pertronix

[66 big block]

with pertronix II anyone try opening spark gap from .035 to??

 

[JohnZ]

The Pertronix module is simply an electronic switch, replacing a mechanical switch - it doesn't create a "hotter" spark.

 

[66 big block]

The Pertronix module is simply an electronic switch, replacing a mechanical switch - it doesn't create a "hotter" spark.

thanks John I was told you could open gap to about .040 so stick to.035?

 

[cfalson]

A pertronix module will not increase spark, it increases duration, a little at startup. Now if you add the coil, you can open the the plug gap to .040
Charlief
66 Coupe

 

[66 big block]

A pertronix module will not increase spark, it increases duration, a little at startup. Now if you add the coil, you can open the the plug gap to .040
Charlief
66 Coupe

charlie yes i did buy coil so ill try .040 gap thanks john

 

[Kid_Again]

Hmmm....no, i don't think that just buying their coil makes any difference....if you use a capacitive discharge ignition system, you can go as wide as .055 but you did not say that you're hooked up to a CD system...if you didn't see the recommendation to widen the gap in your instructions, stick with .035

 

[cfalson]

If I remember correctly the Pertronics coil, has a higher secondary to primary winding ratio than stock and supplies more voltage allowing you to open the plug gap.
Charlief
66 Coupe

 

[grumpyvette]

http://www.msdignition.com/ignition_6_6420.htm

add something like this to that pertronix II ignition switch and a matching blaster coil and youll see a noticable increase in spark AND it tends to keep the plugs cleaner and the car tends to idle better
thier tech line is

1-915-855-7123

http://www.msdignition.com/downld1.htm

 

[Kid_Again]

OK, I'm no electronics expert so I'll sign off with this final thought. I simply do not believe that a conventional coil (even one that throws out a few thousand more volts), coupled with an electronic switch such as the Pertronix Ignitor will make a measurable difference in your spark. Yes, there's a bit more energy going through your sytem but if you widen your spark plug gap, you will, in my opinion, reduce the efficiency of your spark.

If you look at the instructions that come with even the MSD Blaster Coil, nowhere do they recommend that you widen the gap.

You only widen the gap when you you go to a very hot, short-term spark such as with a CD ignition system. The instructions to widen the plug gap are only found in the instructions that come with a CD system.

The benefits derived from going to a Pertronix unit, in my experience, are there because most guys simply don't know how to properly set up a set of conventional points.

Good luck!

 

[jims427400]

66,
I also recently installed a ignitor system on my 67/427 becuase I didnt want to deal w/ points.After saying that I put a dwell meter on it this weekend and it was reading 25*(not 28*to32*)I have a question about that! Also reset timing to 4*btdc and car still ran poorly at higher rpms. Increased it to 10*btdc and it ran a little better.
My next question is could it be fuel pump,spark plug wires??
BTW tripowers were just completely rebuilt.. Any thoughts anyone??
Thanks JIm

 

[BarryK]

Jim
you say you increased timing to 10* - I'm assuming you mean on the intial. After you did that where was the timing on the total (with the vacuum hose disconnected from the vacuum can and plugged).
how much mechanical advance is your distributor giving you?
it may feel like it's running better but you better be sure you aren't going too high on your total timing and running into detonation issues.

Also, where is your vacuum can plugged into for vacuum on your carb? Is it a full vacuum port or a ported vacuum port? You want to make sure it's on a full vacuum port.

 

[JohnZ]

The factory setup on the '67 tri-power cars has the distributor vacuum line fed from a "ported" source on the center carburetor. They run a LOT better if you cap that port and tee the distributor vacuum line into the short hose that feeds the choke pull-off diaphragm on the center carb, which is a manifold vacuum source - makes a big difference in idle stability, idle cooling, and throttle response. Takes about two minutes to make the change, then re-set idle speed and mixture (idle speed will increase when the hose is moved, as the vacuum advance will be fully-deployed and add 15* of idle timing).

 

[atmmac]

i actually had bad luck with pertronix ignition on my impala. I ended up putting in Accel HEI. Id go HEI or stick with the points. The pertronix stuff is kinda cheap.

 

[BarryK]

John
why didn't the factory hook up the vacuum that way from the factory? was it some kind of emissions game they were doing?

 

[JohnZ]

John
why didn't the factory hook up the vacuum that way from the factory? was it some kind of emissions game they were doing?

Apparently - the '66 L-72 was done the same way, and responds nicely to the same cure.

 

[jims427400]

Barry,
I wish I could give you all the answers to your questions.1st I put dwell meter on and read 25 not the 28-32.
Then hooked up timing light and read basic time,4*,drove car and ran horribily.Then per Craig "our carb guy"and he recommended setting to 12*I compromised to 10*,like I said it ran a "little"better.
I'm trying to rule out any other items that need to be looked at,ie
-plug wires
-fuel pump
-distributor(possible rebuild)was your car missfiring at rpms above 3000??
-go back to points
-did Craig mess up my carbs too ???
I'm considering taking to a professional (if I can find a good one)Getting pretty frustrated cause I thought this was going to be easier than its turning out to be.(I really want to keep my tripowers !!! Jim

 

[BarryK]

Jim
as we all know, I'm NO expert by any means but what I've learned so far is to start back at the basics and work up from there. If it was me what I would do is this....... and if I'm incorrect in any of this be sure someone will correct me!

1.start by changing out the vacuum hose to a full vacuum port like John suggested.
2.readjust idle and mixture as it will change like John said
3. it were me, I'd swap out the electronic module in the distributor and go back to hi-tension points.
4.readjust your dwell for 30*
5.check dwell at increasing rpms and see if it stays steady or if it varies. It should not vary with the electronic module in it but if you go back to points and it does vary you have too much endplay in the distributor and you need to get it shimmed.
6.than, if you haven't done it yet read JohnZ's paper on mapping your advance, if you don't already have it you can download it off my website in the tech article section or I can email it to you.
7.you NEED to find out what your distributor is doing and what kind of mechanical advance curve it's giving you. I don't know with the BB tri-power motors what your factory timing specs should be but i'd set them up with the factory specs on initial and mechanical advance timing settings.
finding out what the mechanical advance is currently giving you is pretty easy. all you need to do is see what the initial timing is, than see what the timing is as you rev up the motor to different RPM points and see what amount you are getting and when it's all in (where it stops advancing). take the highest reading, subtract your initial away from that and you will determine how much initial advance the distributor is giving you. Check that against what the factory specs call for.

if you are getting a lot of variance in your dwell and/or your mechanical advance is way off the factory specs than you will probably need to have your distributor worked on. Mine is out right now because of that. mine was giving me 32* of mechanical advance rather than the correct 24*.

Believe me, these steps are NOT hard to do if you have a dial-back timing light. If an idiot like me can learn how to do it ANYONE can!

 

[Marlar]

The guys on the Forum instructed me very well re the way to set up the Vacuum and centrifugal timing and it all starts with going to manifold vacuum. I also did not realized that there are different vacuum pots for different engine-cam combinations. After going thru all f that, I also used less strong springs on the centrifugal weights in the distributor. My '65 327 c.i. 365 hp isn't yet pulling thru the rpm range completely smoothly now, but it is a whole lot better.

Dump the ported vacuum port an never use it again!