Timing with Petronix

Java74 · 06-07-2011, 06:16 PM

Ok, I just re-installed my distributor with new Pertronix ignitor and after grunting in the 90 degree heat of my garage for 45 minutes, figured out why it wouldn't start and fixed it up. Now it starts and run well but idles much faster than it previously did before the ignition changes. Since the Pertronix has fixed dwell, I'm assuming my timing needs adjusted....only problem is.....my battery is up in the front trunk and my timing light connections don't reach that far!! UGH!! Anyone else have this problem? I guess I could borrow a battery to hook the timing light to?
So, my question is: do I adjust the idle speed before or after the timing is done? I guess
I should consult my books in the mean time but I decided to post this first while having a beer! Thoughts? Despite my cursing fits, I am loving my new (to me) 914 and it's just an absolute blast to drive!!

rockerarm · 06-07-2011, 06:36 PM

Well congradulations on your "upgrade". And welcome to the site.
Regarding your timing, we need to know what model car, engine, fuel system ( carb or oem fuel injection ), and distributor you have. Nearly all the 4cyl 914 or vw have an idle timing spec. But, there is a 914/vw that sets timing at 3500rpm. So, basically need to know more.
If your car idled fine prior to this and you have not turned other screws, more than likely just setting the timing will sufice and your idle will come down near spec and a small deviation (adjustment) may be in order. Just assure your throttle plate is closed and vacuum hoses are attached.
Not to slander anyone, but on another site (thesamba.com) some people had failure issues with the pertronics and compufire systems. So I would suggest carry your points and condensor in a zip lock bag along with tools to revert back if needed.
As far as timing lite hookup, ground is obvious and you can use terminal 15 (+) on the coil. You can also make up some 6' test leads.
Hope this helps, Bill

Java74 · 06-07-2011, 06:48 PM

It's a '74 914 2.0L, stock fuel injection, stock dizzy... not sure of the serial # on it but it's a Bosch 039. I've just replaced all of my vacuum hoses to fix a low idle/stalling issue and it was idling well around 975rpm. I will make sure no hoses came off in during my work on the dizzy. I didn't get to drive it as it was getting late but will investigate further tomorrow. My timing light is an old Actron inductive light; should I be looking for a newer
unit that has better features? Any suggestions on a good timing light? Thanks!

Java74 · 06-07-2011, 06:50 PM

Oh, and I am aware of the possibility of this elec. ignition failing and plan to keep a back up set of points and condenser in my toolkit just in case! I had a unit like this in my Ghia and never had an issue but one never knows!

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Set the timing at 3500 RPM (27 deg BTDC). That will likely bring your idle back to where it was. If not, then adjust the idle using the screw in the side of the throttle body. But only after setting the timing.

I've gotten the timing very close by turning the distributor until the idle sounded like it did before I took the distributor out, actually. But definitely a good idea to check with a real timing light.

--DD

Tobra · Tobra's Garage

I get them close by ear like Dave suggests, then check with the light, always been pretty close.

You could always use jumper cables from the front to the back, or middle I guess. Connect the light to the cables and the cables to the battery.

Dave at Pelican Parts · Dave at Pelican Parts's Garage

Oh, for the connections:

All you need is a "hot" and a ground. You can probably get away with hooking the red wire from the light onto the + terminal of the coil. Hook the black wire from the light onto a ground, like some exposed part of the crankcase.

--DD

Java74 · 06-10-2011, 03:57 AM

I have another query about this dizzy/ignition setup: the ground wire in the dizzy, does it still need to attach to the contact plate? Mine is only soldered to the base and isn't touching or soldered to the contact plate. Could this be causing my hard start issues with this? I don't know if it was attached prior to installing the Pertronix or not but I am assuming that it has somehow gotten loose, broken or whatever....
I am thinking that this ground is still necessary without the original contact points, correct? I just wonder if it was sandwiched between the plate and the old points prior to me removing them to install the Pertronix module....

Dave at Pelican Parts · Dave at Pelican Parts's Garage

I am pretty sure that the Pertronix still needs to ground, so the ground strap should be attached to both the distributor body and to the upper contact breaker plate. I have heard that by the time the ground strap breaks, the breaker plates are probably pretty worn, so it is a reasonable idea to replace them.

Advice I haven't actually taken myself, mind you...

--DD

Java74 · 06-10-2011, 03:36 PM

Thanks Dave! Got the ground wire reattached, now just have to reset the timing a bit and I think it will be all good. By the way, my idle is now at the point where it stalls so my high idle issue is gone! Will fiddle with the timing tomorrow....but all the weirdo cranking and not starting issues seem to be gone and it sounds like it did prior to installing the Pertronix so I believe the ground fixed that problem. I appreciate all the help!!