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TR4/4A TR4 misfiring under load, fouling plugs

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"Tom, I removed the condenser from the distributor, put one lead on the wire end and the other on the condenser body. The ohms rose until it read OF. I switched the leads and it did the same. I had heard that's how you do it, anyway. Would you agree?"

Agreed. Exactly the way I tested mine - with the same result. Well done!
Tom
 
So I set the timing today and each time the points opened, they sparked. That didn't seem right to me. Is this a sign that perhaps my condenser is bad after all?
 
SMGoose, unfortunately that's the part that causes points to get pitted and wear out. Yeah, that is the norm.

Wayne
 
New cap, rotor, wires and plugs. I started it up but it isn't happy. Something is amiss.

This ignition coil with external ballast resistor is bothering me. There's a white wire from power plugged into one end then a blue wire from the resistor to the (+) of the coil. That's it. The (-) goes to the distributor. First of all, this is how it was set up from PO with a positive ground. Shouldn't it have been flipped with pos ground? As I said, I changed it over to negative ground when I installed the fuel pump. I left the power going to (+) and exiting to dizzy through (-).

Second: shouldn't there be another wire or something? I mean, isn't the resistor supposed to be bypassed during startup? How does that happen? If so, would this be causing my problems?

I'm thinking I should just go ahead and replace the condenser, too.
 
One more question: how do the spark plug wires connect to the socket type, female distributor cap? The old one is just the wire inserted with the pointy screws clamped into them (I don't know how that works, btw, but what do I know?). The set that I bought has metal connectors on the end like this: https://images.oreillyauto.com/parts/img/large/acc/4046.jpg

I just shoved those metal ends in and clamped 'em down with said pointy screws. Should I remove the metal end or is that how it's supposed to work? Just one more thing that I keep second-guessing!
 
SMGoose said:
This ignition coil with external ballast resistor is bothering me. There's a white wire from power plugged into one end then a blue wire from the resistor to the (+) of the coil. That's it. The (-) goes to the distributor. First of all, this is how it was set up from PO with a positive ground. Shouldn't it have been flipped with pos ground? As I said, I changed it over to negative ground when I installed the fuel pump. I left the power going to (+) and exiting to dizzy through (-).

Second: shouldn't there be another wire or something? I mean, isn't the resistor supposed to be bypassed during startup? How does that happen? If so, would this be causing my problems?
Click to expand...
Definitely try another condenser, "just because". They can fail in strange ways that won't show up during a low voltage test. And if it turns out not to be the problem, you can save it for the next tune-up or to carry for an on-board spare.

The coil was connected backwards, but it only makes a small difference anyway. Having it backwards might make the engine fractionally harder to start but generally it won't even be noticeable. And you've got it right now, so that's OK.

Likewise, the connection to short out the ballast during starting is optional. It was added later to improve starting in extremely cold weather; but usually it won't make any noticeable difference. It only does anything during starting anyway, which doesn't seem to be your complaint. And after all, that is the way the car was originally (although the resistance was inside the coil rather than outside).

The only question I have is whether that coil really requires an external ballast or not. I couldn't find it listed in my (old) Lucas documentation. Might be worth double-checking the primary resistance (which should be around 1.5 ohms if it needs the ballast; around 3.0 ohms if not). Or just trying a different coil. Coils also can sometimes fail in strange ways. And a couple of years ago, I had a nearly new Lucas coil do something similar (although in my case, the engine was also abnormally hard to start).

FWIW, I ran an external ballast and a cheap, non-Lucas coil for several years, back when I lived in a colder climate. After the alternator conversion (and the biggest battery I could buy), that TR3A would start even when others would not! I used to give other people jump starts in cold weather.
 
SMGoose said:
One more question: how do the spark plug wires connect to the socket type, female distributor cap? The old one is just the wire inserted with the pointy screws clamped into them (I don't know how that works, btw, but what do I know?). The set that I bought has metal connectors on the end like this: https://images.oreillyauto.com/parts/img/large/acc/4046.jpg

I just shoved those metal ends in and clamped 'em down with said pointy screws. Should I remove the metal end or is that how it's supposed to work? Just one more thing that I keep second-guessing!
Click to expand...

First thing to check is what kind of conductor the wires have. Practically all modern spark plug wires use a "carbon" core that really isn't suitable for use with the original "pointy screw" cap. With that cap, the end of the wire should be just cut off flush, and the screw is supposed to pierce the insulation and poke into the center conductor. Works great with the original copper core wires; but with carbon core, the carbon tends to burn away around the screw and eventually create a bad connection.

The other option is to use a later "top entry" cap that is designed to take the metal ends (eg Moss 163-810)
 
Thanks, Randall! I tested the coil a few days ago and got a reading of around 2 ohms. It was difficult to get a steady reading, though. In my Internet search, I found one for sale on eBay https://www.ebay.com/itm/LUCAS-CL-7...L-BRACKET-ALL-MODELS-Made-Japan-/271101282695

While mine only says "Lucas CL 73 12 volt", that one also adds "Use with external resistor".

I definitely want to convert to an alternator with thin pulleys all 'round, but my fiancée says "get it running then you can worry about 'those kinds of things' after the wedding" haha. So that will have to wait! Although I'm seriously considering the electronic distributor now!

As for the wires, they say "suppressor" core material...
 
SMGoose said:
I definitely want to convert to an alternator with thin pulleys all 'round, but my fiancée says "get it running then you can worry about 'those kinds of things' after the wedding" haha. So that will have to wait! Although I'm seriously considering the electronic distributor now!

As for the wires, they say "suppressor" core material...
Click to expand...
Well, your fiancée has a good point. Your car should run just fine with the original equipment, and my current TR3 daily driver is still wearing it's original generator (or a close facsimile) even though I put an electric fan on it. I'm also still running points (although I switched to a Pertronix coil after the new Lucas failed). I've done a lot of miles with various electronic conversions, but I wouldn't call them any great improvement in reliability, especially since they are usually harder (and more expensive) to replace when they fail. Points certainly require more maintenance, but are only one item on a list of many.

"suppressor" wires would almost certainly be carbon core. If you look up through the center of the metal terminal, you should be able to see where the core is folded over to go back under the metal crimp. If it looks black and smooth, it's carbon. Copper will look like ordinary stranded wire (since that's what it is).

They should do for now (cut the metal ends off), but I would consider replacing them at the next tune-up.

PS Congrats on your upcoming nuptials. As they say, a man is incomplete until he is married. Then he is finished.
 
Haha thanks, Randall. She's been very supportive throughout this car process so I know I got the right one ;)

As for the car, cutting those ends of the spark plug wires and installing that way seems to have helped. It's running better but still doesn't like too much throttle.

I went to the carbs, lifted the piston on each and felt good resistance (dashpots have new oil in them) but neither fell back down as quickly as it should. So, as you said before, Randall, it seems like I'll have to center the jets. I've never done that before so this should be fun.

Now I have a transmission/clutch issue, but I'll post another thread for that one!
 
Scott, is that a "black" TR4? What shape is your paint job? Looks like you should show that car off a bit.
 
Thanks for the interest! Is that a black TR4 in your avatar, too?
Yes mine is black, courtesy of the PO. However, whoever he got to do the job was terrible. He admitted this himself. It looks fine from afar, but there's some cracking in places and you can see the previous (original?) red color underneath. The red peaks out in other less conspicuous places where it just wasn't painted (e.g. behind the fuel tank). It clearly wan't sanded and primed very well if at all before slapping the black paint on. But it's a good-looking driver, so I can't complain too much.

I will definitely show it off soon! I've been working on getting it in good road condition. I just pulled it out of the garage for the first time in 3 months, so it's almost ready! I'm about to go back out there and put the interior back together and take it for a spin to the gas station. I'll post something this weekend if all goes well!
 
Yes, mine is black, too. It's a great color on a TR4. I'm not sure which of the prior owners (there were 3) on my car resprayed it. But the local shops always tell me that someone really knew what they were doing. It makes me want to learn more about paint and types of paint jobs just in case mine ever needs it again. I don't know if it's an acrylic or hand rubbed lacquer or whatever--but I do know that all paints and painters aren't alike. Take care of that car, and one day you might decide to do something about that cracking and the red peeking through. Shucks it's only money!! BTW, when I bought mine back in '04 I spent 6 months just redoing the front end bushings and springs, handling the tuning, alignment, POR15 for the frame, new wheels, new rear shocks and shock links, and stuff like that. I was lucky, and it all ran like a new car when I took it out on its first new ride. Later, I added a new fiddleback walnut dash from Randy Keller (Prestige) in Santa Ana. IMG_1807.jpg
 
Thanks for the words of encouragement. That dash does look good! As does the rest of the interior as far as I can tell. Mine needs a little work, but I'll get there eventually!

I took mine for a spin yesterday in the 70 degree weather :cool-new:
Here's one picture for now from the drive.
295639_10100164986198159_392782845_n.jpg

The new clutch and gearbox were silky smooth. Pretty happy with that. After it warmed up, it ran great. However...

When I shut it off the engine, I'm still getting that "running on" problem from earlier in the thread. It was really bad this time. Started to die like normal then wanted to fire up a bit then shook pretty badly before finally coming to rest. Makes me cringe just thinking about it. In addition to the tuning up done before the gearbox problem, I checked the valve clearance, centered the jets, cleaned, and retuned the carburetors. My idle was around 800. Is that too high? Would that be better if I were closer to 500?
 
Very nice. Others here may disagree, but I keep mine at 900 to 1100, and in many years haven't been able to settle for less. Also, just let the idle slow before shutting down, then shift into 2nd gear then let the clutch out to slow to 500 rpm and shut it off. Forget spending any valuable breathing time trying to solve moderate preignition. You won't succeed to any reasonable degree all things considered.
 
I agree, except I don't worry about shifting into 2nd. Any gear will do, just keep your foot firmly on the brake. With a little practice, it becomes second nature and so smooth that you won't know if the engine would have run-on or not.
 
Yep. You'll get so good at doing it smoothly that passengers or spectators won't notice the procedure.
 
Sounds good I'll give that a try. Definitely don't want to mess up the engine now after all this work!

My dad suggested that the timing might be too far advanced. I first had the timing set at the mechanic who used a timing light while it was running. I set the timing cold according to the manual when I did the tune up and it was off from what the mechanic did (can't remember now if it was too far advanced or retarded). In both cases, however, the run-on was present. What do you guys think? I'm thinking about retarding it a tad, but it's not really something I want to test out very much!
 
Scott, Do as others have said and let the clutch out. It is really scary to watch one of these engines going back wards, can't be good.

Wayne
 
Scott, just time it static. The light always seems a waste. Not sure why, but I only use the light out of curiosity. If you set it static to the hole in the pulley, then go one more notch with the dial, you'll be fine at 4 BTDC. Don't try to solve preignition with a timing light, and, yes, probably start by retarding just a bit if your idle is fast.
 
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