altezzaclub Posted March 21, 2011 Report Share Posted March 21, 2011 (edited) So... I went and bought a KE Motorsport electronic dizzy, read up about it and fitted it. 10minutes work! Two wires, vac advance on, check idle timing... done! How to do it is here- http://www.rollaclub...70/page__st__45 Jumped in, drove away, and...... it was a DOG under 3000rpm. Even after that it wasn't fast... So I stopped and wound on some advance, tried it, added advance, tried it, did it again. When I got home I put a timing light on it, and it was running 18deg at idle!! Research time- read some topics here on Rollaclub & it appears they are for HiAce vans! Time to find out what is wrong- First up, I put the timing mark on the crank pulley back at the 20deg mark on the cam cover and white-marked the pulley rim forward every 5degrees. Then I put the last mark back at 20deg & repeated, so now I had a pulley marked every 5degrees out to 40deg. I got the wife to sit inside and give me 500rpm at a time while I read the timing light, and I repeated it with the vac advance hose off. This is the curve it generated, and you can see it has no advance under 3500 worth talking about. The Piper dizzy is a sports distributor with a similar curve to a 1980s Prelude, and I thought that would be a reasonable comparison. What I thought from this was that the port vac figures were crazy. Anyone in the class know what this shows?? The boy in the corner.... Yes, it shows that you don't read vac advance by revving a motor in the garage! Go to the top of the class! A quick drive with a vac gauge showed 12"Hg just off idle, falling off the moment I drove away, & coming back when I lifted off the throttle on over-run. So all work was done without the vac advance. Edited January 8, 2020 by altezzaclub Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted March 21, 2011 Author Report Share Posted March 21, 2011 Having got a curve I figured it was time to see what was inside. Taking off the top, the first screws out are marked here. They hold in an electronic unit I assume is the ignitor. Make sure you start this on a clean concrete floor with good light, because over the many times I pulled this thing apart I dropped washers or screws twice, and they took ages to find! Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted March 21, 2011 Author Report Share Posted March 21, 2011 Next is the vac unit, the screw marked C and the circlip marked D. (which I suppose I should put back on now...) That is all that holds the rotating base plate in place and you might need to rotate it to remove the arm. 1 Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted March 21, 2011 Author Report Share Posted March 21, 2011 Initially I took the sensor off the rotating baseplate, then I realised there is no need to. Just take out the screws holding down the whole base. Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted March 21, 2011 Author Report Share Posted March 21, 2011 Now you can see the two boomerang-shaped weights and the springs that they work on. There is no need to take anything else out apart from those two springs. You can see that as the weights get flung out by the revs they push the rotor shaft plate around and the max advance slot moves past that pin. When the pin reaches the other side of the slot there is no more advance available. The rotor shaft plate has a strange shape as outlined. Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted March 21, 2011 Author Report Share Posted March 21, 2011 OK, first up I ran it with one spring- definately better but not advancing low down anywhere near enough. Then I measured the length of the springs and stretched one from 21.5mm to 22.9mm. This was done in a few careful stretches and measures, and once I had it too long I bent the end circles in a whisker to get under 23mm. This allows the weights to move out easily low down but the spring slows the advance from half-way onwards. Then, to make sure the weights returned at idle, I fitted a ball-point pen spring to the other side. All looked good- Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted March 21, 2011 Author Report Share Posted March 21, 2011 (edited) But the graph only showed a 2degree increase at 1500rpm. I tried the ballpoint by itself, thinking it would max out straight away, but it only went to 28deg... WTF?? Then I realised that although the ballpoint spring held the weights in nicely when I looked at it, when it was running at 1000rpm and I set the timing to 10degrees, the weights had moved out & it was already well into the advance curve, so there wasn't enough movement left to get to 36deg. So, ballpoint spring out and I went to the place where all small springs can be found.. the workshop windowsill. It is a well-known phenomena world-wide that small springs roll away in the dead of night and crawl to the workshop windowsill to hide amongst all the odd bits and pieces thrown on there! I gathered up the half-dozen who had made it that far and measured them. For those who were still pissed from the night before when the lecturer explained coil spring rates, all you need is the wire diameter, the springs outside diameter, and the number of free coils (don't count the end ones) Then look up this website, or any like it- http://www.pontiacracing.net/js_coil_spring_rate.htm The nice thing is you can cut a spring to the number of coils that gives the rate you want.... within reason! So, my stock spring had a rate of 53, my ballpoint spring a rate of 6.5 !! The stock Bosch springs were 38 and 133, and my other springs were 20, 49 and 5. I picked the 20, which was slightly tapered down its length, cut it to calculated length and fitted it. It was just tight at zero revs and generated an even better curve. So we were almost there, just not quite as fast as a Piper. The final trick was to take the stretched stock spring out and just run the taper spring... POW! all the advance in by 3000. Edited January 8, 2020 by altezzaclub Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted March 21, 2011 Author Report Share Posted March 21, 2011 (edited) So, I went from two springs at a rate of 50 each to one at a rate of 20. That's what makes these dizzys work! Now I have the advantage of no misfiring at lean mixtures slugging out of a left turn intersection, no rich misfires in the morning, AND it gets up and goes smoothly and sweetly straight over 5000rpm, all on 95octane 10% ethanol. Orange is at 2500ft, so sea level might need a couple of degrees less. I'm afraid I can't tell you what spring to buy, it was .03" wire, wound to 0.23" diameter and I used about 8coils. Here's the sprngs I have left over- the ballpoint is in the top middle, the dizzys (Bosch & KEmotorsport) at the bottom. Three days work and education, or $75+post to Performance Ignition in Melbourne.... :laff: Edited January 8, 2020 by altezzaclub Quote Link to comment Share on other sites More sharing options...
WET.K30 Posted March 21, 2011 Report Share Posted March 21, 2011 would you say its worth going threw all this trouble?? what did u feel the car gained from the electronic dizzy, apart from less maintanance? Quote Link to comment Share on other sites More sharing options...
Evan G Posted March 21, 2011 Report Share Posted March 21, 2011 question, are the points counterweight springs the same as the electronic one? I'm pretty sure you can remove the hall effect sensor and install it on the points counter weights/shaft see the hows there a plastic cover on the top of the dissy. remove that and theres a screw under there to remove it Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted March 21, 2011 Author Report Share Posted March 21, 2011 It definately runs smoother low down, where twin carbs and ground cams struggle a little... getting off the lean burn of deceleration or driving cold in the morning. The plug gaps can get a bit larger and the spark is greater. Changing points never worried me, the odd misfire was a pain especially as I run it pretty lean, down around 17-20 with foot off. Evan, the weights are quite different, in fact I don't think any of the shaft/plates/weights/springs would interchange. Quote Link to comment Share on other sites More sharing options...
Felix Posted March 21, 2011 Report Share Posted March 21, 2011 question, are the points counterweight springs the same as the electronic one? I'm pretty sure you can remove the hall effect sensor and install it on the points counter weights/shaft The springs might work. If you have a Bosch dizzy look at sigmas with Bosch based electronic dizzys. Bosch dizzy parts are a lot more interchangeable than Nipondenso ones. Heaps of different cars to look at for alternate springs and weights. Ideally with a modded motor the advance curve should be shorter as well as more aggressive. I've found the electronic (internal igniter) dizzies give better starting, but then decrease performance across the rev range. They most definitely need recurving. Quote Link to comment Share on other sites More sharing options...
Evan G Posted March 21, 2011 Report Share Posted March 21, 2011 (edited) my electronic dissy shaft/bushes were so worn out. had like 2mm side to side movement. i push the old bushes out. swapped shafts with the points one. used the electronic weights etc etc. but if i remember correctly the weights are held on with small circlips so they can be removed etc. edit - felix i got a sigma electronic dissy in the shed. ill take some pics of the internals and compare em to the points dissy Edited March 21, 2011 by Evan G Quote Link to comment Share on other sites More sharing options...
altezzaclub Posted March 21, 2011 Author Report Share Posted March 21, 2011 (edited) Here's the mechanical Bosch the KE70 came with, and the ND electronic insides. They won't swap anything between them. The Bosch spring rates are 38 and 133, the NDs are both 50ish Edited March 21, 2011 by altezzaclub Quote Link to comment Share on other sites More sharing options...
towe001 Posted March 21, 2011 Report Share Posted March 21, 2011 Good work :2thumbs: I vote pin the thread Quote Link to comment Share on other sites More sharing options...
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