Hello, Apologies in advance for this non-traditional forum topic, but I know a lot of you run ‘em, and this is one of the busier forums I am a member on. I just installed my first “Multi-Spark” electronic ignition, and I am having a helluva time getting the engine to run right. I am working with a Pertronix Ignitor III which has “Multi-Spark” across the entire RPM range as opposed to an MSD which only have “Multi-Spark” below 3,000 RPM. I have a digital dial-back timing light, and that may be 100% of my issue, but please read on...I don’t think it’s that easy. I am working on a 289 Ford V8. I have a healthy cam, and when I have an engine with a choppy idle I tend to set “total timing” as opposed to initial advance at idle. My Pertronix “Stock Look” Flame-Thrower Ignitor III distributor is supposed to have 21° of mechanical advance all in by 3,000 RPM (vacuum advance is disconnected), so I set my timing at 36° at 3,500 RPM, and took the car for a drive. I had “sneezing” (popping, backfiring, etc) out the carb anytime I would accelerate hard from a dead stop), but then it ran like the proverbial sexually mis-treated primate; weird to have both situations at once, so I came back home and checked timing at idle. I only had 6° initial. I revved the motor back up to 3,500 RPM to make sure nothing had changed, and it was still right there at 36°, so I kept revving higher, and the timing kept advancing all the way to 40° @ 4,500 RPM. The light is also totally steady and easy to read. So now I’m really scratching my head. I read up some more on the distributor, and the advance curve is supposed to start at about 900 rpm, and again, all in by 3,000 RPM. I check and find I’m not getting ANY advance until 2,000 RPM. So I read some more. I see two more posts that suggest that a dial-back timing light will only work if it’s set on zero. Luckily I have a degreed balancer, so I check that way, and I get the exact same results. I bump base timing 2° and get the same readings, plus 2° throughout the entire RPM band. So, at this point I’m pretty convinced that I’ve got a defective distributor, and I call Pertronix, but they tell me it’s 100% my timing light. But, wouldn’t the timing light just read erratically? Would I really get a steady reading from idle to 2,000 RPM if the timing WAS actually advancing. Would I see timing advancing past 3,000 RPM all the way to 4,500 RPM if it was NOT advancing at all!? I guess I need to go find a standard strobe type timing light and check again, but I’m pretty convinced that this distributor is faulty... ***UPDATE*** I just borrowed an old KAL Equip #904 non-digital timing light (it’s still a “dial-back”, but it’s an old solid state unit from the 80’s at the newest), and with the knob set at zero I get the exact same WAY OFF timing curve... Look forward to the HAMB’s advice... Casey
I think you're right. Have the person at Pertronix explain what is wrong with your timing light, to make it show the advance curve is wrong.
My dialback Cornwell timing light works great on MSD7 boxes..... But not on MSD6 boxes. Timing will be off as much as 15 degrees. I had to use an old non dialback on cars with a 6 box. MSD website has info about it. Never tried it on Pertronix though.
Gotta agree with the above-all^^^^^^^ Even if you set your light at 0*, instead of dialing it back, your tape is your back up....... Something need's a lil 'splaining by the P people.......
The engine's actual performance problems also back up the fact your readings are right. Anything with a bigger cam like that is going to want a lot of initial timing, in the 12-20° range....with it only showing 6° and no advance movement until 2000 rpm there is no wonder it is popping, banging, and farting when you stomp on it. Acting no different below 2000 rpm than a locked distributor set way too low(retarded timing) or like an HEI where the rotor mount has seized around the shaft, locking it up or severely limiting advance movement. Ask Pertronix why it also runs so poorly if it is all in the light being wrong??
Thanks to everybody for the positive reinforcement. Their answer was “time it by ear”. Luckily Summit said “just send it back”. Thanks Again!!
Also, you'd be surprised how fast you can go with a point distributor and a stock ignition coil. Most, but not all, ignition hot rod stuff is mostly hype, and not needed.
Agree with squirrel points can go pretty good. I went high 10s with points. My buddy was convinced I’d go faster with an MSD, so we stuck his system on and while it did start faster, there was no difference in the time slip Modern ignition sys are good, just harder to disagnois a problem. IMHO
The Pertronix II I bought with their coil and still using the stock ballast resistor has performed flawless for 6 years after 2 failed condensers. I installed it in a 57 distributor.
Yup, you need to get good parts, no matter what system you use. And good parts are getting harder to find, for just about any system. That's why we're having this discussion in the first place
X2 !! I read post a few times , If 6 is initial timing that's way too low, I would say 12 pluse on initial Timing, use a vacuum gauge to determine initial timing that the engine likes, Then carb adjustments will be required again . Then set your total of Total timing inside distributor ,weights Springs stops limiters. There has been several complaints about The Pertronix , here on HAMB, I have a few knob style timing lights, Sears craftsman from the 80s snap on early 90s and a cheap$80 Digital Nonova timming light , I personally have not had any issues using on MSD boxes 6 -8 , and I also have self power timing light for magnetos.
I would run points and use them to trigger the MSD. That's one of the oldest and best ignitions going..
21° of advance in the distributor? Probably 10° in the distributor which would give you 20° at the crank. What does engine idle at? I think your vacuum advance is floating around, wedge it full retard and set the timing and run the car.. With a hot cam [how hot?] I think vacuum advance just gives carb tuning issues and because of low vacuum its not going to due much towards gas milage which is the only reason to try to use vacuum advance....
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