Inliners International Forums General Discussion Electrical HEI distributor on Chevy 153?

So I'm having a strange ignition issue with the 153 in my CJ2a. It has a miss, and in checking the timing I noticed the timing light does not fire consistently on the #1 cylinder. I put the light on the other cylinders and they all seem to fire the light consistently. The #1 plug is black and sooty, the other three look normal. I swapped the plug wires between #1 and #2, same result, (#1 is still inconsistent, #2 is normal). I'm a little baffled by this as the cap and rotor look fine. I ordered a new cap and rotor anyway. I put a pertronix in this distributor about 4 years ago, could it be failing?
Question: My spare motor has an HEI distributor on it. Can I just swap that in? The only connections I see on it are for "BATT" and "TACH". Can I just give it 12V from the battery and run it? Doesn't it need a ground like the older coil has?

Try a different plug before you go swapping the distributor. If it still fires badly then more the likely the Pantronix unit is your issue.

Did you check the compression in that hole? Yes, try another plug.
Time on the side of the road has helped form my feelings about aftermarket HEI. When I ran it in my '53 pickup there was always a spare module in the glove box and a complete points distributer under the seat. Is the height on the other engine aftermarket or GM? I think there were two GM HEI distributers a small one & a big one. The big one is best but ugly.

So I changed the plug in #1 and that cured the timing light not firing. I put in new plugs, rotor and dizzy cap, and reset the timing. It started more easily and idled well, but it still stumbles on acceleration and I am hearing what sounds like a rod bearing knock under load. I swapped out the pertronix with points and reset the dwell, The engine ran the same, still stumbles and knocks under a load. I cannot hear the knock at idle anywhere using a stethoscope. I would have thought that I'd hear a bad rod bearing even if it wasn't under load. Could a bearing going bad explain the stumble on acceleration? Maybe I need to move this question to the engine forum.

Glad to know the plug fixed your first issue. as to a bad bearing making it stumble more than likely NOT the stumble could a carb or timing issue Or a combo of both.

What Larry said. Rods tend to knock as the load is coming off. That little slack time when it is not under heavy compression or power as you back off. It could be a wrist pin. I once had a knock that turned out to be an exhaust leak. As Larry said the stumble could be the carb maybe the acceleration pump or just some dirt in a jet.
No more traffic than is on this site I doubt if it matters where you post your question.

Timing is set to 4 deg BTDC, where it's been for the last four years. It definitely advances mechanically when I rev it a bit. Could a lack of fuel under load lead to the knock? Carb is a Weber 32/36 which is always a little limited on the accelerator pump as it only has a pump on one bore. But this is different. I'll try putting some vacuum on the distributor to see if it advances

Try bumping the timing up some more.

I gave it a thorough going over this morning. bad news is that cylinders #3 and #4 only have 55 lb compression. So I think I'm looking at a rebuild, at least the top end. I can check the rod bearings once the head is off, but this will have to wait until after hunting season as it seems likely to be more than a weekend job.

Might be the right time to look at a 181?

I thought about that. I happen to have two 153's, (both of which now need a rebuild), and I'm not sure I really need the extra HP from the 181, and resulting decrease in gas milage. I'd need to move up to a bigger carb, (which wouldn't be progressive), and fuel economy is a real concern for me as the CJ2a tank is only 10 gallons, and my driving is typically into the woods, away from any gas stations.