Daves1940Buick56S Posted February 5, 2020 Share Posted February 5, 2020 Well, it finally happened. Breakdown on the road. I was returning home after having the front shocks, motor mounts and clutch replaced on my 1940 56S. About 60 miles from the mechanic's shop to my house. Everything was truly great at first. The car rode better than it ever has and was very smooooth. It just wanted to go 55 to 60 mph and the speed kept creeping up if I didn't pay attention. And I finally got a properly functioning clutch as well (I will do a separate thread on that later). A little more than halfway home, I started getting intermittant engine stuttering - what felt like either vapor lock or some kind of fuel starvation, although I wasn't getting the backfiring thru the carb. In fact, it seemed to be thru the exhaust, more like afterfire. It slowly got worse, and was especially bad trying to pull away from a traffic lite. It still was idling ok, but after a while even that was bad - intermittant 5+ inches vacuum drop. Finally, about 5 miles from home, it got so bad that I felt I could do other damage by proceeding further. So I stopped and called for the Tow of Shame. While I was waiting I tried a few things. Remove fuel tank cap - no change. Got elec boost pump working (it was not on the trip) - no change. Fuel pressure good. The clear gas filter before the carb was not conclusive regarding fuel flow, just confusing. I pulled the plug on the side of the bowl and fuel looked at proper level. I jiggled the floats and fuel appears to be flowing fine. I had no instruments with me to check ignition. The backfiring was not terrible but was definitely thru the exhaust. So Fri I am going to start with a fuel flow capacity test, but at this point I am thinking ignition capacitor. Thoughts? Cheers, Dave Link to comment Share on other sites More sharing options...
Matt Harwood Posted February 6, 2020 Share Posted February 6, 2020 Backfiring is almost always ignition-related. Since it was a gradual thing that came on with driving, I'd check coil then points and condenser. Maybe check wires if they're under the engine cover--they get cooked and brittle and since they're smaller than modern wires they can cross-fire when they get old. This is something easy, I'm sure of it. 2 1 Link to comment Share on other sites More sharing options...
Bloo Posted February 6, 2020 Share Posted February 6, 2020 Yes, change the condenser. Set the points. If the points have a mountain-type growth on them, replace. While you are in there, look at any flexible wires inside the distributor that move with the breaker plate. There is probably one to ground the breaker plate to the distributor housing, and another running from the binding post to the points. They move whenever the vacuum advance moves, and can break inside the insulation. they shouldn't stretch. 1 Link to comment Share on other sites More sharing options...
2carb40 Posted February 6, 2020 Share Posted February 6, 2020 Keeping with "kiss" principle, suggest U look at the dist cam surface. If it hasnt had lube it can surface rust and become a grinder that takes the "phenolic/plastic" rub block and sands it right off where it rides on the dist shaft cam flats. Quick and cheap to do. Good luck! 2 Link to comment Share on other sites More sharing options...
FLYER15015 Posted February 6, 2020 Share Posted February 6, 2020 Dave, I'm with those above. Points, condenser, and coil. Tell us what the plugs look like when you pull them 1-8. Also, do a test on your vacuum advance. Question, do you still have the 3 balls holding the distributor plate, or did you put the 3 plastic sliders in ? I have the plastics in my '40 LTD and it is sooo much smoother now. Mike in Colorado 6 Link to comment Share on other sites More sharing options...
Brooklyn Beer Posted February 6, 2020 Share Posted February 6, 2020 Funny but I had this happen to me on my daily driver 53 Plymouth. Surging at high rpm but ok at idle. Made it home the 10 miles and popped the hood. Found that when I had pulled the water tube I had somehow pulled the coil wire loose. It was NEXT to the coil. Drove it for a week before it started acting up. One hell of an original coil to jump a 1/2 gap and still be drivable. Yep, check simple first. 2 Link to comment Share on other sites More sharing options...
dibarlaw Posted February 7, 2020 Share Posted February 7, 2020 So sorry to hear of the "Tow Of Shame". Been there, done that. But ours was at 57 miles into our aborted 1,100 mile trip to Springfield MO. back in 2015 with the 1937. Embarrassing roll back ride back thru the neighborhood. Our problem was the stopped up radiator I had to have re-cored. I am voting for a simple ignition issue. Larry Link to comment Share on other sites More sharing options...
Larry Schramm Posted February 7, 2020 Share Posted February 7, 2020 (edited) 1 hour ago, dibarlaw said: So sorry to hear of the "Tow Of Shame". Been there, done that. But ours was at 57 miles into our aborted 1,100 mile trip to Springfield MO. back in 2015 with the 1937. Embarrassing roll back ride back thru the neighborhood. Larry Being the other Larry, also, been there done that. There are typically two types of old car people. Those that drive their antique cars and admit to being towed and the liars. Edited February 7, 2020 by Larry Schramm (see edit history) 2 Link to comment Share on other sites More sharing options...
Daves1940Buick56S Posted February 7, 2020 Author Share Posted February 7, 2020 And the answer is...coming tomorrow! Weather today not conducive. Link to comment Share on other sites More sharing options...
neil morse Posted February 8, 2020 Share Posted February 8, 2020 2 hours ago, Daves1940Buick56S said: And the answer is...coming tomorrow! Weather today not conducive. What a tease! 😄 Link to comment Share on other sites More sharing options...
neil morse Posted February 8, 2020 Share Posted February 8, 2020 PS: Dave, your car looks great, even on the "flatbed of shame." Link to comment Share on other sites More sharing options...
valk Posted February 8, 2020 Share Posted February 8, 2020 Dave, sorry to hear of your public humiliation. Let me know if you need an extra set of hands or eyes. Peter Link to comment Share on other sites More sharing options...
60FlatTop Posted February 8, 2020 Share Posted February 8, 2020 If you bought a new condenser within the past 15 years and installed it as part of a thorough tuneup look for the old condenser and put it back in. Or buy an old stock one on Ebay. It is really hard to find a good new one. Cost me a flatbed ride a few years ago with my '60. I put the old one back in, still on the bench, the new one lasted a week. I haven't needed one since but if I do the replacement will be old stock or maybe an Echlin from NAPA. We'll see. The condenser in the car now must be over 25 years old. Unless the points pit or it fails completely it will be in there another 25 years. Bernie 2 1 Link to comment Share on other sites More sharing options...
Daves1940Buick56S Posted February 8, 2020 Author Share Posted February 8, 2020 Aaaand...you all were correct 100%. Bad capacitor (condenser). My analog analyzer has a position that shunts in another one and when I switched it in everything smoothed out. Also point resistance up so it likely took the points with it. In 50 years of driving with about half of that on the standard ignition I have never had a capacitor fail. So maybe this is the Condenser of Shame? Anyhow, I know I have at least 2 or 3 unused point sets but I'll be damned if I can find them right now. I do have a NOS ACDelco condenser so I put that in and cleaned and burnished the old points. I also replaced the lead to the feedthru (the old one was pretty chewed up). I know standard wiring only lasts so long there but a friend has some of the hi-flex wire used on motorcycle fuel injector to wiring harness and I will replace when I put the new points in when the weather warms up more. It'll be fine for around town this winter. Cheers, Dave 3 Link to comment Share on other sites More sharing options...
Bloo Posted February 8, 2020 Share Posted February 8, 2020 If you mean the piece that runs inside the distributor to the points, normal wire wont do, flexible or not. Wires made for that purpose are strands of copper and spring steel. Copper work hardens with the movement and wont last long at all. Same for the breaker plate ground. If the correct part is not readily available, there is probably a NAPA one for a much more recent points distributor that will work. Only the wire to the points must have insulation. The ground wire can be bare and in newer cars it often is. Link to comment Share on other sites More sharing options...
Daves1940Buick56S Posted February 8, 2020 Author Share Posted February 8, 2020 Yeah I know. The wire I referred to above that my friend has is like you described. On motorcycles the connection to the fuel injectors has to withstand constant movement. I think it is basically the same. Cheers Dave 1 Link to comment Share on other sites More sharing options...
Bloo Posted February 8, 2020 Share Posted February 8, 2020 It can really catch you by surprise when that wire breaks. It's like turning the ignition off and on. In 1987 I blew the sides out of 2 mufflers in 6 blocks on the way to work. The DPO had replaced those wires with copper and the ground had broken off. Link to comment Share on other sites More sharing options...
hidden_hunter Posted February 9, 2020 Share Posted February 9, 2020 3 hours ago, Daves1940Buick56S said: Anyhow, I know I have at least 2 or 3 unused point sets but I'll be damned if I can find them right now. I do have a NOS ACDelco condenser so I put that in and cleaned and burnished the old points. I also replaced the lead to the feedthru (the old one was pretty chewed up). I know standard wiring only lasts so long there but a friend has some of the hi-flex wire used on motorcycle fuel injector to wiring harness and I will replace when I put the new points in when the weather warms up more. It'll be fine for around town this winter. I keep a set of spare ignition parts under the drivers seat so I always know where they are Link to comment Share on other sites More sharing options...
Larry Schramm Posted February 9, 2020 Share Posted February 9, 2020 (edited) If you really want wire that is made for lots of movement, get some wire from an old front wheel bearing that has a wheel speed sensor from a newer car. That wire is also called hi-flex wiring. Edited February 9, 2020 by Larry Schramm (see edit history) Link to comment Share on other sites More sharing options...
Frank DuVal Posted February 9, 2020 Share Posted February 9, 2020 I use test lead wire. So far so good.😉 1 Link to comment Share on other sites More sharing options...
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