Car ignition coils on an XJ600, IT WORKS, VIDEO INSIDE

yeah, you read correctly, Im getting damn cheesed off with the availability of decent TCI coils at decent prices over here in the UK so Ive got a crazy (you may believe) idea.

If i can get a coil pack of a 4 cyl wasted spark ignition style car, such as:
http://cgi.ebay.co.uk/Ford-Escort-lead- ... 3365aff8cc

Then I plan on mounting them instead of my knackered old coils.

Now Ive been reading up about TCI/CDI stuff for the last week now, and i know the respective differences that CDI coils are fired from the CDI wereas TCI coils are charged up ready to go until the TCI earths them.

HOWEVER... I still cant find a reason not to use car ignition coil packs (which i assume are CDI), Surely if they coils have the correct primary and secondary resistance then they will work, not melt my TCI unit, and have a much easier job of changing leads when they fail, as well as completely waterproof connectors, thus solving the 'damn its raining, bye bye 2 cyl' issue.


Anyone got any ideas/insight I might have missed here?

Cheers
John


P.S, I'll be keeping this thread updated as and when i get around to the conversion.

 

Re: CAR ignition coils on a xj600 92

I suppose it would work. It all depends on the prinary resistance of the coils, they must match. If they don't you risk frying your ingitin box. A TCI versus a CDI igniton systen generally have different coil resistances. Is there any problem mounting the new coils?

 

Re: CAR ignition coils on a xj600 92

the primary resistance is the key, higher resistance = less spark, lower current but could work. Lower resistance = more current and a chance to fry the TCI
i wouldn't worry about secondary resistance, tci or cdi doesn't matter

 

Re: CAR ignition coils on a xj600 92

Pollock, Thats what I wanted to hear, thanks for confirming my beliefs.
Before attempting I'll check the primary resistance and if I need to I'll put a resistor inline. The only reason I worry about putting CDI coils on a TCI system is if leaving CDI coils charged up (as the TCI unit would do) could damage them.

mlew... not tried to fit one yet, but I assume it wont be too hard, this is the ratbike it'll be going on, lovingly built from second hand parts from frame up by myself so im sure I can fit a coil pack without any major issues.


Cheers
John

 

Re: CAR ignition coils on a xj600 92

GM HEI
you might be interested in this

 

Re: CAR ignition coils on a xj600 92

Interesting link there, I'll keep that in mind as a workaround should my TCI die but I se 2 issues already.

1) GM parts arent very cheap or easy to get hold of this side of the water, kind of detracting from the point of a rat as should it fail I want to be able to find a new one at a breakers to get her back on the road.

2) seems to be for mechanical advanced ignition systems rather than electronic advance curves, so would possibly only give one level of ignition advance (resulting in a pain in the ass to start because its too advanced, or no top end because its too retarded)

Cheers
John

 

Re: CAR ignition coils on a xj600 92

Love the trailer virus.

 

Re: CAR ignition coils on a xj600 92

LOL, sure illustrates how different these systems are from the other breaker systems employed in the 70's and 80's. One of the first things we would do was to switch out the ignition coils with auto coils, sometimes bought at Kmart for 5 bucks each. The spark that they produced would easily jump a .45 gap and never left a doubt whether you had a strong enough spark or not. I thought about switching my coils on my turbo but not being an electrical engineer, I gave up on the idea rather then fry any expensive parts. So I'm following this thread with vested interest.

jeff

 

Re: CAR ignition coils on a xj600 92

mlew, cheers, comes in very useful thats for sure.

Jeff, I know what you mean, I only thought of the idea as Ive got a friend running a car ignition coil on a MZ250 rat, points ignition replacing the distributor so to speak and away it goes. This led on to more digging to find another friend fitted 4 to a gsx550 (which is CDI ignition). Thats what got me wondering if TCI could do it... surely if CDI can then TCI cant be too far off?

I'll let you know in a week or 2.

Cheers
John

 

Re: CAR ignition coils on a xj600 92

First point is XJ bikes are not CDI.
They are actually a traditional style of electronic ignition (same as many cars) and have a positive supply to the coil and the TCI unit grounds the negative of the coil (the removes the ground to fire the coil)

Standard coils are around 2.5 ohms which has the TCI unit switching around 5 amps.

Most late model car (and Bike) coils are around 1 ohm (12 amps). The XJ unit will not switch 12 amps (long term).

Replacing the transistors in the TCI with higher rated devices (something like a VB921z) would help, but then you will need to see if the XJs dwell time (coil on time) is the same as what the new coil needs. Too long a dwell will overheat the coil.

Option 1; find a replacement coil with 2.5ish ohm primary.
Option 2; get creative and modify the TCI unit or find a programmable replacement.
Option 3; try it anyway 8O

 

Re: CAR ignition coils on a xj600 92

I'll take option 4, measure primary resitance on the coils and add resistors inbetween coil and TCI box to bring them to the specification the TCI box requires to not melt any components.

Cheers
John

 

Re: CAR ignition coils on a xj600 92

Just get high enough wattage resistors, and don't mount them where they can melt/burn anything. The precursors to high energy electronic systems used a ballast resistor, but only at about half the current.

Would certainly work though.

Just don't forget that a lower resistance primary will mean a lower inductance coil which will charge up quicker and may need a reduced dwell time to keep coil temperature down.

 

Re: CAR ignition coils on a xj600 92

Well I thought Id update, my chosen coilpack is here, Its a ford mondeo 1.8 zetec coil pack.

Resistance is as follows:

wire 1-2 = 0.5ohm
wire 2-3= 0.5ohm
wire 1-3= 1 ohm

As far as I can work out (and is being checked by a mechanic friend of mine on an autodata CD) wires 1 and 3 are the pulse wires and wire 2 needs constant 12v.

Secondary resistance is 12.7ohm and 13ohm across the HT lead connector pairs.

Im about to start trying to find suitable resistors to bring the resistance into spec of the TCI box, I plan to go for 3ohm total resistance as that is what the dynacoils use instead of the standard 2.5ohm as I believe the dynas are more powerful.

Cheers
John

 

Re: CAR ignition coils on a xj600 92

 

Re: CAR ignition coils on a xj600 92

You can get ballast resistors used on older vehicles that use points. The resistors are usally white ceramic on the outside and typically about 1 to 2 ohms.


There is a picture of one.
http://www.mopartruckparts.com/images/b ... 206436.jpg

 

Re: CAR ignition coils on a xj600 92, UPDATED

Ok so its almost Z-Day for the changeover.

Ive got the car coil, worked out that the pulsers need to be on pin 1 and 3 and a 12v input on wire 2, Ive been given 2 50w 2.2ohm resistors so that will take it to 2.7ohm resistance to keep the TCI safe.

All I need to do now is get some decent soldering on the go to fit the resistors, make up a mounting plate for the resistors and coil to go on the bike then get some new HT leads as ive only got a stump of whats left then I can try it and see how it goes.

Fingers crossed I might get some soldering done on sunday as thats my next free day, I'll update as and when I get any progress.

Cheers
John

 

Si I finally got around to sorting it out, Got some leads, Soldered up the right resistors in the pickup wires (1 and 3) to get the primary resistance to 2.7ohm and this is what happened.

http://www.youtube.com/watch?v=WyLtD3QZ-fQ


Cheers
John

 

Cool fires right up, what was the coil resistance without the resistors.

 

that was a cold start with half choke as well, it used to be a full choke 3 seconds on the button to start bike.

Pri resistance on the mondeo coils was .3 ohm as said on page one.

Cheers
John

 

thought id throw up a few pictures, the resistors can be seen in the first picture, the brass rectangular shiny things (notably one of the few actually shiny components on the bike :lol





Cheers
John

 

Virus, congrats on your achievement. Now about your bike's appearance: back in the 80's, a brazilian bike magazine I used to read mentioned a "tribe" of european bikers that would have their wheels mechanically flawless - but appearing as rotten as possible!
They called themselves "wellards", and seem to have vanished in time since then. The only "wellards" associated with motorcycles I could find is via google is a repair shop down in australia.
Tellingly, my 20+ years old e-mail direction at yahoo is "wellard_br".
I guess the old wellards were actually rat-bikers lol!
All the best vibes from Israel to you, pal!
Aharon

 

Thats pretty much the mentality behind ratbiking, why waste money on cosmetics when you can spend it on improving performance or getting more fuel?

This for example is a honda frame with a XJ engine and kawasaki GPZ900r Front forks, It cost me 250 pounds to build and out performs all of the local 'fast' cars.

Cheers
John

 

You should market these. What was the total cost? Or how about a detailed "How to"?

 

total cost was 25 quid all in, it would have been cheaper If i could have found a coil that came with leads, theres plenty on ebay cheap enough I just wanted a ford one because the ford system is used on a hell of a lot of cars over here, pretty much all 4 cyl fords have it so spares are in abundance in breakers yards should it ever fail.

Not really worth marketing, all the details are in this thread at some point, basically you need to connect 12v positive to the centre pin and then connect the pulse wires to the outer 2, making sure the resistance is somewhere between 2.5 and 3 ohms.

Cheers
John