Classic Retrofit CDI

[Manni187]

Looking for user experience with these. Purchased a 3 pin Classic Retrofit CDI box as well as a Parts Klassic CDI box and both the associated coils to try. Found better response from the Classic Retrofit. However with both CDI boxes when the car gets hot and I leave it for 30mins to an hour and try to restart there is no action. I have to tap the CDI box and then the vehicle will start. Does anyone else have this issue?

[P-Kay]

I would message Classic Retrofit themselves directly John or something? Pretty sure he is a member here!

[Russ]

if both are doing it - i'd have a look at the wiring/components on either side.

how new is the rest of your ignition system?

[Manni187]

All ignition components are new - wiring appears to be fine - just unusual that as soon as you tap the cdi box the car is able to start.

[P-Kay]

here you go -->  @Jonny Retrofit

Hi Jonny - Any insight for our fellow enthusiast?

[patrick911]

looks like Jonny hasn't been here for the last 18 months.

[Mike D'Silva]

Interesting.... I'm potentially in the market for a Retrofit Cdi, purely so I can input my own ignition curve. Did you find that part of it quite easy to achieve?

 

 

[wg911]

I fitted a 5 pin to my 911SC after a recent engine rebuild using the original coil. It has done about 3000 trouble free km so far.

It was just “plug and play” as the distributor was fully rebuilt and recurved and I considered it unnecessary to use the programmable function.

So far it has worked fine starting quickly from cold or hot, and seems especially smooth and responsive at all times, but especially on first startup and drive from cold.

It is production # 821, but I think I read somewhere that a few early units had issues, but they were sorted.

I have kept the original Bosch unit as a backup.

Warwck

[Peter M]

17 hours ago, Mike D'Silva said:

Interesting.... I'm potentially in the market for a Retrofit Cdi, purely so I can input my own ignition curve. Did you find that part of it quite easy to achieve?

Mike,

The instruction manual makes it seem pretty straight forward: Microsoft Word - Classic Retrofit CDI+ Manual.docx (dropboxusercontent.com)

I was initially concerned that it wouldn't have load sensing but it appears the vacuum advance mechanism can still be used to give some limited load sensing capability.  It also allows you up to 20 points across the rev range to optimise an ignition map that can either replace the centrifugal advance mechanism or "overlay" it to add or subtract from the standard curve.

So for a carburettor car, it looks like a good upgrade to be able to do some ignition mapping to maximise performance but still keep the original look.

The other alternative would be a Haltech VMS that would then allow full 3D ignition mapping against load.

These engines are transformed by twin plugging so that's also something to keep in mind too.

[Jonny Retrofit]

On 15/12/2021 at 02:54, patrick911 said:

looks like Jonny hasn't been here for the last 18 months.

You missed me?  Time flies doesn't it?

@Manni187Oddly enough, we just had Tuthill's return a box saying that it 'cut out' over bumps.  Well, I shook it 'like a Polaroid picture' whilst connected to our tester and could find nothing wrong.   We sent it back and silence so I guess the fault was elsewhere.

There is a difference in the grounding on the 3 pin unit in that it uses the case itself, rather than a dedicated pin.  Internally, our circuit board is grounded by the locating screws at each corner and they need to be tight.   We moved to using a torque wrench for assembly some time ago to ensure this but never say never with humans!   That is about the only thing that could cause a 'tap to fix'.  

TBH, we rarely get faults these days, usually just finger trouble or using with the wrong coil (must be a Bosch CDI coil), recent example being a unit returned from USA with a 'high RPM misfire around 7000 RPM'.  Yep, that's default setting for the rev limiter...  

[Manni187]

5 hours ago, Jonny Retrofit said:

You missed me?  Time flies doesn't it?

@Manni187Oddly enough, we just had Tuthill's return a box saying that it 'cut out' over bumps.  Well, I shook it 'like a Polaroid picture' whilst connected to our tester and could find nothing wrong.   We sent it back and silence so I guess the fault was elsewhere.

There is a difference in the grounding on the 3 pin unit in that it uses the case itself, rather than a dedicated pin.  Internally, our circuit board is grounded by the locating screws at each corner and they need to be tight.   We moved to using a torque wrench for assembly some time ago to ensure this but never say never with humans!   That is about the only thing that could cause a 'tap to fix'.  

TBH, we rarely get faults these days, usually just finger trouble or using with the wrong coil (must be a Bosch CDI coil), recent example being a unit returned from USA with a 'high RPM misfire around 7000 RPM'.  Yep, that's default setting for the rev limiter...  

Thanks - I check the grounding and all good - also installed some of your Fuse panels for good measure - used nut rivets instead of the bolt and nut for the cdi units. It also only happens when the car get very hot - is there any thermal capacitors that are needed externally - unsure if the car has been meddled with.

[Jonny Retrofit]

2 hours ago, Manni187 said:

Thanks - I check the grounding and all good - also installed some of your Fuse panels for good measure - used nut rivets instead of the bolt and nut for the cdi units. It also only happens when the car get very hot - is there any thermal capacitors that are needed externally - unsure if the car has been meddled with.

No need for anything extra externally.  Next time it happens, see if the green light on top is flashing when you crank.  This indicates distributor signal is being ‘seen’.  Green light is next to top mounting bolt.  

After that do a basic spark test.

I have seen the wires hanging by a thread on the 3 pin connector more than a few times.  Inspect them closely. 
 

TBH,  if this was for the ‘tapping’ I’d say this sounds more like a fuel issue. 

[epilot]

Hi,

I have CR CDI's in both my cars, 2.2 and 2.4 E with MFI.

The 2.4 was only recently fitted and to quote my mechanic "ran like a dog" when first connected to the CR CDI.

The unit was drawing too much power and Simon placed a relay in line to it which solved the problem. Car runs perfectly now.

 

[Jonny Retrofit]

12 hours ago, epilot said:

Hi,

I have CR CDI's in both my cars, 2.2 and 2.4 E with MFI.

The 2.4 was only recently fitted and to quote my mechanic "ran like a dog" when first connected to the CR CDI.

The unit was drawing too much power and Simon placed a relay in line to it which solved the problem. Car runs perfectly now.

 

I’m glad you have the car running well but I don’t think power was your issue - our units draw pretty much the same current as the Bosch units.   Around 3A at idle up to 7A at 7000 RPM.  

[pocketscience]

I've been super happy with the CR CDI in my 2.2. Zero install issues and it improved the running right away.

[wilburforce]

3 hours ago, pocketscience said:

I've been super happy with the CR CDI in my 2.2. Zero install issues and it improved the running right away.

Did you lock lock your distributor?  Looking at this for my SC 3.0.

[pocketscience]

38 minutes ago, wilburforce said:

Did you lock lock your distributor?  Looking at this for my SC 3.0.

Nope. Weights and springs still in action.

[Mike D'Silva]

I'd love to have one of these; make your own ignition map!