View Single Post
  #22   IP: 206.125.176.3
Old 09-23-2011, 11:47 AM
sastanley's Avatar
sastanley sastanley is offline
Afourian MVP
 
Join Date: Sep 2008
Location: Solomons, MD
Posts: 7,016
Thanks: 1,134
Thanked 600 Times in 442 Posts
Lightbulb Hmmmm.....

Quote:
Originally Posted by smosher View Post
Hi Shawn, was that a 3 ohm oil filled flamethrower ?

Steve
Steve - Yes..it is oil filled..the only difference is it was just the chrome model (#40501). My new one is the boring black (#40511).

Quote:
Originally Posted by Loki9 View Post
Hey Shawn-

An off topic question: where can I find a raw water strainer like the one that you have? Who makes/sells it?

Thanks!

-Jeff Taylor
Jeff - No problem - Neil turned me on to that cool simple strainer. Check out the "BoaterBits" store on ebay..they sell them for all types of different hose sizes..and cheap! Who needs a $200 bronze strainer? Also, here is a link to their website - http://www.boaterbits.ca/

and now back to our regularly scheduled programming:

Neil, Wow..this is interesting information to say the least. However, your theory is supported by some facts that a typical older installation (mine certainly met that criteria) with long runs and voltage drop between the alternator and the coil (& possibly undersized wire with old, or inferior terminations) could be helping the coil.

Remember this spring, the ONLY thing I did was remove my ammeter completely from the circuit and replace all the primary (4 gauge) cables in my electrical system with nice new wire & nice tinned copper lugs. The runs actually got longer, but I eliminated a lot of small wire sizes & inferior connections. So, the result, the first 1+ hour run on the coil, BAM!, failure.

As to your question about coil & ballast resistance as compared to what is on the packaging: My personal experience has been that the numbers run slightly high, meaning they are built with a tad more resistance than advertised...maybe providing a little bit of a safety net, but not when you jam it with too much voltage and fresh, big gauge wire runs like I did.

I did not measure voltage the way Pertronix recommends. I did my readings right on the two terminals of the coil. I can re-measure pretty easily.

So, with that, & working from memory (my notes are not with me at work):
My NAPA/Echlin 1.35 ohm ballast resistor = 1.6x ohms (part # ECH ICR11)
My Accel 1.5 ohm coil = 1.70 ohms.
Need to measure my new Pertronix 40511 oil filled (boring black) coil = x.x

currently in the spares bin -
My dead Pertronix 40501 oil filled chrome coil = 3.3 ohms
My NAPA/Echlin 1.82 ohm ballast resistor = 2.1x ohms (part # ECH ICR13)

When my charging voltage jumped with the new wires to near 15v (i know, too high) I was seeing 13.95-14.05 volts at my (now dead) coil. That puts the amps at 4.26. That sounds to me like it is over the threshold. When that coil was seeing 13.1-13.2v last year with old cabling, I was probably right at the edge. Actually, 13.2/3.3 = 4.00amps

Now, I have done the following:
Adjusted my charging voltage down to 14.1v
Currently running the 1.35ohm resistor ahead of the 1.5ohm coil. Using actual numbers measured above that is about ~3.3 ohms. Assuming we have a drop of 0.9 volts at the coil to 13.0v from the lowered charge voltage I am right on the edge at ~3.93 amps. I need to measure this to be sure, I think I mentioned somewhere else I was seeing lower voltage than this at the coil.

So..there's my numbers..Neil, I am thinking about maybe incorporating BOTH resistors into my system..maybe trying the 1.35 ohm in front of the 3 ohm coil and the 1.82 ohm in front of the 1.5 ohm coil and re-testing. It may also be interesting to try one of those resistors in front of the OLD coil and see how long it would last.
__________________
-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!!)
http://www.moyermarine.com/forums/signaturepics/sigpic3231_6.gif

Last edited by sastanley; 09-23-2011 at 11:52 AM. Reason: removed info that clouded the issue
Reply With Quote