Board Logo

accufire dwell angle
76camper - March 17th, 2006 at 05:51 PM

Installed my empi accufire kit (elect ign) a while ago. After i installed it i measured the dwell and set timing. Dwell was reading around 25 degrees at idle, measured on my new 2nd hand dwell meter. I thought the meter was buggered and forgot about the prob coz bus was running fine. Today i thought i would have another go and measured the dwell. Same, 25 degrees at idle. I then reved the engine and the dwell went to around 60 degrees at 2500-3000rpm.

Have i got the dwell meter hooked up wrong?

How can i adjust the dwell on my accufire kit? I thought it was fixed and found this page, http://www.ratwell.com/technical/PertronixAdjust.html 

Tried to raise the rotor plate a bit but didnt do much... any ideas ?

how should i have the dwell meter hooked up? Got one black wire and one red.

can i adjust the dwell on the accufire kit??

cheers


tassupervee - March 17th, 2006 at 06:13 PM

Id suggest you might have the dwell meter set on the wrong range. Ie: 6cyl or perhaps 8cyl.

Messing with electronic systems to reap a couple of degrees of dwell here and there is close to (no pun) pointless!

Set your timing, put your dwell meter away and enjoy the fact that thats the last time you ever need to set points and timing again unless it loosens itself off or you remove the dizzy for whatever reason.

L8tr
E


modulus - March 17th, 2006 at 06:24 PM

Usually red lead to negative, black to engine ground. Check that the dwell meter (if it's thae tach/dwell type is set to Dwell.

Dwell angle shouldn't vary with RPM (dwell *time* decreases with + RPM, of course). When measured correctly, varying dwell angle usually indicates the distributor is ready for rebushing, but even a bad one won't go 25-60 degrees! P-ossibly your hookup is not right.

With the accufire, you should be looking for 50+ degrees, but the actual number is not as critical as with mechanical points.

If you get some useful, repeatable results, write a little tech article on how to set dwell on electronic ignitions; I'm sure lots of folk would like to know.

[While I was composing my deathless prose, Tas snuck in with, arguably, a better answer - don't sweat it]

hth

[ Edited on 17-3-06 by modulus ]


76camper - March 17th, 2006 at 06:37 PM

hehe, thanks guyz. The bus is running fine so something sus is going on. Am loving not having to set points or timing :D. Next ignition mod i think will be the universal high energy discharge kit from jaycar. $95 with some pretty nifty features.

As for the settings on the dwell meter, it has only a dwell/ tach switch. tachometer function works fine... and has two scales for both dwell and tach, one for 4cyl and one for 6. Then bottom right of scale says, 8cyl=4cyl X 1/2.

thanks for the replies and as modulus said, be intresting to see if dwell is adjustable some how!


tassupervee - March 17th, 2006 at 07:38 PM

Nah apart from the chicanery mentioned in that article you pointed out, the dwell is set at a given figure and is for all intentions and purposes, not adjustable.

Adjusting the dwell requires some pretty sophisticated electronics changes and your system will be sealed and dwell will be fixed.
Unless you can find a setscrew or a knob labelled "Dwell Adjust" dont worry about it! LOL

Enjoy.
L8tr
E


76camper - March 17th, 2006 at 08:10 PM

yea, thanx. Not too fussed just wondering if it were possible. thanx


tangblog - March 31st, 2006 at 03:56 AM

Hi Camper 76,
The electronic dizzy module is meant to have a variable dwell reading it changes from 30 degrees at low rpm up to around 55 degrees under load thus giving you the best dwell angle for your situation. Just be care full with this type of module and dont ever leave you ignition on with out starting the car as it will over heat the coil and then fry the module and then nothing works.


koolkarmakombi - March 31st, 2006 at 07:52 AM

What tang said....

ps whats all the gizmos about with the jaycar kit?


76camper - March 31st, 2006 at 09:42 AM

Universal High-Energy Electronic Ignition System. available from Jaycar for $95
Features:
slectable dwell period
Coil shut down when engine is not running
Dwell extension with low battery voltage
minimum spark duration of 1ms
two points debounce periods (counteracts points bounce on points ignition systems)
anti theft ignition disable switch option
optional inverted trigger signal operation

Input Triggers:
Reluctor
optical
hall effect (accufire, pertronix etc)
ECU

maybe give it a search on google or something, my dentist photocopied an article from a car magazine featuring the kit... looks the goods to me


76camper - April 1st, 2006 at 09:35 PM

found the kit on the jaycar web site

http://www.jaycar.com.au/productView.asp?ID=KC5419&CATID=&keywords=&SPECIAL=&...

doesnt go into as much detail as this article but theres the price and a bit of info.