#26
IP: 206.125.176.3
|
||||
|
||||
Yup....flying down the creek at 2,000 RPM!
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#27
IP: 24.152.131.220
|
||||
|
||||
Quote:
I think but as yet cannot prove a big part of what is aggravating our coils is the dwell common in electronic ignition. What's our A-4 specified dwell, 31 degrees? Well, my Pertronix measured at 62 degrees and there ain't nuthin' I can do about it. I can't see any other difference between the two (points and EI) but this difference is significant.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others |
#28
IP: 75.68.130.228
|
|||
|
|||
More dwell means more amps is flowing through the coil, generating more heat.
If we knew the minimum amps needed to create the spark needed then we can calculate the total resistance needed to stay below the 4 amps The other solution is maybe there's another coil that can take the higher amps Steve Last edited by smosher; 09-23-2011 at 04:32 PM. |
#29
IP: 174.65.54.224
|
||||
|
||||
This is an excerpt from Wikipedia on Resistors:
"The term also refers to an automobile engine component that lowers the supply voltage to the ignition system after the engine has been started. Because cranking the engine causes a very heavy load on the battery, the system voltage can drop quite low during cranking. To allow the engine to start, the ignition system must be designed to operate on this lower voltage. But once cranking is completed, the normal operating voltage is regained; this voltage would overload the ignition system. To avoid this problem, a ballast resistor is inserted in series with the supply voltage feeding the ignition system. Occasionally, this ballast resistor will fail and the classic symptom of this failure is that the engine runs while being cranked (while the resistor is bypassed) but stalls immediately when cranking ceases (and the resistor is re-connected in the circuit)." I thought it was interesting as to "why" our coils are designed to operate at the lower voltage.
__________________
"Jim" S/V "Ahoi" 1967 Islander 29 Harbor Island, San Diego 2/7/67 A4 Engine Block date |
#30
IP: 151.200.21.32
|
||||
|
||||
Jim...my understanding is that coils were originally built at 6 volts & they supplied sufficient voltage for spark plugs to work. the coil technology hasn't kept up with the shift to 12v apparently..This is an entirely layman's answer and I don't really know...just my own personal theory. You'd think a slight change in the number of wraps on one side or the other of the coil would fix the issue.
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#31
IP: 173.69.145.176
|
||||
|
||||
Unless your A4 is wired other than stock, it was designed for a 12 volt coil. When I bought one from the local Western Auto the parts guy asked if the engine used a ballast or not and looked up the part # for a 12 volt coil.
BTW, going from the Indigo system to points seems to have ended my endlessly burning out coils |
#32
IP: 50.104.123.38
|
|||
|
|||
Hot Coil
Have read above discoveries with interest. I changed to Pertronix EI a few years /ago and also bought Moyer stock coil, said to work with EI, ie 3 amps. Big improvement, but was concerned about how hot the coil got. Coil ran hotter than adjacent engine block and could be touched only momentarily.
Two years ago switched from ammeter in start panel to voltmeter to discover 15-16v. My original regulator started to ooze black mastic sealant. This was about time that Shawn recommended the adjustible voltage Transpo through ASE which I also installed and gave 14.2 out of box and was a direct bolt on replacement. Also resulted in full battery charging, 12.8 volts at rest. Based on others experience above, I'm still concerned about the coil heat, so have now ordered a 0.8 external ballast resistor to suppliment just in case. Can't measure coil temperature but hoping to note cooler to the touch operation. Was also thinking of wrapping the coil with aluminum with fins folded in for greater head dissipation. |
#33
IP: 24.224.206.117
|
||||
|
||||
Don Moyer,s coil thread.
Swallace,
This is a link that Don Moyer wrote. It's worth a read. http://www.moyermarine.com/forums/sh...t=filled+coils
__________________
Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. |
#34
IP: 151.200.21.32
|
||||
|
||||
wow - 4 amps!
Mo, thanks for posting that..if you read the details, it has the same info that Neil recently found regarding max amps, but Don wrote that piece in 2005!
I dunno why I didn't see it before. Maybe we need Admin Bill to add extra tags to anything Don Moyer writes, so that when we do a search on a particular subject in the forum, his comments are always at the top of the list. It would probably save us newbies a lot of trouble.
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#35
IP: 24.152.131.220
|
||||
|
||||
Yeah Shawn, had we simply followed Don's treatment we could have saved a lot of grief.
Which brings me to my Pertronix gripe - not their product but actually their customer support. Problem 1 You and I independently approached them with your recent coil overheat and failure. I actually cut and pasted your data set and sent it to them as if it were my own. Their responses were from different techs/engineers and were completely different from each other!! This did not instill confidence that they had any idea what was going on. Problem 2 They specify a 4 amp maximum system current with their Ignitor electronic ignition product. They recommend their 3 ohm Flamethrower coil for this system, "The perfect match." They have to know every 12V alternator in the civilized world puts out 13.8 or more volts. So their recommended system results in at least 4.6 amps, contrary to their own specification!! To adhere to their spec we have to use a resistor which they don't mention anywhere visible. If they do it's three layers deep in some tech troubleshooting page. OK, that rant is done. I'm feelin' a huge sermon coming on over Pam's shyster mechanic.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 09-24-2011 at 05:30 PM. |
#36
IP: 24.224.206.117
|
||||
|
||||
read it last spring.
Hey Guys,
I'm no electrical wizard. I remembered reading it last spring and thought that swallace could gain some info regarding oil filled coil heat. You guys are the ones doing all the testing and to be honest, I'll suck up the information that you guys come up with.
__________________
Mo "Odyssey" 1976 C&C 30 MKI The pessimist complains about the wind. The optimist expects it to change. The realist adjusts the sails. ...Sir William Arthur Ward. |
#37
IP: 174.94.23.187
|
||||
|
||||
Quote:
Actually...it does sort of remind me of a drag race Hanley and Shawn. You know that part of the race I mean Hanley - where you look on one side and the guardrails are flashing by at light speed...and then you look at your closely matched opponent and it seems he is gaining/losing on you by a snails pace. I think they call it a paradox...or something like that! |
#38
IP: 50.104.123.38
|
|||
|
|||
Hot Coil
Thanks much Maurice for pointing this out. I now remember reading this FAQ sometime ago. I've been through all the major systems on my A4(Tartan 30) and it is running extremely well. Smooth idling, easy starting, steady 160 deg temp. 115 compression. On a recent 100 mi trip, had to motor part way and got about 0.55 gal per hour at 5.25 kt. To keep it that way I try to keep up on small improvements such as external ballast resistor if making system more fail safe. With 4 ohm coil, seems the safety factor is already built in. This thread has provided a great learning experience.
|
#39
IP: 75.207.105.23
|
|||
|
|||
Perhaps the answer lies in powering the ignition off a hot lead from the battery or key switch rather than directly off the alternator where the voltage would be more consistent.
|
#40
IP: 107.0.6.242
|
||||
|
||||
Good point. The voltage coming right off the alternator is going to be the highest in the (dynamic) system. Moreover, it is "dirty", that is ahead of the noise suppressor and possibly subject to spikes. Ignition should be tapped well downstream of the alternator - I run mine from the main buss bar thru a toggle and then an oil pressure switch.
|
#41
IP: 76.230.233.30
|
|||
|
|||
I am reading this thread with more than passing interest given my own coil/alternator issue. I also converted to EI a couple of years ago.
It seems that all of calculations in the postings here assume that the coil (-) is 0v or ground. However, I noticed that while my coil (+) is 17.4v (which obviously is too high) the coil (-) is approximately 9.2v. I am not sure if that is what it should be or it should be 0v. I traced the coil (-) wiring - one wire goes to EI (-) and the other goes to the tach. Is the tach or the EI (-) suppose to be grounded? In my case, my coil was recently fried. The alternator is putting out 17v as mentioned. I still have not found out the root cause. If it is even implied that EI could be cause I am going back to points, condenser system. I still have a new set as back up. Last edited by Triton106; 09-26-2011 at 01:26 AM. |
#42
IP: 193.253.220.149
|
||||
|
||||
Quote:
Thanks for expressing with words my secret grievances. Shawn- Quote:
Also, measuring as per the Pertronix recommendations: 11.6 Volts at coil+ with the starter switch on run.
__________________
Kelly 1964 Cheoy Lee Bermuda Ketch, Wind and Atomic powered |
#43
IP: 199.173.226.236
|
||||
|
||||
FYI: Coil current would only follow the I=V/R formula with the points (or electronic equivalent) closed and the engine OFF.
I don't want to bore you all with the details of inductance and what is essentially a high frequency AC system, but the only good way to actually know what the coil current is would be to actually measure it with the engine running. I always thought it would be nice if someone made an "old low RPM engine electronic ignition" that used less dwell than a modern system. Not saying this is an issue, but it seems like it could be. |
#44
IP: 206.125.176.3
|
||||
|
||||
Thanks Kelly..just trying to build a little database in my head for these things. I never bothered to measure my 'bad' coil before it went bad, so I was wondering if my 3.3 ohms I was reading was similar to other coils or if burning up the coil had changed the resistance from 'stock'. When I get back to the boat, I will measure the resistance of my new Flamethrower that has never been used for comparison.
Never made it to the boat this weekend (man, the weather here on the US East Coast has been awful!) so, no new news to report. Cheers!
__________________
-Shawn "Holiday" - '89 Alura 35 #109 "Twice Around" - '77 C-30, #511 with original A-4 & MMI manifold - SOLD! (no longer a two boat owner!!) |
#45
IP: 72.83.115.32
|
||||
|
||||
I am so THOROUGHLY SICK of rain!
__________________
@(^.^)@ Ed 1977 Pearson P-323 "Dolce Vita" with rebuilt Atomic-4 |
#46
IP: 193.253.220.149
|
||||
|
||||
Can anyone point me to a reliable source for ballast resistors?
__________________
Kelly 1964 Cheoy Lee Bermuda Ketch, Wind and Atomic powered |
#47
IP: 174.65.54.224
|
||||
|
||||
Triton asks a good question.
__________________
"Jim" S/V "Ahoi" 1967 Islander 29 Harbor Island, San Diego 2/7/67 A4 Engine Block date |
#48
IP: 24.152.131.220
|
||||
|
||||
Kelly et al,
Please keep in mind that all this resistor business is as yet untested, purely what we're thinking at this point. I picked up my resistor yesterday and will get it installed and tested for hopefully reduced coil temps as soon as I can. There are a few other listmates at a similar level of progress. We think we're on to something based on theoretical analysis but until real world testing is complete we don't know for sure. Something recently dawned on me though. Have you noticed that with the recent rash of overheating coil reports not a single one was a Moyer coil? Why would that be? What's different about his coils? I'm pretty sure it's the internal resistance. The auto parts boutique coils - and the Flamethrowers - are 3 ohm coils and Moyer's are 4 ohm. That 1 ohm difference doesn't seem like much until you look at it in terms of percentage. Moyer coils have 33% more resistance than the others. Well, enough talk-talk. It's time to get the testing done. Triton, The coil - post is not a ground. Disconnected it has continuity to the coil + post reduced by the internal coil resistance. A switching ground is provided to the - post by the ignition regardless of whether it's points or EI. Readings taken at the - post will be confusing as it's switching on and off. Actually, to confuse matters more, what you're reading at the - post mimics alternating current. The significant reading you need is from the coil + post to the engine block with the engine running. That reading should be equal to the alternator output minus the ignition wiring voltage drop. On my boat the voltage drop is 1 volt. Further, your alternator output voltage indicates it and your regulator need to be repaired or replaced, period. 17 volts is not right and will damage components as you have already seen. In my estimation, based on your description and my affection for single wire internally regulated beefy alternators, I'd replace the alt with a new one (I love my Delco), replace the coil with a new 4 ohm and replace the EI because it too has been stressed. All this will cost a couple o' hun but you'll be done with it and back out on the water.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 11-06-2014 at 10:28 AM. Reason: Technical correction |
#49
IP: 107.0.6.242
|
||||
|
||||
1 ohm ballast resistors can be had at the Radio Shack or other electronics boutiques (wicked cheap). They can be lined up in series ahead of coil+ until you get the desired voltage. If you want to be fancy, run a starting circuit override from solenoid "R".
|
#50
IP: 24.152.131.220
|
||||
|
||||
Here's the resistor I bought. It's rated at 0.85 ohm but measures at 1.0 ohm on my tester.
We'll have to see what Kelly comes up with in his neck of the woods, might give a new meaning to French Resistance.
__________________
Neil 1977 Catalina 30 San Pedro, California prior boats 1987 Westsail 32, 1970 Catalina 22 Had my hands in a few others Last edited by ndutton; 09-27-2011 at 11:27 AM. |
|
|
Similar Threads | ||||
Thread | Thread Starter | Forum | Replies | Last Post |
Some Comments About Coils | Don Moyer | Ignition System | 42 | 10-17-2017 05:03 PM |
Hot Coil and High Alternator Output | Triton106 | Electrical | 53 | 10-02-2011 07:12 PM |
engine stops | Possum | Troubleshooting | 4 | 04-20-2011 09:19 AM |
Information about information and oil pressure issues | Don Moyer | Announcements | 0 | 04-14-2009 08:30 AM |
Hi, new member with a problem | cpdeeley | Introductions | 10 | 01-11-2009 01:43 PM |