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chinkamon

Elec ignition to sort a flat spot?

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Hi all

 

So since having my MK1 1500 cortina it's always had a slight flat spot, the original single barrel carb, the 1600 gt carb and the correct 1500 gt carb all have the same issue, if u drive like a loon, it loves it, 0 to 60 is quicker than it should be, it shifts lovely etc but driving like a normal person in traffic and between 1800 to 2200 it isn't happy, I'm running new points and condenser new plugs new leads from non cheap brands.

I have a set of accuspark elec ignition I bought an fitted when I first got the car up and running but due to the flat spot I reverted back to points to rule out any my interference being the issue.

My question is, 

A, would this help

2, is buying a new set a good idea or use the set I already have.

C, should I keep the points and buy a sparkrite sx4000 unit that runs off points and condenser but apparently auto adjusts ??

Or

4, just drive it like an arsehole everywhere? 

 

Cheers in advance 

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A perfectly working set of points will be no different to an electronic ignition - they both make sparks, that's all they do! As you have a flat spot at a certain revs it can't be either of the above as you've proved they both work at revs above and below. Normally i'd say carburation, but you seem to have covered those bases x3. So that leaves one thing that is dependant on rpm - the distributor, or more directly, the mechanical and vacuum advance units. The revs where its happening would be where the bob weights are moving to advance the ignition so i'd look there first. Vacuum is unlikely as it appears at low load / low revs where vac. isn't a big mover!

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Ah that's the other thing,

I had the original dizzy in there first, then when I found out there was a GT dizzy, I bought a (second hand ) one of those an fitted it, still had this issue?

Could they both of been worn?

Maybe buy a new dizzy from accuspark?

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Don't forget the dizzy advance curve has to match what the engine wants - a race engine won't like a std. unit, nor a stock engine work well with a race unit. For what it costs - nowt - a strip, clean, check and rebuild won't hurt! I still favour fuel for misfires - i'm guessing all the carbs had identical settings?

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It's a standard 1500 precrossflow. first with the original single carb, then put a 32 36 dgv jetted for as close as possible, then the 28 36 DCD from the 1500 GT, jetted correctly, 

All had the same issue, then I bought a GT dizzy off eBay as apparently it is different and fitted yet still the same issue 

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So an update...

I fitted the electronic ignition I had from accuspark. Replaced the coil with the one that I ordered with the kit and refitted everything, 

Fired it up, no difference.

Then realised I had the vacuum attached still from the carb so disconnected that an bunged up the hole on the carb an the 1800 to 2200 rev flat spot had all but vanished! 

Gonna stick the timing light on it tomorrow and stick the emission tester up her ass an see what tweaks need to be done but I think I got it!! 

Wooooooooo

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