#6 not firing with eBay HEI, any ideas?

[1969_CM2590D]

It's been pretty impossible to get the The Mule timed. Right now, to get it to run. I've got the timing way past 10 deg to get something resembling a smooth idle. Starting ain't easy either.This morning I checked for juice to the plugs. Hooked up the timing light on each plug wire to check for power. #6 was dead- no flash to the timing light. I fiddled with the boot at the distributor, and got a spotty and very intermittent (about no) timing flash. Also#3 and #2 flashed regularly, but had a very infrequent, rare "skip" to it. The rest are steady and ok.

I'm going to check the plug wire distributor boots first, and want to check and see if power is coming out of the #6 distributor terminal. So I'd like to know how I might check that output on #6. Of course, i want to hear any ides on what this might be and how to cure it. I've got a few ideas, but I'd also like to pick some brains on this.

Obviously with the original, it's all mechanical, and I'd easily sort that. Maybe something in the electronic guts of the HEI? What that might be? I'm doubting it's in the electronics as there is obviously power.I'm leaning to the boot/cap/rotor button zone

At least I'm not totally confounded anymore! :D

Thanks!

[BarryGMC]

Put the stock dizzy in. I don't think any gmc v6 benefits from am hei. The hei was developed for higher compression lean fuel issues. This is not a problem with the jimmy v6. I have run the jimmy v6 over 250.000 miles on points ignitions. And still run them that way. In my opinion it's. Waste of money to put an hei in. I don't care what any one says I have run these old motors all ways. Including Efi. Please don't over think it. Barry. C.

[bigblockv6]

Really?? I noticed a substantial difference when converting to an HEI back in 1991 on my 305E V6. The combination of the Holley 500 and 2 1/2 inch dual exhaust turned out to be a great combination, all these improvements have been carried over to my 478M conversion. I would have to say the majority of members of this site can attest to these improvements and you're out numbered! The HEI was introduced during smog choked up 70's when compression ratios had dropped down drastically.

[FetchMeAPepsi]

They make a spark plug tester that's about 14 bucks at the auto parts store. it'll light up when it fires.

About the HEI debate, he already has HEI so I guess its not really a debate. I'll never go HEI, but thats because I like my truck to work even if the russians decide they're hungry for land again. Putin is crazy. :poke:

[melmashman]

When I took my '65 with a 305e from California to Alaska in 2008 my main problem related to points and condenser. It was always getting out of tune. It turned out to be a bad condenser which I had trouble replacing.
Getting parts on the road was not easy. Carrying tuning equipment and every possible part is not what I want to do when I am driving to Newfoundland in 2015.
I went for the electronic distributor along with a corresponding coil to hopefully avoid these problems. Time will tell, but keeping it simple sure makes sense to me when I am going to be a long way from home.

[Irishbleueyes]

Nothing beats an electronic ignition. If you vie for points you clearly haven't used one. HEI will give miles and miles of maintenance free performance and will ignite all the fuel in the head chamber. After market HEI dist can have junk parts, make sure to use a GM module, cap and rotor. Also, spiral core spark plug wires should only be used. My brother in law just switched over to HEI in his 305 v6 and was blown away how well if worked, instant start, better performance. Points are cool if your're die hard original but they are a thing of the past.. with all the perf upgrades with added ignition control like MSD and now AFR gauges to really dial it in I would have an old carb car or truck over any fuel injected crap today...

[adamfgarner]

I am the brother-in-law in the post above; I will admit that I am no master mechanic but do have some experience and aptitude. First, I do respect BarryGMC's opinion's and feel his experience is valuable. However, in my own experience having to constantly source and adjust points to get the engine to run right doesn't interest me at all...I do have them in a box with the original distributor and the Stromberg in case we get EMP'ed though Pepsi. With the switch to the Holley and the HEI, once I set my timing (screw the listed settings - it ran poorly until Irishbleueys converted me to "seat-of-the-pants" timing adjustments) this truck starts quicker than my EFI vehicles, and runs MUCH better that the points (which were newish and well-adjusted)...the wider gap you can run (got mine at .060) insures better burn and virtually no warm-up time...I vote for the HEI as the members above and for the same reasons...unless you're a purist (truly even these guys are posers as very little is "original" any more) points make little sense to me as I don't like to fiddle-fart around unnecessarily to get my beast to growl. ...on a side note I had to twice remove my HEI to drill consecutively larger weep holes in my billet shaft because of a problem getting to much oil through the top bushes...

[adamfgarner]

oh, to answer the original post....sounds like you got a bum cap...or wire...if you haven't replaced your wires (shame on you) do so with at least a quality 8mm double shielded cable...I got a great set from ebay made for a 6 cylinder jeep by CARQUEST...just be sure to install the number 2 nipple of the distributor as close to the #2 cylinder is one of the wires wont be long enough 'less you do

[adamfgarner]

...that was meant to say " a great set FOR $15....complete with proper booties"

[bigblockv6]

For those that want to maintain the stock look the Pertronix kit is a good alternative, easy start up just like the HEI but not quite as potent.

[GMCDAC]

For those that want to maintain the stock look the Pertronix kit is a good alternative, easy start up just like the HEI but not quite as potent.

I was wondering about that but didn't want to mouth off since I don't have a V-6 GMC. Didn't know if one was available. I had issues with my '55 GMC keeping dwell so I bought the Pertronix conversion--under 100 bucks, and it has been smooth as silk since. I didn't even have to pull the distributor to do the conversion but I did anyway just to feel the bushings and side play. The engine is a mid sixties 230 inliner.

DAC

[turbobill]

Over the years, I've had many interesting problems with distributor caps, rotors and wires. From rotors that short to ground (spark from the coil but not to any plug wire), open/shorted distributor terminals (no spark at that wire), no spark at a cylinder period (open or shorted wire) to the normal assortment of cracked and/or carbon tracked caps.

One interesting case happened on my '68 Buick Wildcat returning home from Florida. 500 miles from home, it developed an intermittent skip. No spark to one particular distributor terminal. Turns out the distributor bushing was worn enough that occasionally the distributor shaft would wobble and the breaker points to one particular cylinder wouldn't open, thus no spark. An HEI shouldn't suffer the same problem.

This being said, if your timing light is not being triggered by current flow in a particular wire, don't rule out a very high resistance or open spark plug as well. Eveything in that particular circuit becomes suspect.

As for the points verses HEI or other electronic ignition, I only have one old vehicle converted to HEI (a 427 Chevy). It has been reliable, but when I take the car on a long trip, I carry a spare stock distirbutor/coil/wires just in case. To be at the mercy of a tow company/garage on the road is asking for bankrupcy.

Besides, a lot of people drove a lot of miles over the years with breaker points and carburetors, me being one of them.

[aphaynes]

For those that want to maintain the stock look the Pertronix kit is a good alternative, easy start up just like the HEI but not quite as potent.

Where can I find more info on this kit?

[melmashman]

I actually had the Pertronix kit put in the distributor along with the recommended new coil. I really do not know the difference between doing this and going with a HEI. Perhaps the HEI replaces the distributor itself?
In the past I always had to use the choke at start-up. Now I only use it if I have started it in several weeks. It am a much happier camper thus far.

[BarryGMC]

The main reason I don't recommend the aftermarket hei is that it's made up of offshore junk. And is not better than the stock dizzy. Second reason is if the stock dizzy is reconditioned or in good shape it's really reliable and simple to maintain. Now the pertronix is not really an hei it's just an electronic pick up sensor with a good coil. You don't really need the coil though. They work fine with a stock coil. But the pertronix is known to fail and does have a failure rate that is less than ideal. Note I do run some of there stuff, but always carry a spare or the stock points. And most of the time the pertronix has to be ordered. Now I have to add I have spent countless hours playing and modifying with the big v 6 engines. Most mods did nothing or very little in the low to mid range where I was trying to build torque and hp. I have had some success and did manage over a hundred hp and 140 pounds of torque increase a 3500 rpm. With a 305. I still have this engine. And will posts some pics and specs one of these days. Barry

[turbobill]

I recall many years ago, in one of the car magazines (Hot Rod or something similar) a comparison test of an HEI and a stock points type distributor. There was no difference in HP or torque.

That being said, I have nothing against the HEI or any electronic conversion. I generally stay with original points (with the one exception).

[Irishbleueyes]

http://www.pertronix.com/ Xlnt product, I used those for yrs in VW's without fail. Simple conversion but not as powerful as an HEI.

[Irishbleueyes]

Low compression engines need the extra ignition help...

[BarryGMC]

It's actually just the opposite. Higher fuel charge densities. Or higher compression require greater spark energy to fire. This with lean fuel ratios is the reason you need hei ignition. Since the v6 really has neither you won't gain any hp over a good points system.

[klausz]

There is one reason why I really like my GMC,it is very simple and it has no hard to understand mysteries.Black Box ,the end of the world as we known it.The real basic ignition system is one of the better arguments for the trucks.Point sets usually come with condensers for a reason,change it all together and you are good.On the road you can set points with a screwdriver and eyeballs.Black Box is go or no go.

[turbobill]

Don't forget to lubricate the rubbing block/breaker cam or the points won't stay in adjustment as long.

[1969_CM2590D]

Well the suspense is over. I ordered new condenser, points, and plug wires from Rock Auto Wednesday. Came yesterday and installed today. I have a new HEI with a new set of Magnacores in the house. I still have to fiddle with the dwell, etc, but the truck runs 1000% better. But then it should- since it now fires on six cylinders instead of five.

So why did I go low-tech? The biggest reason was frustration. I've been fiddling with the truck for over three months and piddled and piddled. Time to get the engine running right and move on to other issues on it. I did buy it to drive ;) But also after reading Barry's initial post, I did some research and some thinking. Barry makes a lot of sense.

And I agree, I like simplicity- it's a virtue.

FWIW, I think the new HEI was fine, I expect I had a faulty wire to #6, since I got spark on five cylinders. But I've not bothered to test it anymore for the time being. I like sixes anyway, so this rig may get corrected and put in a Corvair, Pontiac OHC, GMC 302, or even a 292. Have to see if I can make it fit. I will say that physically, I found the eBay dizzy and the Magnecores to be clumsy in my truck. The HEI with it's coil on top was a tight fit in the firewall cove of my truck- there's not a lot of ways to get it in and turn it. With that, the wires could have used a few more inches, as they were close to being stretched when installed. There is so much more working room and slack with the original Delco-Remy and the noticeably longer Rock Auto wires.

HEI makes a lot of sense in the passenger car engines of the '60's and later. They rev higher, emissions and mileage weren't a concern- most weren't originally designed to run on lower compression ratios and no lead gas. So a surer, stronger spark was needed. The points and condenser wouldn't be able to keep up, especially above, say 4000 RPM as ignition quality degrades at those speeds with old-timey ignition.

The V-6, however is not that sort of engine. As a lugger, it winds out to top end at an engine speed my company minivan gets to for a slightly quick freeway entry. With a top end of 34-3800 RPM, the degradation of the ignition quality with points is negligible at worst. There's also that low compression which makes one wonder if it will burn anything this side of kerosene with some massaging. The thing was designed at the outset to run lean and on not the best fuel. Now, if I were running a '69 C20 with a 350 or 396, I'd definitely be looking at HEI.

I'm not totally against switching from points. I run a German Bosch 009 with Compufire in the '64 Karmann Ghia. It's quite nice and maintenance free (and I keep a set of points in the glovebox!). It works wonderfully with the 40 HP 1200 motor. I'm glad I did it.

The HEI has its advantages in any vehicle. Instantaneous starting. No maintenance- just check the timing when you change plugs. With a carb and points you have to bump the key a time or few- and a bit of fussing with a tune up.

I conclude that if your old dizzy is toast, go for HEI in a V6. A new old style one ain't cheap- like $250 at NAPA. If you throw in a new set of wires, you are mighty close to the custom eBay HEI.

[BarryGMC]

It's good to hear its running better. Get it on the road that's the fun part. Barry

[Cayoterun]

I'm glad you reached that "AaHaaa" moment. It feels good to finally hear a "problem child" running good again.

Petronix: We started using them when they first came out years ago on the farm irrigation wells. What a big improvement. Simple to convert, less adjustments, hotter spark, longer life, and affordable enough to keep a spare.
I still use them in the V12s I restore.

Easy to re-install the points and condenser we kept in our tool box, just in case, one did quit in the middle of the night.

Needless to say, I'm a big fan of them, had great service using them, so am biased.
Enjoy your truck, regardless of what you use.

[Ed Snyder]

I agree with Cayoterun -- Pertronix is the way to go. I've had bad modules in GM HEIs leave me stranded more than once. I've installed Pertronix in at least four different GMC V6s so far, and have never had one fail. But since anything electronic can eventually fail, it would be interesting to see failure rate statistics comparing the HEI to Pertronix ignition.