6V Condensor - 1929 Std 6 "lack of performance"

[Poppy510]

Hello all,

I have worked through most fuel, lubrication, cooling, and braking issues, and I am now down to "performance".  Understanding that the car is nearly 100 years old and the term "performance" is relative, I have felt that the performance under load is fairly sluggish. I also experience some slight stumbling under heavier load and at the upper rpm range. Timing is checked, wiring is good, points are good, plugs are good. Also confirmed with a timing light that the mechanical advance is functional. Plenty of fuel is available at the carb.

 

As I would expect, the best performance under load is with full advance. If I retard the timing at all with the hand lever, performance drops of dramatically. Thinking that a little more advance might be beneficial, I rotated the distributor slightly, but this only resulted in an occasional backfire through the carb, along with the general stumble. Honestly, its not bad and if a just putted along at 25 and only went to high gear on the flat or downhill, I would probably never even notice the stumble.

 

My next step is to replace the condenser. Do I need to go straight to Myers Dodge for a special 6V condenser, or is there a known replacement available at NAPA? Any other thoughts?

 

On a separate note, I can hear an exhaust leak coming from firewall side of the exhaust manifold but I cant find it for the life of me. I'm thinking may be a crack in the back of the manifold or something. I cant however imagine that this would cause the performance issue I am observing.

[JACK M]

6 minutes ago, Poppy510 said:

 

 

On a separate note, I can hear an exhaust leak coming from firewall side of the exhaust manifold but I cant find it for the life of me. I'm thinking may be a crack in the back of the manifold or something. I cant however imagine that this would cause the performance issue I am observing.

 

I keep a stethoscope in my tool box for just this reason.

[Kenendcindyc]

My experience is that any condenser will work, there are different capacitance ratings and the wrong one will result in faster points wear. But they should still work. On mine when I had misfires in the upper rpm range I traced it back to worn distributor shaft bearings. Once tightened up it revs smoothly to 3600rpm. The other issue I had with sluggish performance was the factory carb was jetted to lean for modern 10% ethanol fuel we have here in NH. Once corrected it runs strong from 10-65 in third and will pull 99% of hills in high. What carb are you running?  What’s your plug gap? Valve lash setting? 

Edited January 11, 2021 by Kenendcindyc (see edit history)

[Poppy510]

14 minutes ago, Kenendcindyc said:

My experience is that any condenser will work, there are different capacitance ratings and the wrong one will result in faster points wear. But they should still work. On mine when I had misfires in the upper rpm range I traced it back to worn distributor shaft bearings. Once tightened up it revs smoothly to 3600rpm. The other issue I had with sluggish performance was the factory carb was jetted to lean for modern 10% ethanol fuel we have here in NH. Once corrected it runs strong from 10-65 in third and will pull 99% of hills in high. What carb are you running?  What’s your plug gap? Valve lash setting? 

Carb is Stewart Detroit lubricator. Plug gap is .025. I haven't measured lash yet.

Wobbly distributor shaft is a promising sounding lead. How did you measure distributor shaft play? I assume the shaft is on bushings which would need to be replaced.

[Poppy510]

1 hour ago, JACK M said:

 

I keep a stethoscope in my tool box for just this reason.

Got one on order now...Thanks!

[Kenendcindyc]

Yes the shaft runs in bushings one upper and one lower. There should be less that .001” clearance I measured mine with a dial indicator pushing the shaft back and forth. 

[Kenendcindyc]

.025 is good on the plugs. I also run a Detroit lubricator carb.  Once tuned it’s one great performing carb that will last 1000 years. 

[Kenendcindyc]

Once you get the misfires and running rough figured out if you get a light surge when running at steady throttle at about 40-45 and it seems low on power she is running lean. I can walk you threw tuning that carb. It will require multiple disassembles and some custom parts made but it’s worth it. 

[hwellens]

Some info if needed:

Edited January 11, 2021 by hwellens (see edit history)

[Poppy510]

38 minutes ago, Kenendcindyc said:

Yes the shaft runs in bushings one upper and one lower. There should be less that .001” clearance I measured mine with a dial indicator pushing the shaft back and forth. 

The rotor shaft has very little radial play (.001 according to my calibrated fingers😁). The body of the distributor has a little more play due to the adjustable nature of the design. My overall sense is that once everything is biased and operating in one direction, there is not an excessive amount of slop in the distributor system. I was somewhat hopeful that I would find the rotor shaft more sloppy. I reset the static timing again and picked up a few degrees on the housing, so we'll see if there is any effect. I am still interested in other ideas out there. Thanks!

[Kenendcindyc]

Does it run smoothly cold and when warm, but starts to run rough hot and loose power when hot ?

[Poppy510]

13 minutes ago, Kenendcindyc said:

Does it run smoothly cold and when warm, but starts to run rough hot and loose power when hot ?

 

I take it pretty easy when cold so I am not totally sure, but overall it does not seem to drop off suddenly when hot.

 

I may have been to generous with my assessment of the points. I inspected the mechanical advance thinking maybe I had TOO much advance due to a broken spring or something. I would rate the point condition as "moderate."

 

Not great but I have seen worse. I appreciate your input.

 

 

 

 

 

 

 

 

[Kenendcindyc]

Ok. I’m not sure what’s going on with yours but I’ll give you more food for thought. After I built mine I followed the spec in the book and set valve lash to .005 with the engine around 170 degrees, because the spec is .005 Hot. The engine ran great, as the summer heated up and I went on longer trips the car seemed to loose power and idled very rough after pulling a large hill. If I let it sit and idle it would smooth out and power would return within five minutes. This had me stumped, played with multiple condensers no change. Thought It was fuel boiling in the carb tried some stuff to correct it, no change. Checked all adjustments , no change. As it kept happening I noticed a pattern only when coolant temp got around 200 and I was working it hard did the power fall off quickly and the rough idle appeared. Then I got a idea, I took the car for a good ride to get everything up to temp then ran it in the garage with blankets covering the radiator so I could regulate the temp to about 200 after a few minutes the rough idle appeared. I pulled off the tappet cover and yup I had zero lash on the exhaust valves. In fact some were tighter than zero and were being held open slightly thus causing my low power and rough idle. You see the valves we’re expanding when HOT decreasing lash.   I reset them all to .005 with the engine running and Hot and it’s run smoothly ever since. Sorry for the long story ,but keep checking stuff and you’ll find your problem. It’s probably something minor that’s being overlooked. 

[Poppy510]

11 minutes ago, Kenendcindyc said:

Ok. I’m not sure what’s going on with yours but I’ll give you more food for thought. After I built mine I followed the spec in the book and set valve lash to .005 with the engine around 170 degrees, because the spec is .005 Hot. The engine ran great, as the summer heated up and I went on longer trips the car seemed to loose power and idled very rough after pulling a large hill. If I let it sit and idle it would smooth out and power would return within five minutes. This had me stumped, played with multiple condensers no change. Thought It was fuel boiling in the carb tried some stuff to correct it, no change. Checked all adjustments , no change. As it kept happening I noticed a pattern only when coolant temp got around 200 and I was working it hard did the power fall off quickly and the rough idle appeared. Then I got a idea, I took the car for a good ride to get everything up to temp then ran it in the garage with blankets covering the radiator so I could regulate the temp to about 200 after a few minutes the rough idle appeared. I pulled off the tappet cover and yup I had zero lash on the exhaust valves. In fact some were tighter than zero and were being held open slightly thus causing my low power and rough idle. You see the valves we’re expanding when HOT decreasing lash.   I reset them all to .005 with the engine running and Hot and it’s run smoothly ever since. Sorry for the long story ,but keep checking stuff and you’ll find your problem. It’s probably something minor that’s being overlooked. 

good ideas here.......got me thinking...Ive never seen temps above 150. Might be checking the thermostat next.

[Grimy]

Try substituting a coil known to be good. That's quick, easy, and non-invasive. Coils frequently break down first  (1) under load (i.e., on the road driving) and (2) when they get warm/hot.

[RichBad]

1 hour ago, Kenendcindyc said:

Ok. I’m not sure what’s going on with yours but I’ll give you more food for thought. After I built mine I followed the spec in the book and set valve lash to .005 with the engine around 170 degrees, because the spec is .005 Hot. The engine ran great, as the summer heated up and I went on longer trips the car seemed to loose power and idled very rough after pulling a large hill. If I let it sit and idle it would smooth out and power would return within five minutes. This had me stumped, played with multiple condensers no change. Thought It was fuel boiling in the carb tried some stuff to correct it, no change. Checked all adjustments , no change. As it kept happening I noticed a pattern only when coolant temp got around 200 and I was working it hard did the power fall off quickly and the rough idle appeared. Then I got a idea, I took the car for a good ride to get everything up to temp then ran it in the garage with blankets covering the radiator so I could regulate the temp to about 200 after a few minutes the rough idle appeared. I pulled off the tappet cover and yup I had zero lash on the exhaust valves. In fact some were tighter than zero and were being held open slightly thus causing my low power and rough idle. You see the valves we’re expanding when HOT decreasing lash.   I reset them all to .005 with the engine running and Hot and it’s run smoothly ever since. Sorry for the long story ,but keep checking stuff and you’ll find your problem. It’s probably something minor that’s being overlooked. 

Spot on I recon - was told the same thing by Bob for the fast fours - especially on the exhaust valves and running modern fuel they need a little more tappet clearance.  I remember someone once telling me a clappy tappet is a happy tappet:)

 

On the plug gap side I was also told that these liked a much larger gap which isn’t a problem on the coil systems (maybe on the magnetos).   I gradually increased my plug gap to 0.040” and it definitely got smoother.  Easy things to try.

[Kenendcindyc]

21 minutes ago, RichBad said:

Spot on I recon - was told the same thing by Bob for the fast fours - especially on the exhaust valves and running modern fuel they need a little more tappet clearance.  I remember someone once telling me a clappy tappet is a happy tappet:)

 

On the plug gap side I was also told that these liked a much larger gap which isn’t a problem on the coil systems (maybe on the magnetos).   I gradually increased my plug gap to 0.040” and it definitely got smoother.  Easy things to try.

Ahhhh yes you are right about the plug gap. I believe I ran .035 until I made my high compression head ,then I had to drop to .025 due to the small distributor cap , I was getting cross firing because of the increased cyl pressure. 

[Poppy510]

How about those points? "Good enough?"

[Kenendcindyc]

Really hard to tell by pictures, if in doubt new ones will be trouble free for a LONG time. Atleast clean them up with a good points file adjust them so they close nice and have sufficient spring tension.