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BillT
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Cylinder not firing correctly
02/17/19 at 21:18:21
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I have one cylinder not firing correctly. When I pull ignition wires, one at a time, 1,2, and 4 the engine nearly dies. When I pull wire no. 3 there is no change in engine sound, and the spark is weak. Pulled the plug, heavy carbon on it but that isnít unusual for this engine. Installed a new plug and swapped ignition wires, still missing. Checked the distributor, everything looks good, points at .020Ē. No tracking or carbon in there. The PO had installed a IAT-4405 vacuum advance distributor,† but the vacuum was never connected, engine seemed to run ok.
Next I checked compression, have 117 dry and 127 wet. Engine intake manifold pressure is 19.5Ē at an idle of 700 rpm
The engine has an intake manifold leak, detected by carb spray, on the section of the manifold in front of cylinder #3.Could this be the problem?
The carb has been changed from a Solex to a Carter WO 636SA freshly rebuilt by Old Jeep Carbs.
The ignition wires are the new style, not copper, they will be changed. As well as a IAD-4008 distributor will be installed.
So what am I missing here? Sure could use some ideas or thoughts.
Added info- this is a 1952 CJ3A with the standard L-134 engine. I have owned since this past spring. The engine has been in the Jeep since 1955 at least, probably the original engine. I have no history of any kind on this Jeep.
« Last Edit: 02/17/19 at 21:24:26 by BillT » 
Reason: Add info 

'52 CJ3A, early M38A1, '70 Commando
25' travel trailer, Lance 855S truck camper
Love to camp
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Re: Cylinder not firing correctly
Reply #1 - 02/18/19 at 06:19:34
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"The engine has an intake manifold leak, detected by carb spray, on the section of the manifold in front of cylinder #3. Could this be the problem?"

Yes.

"The PO had installed an IAT-4405 vacuum advance distributor,  but the vacuum was never connected, the engine seemed to run ok."

Won't hurt to connect to vacuum at the base of the carb.

Start there.
  

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BillT
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Re: Cylinder not firing correctly
Reply #2 - 02/18/19 at 07:53:22
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Thanks Rick, I have about given up on the manifold on this engine. I have a spare engine and will pull the manifold from it and give it a try.
I also have a spare distributor and will try it if no favorable results with the manifold.
  

'52 CJ3A, early M38A1, '70 Commando
25' travel trailer, Lance 855S truck camper
Love to camp
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64CJ5
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Re: Cylinder not firing correctly
Reply #3 - 02/18/19 at 11:26:51
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If the spark is week try a different distributor cap and the spark plug wire from cap to plug.  Easy things first.
  

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Re: Cylinder not firing correctly
Reply #4 - 02/18/19 at 12:03:04
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BillT wrote on 02/18/19 at 07:53:22:
Thanks Rick, I have about given up on the manifold on this engine. I have a spare engine and will pull the manifold from it and give it a try.
I also have a spare distributor and will try it if no favorable results with the manifold.

Easier if both manifolds are off. Mate the two on the bench, stretch a straight edge across the length of the pair from ear to ear to check for mismatched gaps that may need some machining to make them all straight and level.
  

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BillT
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Re: Cylinder not firing correctly
Reply #5 - 02/18/19 at 12:25:27
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64cj5 thanks for the help but I tried that Saturday, no change. More thoughts are welcome.

Rick I had done that with the current manifold, machined and all. After that failed I pulled it back off and sprayed copper sealant on the manifold to block gasket and the gasket between the two manifolds. No change

I have ordered a set of copper core plug wires and a new gasket kit. Probably be here by the end of the week.

I may go ahead and stick the other distributor in to see what change that makes. I'm thinking about a new coil but I hate to just throw parts at it for a repair, I didn't do that when I got paid for working and don't want to do it now.
  

'52 CJ3A, early M38A1, '70 Commando
25' travel trailer, Lance 855S truck camper
Love to camp
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BillT
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Re: Cylinder not firing correctly
Reply #6 - 02/23/19 at 20:55:27
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Thursday I pulled the manifold from the donor engine. This is some kind of a commercial engine, welder, or compressor, etc. Soaked it a good 24 hrs in diesel fuel. Due to the condition of the four bolts securing the two manifolds I did not separate them to change the gasket. Changed everything out and guess what? No more leak!!! Cylinder no.3 is firing, exhaust no longer putt putts. Yea! Time for a cold beer, or four, after all itís Saturday.
But all is not good. The exhaust pipe to manifold, the blind bolt hole,  stripped out. Itís not leaking for now but itís only a matter of time. Only in a Jeep...... oh hell ..... I luvíem.
  

'52 CJ3A, early M38A1, '70 Commando
25' travel trailer, Lance 855S truck camper
Love to camp
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