Is the MSD Blaster igntion coil compatible with the CDI unit in the 1973.5T 911?

[Sunroof]

My car has been known to suddenly die after a long run on the road and I thought it might be fuel related. Lately though someone suggested that the MSD Blaster ignition coil I installed might be overheating and causing the shutdown after a nice run with the car. The questions came up as to whether I was using a non-resistor rotor? does the Blaster has an internal resistor? or I have external ballast resistor?

I do use the 6500 rpm cut off rotor, which I just realized is not the "non resistor rotor". I will switch to the non resistor rotor, but can anyone shed any light on what's going on with this system set up. And yes, I have bought the silver made in Brazil coil, which failed me miserably after purchase.

thanks

Bob
1973.5T

[matthewb0051]

Bob,

I was searching for the same issue a few years back. I don't remember where I found it in this Forum, but there is a post from either Warren Hall or Grady Clay regarding the MSD master blaster coil. From the testing that he did, he determined that the coil was the exact same spec as the original factory coil.

Not sure if that answers the question but hopefully can point you in the right direction.

Matthew

[911tracker85]

dont know about your question. but during the build of my 951 DE/street car I installed a MSD blaster coil. it died on the first drive within minutes. replaced with another MSD and it died after a few months.

put the original coil back in for now, until I decide if I am going to go a full MDS / AL6

good luck.

[wwest]

Best...


Accel 140008 E Core Electronic Super Coil 42K Volts | eBay

[304065]

I wouldn't go near an e-core coil the specs are absolutely wrong.

Here is my compilation of coil data:

A lucky eBay find: NOS SWB Coil

[Sunroof]

Appreciate the data.

Bob
73.5T

[dicklague]

Best.....
102002 Daytona Sensors Ignition Coil CD 1 System | eBay

[dicklague]

Better.....
ProFire

PFC-M75, CD Ignition I ran one of these for years with Bosch CDI and it was great. I still have it if anyone is interested in purchase. Switched to Daytona CD1 coil that came with kit.

[dicklague]

This is the NOLOGY COIL. The bracket fits right on the studs on the fan mount.

[Larrybrook]

Lets see how they look mounted...

[dicklague]

Originally Posted by Larrybrook

Lets see how they look mounted...

I care how they work. E coils have been great for me. the Nology coil was great with the stock ignition, the other Daytona coil matches my CDI and has been flawless.

[LakeCleElum]

John Walker would know. When I did the MSD and MS coil, we had to change the rotor.....He picked up a common one at a local FLAP store....I thought still had the box with the part number, but no cigar....

[emac]

dicklague

Sent you a pm
Ernie 81sc

[wwest]

Originally Posted by 304065

I wouldn't go near an e-core coil the specs are absolutely wrong.

Here is my compilation of coil data:

A lucky eBay find: NOS SWB Coil

Which specs?

[Jonny H]

I can't give an absolute yes or no to the OPs question as I haven't personally tested an MSD coil.

The CDI box and coil, although separate parts, are part of the same circuit so they are matched at design time. If the coil is changed to a different type with different characteristics, this could result in excess heat being generated in either the coil or the box. In extreme cases, the CDI output circuitry could be destroyed.

This is why most aftermarket ignitions require that you also use their coils.

You need to compare the MSD and original Bosch coil specifications for primary resistance, inductance and number of turns. See whether they are in the same ballpark.

[wwest]

In both cases the not unsubstantial energy left in the magnetic field post plug firing will be returned to the "charge" capacitor.

(page 43, "-100")

"I" core: That 60% energy level loss due to magnetic field "leakage" will be dissipated as HEAT with in the coil structure.

(Page 48)

http://www.worldphaco.net/uploads/CAPACITIVE_DISCHARGE_IGNITION_vs_MAGNETIC_DISCHARG E_IGNITION..pdf

[wwest]

Originally Posted by Jonny H

I can't give an absolute yes or no to the OPs question as I haven't personally tested an MSD coil.

The CDI box and coil, although separate parts, are part of the same circuit so they are matched at design time. If the coil is changed to a different type with different characteristics, this could result in excess heat being generated in either the coil or the box. In extreme cases, the CDI output circuitry could be destroyed.

This is why most aftermarket ignitions require that you also use their coils.

You need to compare the MSD and original Bosch coil specifications for primary resistance, inductance and number of turns. See whether they are in the same ballpark.

"..excess heat...."

How, where...?? The primary components affecting the coil, or being effected by the coil, are reactive, very low circuit resistance to dissipate energy as heat. Plus moving from ANY "I" core coil to an "E & I" would obviously reduce spark energy loss substantially

"..aftermarket... ignitions require..."

Read: COILS

http://www.msdignition.com/uploadedFiles/MSDIgnitioncom/Products/Ignitions/6420_instructions.pdf

http://static.summitracing.com/global/images/instructions/sum-850610.pdf

[Jonny H]

^ Ok, feel free to stuff any old coil in there then. It doesn't matter what the designer of the circuit intended the CDI circuit to drive. A few turns of wire round an old shoe will do and is cheap and easy to make. Wire coat hangers make great ignition leads as well and you can insulate them with tape and chewing gum.

Remember, Porsche really didn't know what they were doing when they designed this stuff. It can all be replaced with homemade equipment or shoddy crap made in China and it will be absolutely fine! Trust me, I read it on the Internet!

[uwanna]

Originally Posted by Jonny H

^ Ok, feel free to stuff any old coil in there then. It doesn't matter what the designer of the circuit intended the CDI circuit to drive. A few turns of wire round an old shoe will do and is cheap and easy to make. Wire coat hangers make great ignition leads as well and you can insulate them with tape and chewing gum.

Remember, Porsche really didn't know what they were doing when they designed this stuff. It can all be replaced with homemade equipment or shoddy crap made in China and it will be absolutely fine! Trust me, I read it on the Internet!

GREAT RESPONSE!! WWEST is kinda like the 14yr old adolescent who can tell you everything there is to know about sex because he's researched it on the internet, but has never experienced it! LOL

[wwest]

Originally Posted by Jonny H

^ Ok, feel free to stuff any old coil in there then. It doesn't matter what the designer of the circuit intended the CDI circuit to drive. A few turns of wire round an old shoe will do and is cheap and easy to make. Wire coat hangers make great ignition leads as well and you can insulate them with tape and chewing gum.

Remember, Porsche really didn't know what they were doing when they designed this stuff. It can all be replaced with homemade equipment or shoddy crap made in China and it will be absolutely fine! Trust me, I read it on the Internet!

Neither of the 2 installation guides I linked suggested taking the issue to such great extremes.

Having trouble eating crow..??