Dwell Angle on Electronic Ignition, OMC 5.0ltr

[metwrench]

Hi all,<br /><br />1988 OMC 5.0 Ltr, Had point ( convetional ) ignition in it. Removed it and put Pertronix Flame thrower II System which Includes, Electronic Pick up, Reluctor wheel, and New 45K Volt 12V Primary side coil.<br /><br />After Installation, Boat had random misfire and the after running on water the Engine Died 15 minutes after running. It almost seemed if the Coil Overheated ? The Coil is designed to run of 12Volts, That I did Verify and thats what is has at the positive side. <br /><br />My question is DWELL angle, My readings of dwell are 5-10 @ Idle, and 30 @ 3500 rpm. Can you read Dwell with these electronic Ignitions ?? can you read the Coil saturation time ? If anyone has a dwell meter and this system could they let me know what Dwell angle they see ?<br /><br />Thanks<br />John

 

[seahorse5]

Re: Dwell Angle on Electronic Ignition, OMC 5.0ltr

Dwell angle is only applicable to points style ignition.<br /><br />You would need an automotive 'scope to watch the coil saturation time, output voltage, etc.<br /><br />Are you running the coil power from the motor's wiring harness thru the resistance wire, or are you using a direct 12V feed from the key switch?<br /><br />What do the installation instructions say about wiring up the coil?

 

[metwrench]

Re: Dwell Angle on Electronic Ignition, OMC 5.0ltr

Thanks Seahorse for the ONLY reply..<br /><br />What ended up happening is I " petronix" The people who made the Ignition told me to send the Unit back. They Tested it and deemed Faulty Unit and coil burned. They did say that Dwell angle is applicable and That it should be near 20 -25 Idle and Go higher on Acceleration...Again mine was 10 or lower.<br /><br />Thanks again for reading and replying

 

[Boomyal]

Re: Dwell Angle on Electronic Ignition, OMC 5.0ltr

Originally posted by John P Spofford:<br /> Thanks Seahorse for the ONLY reply..<br /><br />What ended up happening is I " petronix" The people who made the Ignition told me to send the Unit back. They Tested it and deemed Faulty Unit and coil burned. They did say that Dwell angle is applicable and That it should be near 20 -25 Idle and Go higher on Acceleration...Again mine was 10 or lower.<br /><br />Thanks again for reading and replying

Whoa! Praytell, how do you set dwell on an electronic pickup? I just happen to have my Pertronix II equipped distributor in hand.(no room left on the Mustang) There is no adjustment. The module comes rivited to the supplied mounting plate that is then screwed into the distributor body. Someone is not coming clean here!

 

[Dunaruna]

Re: Dwell Angle on Electronic Ignition, OMC 5.0ltr

My understanding (limited at best) is that the dwell is programmable. I would suspect an assembly line fault, they will probably throw it in the bin and give you a new one. <br /><br />Aldo

 

[Don S]

Re: Dwell Angle on Electronic Ignition, OMC 5.0ltr

My readings of dwell are 5-10 @ Idle, and 30 @ 3500 rpm

You might want to check your terminology. I think you are talking about Timing , not dwell.<br />Normally, the static timing (at idle) is between 8 and 10 degrees for a Chevy V8. In marine applications the timing should advance to 30 degrees around 3000 rpm.<br /><br />Go to THIS LINK and scroll down a ways to a section called Dwell.<br />No way is a dwell setting used in electronic ignition.

 

[Dunaruna]

Re: Dwell Angle on Electronic Ignition, OMC 5.0ltr

Don, with all due respect, your wrong.<br /><br />In elec ignition it is not user adjustable but adjustable just the same. In fact it often changes. If a dwell setting is not used in elec ignition, why would it need to change with RPM? <br /><br />A C&P from your link:<br /><br />"In newer CDI systems this term is near meaningless for several reasons. Solid state transistors control the discharge pulses electronically with near instantaneous timings. So the dwell times can be finely controlled to achieve the best coil / spark outputs for any given RPM. Transistors can handle a LARGE amounts of voltage/current (compared to points). And, newer generation coils are extremely fast. Their coil pulse "voltage rise time" to the plug is VERY fast at around 6 microseconds). So charge / discharge times are not a huge factor (unless racing). Newer racing ignitions (like MSD) are NOT producing bigger sparks with long durations but in fact getting more effecient burn by producing very controlled multiple short duration sparks to the plug."<br /><br /><br /> "So the dwell times can be finely controlled to achieve the best coil / spark outputs "<br /><br />BTW, good pick up with the timing/dwell mixup.<br /><br />Aldo

 

[Don S]

Re: Dwell Angle on Electronic Ignition, OMC 5.0ltr

I may be wrong, and trust me, it won't be the first time. My point is, I seriously doubt there are any "Dwell" Tests in any of the pertronix instructions for installing and adjusting the units. Just the fact that the timing and dwell numbers are so similar to what timing would be that there may be just a problem with terminology. Guess we will all see when John replies next

 

[Dunaruna]

Re: Dwell Angle on Electronic Ignition, OMC 5.0ltr

Originally posted by Don S:<br /> I may be wrong, and trust me, it won't be the first time.

Hey, you can't say that, I've got copyrights on that quote

 

[Don S]

Re: Dwell Angle on Electronic Ignition, OMC 5.0ltr

Geez Aldo, I'm the one that said it.....shouldn't I get the copyrights on it , , ,

 

[deputydawg]

Re: Dwell Angle on Electronic Ignition, OMC 5.0ltr

Dwell is the length of time the points stay open. On electronic egnition you do have to have a period of time when the coil is charged or saturated, then the field collapses, but this is the first I have ever heard of dwell on electronic ignition. Very intersted to learn about this though! Could be useful on the drag strip with my hot rods. <br />I have used accell ignition (on land vehicles) that use an allen wrench in the vacuum diaphram for the spark advance, this shifts the plate and pickup in the distributor. maybe this also changes dwell angle. <br />How is this dwell adjusted if you don't have points to set?

 

[achris]

Re: Dwell Angle on Electronic Ignition, OMC 5.0ltr

Nope! You got it wrong DD. Stupidity should be fatal.

 

[KaGee]

Re: Dwell Angle on Electronic Ignition, OMC 5.0ltr

Originally posted by Don S:<br /> ...Guess we will all see when John replies next...

Seeing how it took him 9 days to issue an acknowledgement and flame everybody for no response, when Seahorse gave him his answer in about 17 minutes, I doubt we will see a reply.