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Old 05-10-2015, 07:03 PM   #1
Slik
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Default #3 & #4 cylinders

Well, after 30 years the old Woody is running albeit not very well. Idles nicely after carb adjustment.
Took it out for a ride and it was pretty easy to diagnose a bad miss. No power whatsoever.

I did compression tests and have 68-70 across all 4 cylinders. The car had new valves prior to being stored and my brother told me that one of the reasons my father put it way was because #3 exhaust valve was sticking and causing it to overheat.
I pulled the valve cover, springs and guides cleaned them all up, along with the value stems. Reinserted the guides and the valves slide nicely.
Got it all back together, started fine, idles ok but still now power. I shorted the plugs, Shorting #1 and #2 caused a significant drop - shorting #3 and #4 had no effect on the idle. Have plenty of spark to all plugs. Rotor gapped correctly, points adjusted and timing is spot on. Also validated the cap is good.
I have a pretty good exhaust leak at #4 (I think the gland ring is hung up) - I'll work to correct that tomorrow. I'll also try the starter fluid trick around the intake to see if there is a leak there.
Any other suggestions or things I might try ?

Also, is there a reliable way to adjust the valves without pulling the head ? Prior to reassembling the top end I relapped the valves and adjusted the valves but I'd like to double check them if possible.
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Old 05-10-2015, 07:27 PM   #2
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Default Re: #3 & #4 cylinders

Sure sounds like a big intake leak back by #3 and #4. Broken spring in the point arm could do it also. It should not idle very well if there is a big leak in the manifold.
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Old 05-10-2015, 07:37 PM   #3
Patrick L.
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Default Re: #3 & #4 cylinders

If the compression is good and the valves are not sticky, then it kinda sounds like a vacuum leak if the ignition system is in good shape [ no carbon tracking in the cap, etc]
How did you adjust the valve lash ? And what are they set at ? Original lifters were not adjustable requiring the seat or valve stem to be cut. Upon many rebuilds adjustable lifters have been installed which means the head does not have to be removed for adjustment.
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Old 05-10-2015, 11:06 PM   #4
Mike V. Florida
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Default Re: #3 & #4 cylinders

Check with a vacuum gauge would be my next step.
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File Type: pdf Model A Vacuum Gauge Tuning from ARSCO.pdf (127.0 KB, 70 views)
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Old 05-11-2015, 12:15 AM   #5
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Default Re: #3 & #4 cylinders

Compression test indicates mechanically sound.
All valves are seating, head gasket has integrity, cam is still in one piece.
What do the sparkplugs looking like, compare 1&2 to 3&4.
I doubt vac leak, you would see gas stain below manifold. If not running out.
Is it possible plug wires are crossed 3&4?

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Old 05-11-2015, 12:40 AM   #6
Chuck Sea/Tac
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Default Re: #3 & #4 cylinders

Check the plugs,if 3&4 are fouled,then it could be in the distributor points or rotor clearance.
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Old 05-11-2015, 10:15 AM   #7
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Default Re: #3 & #4 cylinders

On a 70 mile run, I dropped #4 cylinder while driving. When I checked it out, turns out the rubbing block had worn down causing the points to close. Once the points were reset, the car ran normal again.
I am only saying, something as simple as point setting can resolve some of these issues.
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Old 05-11-2015, 11:24 AM   #8
Mikeinnj
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Default Re: #3 & #4 cylinders

"Also, is there a reliable way to adjust the valves without pulling the head ? Prior to reassembling the top end I relapped the valves and adjusted the valves but I'd like to double check them if possible."


You said that you adjusted the valves so that means that you have adjustable valves.

What did you set them at ? To re-check them, you have to turn the engine over by hand until the lifter you are checking is on the heel of the cam. ( lifter all the way in the down position.) It helps to have someone assist you and with the spark plugs out of the head. Set them with the engine cold.

I use a "go" - "no go" system when checking clearances. For example if the valve setting is .013 you check the clearance with a .012 and then with a .014 feeler gauge and if the .012 feeler gauge "goes" and the .014 does not, then you have a setting of .013
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Old 05-11-2015, 12:32 PM   #9
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Default Re: #3 & #4 cylinders

Sounded like you said you had good spark to the plugs - but is the spark jumping the plug gap or have the plugs shorted????
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Old 05-11-2015, 07:19 PM   #10
1931 flamingo
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Default Re: #3 & #4 cylinders

Have you changed the timing gear or verified it's correctly positioned to the crank pulley??

Paul in CT
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