The Stovebolt Site Forums The Shop Area Engine Shop Thinking about a Pertronix conversion

I've got a 1959 235 straight six in my 1952 GMC truck. About a month ago, my coil went bad. It had leaked all over the place. So I stuck another coil on it. However, it had been running poorly for awhile and upon inspection, I noticed the points were badly worn. So I bought a new set of points, cap and rotor, set the points, and it's better AND worse.

It's better because now I can rev beyond 3000 rpm. But it's worse because when it's cold, it keeps choking while I accelerate. It gets better when it warms up, but I still feel it. This is very strange. I don't know what I did that was different. It seems I upset some kind of delicate balance and now the points run like crap.

So anyway, I looked into a Pertronix kit for $82.95, and I've had good luck with them before. It's basically a Hall effect induction system with flying magnets. It's a lot more than I remember it costing, but I'm sure will solve my points delimma.

It sure would be easier if my points would just frickin work like they were designed. Any ideas?

I installed Pertronix 3 yrs, 29000 miles ago and have never given it another thought.

Electronic ignition is the way to go. Once you get the timeing set right it stays that way. It seems Petronics has 2 models out now. One is a premium version.

HotRodDad,

I've also been thinking about doing this conversion, and have been doing some shopping.

There are a couple of people on E-Bay that are selling the units (NIB)for the low mid $60 range.

That price is for 12-volt. I've contacted one of the sellers, and he advised he can provide a 6-volt version for $10 more. (I didn't know they made a 6-volt version?)

Another vote for the Pertronix. I'm using two of them. No problems in five years of use. One is running with a ballast resistor and one without. I bought mine from an outfit called Retro Rockets or something like that. They each cost less than $70. Do a google search for Pertronix and they should come up.

Speaking of ballast resistors, are you running one on your truck now? If not, it might be part of the cause of your troubles. The cold running problem is probably the Rochester B carb though. I have the same problems with them. I drilled my main jet out a little and it helped. I think the ethanol in the gas these days requires the carbs to run a little richer than they did with 100% gas. The ethanol only has 50% of the energy in it that gas does for a given volume.

Hot Rod Dad,

If you have a dwell meter, use it to check your gap...no guessing with this!. I am a firm believer in "if it worked before and it doesn't now", then you did something it didn't like. Check everything again, timing, vacuum advance etc. You might find something that isn't kosher!

Stuart

I don't have a dwell meter. I set it at 0.018" gap.

Hot Rod,

The meter isn't necessary, just more positive than a "feel". The .018 gap is fine. Did you take the distributor out for the points change and maybe not re-time the engine with a light. Vacuum line is on nice and tight and the advance plate moves freely by hand? Would it run if the primary lead wire and key wire were reversed? Plug wires in proper firing order? I am just stabbing in the dark here, but If you worked on the ignition system, and the truck didn't exhibit any of these symptoms before, I would focus on what was done. You didn't mention plug wires and plugs.

If a engine falters under heavy throttle or load, sometimes it is a weak ignition that can't fire the fuel mixture under that load. If you can put a timing light on it, make sure you have vacuum AND mechanical advance.


Stuart

I didn't take the distributor out. I didn't want to hassle with that, so I changed the points with the distributor still in the engine and just bumped the starter until I got on a "corner" so that I could properly set the gap. I never did have a working vacuum advance. I plugged the vacuum line because the diaphram was leaking. The mechanical advance works fine though. I don't yet have a source for things like that. Most of the parts stores don't seem to have too much for these engines.

To answer an earlier question, no, I don't think there is a ballast resistor, and I am on a 12 volt system. The voltage measured at the coil is the same as the battery voltage, no drop. But it's always been like that, so that doesn't explain the sudden loss of cold drivability either. I haven't changed the condenser, mainly because they are surprisingly expensive. It's about a third as much as an entire Pertronix system, so I'd rather invest in the conversion.

I found those Pertronix units on ebay. It's $70 versus $83 at Summit. However, Summit is a lot cheaper for shipping. They want $9 bucks for shipping on ebay. Sounds to me like it's a little hidden profit. Are they new units, does anybody know?

I would go with Summit at least you know that it is new especially if it is that close in price and you might have a warrenty.

Hot Rod,

The condenser and the vacuum advance unit would be VERY important things to address. I wouldn't attempt to resolve anymore issues without replacing both of these items. The condenser should be cheap and available anywhere. Find a counterperson that doesn't have a nose ring..they might be better able to help you.

Stuart

You say that you don't have a dwell meter and set the points at .018". Ok, probably. I didn't hear you say anything about checking the timing. This isn't an option. Anytime you change/adjust or do anything to the points, you have to check and probably reset the timing. If you think you can bolt a Pertronix unit in there and all your problems will be solved. BACK AWAY FROM THE TRUCK. You still need a timing light.

Okay. I'll double check the timing. I didn't check that because I never moved the distributor. I changed the points with the distributor in the truck.

The guy I talked to at Summit Racing was a little bit insulting. He said if I was a "real" mechanic, I'd stick with the original points and get it working well. Know what? I don't have any problem with updating the technology of this engine, and that includes eventually getting rid of the unbelievably crappy 1bbl Rochester carb. If that makes me an "unreal" mechanic, then fine. But the mods I've done to my big block Corvette and big block Firebird make them serious sideways machines, and if anything, the modern Pertronix has added nothing but maintenance free reliability, which is ultimately what I'm after with the truck too.

By the way, the condenser was almost $30 at Pep Boys. I was shocked at the price, to say the least. Maybe that would have solved my problem, I don't know. But I'd rather apply that $30 towards a maintenance-free and far superior Pertronix conversion than ancient technology points. Even at the risk of being considered not a "real" mechanic by some.

Hot Rod,

Forget the "real" mechanic comments..the bottom line is enjoyment. Don't let this "hobby" become a frustration. The electronic unit will make life easier and the truck more reliable. If that is what you want, GET IT, and have fun.

Stuart

30 bucks for a condenser is way off,, should be about 2 bucks............Fred

I am in a similar situation. I would consider conversion but not confident enough in the condition of my distributor. The vac advance barely wiggles, I assume that mechanicals need to be sound as the abvance and all would still be used with the new electronics.

I installed a Pertronix conversion about 1 year ago. The installation was very simple. I think I paid about $80 +/- but am very glad I upgraded. The truck runs a better and I have had no problems. I still carry my old points around, just in case, but I don't think I will ever need to use them.

Adam

I recently purchased the Pertronix conversion kit along w/ their 40K Volt "Flamethrower" coil. But my real question is the mechanical vacuum advance still bolted to the distributor. Is it still needed after the conversion?

Vacuum advance do two things: one is to allow the engine to start under ideal conditions, second when started it moves the firing to ideal running conditions, both of these are very Important! Its preset condition is at starting, so if you don't feel you have adiquete power or Can't get it to idle good or even stay running in cold conditions, check your vacuum advance it is a very important part of your Ignition!

Mark

Probably a big part of my problem. I'll try to fix my vacuum advance.

I discovered something today. It was really cold this morning, so I left my choke cable pulled out just a bit for the drive in, and I noticed that once it warmed up, it wasn't jerking and trying to die several times a minute. In fact, it didn't do that at all the entire way to work. So I wondered if somehow my mixture was way too lean. I turned the mixture screw out a turn and a half and it did run better coming home...except if I got into the throttle too fast. In fact, it was acting like I had a lean condition.

I know Holley's have an accelerator pump for that extra squirt of gasoline when you need to take off. If you have an inadequate squirter size on a V8, it will do the same thing. I had always thought the Rochester 1bbl ran too rich, so I leaned it over the summer. I got away with it because it was very warm. With the colder weather and denser air, I think the problem became more obvious to the degree of causing a drivability problem.

I really never felt that a single barrel carb was anywhere near enough capacity for a straight six. I am contemplating a change in induction before a change to electronic ignition. Like maybe a Holley Webber 2 bbl...see how that works, and then convert to Pertronix afterwards.
...Oh, and definitely to get my vacuum advance working.