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Looking to buy a 3pin CDI+ for my 911G 74 SC Targa


Peter Henry Andersen
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Hi,

 

I have old CDI unit and my RPM needle is bouncy at idle and more bouncy at speed/movement... I suspect the CDI unit as it's old, but my attention is also to the coil. When I bought the car it had a black BOSCH coil worked fine, but wanted to replace it with anew on. So bought a Sliver BOSCH from rosepassion. This was 1,5years ago. After a drive 300km the RPM needle started to act funny / bouncy. Got home. Next it was fine again, but start to bouncy some days later and now it's not stopping. Car feels tired....

So my question. Which coil is the best with this CDI+ unit. I want the best for my 911.

I found this one from Perma tune: https://www.hovwdiaudi.dk/product/?id=1691600500&cbrand=porsche&cmodel=911/930

And there is a black BOSCH and a SILVER - Which is the best and give the best spark.

 

Thanks in advance.

Best regards

 

Peter Henry Andersen

 

 

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Hi Peter

Bouncing tach needle is often a sign of a failing voltage regulator so check that out.

We've tried all sorts of coils with our CDI+ and the original is currently the best. So you might find that old black coil and refit it. Silver coils are not good. I could tell you a few stories about aftermarket vendors but let's just say the only way forward for us was to make our own unit, which we have done.

The good news is that we have several brand new Classic Retrofit prototype coils in test with engine builders in the UK and US and we are also running a prototype coil on our own car. Handbuilt to a very detailed specification, it comfortably outperforms everything else. We expect a product launch in Q2 2021, subject to more testing hours clocked up in the interim.

Next week's video will give a look at the coil - watch out for that!

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  • 1 month later...

I had a very similar experience, car ran fine, then suddenly lack of power and tacho needle all over the place. Searched for electrical faults, swapped CDI, no help. Then my mechanic had a feel of the distributor button - the bearing was worn, causing the cam to wobble, causing irregular sparks. New old dizzy fixed this!

Still upgrading to the CDI+ though, so many advantages, and how long will my original CDI last.....?

 

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Of course it is!😇 - xmas cant come soon enough, so I can fit it!

Any suggestions how to disable the centrifugal advance on a 74 911, the old style distributor?

As I understand it the suggested method, and locking collar only works on the later ones....

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On 10/29/2020 at 11:29 PM, HX911 said:

Of course it is!😇 - xmas cant come soon enough, so I can fit it!

Any suggestions how to disable the centrifugal advance on a 74 911, the old style distributor?

As I understand it the suggested method, and locking collar only works on the later ones....

Correct, the locking collar is only for the SC and Turbo distributors.

Locking an earlier distributor is fairly easy.  If you remove the vacuum unit, points, side clips and the 'spade' connector, you can pull out the internals to reveal the weights.

I am not sure if all units are the same but on the early ones, there is a rectangular steel plate with the weights beneath.   Put the unit in a vice, to stop the gear rotating and turn the centre shaft and watch the weight move.  You want to lock the weights so they are fully out.   best way is to drill and tap an M4 hole in the steel plate and insert an M4 screw as shown (top right of steel plate).

 

IMG_5123.thumb.jpeg.c70d99460fd2356b8939b316c46875f4.jpeg

 

 

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