The Stovebolt Site Forums The Shop Area Engine Shop Distributor Questions with Petronix

Went out in the truck and it broke down traced the problem to lack of spark. Changed the coil and it started up and ran fine. I was running the truck on the drive and noticed the replacement coil was getting hot. When I bought the truck it had a Petronix ignition and coil. I think this may be pulling the coil to ground more than it should causing it to overheat.

Questions

1) I noticed that the Petronix igniter is picking up directly from the distributor cam and doesn’t have a magnet ring. I don’t think this is normally but I don’t know. Anyone had this problem or has the same arrangement?

2) I am a bit confused about the make of distributor I think I have a Delco unit but are there different types. I’m going to buy a new Petronix igniter and want to ensure I get the correct one.

Thanks Regards Chris

That's an original equipment Delco distributor. If you plan to continue to use the Pertronix trigger instead of points, let me encourage you to acquire another distributor with points, and an original Delco coil to carry as a backup for the situation of when (not if) the Pertronix takes a dump and strands you in the middle of nowhere. Do a site search and you'll find plenty of anecdotal evidence of the unreliability of those units. If you're running a 12 volt electrical system, swapping to the General Motors HEI distributor is a much more reliable conversion to eliminate the points.
Jerry

Hello Jerry

Just wondering if you can provide a link to the HEI distributor. We did put after market an HEI unit on my friend C10 and it made a big difference to the running. Looking at the cost of buying another original distributor and having to return a core for rebuild I would much rather just buy a new distributor with HEI. I’m running a 216 in a 53 Chevy. The one we put in the c10 has the coil built into the distributor but that’s a total different engine.

I’m not sure if any parts were removed to fit the pertronic igniter so I may be missing parts to put the points and condenser back in. Alternatively I would probably buy a second Petronix igniter as they are not ridiculously expensive and easy to swap out. I heard the model one of the igniter failed a lot but heard good reports for the new model two. Let’s face it points aren’t great either, but easy to work on when they fail ,agreed.

Sorry for the hand feeding questions but as I have to import everything from the USA it’s difficult to return items if I order the wrong parts so it’s always good to get a recommendation from people with more experience as I am new to American automobiles

Thanks Regards Chris

Late-1970's and newer 250 and 292 Chevy 6 cylinder engines came equipped with the GM High Energy Ignition distributors. They only require a slight modification to the housing to fit an early stovebolt engine, machining off the shoulder that meets the engine block and fabricating a collar that clamps onto the housing to allow the distributor drive gear to fully engage the camshaft gear. There's only about 1/4 inch difference in depth, but it's critical for proper oil pump drive engagement. Since the HEI is a completely self-contained unit with the ignition coil built into the cap, nothing but a 12 volt power wire from the ignition switch to the distributor is required to complete the project. Set the ignition timing with a strobe light exactly like it would be done with a point-type distributor- - - -pointer and ball aligned to begin with, then adjust a bit at a time to find the best performance.
Jerry

No question that some people have had trouble with Pertronix. Surprised they are still in business if the failure rate is as high as stated. As one data point, the set in my truck has worked flawlessly for 6 years and the one in my tractor for 10 years.

I have been running the Petronix system in two classic vehicles and not had a problem with it. I run it a 51 3100 and ran it in 73 Tr6 for years. I have always installed it with the recommended coil from Petronix I also have kept the original points and hardware just in case. Not had to use them....yet.
Just my 2 cents.

In 1976 the chevy novas with a 250 engine had a seperate coil that was mounted to the block, it was square. The distributor cap was smaller.

Landon sells a nice modified 2.8 V6 distributor, small & works well.

That distributor looks pretty rough. The lobes are messy, dirty internally, rusty, not as water tight at the wires as it should be. Whether the mechanical advance is working properly is anyone’s guess. You should consider a little refresh of the distributor.

Points, very reliable, easy to repair. The Petronix is just a trigger for the coil, just like the points, so it’s not a high performance upgrade. I have run points for years. A little maintenance here and there and they give great service and frankly have never let me down.

That being said, the Petronix will not fix a poorly working distributor. I would get a replacement, a good replacement with a nice clean set of lobes, and have it properly rebuilt. Then if it were me, I would run the points. If you want to go with Petronix, install a new unit. If HEI is what you want, head over to:

http://forums.devestechnet.com/foru...our-old-stovebolt-timing-and-compression

Deve is a member here and has a kit for converting a Delco distributor to HEI or Langdon at stovebolt engine company has a HEI based on a 90s era v6 GM distributor.

Speedway has an adjustable hold down collar for an HEI with the shoulder removed for under ten bucks. Part # 91044030. I have a Pertronics on my 46 Ford Coupe since it never goes on long trips and it has been trouble free. That said, on my 37 Buick that goes on very long trips I have a re-worked Oldsmobile V8 HEI as I know the coil in cap HEI is one of the most problem free units ever made AND I can get parts anywhere. Many, if not most, parts stores do not have a single set of points of any kind so I go with what makes sense for long trips. The big cap HEI is ugly on an old inline engine so I may start using the newer non computer small cap ones.

[img]https://i.postimg.cc/4mrfXXSS/Dar-Dog-HEI-003.jpg[/img]

Note the points coil is still in place and the dizzy is in the trunk along with a fuel pump and water pump. Like I say, l-o-n-g trips.

Thanks for the link Evan, I'll be mod'ing a 79 6L HEI for my 235 and I'll be needing that clamp.

I've never run a Pertronix but did trade for an old car that had one in it, and it didn't run. I changed it back to points/condenser. To b fair I changed it over to another brand of aftermarket electronic ign (Hot Spark) and it performed flawlessly for the 3 yrs I owned & run it afterwards.

I think what pop's some of these aftermarket Elec Ign's is charging systems that produce too many voltage spikes and/or run too hot (i.e. >14v). A bad ground to the Dist is also be a cause....

Good luck
Dave

Well thanks for the tips. I really like the look of the Landon distributor but they have none in stock, but may be long term solution. I have nothing against conventional points but they are not as reliable as electronic ignitions, just easier to repair in the field.

I need to get to the bottom of why my coils are getting hot. I can only think is a dwell problem caused by the igniter lobe sensor or a faulty igniter that’s not turning off properly.

Following another thread on here about distributor caps and rotor arm long and tall. I had to bend the centre electrode up on my rotor arm. Someone mentioned it likely my spark is having to jump,further this will make the secondary coil voltage higher wonder if this could be affecting the primary current in the coil.

Going to look at the primary voltage wave on my oscilloscope tomorrow so that should give me some more information to work with.

Thanks again to all you guys that take time to contribute and help me. I’m here in the U.K. with only a handful of these vehicles it’s not easy to find people to chat with and get experience. I guess a 60 year old motor is always going to be a bit more work. I’m still trying to gain my confidence working on the truck etc. It really is a god send to have your help and comments.

Shame there is not a U.K. bolters section perhaps I should start one

check out my build diary etc if you want to see my rolling restoration. Well it is more break down and roll to a stop usually on a deserted country road with no mobile reception!

Thanks Regards Chris

Interesting that there is no magnet piece in that dist. I cannot see how it would run at all .

I have had pertronix in my 216 for over 20yrs now , carried points for ever , Never needed them .

Chris, some models of the Triumph TR-6 were equipped with a Delco distributor that uses the same points and condenser as a stovebolt Chevy.
Jerry

Thanks I will have a look some TR6 information

I recently rebuilt a Pontiac 455 Ho distributor for a friend. The top bushing seized to the shaft from setting. Being a rare distributor and numbers matching, I hunted down bushing to repair the damage. All was good, had new points and setting it up on my distributor machine was easy enough. It worked great up to 4000 rpm, then the spark started jumping. Jump ahead a week I was at a swapmeet and came across a guy selling NOS ignition parts. I picked up a set of Delco points and condenser for $5. Installed them in the distributor, spun it up to 6500 rpm, not one wiggle or misfire. The new points I replaced had a very weak spring compared to the Delco set, that let the points bounce at higher rpm, the 40 year old Delco's set rock solid.

My point to all this is, know what you are buying!

A clarification, the remote mount HEI coil and distributor cap for the 250's, have the same large diameter cap as any HEI, just shorter.

On the race distributors we used to double-spring the points to eliminate high speed bounce. That was rough on rubbing blocks, but most race engines didn't last long anyway and point life wasn't an issue. Hot-spark coils burned the contacts out long before the rubbing block wore out.
Jerry

get rid of the pertronix is a good start, I have had 2 of them fail on me. I posed a question on this and another forum, as to other peoples experiences with the pertronix, Out of 11 replies, 5 were of the negative variety. Not such a really good score. I found a whole can of OEM points (10 set) and looking back I don't ever recall points being any trouble in any of my cars over the years. I can mess with points for the rest of my life and still not equal the misery of that day out in the wind and rain putting the points back in.