Running on two cylinders...

[Forged906]

Hi all, I have a problem... (well, we won't get into the mental stuff here...)

About a month ago I took my 1914 Touring car for a nice 100ish mile run. Ran beautifully. I stopped by a friends place to give him and his family a ride. I am always surprised by how much the weight of a few people, or even just one passenger effects the performance. It was running very rough and I had a tough time getting into high gear with the extra weight. I drove it home (just me in it) and it did just fine, save running a little rougher than normal on some longer hills. And by rough I mean a little coughing.

When I drove it about a week later it was running quite rough - stuttering, coughing, and lurching. So, it was time to investigate.

Problem #1 I found, the vaporizer needle (a copper one in this case) was mushroomed. No problem, I retrofitted and reground a new steel needle, and replaced carb gaskets. I re-started the car and running just as rough and coughing. By grounding out the plugs to the engine head I determined it was only running on two cylinders (JUST LIKE ME!). Cylinders 1 and 2 did nothing when I touched them with screwdriver to engine.

Here is what I have done so far:
-re-ground vaporizer needle and replaced carb gaskets
-cleaned fuel lines and assured fuel is flowing
-tested and replaced buzz boxes if bad
-clean all contact points on buzz boxes and inside coil box holder. Coil box holder has plastic liner upgrade instead of wood.
-checked continuity in spark plug and timer wires from end to end, and from coil box holder to ends.
-checked compression - all good when I hand crank
-checked that there were no stuck valves and inspected head gasket at this time
-replaced intake and exhaust manifold gaskets
-replaced timer - timer that was on was a carbon brush timer that was wore down - could not find a replacement, so I bought a New Day timer, and also installed a new wiring harness for it
-new spark plug wires
-swapping spark plugs and trying new ones

When I lay the 4 spark plugs on cylinder head and crank over slowly I get a good strong spark on all 4 plugs, and the buzz boxes each buzz when they should. When I install the plugs and run the car and ground out the 4 plugs with a screwdriver to the engine only #3 and #4 make the engine stutter. I then remove the plugs to find plugs from #1 and #2 are wet with gas and #3 and #4 are dry as if they have fired. I get same issue regardless if I run on battery or on mag.

I am getting good strong spark when I should, but no spark when in the cylinder. I have swapped out plugs and get the same results.

I am beyond perplexed. Thank you for your time and consideration.

[Dan Hatch]

Vaporizer?? On a 14??? Show pictures.

[Forged906]

It has a Holly G carb, which as I understand it is a 15'. I don't know the finer points of all the details of parts versus years yet.

[RajoRacer]

Holley G is correct - we run one on our '14 Touring - they can be finicky on float level - sending it off to Corey Walker will eliminate carb. issues !

[speedytinc]

Test the plugs under pressure. You could try gapping the plugs to .024". Do a compression test.
You switched the plugs, did you switch coils around?
I would spray brake clean or starting fluid around the intake manifold looking for vacuum leaks.

Fuel level is easy to check on a G in the car. Remove the top cover & look @ the fuel level in the jet bowl.

[speedytinc]

Where is the hi speed needle set? S/B 1 1/4 turns open.
Consider a rear port vacuum leak. Carb gets set extra rich to run those 2 cylinders while flooding out the front cylinders.

[TXGOAT2]

Cracked intake manifold? Valves set too tight? Valve spring issues? Valve sticking issues? Badly worn or mis-fit valve guides?
It's not uncommon for coils to fail to make a secure physical contact with the contact springs in the coil box, even if everything is clean and in good order. Vibration of the moving car can make the problem come and go, or get worse at certain speeds. The cure is to use cardboard shims between the coils and the side of the coil box in order to assure that the coils are making firm contact with the contact springs on the sides and bottom of the coil box. A loose or abraded wire, or a problem with the ignition switch or magneto contact can cause similar symptoms.The car should run smooth at any speed, and the number of passengers should not affect how smoothly the car runs. It should ride smoother with a load on board, and it should have adequate power with a full passenger load for any ordinary circumstance.

[Scott_Conger]

failure to fire between 1-2 or 3-4 cylinders is almost always one of two things: blown head gasket between the offending cylinders or an intake gasket failure or manifold crack.

In circumstances similar to this, sometimes the person that asks for help will wait for 20-30 responses to say "oh, by the way, I had just done abc before xyz happened".

So, FWIW, if you did ANY work to your car shortly prior to the problem manifesting itself, it is kinder to mention it now rather than weeks from now. It will also have a strong influence in the answers you receive here.

[speedytinc]

One of our smarter guys had an interesting idea.
Check to see if 1 & 2 timer wires were mixed up.
Those 2 cylinders not firing @ the right time?
You did Change the timer.

Let us know when you find out.

[TXGOAT2]

Information can serve to focus speculation.

[Forged906]

I have tested the plugs under pressure, as well as swapped them out and rotated. I have also swapped out/rotated coils as well to no avail. I tried to shim the coils but they are already a very tight fit in the coil box. The coil box has the upgraded plastic 'liner' too. I've gotten good continuity from wires, posts, timer, plugs...

I've done a compression test, multiple times and getting good and consistent pressure in all 4 cylinders. When hand cranking, I get 32-35psi on all 4.

I believe my plugs are set at .025 currently.
I did replace the intake and exhaust manifold gaskets with new steel glands and copper gasket, but I will try spraying some starting fluid around them today to test for surge (leaks)

I had removed the cylinder head to take a look at the valves. no stuck valves, no play, and all set where they should be. The old head gasket was in decent shape, but I replaced it anyways (copper one)

Scott You are sure right about that! Like the non-handy homeowner messing with electrical before calling an electrician and not telling him what he messed with. Before the problem arose, I did no work to the car. After the problem, Other than the vaporizer needle I did not do any work or digging on it.

I will quadruple check the timing wires today.

Thank you for all the replies and help!!! I will try a few things today and report back.

[Mark Nunn]

When you replaced the intake gaskets, did you check for a dirt dauber nest in the front intake runner? It's happened to others with similar symptoms.

[Bill Robinson]

Have you considered "carbon tracks inside of the wood in the coil box?"
That was a very common problem with ignition problems until John Regan started selling a type of new waterproof material that will put an end to misfiring of coils caused by dampness. Replace the wood in the coil box with the waterproof material and the once "carbon track" problem will be gone.

[RajoRacer]

He stated that the coilbox wood WAS replaced with the modern stuff !

[TXGOAT2]

Sometimes, what you know is right is what's wrong.

[Charlie B in N.J.]

I’ve reread this post and I’m not sure of something: do you get spark at 1 & 2 when it’s running? Something is changing when you crank and check as opposed to when it’s running. You’re missing something very basic.

[Scott_Conger]

Aaron

you mentioned that you had good strong spark when plugs are out of the car but no spark when IN the car

I am going to assume you have concluded this because 2 cylinders are not firing as indicated by shorting the plugs out with a screwdriver and the car remained operating the same when 2 specific plugs were shorted...If I am correct in understanding/interpreting your logic, then I will state that you may IN FACT have firing plugs but simply have poor/wrong fuel mixture headed to those two cylinders.

You can verify or debunk the "plugs not firing when in the car" by shorting the plugs to the head (again) and this time looking for a spark to jump from the screwdriver to the head. I'll bet that they will spark and if so you will have verified that you DO have spark at those cylinders. Verify 1, 2, 4, 3 firing order AT THE PLUGS and you will have narrowed it down to fuel mixture at those two cylinders (since you have already verified compression at the cylinders, and tested the individual plugs under pressure)

If all of my previous paragraph are "true" then you have a vacuum leak.

finally, what you are calling the "vaporizer needle" is the mixture control needle and any malformed tip will affect the relative ease of adjusting from cold start to hot running (on all cylinders) and will not affect individual cylinders alone. It's always best to have proper geometry on this part but having a damaged needle is common and is not fatal to the cars being able to run as is the case for you right now.