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jcambo7
So after a little over three years I finally got some free time and money to get my 914 running again. Got her started up after changing oil, filter, and cleaning the gas tank. While I was trying to start it again after it quit running while I was tuning the carbs I found the ignition rotor to be fried and melted a bit.
Dave_Darling
Heat melted it. (No s**t, Dave!) The heat is likely caused by resistance and lots of current. Usually there is a decent amount of current and very low resistance here.

First, do you have a "super" coil of some kind? The 914 seems to work best with a coil that has a resistor, either incorporated into the coil (as in stock or Bosch blue coils) or externally.

Next, what does the inside of the cap look like? How about the connections on the plug wires, and the plug itself?

--DD
jcambo7
QUOTE(Dave_Darling @ Jun 26 2017, 06:27 PM) *

Heat melted it. (No s**t, Dave!) The heat is likely caused by resistance and lots of current. Usually there is a decent amount of current and very low resistance here.

First, do you have a "super" coil of some kind? The 914 seems to work best with a coil that has a resistor, either incorporated into the coil (as in stock or Bosch blue coils) or externally.

Next, what does the inside of the cap look like? How about the connections on the plug wires, and the plug itself?

--DD

I have an MSD coil. The cap, wires and plugs look fine. No burn marks or fried wires elsewhere.
michael7810
The rotor in my car lasts about 8-10K miles before it fries. Never looked as bad as yours but the epoxy on top burns and cracks and that causes a severe misfire. I just changed it after 6K miles because the epoxy was getting black although it was still working OK. I have MSD and set my plug gap at .042. I figure the MSD plus larger plug gap are causing the shortened life.
yeahmag
If you're using a high-performance coil, you need to dig the resister out of the epoxy. From there you will need to solder in a piece of stranded copper wire to take its place. I believe John at aircooled.net sell these premade.
michael7810
QUOTE(yeahmag @ Jun 26 2017, 08:02 PM) *

If you're using a high-performance coil, you need to dig the resister out of the epoxy. From there you will need to solder in a piece of stranded copper wire to take its place. I believe John at aircooled.net sell these premade.

Thanks. I'll contact John and see what he has. I'm using an MSD Blaster coil
porschetub
Looks like he is running a six,skipped MSD has not proved to be up there for dependable service,other opitions are out there.
Massive resistance @ that rotor,bad leads or fused points....who knows,don't understand why anyone runs points anymore...that's the bottom line.
'73-914kid
CB Perfomance sells a new rotor with just a brass strap. No funny business with soldering in a heavy wire. Only downside is that you lose the ability to run a Rev limiting ignition rotor.
https://www.cbperformance.com/product-p/2004.htm
jcambo7
QUOTE(porschetub @ Jun 27 2017, 12:43 AM) *

Looks like he is running a six,skipped MSD has not proved to be up there for dependable service,other opitions are out there.
Massive resistance @ that rotor,bad leads or fused points....who knows,don't understand why anyone runs points anymore...that's the bottom line.

It is a six. I had the pertronix magnetic pick up on it when I bought the car but it kept having issues. I went through two or three of them. When I had sixnotfour look at it since he built the engine he swapped it back to points.
'73-914kid
Do you run an MSD box, or just the MSD coil with pertronix?
jcambo7
QUOTE('73-914kid @ Jun 27 2017, 11:11 AM) *

Do you run an MSD box, or just the MSD coil with pertronix?

MSD 6AL box and coil. No Pertronix.
yeahmag
QUOTE(jcambo7 @ Jun 27 2017, 09:12 AM) *

QUOTE('73-914kid @ Jun 27 2017, 11:11 AM) *

Do you run an MSD box, or just the MSD coil with pertronix?

MSD 6AL box and coil. No Pertronix.


Yeah... That's absolutely what's causing the failure. Use the 6AL to limit the rpm and a non-limiting rotor.
sixnotfour
Have John get you e non rev rotor from worldpack
jcambo7
QUOTE(sixnotfour @ Jun 27 2017, 01:30 PM) *

Have John get you e non rev rotor from worldpack

Bovey?
michael7810
QUOTE('73-914kid @ Jun 27 2017, 08:24 AM) *

CB Perfomance sells a new rotor with just a brass strap. No funny business with soldering in a heavy wire. Only downside is that you lose the ability to run a Rev limiting ignition rotor.
https://www.cbperformance.com/product-p/2004.htm


That's a smokin' deal if it fits your distributor. I don't think it will fit mine and just ordered one from Airooled.net for 3.5X the price to fit my Aircooled.net SVDA.
Mark Henry
QUOTE(porschetub @ Jun 27 2017, 01:43 AM) *

Looks like he is running a six,skipped MSD has not proved to be up there for dependable service,other opitions are out there.
Massive resistance @ that rotor,bad leads or fused points....who knows,don't understand why anyone runs points anymore...that's the bottom line.

Sounds like you've been talking to guys using cheap ebay Chinese MSD clones. Sure a MSD can fail, but it doesn't happen often to the real deal. The old 6al is gold to the V8 crowd up here.
Nothing wrong with running a MSD with points, with a MSD the points become a simple low voltage on/off switch, they don't burn like on a stock system.

I've seen more pertronix failures than points failures. On the side of the road I can fix points with a screwdriver and a folded business card. Failed pertonix and yer done, call AAA.

I agree ditch the rev limiting rotor and use the MSD for rev limiting.
HarveyH
Do-it-yourself project:
High Energy Rotor

welder.gif
yeahmag
That's exactly how I did it before I switched to a Mallory Dizzy.
jcambo7
Could this had fried the distributor also if I kept trying to start the engine a few times or more before I noticed the rotor being fried?
'73-914kid
I would be very surprised to see any damage to the points. With an MSD box, they are just a trigger mechanism.

For a quick test, grab a vw type 1 rotor (with resistor would work fine for a quick test) and try and start it. Brief running time on the rotor won't damage anything.
jcambo7
QUOTE('73-914kid @ Jun 28 2017, 11:21 PM) *

I would be very surprised to see any damage to the points. With an MSD box, they are just a trigger mechanism.

For a quick test, grab a vw type 1 rotor (with resistor would work fine for a quick test) and try and start it. Brief running time on the rotor won't damage anything.

So I bought a VW type 1 rotor and a replacement rotor like the one I fried. The engine still didn't start. I need to do some volt meter testing. I'm curious still though if the distributor could have been fried when I continued to try and start the engine when I fried the ignition rotor without realizing it?
Mark Henry
Are you using a MSD or just a MSD coil?

If just a coil that likely fried the condenser.
There is a small ground wire inside the dizzy, plate to body, check that as well.
jcambo7
QUOTE(Mark Henry @ Jun 29 2017, 12:33 PM) *

Are you using a MSD or just a MSD coil?

If just a coil that likely fried the condenser.
There is a small ground wire inside the dizzy, plate to body, check that as well.

What is the condenser? I have the MSD ignition module and coil. The ground wire has been like that since I got the car. I checked the OHM's on the spark plugs and they are 3,930 and I was reading that they should be 10,000? Don't know how true that is for this car though. I'm getting 12v at the coil also when trying to start.
Dave_Darling
Have you definitely confirmed that you are not getting spark?

--DD
Mark Henry
Little ground strap, right side in pic, still attached good?
Looks a little banged up, but attached in the pic.
jcambo7
QUOTE(Mark Henry @ Jun 29 2017, 01:05 PM) *

Little ground strap, right side in pic, still attached good?
Looks a little banged up, but attached in the pic.

It's still attached good and it's been like that since I got the car.
jcambo7
QUOTE(Dave_Darling @ Jun 29 2017, 01:03 PM) *

Have you definitely confirmed that you are not getting spark?

--DD

As far as my electrical troubleshooting knowledge goes (which isn't far) I am not getting spark to the plugs. I took a plug and connected it to the #1 wire and held it close to engine case bolt and saw no spark. My points are gapped properly also.
Mark Henry
Looks like a lot of corrosion on the dizzy cam lobes. That would wear the points blocks PDQ.
Hows the shaft play, both side to side and up/down?
jcambo7
QUOTE(Mark Henry @ Jun 29 2017, 01:17 PM) *

Looks like a lot of corrosion on the dizzy cam lobes. That would wear the points blocks PDQ.
Hows the shaft play, both side to side and up/down?

The shaft doesn't move side to side at all and goes up and down very slightly.
Mark Henry
QUOTE(jcambo7 @ Jun 29 2017, 02:14 PM) *

QUOTE(Dave_Darling @ Jun 29 2017, 01:03 PM) *

Have you definitely confirmed that you are not getting spark?

--DD

As far as my electrical troubleshooting knowledge goes (which isn't far) I am not getting spark to the plugs. I took a plug and connected it to the #1 wire and held it close to engine case bolt and saw no spark. My points are gapped properly also.

You have to hold the plug to the case, look for the spark in the plug gap.

Also:
https://www.msdperformance.com/support/trou...ing_techniques/
craig downs
Where is your condenser? It is a little round part that is about 3/4 in diameter by 1" long that usually is attached to the outside of the distributor with a wire running to the points.
jcambo7
QUOTE(craig downs @ Jun 29 2017, 11:37 PM) *

Where is your condenser? It is a little round part that is about 3/4 in diameter by 1" long that usually is attached to the outside of the distributor with a wire running to the points.

The dizzy has never had one since I have owned the car.
IronHillRestorations
Bingo!
Mark Henry
QUOTE(craig downs @ Jun 30 2017, 12:37 AM) *

Where is your condenser?

MSD the points are just a trigger, no condenser needed, no ballast needed.
Points are only seeing milliamps, not enough to do that damage IMO.
One thing I have heard of is the points can't burn away any oil mist, not a big issue in our engines, but you do have to keep an eye on dirt and grime.

IPB Image
IronHillRestorations
I was mistaken, I missed the MSD part.
larryM

http://forums.pelicanparts.com/porsche-911...rpm-solved.html
"Resistor-less rotors are a must, especially when the plug gaps get opened up to .040-.045 as they should.
______
Steve Weiner
Rennsport Systems"
****************************

fwiw - i ran MSD 6A & Blaster coil with pertronix-ignitor and 911 resistor-rpm-limited-rotor & stock 911 wire set (solid wires with suppressor at end) for about 15 yrs on both 2.8 & 2.7 with no failures such as displayed in O.P.

note that MSD also recommend drilling holes in our smallish Bosch cap to relieve ozone buildup - tho i did not do that until the last couple yrs

https://forums.msdperformance.com/forumdisp...ation-Questions

****************************
QUOTE(Mark Henry @ Jul 4 2017, 07:03 PM) *

QUOTE(craig downs @ Jun 30 2017, 12:37 AM) *

Where is your condenser?

MSD the points are just a trigger, no condenser needed, no ballast needed.
Points are only seeing milliamps, not enough to do that damage IMO.

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