Engine quitting when it reaches 160

[tac]

Coil Location

Neal is right advising caution without concrete evidence. I’ve had the Indigo electronic ignition, with the Crane Cams/FAST XR700 control unit, since 2000 (newly installed hour meter - 0 hours). I had 3 coil failures in 12 years (1340 engine hours). The three failed coils had no ballast resistor. After the last failure in 2012 I added a new Indigo 3.3 ohm coil, also mounted on the engine, with the Indigo 1.5 ohm external ballast resistor. I added the ballast resistor based on this forum’s, especially Neal’s, work. In this configuration the coil temperature after 1-1/2 hours at only 1100RPM was 187 deg F.

In 2015 (1370 engine hrs) I moved the coil and ballast resistor off the engine to a nearby bulkhead, with a small cooling fan. Coil temps now were in the 102 deg F area.

In May 2018 (1700 engine hours) I changed the XR700 control unit to the XR3000, and changed the coil to a NAPA 1.4 ohm one with NO ballast resistor and no cooling fan, both still mounted off-engine.

Also in 2018, I mounted an old Bosch 3.6 ohm coil on the engine, not electrically connected up, to measure the coil temperature due principally to conduction and convection from the engine’s proximity. A test was started with a block and coil(s) temperature of 71 deg F. After running 1 hour at 1400 RPM in gear, the off-engine active coil was 107 deg F (36 deg F rise). The engine-mounted inactive coil was 114 deg F (43 deg F rise). Block temperature where the Bosch coil was mounted was 180 deg F.

My conclusion is that, for this test, block mounting alone results in a coil temperature rise of 43 deg F.

[tenders]

Wow, joe_db, the elusive 0-5psi pressure gauge, impressive!! I'm a bit confused at the reference to 5V...does the gauge connect to the regular 12V and internally step down to 5V for the sensor?

(I will say the inexpensive 0-15psi gauge has been more than enough to be extremely useful in troubleshooting despite the unused 4-15psi part of the gauge.)

Regarding the coil, might there be any value in adding an insulating pad of 1/4" G10 to the back of the block-mounted coil to keep it away from metal-to-metal contact and still reduce its operating temperature by a few dozen degrees? Perhaps that would require a nonmetal strap modification, too, to make a difference.

[tac]

I didn’t mention that in 2015, before moving the coil off the engine, I mounted it on the engine with 1” nylon spacers for each bolt. This held the coil off the engine by an inch, but still held in place by two 5/16” bolts (a path for conducted heat). After running the engine for 1-1/2 hours at 1100RPM in gear, the coil temperature was 180 deg F. Next I added a polished aluminum heat shield between the standoffs and the coil. Again at 1100RPM after 1-1/2 hours, the coil temp was 155 deg F, the heat shield was 318 deg F.

Throwing my hands up in defeat, I moved the coil off the engine.

[joe_db]

Wow, joe_db, the elusive 0-5psi pressure gauge, impressive!! I'm a bit confused at the reference to 5V...does the gauge connect to the regular 12V and internally step down to 5V for the sensor?

(I will say the inexpensive 0-15psi gauge has been more than enough to be extremely useful in troubleshooting despite the unused 4-15psi part of the gauge.)

Regarding the coil, might there be any value in adding an insulating pad of 1/4" G10 to the back of the block-mounted coil to keep it away from metal-to-metal contact and still reduce its operating temperature by a few dozen degrees? Perhaps that would require a nonmetal strap modification, too, to make a difference.

These "5 volt gauges" use a series of senders that produce 0-5 volts. The gauge was a wiring harness that connects to the 12 volt bus and a cable that connects to the sensor. The sensor produces 0-5 volts.
Here is a long connector cable for this:

https://www.ebay.com/itm/Wire-harness-for-pressure-transducer-10-3-meters-long-UL-listed-wires-/261279660259

I really like running wire as opposed to fuel hose. Another electrical fuel pressure setup is here:

http://www.chiefaircraft.com/iss-cafpc-01.html

[ndutton]

tac, did you perform any testing that concluded engine mounting caused a coil failure? I read in your post the failures occurred prior to the addition of a ballast resistor, none since regardless of coil location. I interpreted the coil relocation was another of those "on principle" things.

edit: I would not consider off-the-block coil relocation in lieu of a properly engineered EI ignition system of maximum 4 amps. Remember that engine mounted coils worked reliably with points ignitions for decades. I'm not saying there's a downside to coil relocation either but with EI the voltage-resistance-current circuit analysis must still be done for a reliable system.

For Joe:

Bonus - a red light comes on when the [fuel] pressure is below 1 PSI.

Yep, same trip point with the EWDS, also indicator light (amber) and audible buzzer.

[tac]

Coil Mounting

Yes, Neil. I moved the coil off the engine out of exasperation but largely on principle. That principle is that heat is the biggest killer of insulation. No more testing was done to determine how engine mounted coils were failing.

Let me summarize the data. First, a link to Tom Stevens of Indigo’s test results from bench tests he ran with electronic ignition with and without a ballast resistor.

http://www.atomic4.com/balres.html

The first row below is Tom’s temperature data on the bench with no resistor. In the second row I added the temperature rise, 43ºF, that I found (post #31 above) for an unpowered engine mounted coil. In other words, the heat contribution of the engine alone to Tom’s test coil temperature if the coil had been mounted on a running engine.

The third row is Tom’s bench data with a ballast resistor. The 4th row is that temperature with the temperature rise added due to engine heat.

A comparison of Tom’s bench value corrected for engine mounting (198ºF) with the engine mounted coil (187ºF) shows a reasonably close agreement.

The remaining rows 5-9 are my test data From post #31.

Bench test, no ballast resistor 195ºF
With 43ºF rise = 238ºF
Bench test, ballast resistor 155ºF
With 43ºF rise = 198ºF
Engine test, ballast resistor 187ºF
Engine test, resistor, standoffs 180ºF
Engine test, resistor, standoffs/heat shield 155ºF
Engine test, resistor, bulkhead mount, fan 102ºF
Engine test, no resistor bulkhead mount 107ºF

[Orion C&C 33]

Your stall sounds like a coil issue.
You may want to read this thread.

• What coil do you have?
• Do you know it's resistance?
• Do you have EI?[/QUOTE]

I believe your are right Jerry.... It has consistently dies at 160 F although it hasn't for a while... So I was lulled into thinking that my engine was getting up to par.

Besides what the other members have inputed to this post... I've pretty much changed or modified my engine enough that there are hardly any old parts left.

Cheers !!!

Mel

[Orion C&C 33]

Hey Mel,

Sure was hot here on Bowen yesterday too! I can imagine that 2000 RPM for 11 hours generated some serious heat in the engine compartment.

We did move our coil to the bulkhead when we went to electronic ignition and a new coil. Before that, we had a couple years of shutdowns. As an added precaution we mounted the coil on a hunk of scrap aluminum as a heat sink.

good luck!

Thanks Marty !!!!

I was burnt to a crisp on Sunday.... I'm so done with testing for spark I did once on a shut down... and there wasn't any. once the engine cooled down it restarted. So my conclusion from recording these events and the time it takes for the engine to cool from 160F to 140F she would restart no problem.

Has lead my to conclude that the coil is the culprit...

Cheers my friend !

Mel

[Sam]

Just to back up guru ndutton I have had early model 1966 A4 for 40+ years still with points [little prestolite distributor]... it's old school but that's what I know. In the past the engine mounted coils were changed about every 8 to 10 seasons, about 250 engine hrs, not because of engine shut down but because they would get extremely hot to the touch. After joining the forum I 'm now "educated". Last year on my winter layup trip I had some engine problems. This spring the old coil tested out @4.6 ohms, my new backup tested out a little less than 4 - I switched them out and with other forum inspired changes the problems vanished. I have nothing against Moyer's Flamethrowers" @ $50 but I use convenient local NAPA liquid filled IC14 at an almost equivalent $38. I am not sure that the quality variability is now as narrow as it was in decades past. [I just saw 1931 Chevy in my friends repair shop with the original/or very old upside down firewall mounted coil and original distributor - distributor had an interesting manual advance cable but I digress]. My point is that the coil is critical and relatively low cost - I would change it out just on "suspicion" or periodically [and if tested high]. About the same as caps, rotors & condensors. [I'm told CIA training is "when there is doubt...there is no doubt. Good advise for a boat]

[tac]

Coil Mounting

Allow me to add my final thoughts on the matter. I believe Neil and I are saying pretty much the same thing: coil failure is caused by coil primary wire insulation breakdown due to heat. That heat comes from two sources,

1. Resistive heating due to the current through the winding. Cure - reduce the current (ballast resistor) to reduce the heating.
2. Conducted and radiated heat from the engine block. Cure - off engine mounting, or standoffs with heat shield.

[ndutton]

No, not quite. I've never subscribed to the factory coil location as contributing to coil failure because of a history of tens of thousands of engines that ran their entire lives with the coil mounted on the block. For it to have been a problem I would expect a consistent failure rate and that is simply not the case.

Contrast that to the introduction of electronic ignition. Engine shutdowns due to coil failure were so common that the symptom set became easily recognizable and those who 'upgraded' carried their old points and condenser pre-mounted on the points plate so they could get home after the expected failure. The failures could be directly correlated to the installation of electronic ignition. My first post on this forum asked why everyone was so enamored with EI if it all but guaranteed a shutdown. Something was wrong.

And so it began . . .

That said, I have no quarrel with anyone who wants to remotely locate their coil, there is no downside. I think proximity to the exhaust outlet flange and hot section, especially if uninsulated, contributes more heat to the area than the engine block. To clarify my position though, the known and verifiable problem was (WAS!!) due to oversaturation of the coil as a result of dramatically higher dwell of electronic ignition. That was thoroughly researched and resolved seven years ago and for those who implemented the resultant recommendations, EI related shutdowns disappeared regardless of coil mounting location, factory or otherwise.

Note to Sam:
Moyer offered Flamethrower® coils at one time but that was long ago. I have one on my spare engine with a 0.885Ω resistor added.

[joe_db]

Our original A4 went thousands of hours on the original coil. IMHO since these old fashioned coils have not been used on new cars in ages, the quality has gone down. I surmise 2nd tier manufacturers make them all now.
You can find coils locally of course, but given that not everyone knows what to ask for and not all parts counter people have a clue about old ignitions, it is well worth buying the Moyer coil if you have any doubt about being able to pick the correct part.
Here on the island we are lucky, the local Western Auto guy will say "you must want an Atomic 4 coil" if you start talking about boats and 4 ohms Probably helps that they sponsor antique car events

EDIT - Neil posted while I was typing. In the dark days of EI without dwell control or ballast resistors, I was going through 2 coils a year Back in the 1940s-1970s coils failing frequently was not a thing.

[Orion C&C 33]

We did move our coil to the bulkhead when we went to electronic ignition and a new coil. Before that, we had a couple years of shutdowns. As an added precaution we mounted the coil on a hunk of scrap aluminum as a heat sink.

good luck!

Hey Marty...

Stopped by a supplier / friend of mine... to pick up a piece of aluminum plate and we discussed your suggestion on a heat sink.

Jim is not only a metal fabricator but also a bit of a motor head... I concurs that the sudden engine stops are due to my coil and yes he too would off mount the coil off the engine block.

So guess what !???? He gave me a huge slab 1/2 inch thick aluminum to act as a heat sink and to mount my coil on the bottom and to use the length to draw the heat away. I'm so pleased with myself.

Going to mount it as exactly as shown with 1/2 inch off stands from the bulkhead to allow ventilation on the back side of the aluminum plate.

I see there has been input from other members... I just want to thank you for dropping by adding your input. It's much appreciated... y'all !!!.

Cheers and happy sailing!!

[ndutton]

Another version

Check this out for a coil heat shield design. I'm close to doing some real world testing to see exactly the difference it makes, will report the results when finished.

Please consider this: creating a heat sink to dissipate excessive coil heat is a work around. Preventing excessive heat in the first place is the corrective action, address the real problem instead of manage it. Excessive coil heat is not normal.

edit: Orion, please be advised the MSD Blaster® High Vibration coil in your picture has epoxy as its potting medium. Oil filled coils are known to tolerate heat better than epoxy filled so if coil heat is the concern . . . . . . y'know?

[sastanley]

Orion...I like your helper..I have one of those too.