Time for a new HEI?

[palallin]

'69 K10, 327, has had an HEI in it for quite a few years. The distributor was used when I got it, and it has served well for many years.

Two years ago, the truck started giving me intermittent problems---running rough and hesitating at various times, sometimes coming off idle but sometimes on the road at speed. The problem would go away for a while, and the truck would run like a top. Then it would come back.

Last year, while I had the radiator out for replacement, I went through the ignition system and replaced the plugs, wires, cap, rotor, coil, and module. At first, everything was fine, and I thought I had cured the problem. But then I'd get a sort of a blip in the smooth purr--just like, for an instant, the engine wasn't running. This happened just once or twice on a 20-minute trip to town, with varied speeds from <20mph over gravel to >60mph on the interstate. As time went on, the "blip" would occur more frequently, and, every now and again, there'd be a backfire out the tailpipes. Now, the "blips" happen frequently and the backfires are beginning to become more frequent,
too.

Based on all this, I think I have an ignition problem. Nothing has changed about fuel delivery (Carter/Edelbrock 1405, IIRC). I suspect the old distributor is worn out. I am looking for suggestions for replacements. I would prefer not to spend much more than $200, less if possible (the $600 radiator really hit the truck budget!).

I could swap the point unit back in--I still have it all these years later, and it should be OK, but, of course, it has who-knows-how-many-miles on it, too. And I'd have to undo the mods I made to use the HEI.

I assume that verifying 12 volts at the distributor (again) would be a good idea, but, assuming the power is there (as it was the last time I checked), should I go with a stocker or look at an aftermarket unit?

What's your experience?

[68bbc/20]

i put a small cap generic brand with external coil on a 65 vette 3 1/2 years ago with a tach drive and it has worked fine. i think it was around $200 then, no tack drive should be in the price range you're wanting. look them up on e-bay.

[Steeveedee]

Check the pickup wires for continuity. The flexing when the distributor advance moves will eventually break the wire(s). Since you appear to have changed everything else, that what I would suspect. If it's bad, you have to take the distributor shaft out to replace it. These last very well. I've only ever replaced one.

[68bbc/20]

theswapmeetparts is the seller i bought thru, they have complete kits for under $200. wires, coil, distributor, everything. only thing i changed was the advance springs to the lighter set (3 sets were included.

[tim_mc]

Maybe disconnect your tach lead from the HEI to make sure it's not grounding out somewhere.

Last June my new GM HEI started giving me problems after only a year or so of use. I first tried a new coil and module from my local Advance Auto Parts, but the new module was suspect after the truck died a couple of times unexpectedly but would fire up after sitting for a minute or two. A Davis Unified Ignition (DUI) coil and module fixed me up.

[68 P.O.S.]

I've been running an Accel 59107 HEI for over 10 years and never a problem. The 59107 is an "OEM Replacement" HEI and it's price is right in your dollar range.

[Big Kev-O]

I had the same issues and thought it must be the HEI so I replaced my cheap MSD StreetFire HEI unit with the more expensive MSD Pro Billet HEI. I changed the plugs at the same time thinking they were fouled up from lack of ignition. Truck ran fine after the HEI & plug swap but the truck started hesitating and back firing from the tailpipe a couple days later. Turned out the intake manifold gasket was leaking and allowing air & oil to be sucked into a couple of the cylinders. I replaced the intake manifold gaskets and the problem was solved.

Turned out the intermittent hesitation and backfiring was caused when oil would foul the plug causing a cylinder to miss. The non-combusted fuel would then ignite in the exhaust causing a loud backfire out the tailpipe.

This is a common issue with vortec heads & performance intake manifolds. The paper gasket Edlebrock recommends does not seal well. The steel framed rubber gasket made by Fel-pro solved the issue.

[palallin]

Thanks for all the input, guys. It'll be a while before I can do anything, so I am open to any and all ideas.

Interesting issue with the intake gaskets. Maybe an excuse to go back to a stock intake . . . . Gotta pull the distributor anyway.

[70STOVEBOLT]

I started my truck for the first time in a couple months recently, and it backfired a couple times. I let it idle for about 15-20 seconds and then goosed it and it did it again. Upon checking it out, I found a loose wire at the bulkhead connector for the HEI. I replaced the male Packard terminal and all is well again. Never had that happen from a loose power wire before.

[sellersrodshop]

Originally Posted by 68 P.O.S.

I've been running an Accel 59107 HEI for over 10 years and never a problem. The 59107 is an "OEM Replacement" HEI and it's price is right in your dollar range.

Been running the same one for almost 22 yrs on mine. no issues at all..