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998 V 1275 Ignition Advance Curves


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#1 Tamworthbay

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Posted 07 July 2013 - 11:57 AM

There are a few members on here having issues with electronic ignition kits (myself included) and it has set me wondering. I used the kit that fits in the dizzy so the advance curve should remain the same. But Accuspark and powerspark do replacement dizzys fairly cheap. On accusparks website, they list two replacement dizzys, one A series, one A+. I am wondering if every engine from 850-1275 had the same advance curve? If they didn't, which engine is the replacement dizzy designed for? If there is significant difference in the curves, this could explain some of the issues some people are having ( not me, mine was a dodgy trigger ring, sorted thanks to PaulColeman).

#2 krusher74

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Posted 07 July 2013 - 12:02 PM

An advance curve is not tailored to a CC of engine unless were talking factory stock, once you have modded your engine it may need a different advance curve to stock to perform best, so for example a modded 850 might like a stock 1275 advance curve.

 

you need an adjustable distributor and rolling road time to dial it in perfectly.

 

With a more powerful spark you may not need as much advance as it lights the fuel charge easier 

 

what ever curve a distributor has you should be able to set it about 8/12 (base timing) at idle and get it to run though.


Edited by krusher74, 07 July 2013 - 12:04 PM.


#3 Tamworthbay

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Posted 07 July 2013 - 12:05 PM

An advance curve is not tailored to a CC of engine unless were talking factory stock, once you have modded your engine it may need a different advance curve to stock to perform best, so for example a modded 850 might like a stock 1275 advance curve.
 
you need an adjustable distributor and rolling road time to dial it in perfectly.
 
With a more powerful spark you may not need as much advance as it lights the fuel charge easier

That seems logical and is what I thought would be the case, so the question is how far out are these aftermarket distributors? Even looking at a complete stock engine, I can't see one dizzy being perfect for an 850, 998, 1098 and 1275. So what ARE they set up for I wonder?

#4 petey81

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Posted 07 July 2013 - 12:11 PM

I asked them once and didn't give me any real answer. I have a 998 with 20thou over bore and few other bits but I have a standard 1275 elec dizzy. Ml motorsport said curve was fine and they told me to run without vac adv.

#5 krusher74

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Posted 07 July 2013 - 12:16 PM

 

An advance curve is not tailored to a CC of engine unless were talking factory stock, once you have modded your engine it may need a different advance curve to stock to perform best, so for example a modded 850 might like a stock 1275 advance curve.
 
you need an adjustable distributor and rolling road time to dial it in perfectly.
 
With a more powerful spark you may not need as much advance as it lights the fuel charge easier

That seems logical and is what I thought would be the case, so the question is how far out are these aftermarket distributors? Even looking at a complete stock engine, I can't see one dizzy being perfect for an 850, 998, 1098 and 1275. So what ARE they set up for I wonder?

 

I come from a VW background and know vw on the aircooleds used over 50 different distributors all with different curves/limits and vac ranges, every change of engine spec go a new factory best curve.

 

I would think they will have picked a generic sport/road curve.

 

If there anything like the same Chinese crap distributors you can get for the vw's they wont even have the same curves from one to the next. O_O 

 

If you have a good timing light with rpm dial etc you can plot you own (centrifugal advance plug vac off) with it.

 

I hope mini people arent going to have the same bunch of nightmares vw people are having, I have seen some of these aftermarket distributors have 10 degrees advance so have 20, some 30 some non!!! Bunch of *******!! :mmkay:



#6 krusher74

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Posted 07 July 2013 - 12:19 PM

I asked them once and didn't give me any real answer. I have a 998 with 20thou over bore and few other bits but I have a standard 1275 elec dizzy. Ml motorsport said curve was fine and they told me to run without vac adv.

That's typical that they cant even tell you a simple thing like the advance curve of there product, 

 

they need one of these 



#7 jaydee

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Posted 07 July 2013 - 03:31 PM

Advance curve may be very different, a 998 is a short engine whilist the 1275 is a long stroke. This means that the 1275 need more advance and  an ingition curve from a 1275 can be too aggressive for a 998



#8 krusher74

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Posted 07 July 2013 - 03:50 PM

Advance curve may be very different, a 998 is a short engine whilist the 1275 is a long stroke. This means that the 1275 need more advance and  an ingition curve from a 1275 can be too aggressive for a 998

the 998 isnt a short stroke engine, Were you thinking of the 970s?



#9 jaydee

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Posted 07 July 2013 - 04:08 PM

The 970 is oversquare- another matter

A 998 is a short stroke compared to a 1275 thats why, although some might work, most ingition curves wont match.



#10 DannyTip

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Posted 07 July 2013 - 04:32 PM

I asked powerspark about mappable ignition at himley hall and he said "he wouldn't touch anything you can plug a laptop into" then continued to demonstrate it could throw a massive spark. What are the bodies they sell? Are they Lucas items or copies?

#11 krusher74

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Posted 07 July 2013 - 05:06 PM

I asked powerspark about mappable ignition at himley hall and he said "he wouldn't touch anything you can plug a laptop into" then continued to demonstrate it could throw a massive spark. What are the bodies they sell? Are they Lucas items or copies?

 

I asked them once and didn't give me any real answer. I have a 998 with 20thou over bore and few other bits but I have a standard 1275 elec dizzy. Ml motorsport said curve was fine and they told me to run without vac adv.

The website ways this

"Should you need a specific advance curve set then we can provide this service ensuring that your engine is provided with the best match with the new distributor." 

Hmmmm :mmkay: 



#12 petey81

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Posted 07 July 2013 - 05:19 PM

I have been running like this for 3 1/2 years with no problems. No difference in mpg and running great.

#13 KernowCooper

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Posted 07 July 2013 - 05:51 PM

Answers to a few points above

 

1275 distributors on standard 998s have a different advance curve for the small bore block

 

Road engines benefit from having a Vacuum Advance connected re Vizard & Calver

 

The new distributors must be new castings done in the east as Lucas dont make any nowdays.


Edited by KernowCooper, 07 July 2013 - 09:50 PM.


#14 Tamworthbay

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Posted 07 July 2013 - 05:57 PM

Answers to a few points above
 
1275 distributors on standard 998s have to much advance for the small bore block
 
Road engines benefit from having a Vacuum Advance connected re Vizard & Calver
 
The new distributors must be new castings done in the east as Lucas dont make any nowdays.

So if 1275 on 998 is too advanced, 998 on 1275 is not advanced enough by a process of logical deduction. Therefore they can't list the same dizzy for all engine sizes and expect them to perform well on all. So I guess the upshot of this is that you are better to use a kit and convert your existing dizzy rather than take a chance on whether the advance curve of the new dizzy will suit the engine or not.

#15 ukcooper

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Posted 07 July 2013 - 06:23 PM

I bought a dizzy and coil package from accuspark for the a+ now it's worked on a standard 998 , 1275, stage 3ish 1275 and now a stage 3ish 1310 and ran great on them all with no messing with the dizzy full stop except timing . none off them where never set on a rolling road or had expert setting up. It dose rev to 8500rpm if I want.

 

But once I wanted to spray there coil red to match the engine so I fitted the rover standard coil and It would not run, fitted the standard dizzy and it ran fine, fitted the accuspark coil and it would not run fitted the accuspark dizzy and it ran. So not sure if its a coil problem.

 

Both times I ran a ignition 12v feed from the fuse box.

 

One last thing to mention that when I fist had mine it had like a plastic coating over the drive end of the dizzy, so I sanded that all off as I thought it might stop it earthing.






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