350 points ingnition without upgrading anthing else?<br />The Blaster comes with a Ballast Resistor that must be use with point ignition.(It plugs in the top of the coil)<br /><br />Rodbolts post on February 26, 2005 05:19 PM says it best, the voltage is there if needed.

 

[cc lancer]

Re: Ignition coil

In reference to Don's link concerning a coil.<br /><br />Frog100 says:ps... a quote from your totally beyond the comprehension of normal folks link don.. easy aint it.. point to a none understandable link.. i could have done that.. he he<br /><br />For you information it was written by Jim Lux<br />senior electronics engineer for the North American<br />Space Administration...uhh NASA.<br />There fore I would to believe anything Mr. Lux said.

 

[Buttanic]

Re: Ignition coil

Of all the parts on an engine that could be replaced with non OEM parts that are not a perfect match to OEM specifications I believe a coil is one of the least likely to affect operation. Swapping carburators and camshafts with aftermarket non OEM spec ones can give you a world of problems unless you are very knowledgable in those areas. Just my opinion from 40+ years of street and racing engine experience.