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Engine behaviour diagnosis/perspectives (195.6)

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1958 rambler super View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1958 rambler super Quote  Post ReplyReply Direct Link To This Post Topic: Engine behaviour diagnosis/perspectives (195.6)
    Posted: Feb/03/2023 at 2:39pm
Ok, i have replaced these pieces of equipment and have gone through the procedures of timing or vacuum or timing light tests and have ruled out... 
dist cap cracks, 
plug wires, 
plugs,
 coil, 
points, 
rotor, 
New fuel filter at new electric fuel pump and new fuel filter at carb, 
New carb, 
bad timing, 
bad engine vacuum as the possible cause to a intermittent engine sound and a shake I still see my engine having. 

The "behaviour" of my engine is a sound that sounds like a "cough" or a "buff" sound, and the engine shakes a little when it happens.

My engine is a 195.6, it's been rebuilt, has new springs and all that stuff, has new pistons made so its got new springs too, it had the crank shaft resurfaced and apparently the cam shaft too.
It has new push rods and also cam followers, and those are flat tappets. 
So the crank and cam shafts are old but rebuilt so to speak. 
The block is old of course, so cylinders were bored to what degree I don't know, and the cylinders were honed, the builder asked me if I wanted them bored bigger for more hp but I said no so that counts for something as to the info I don't have but can offer.
The head was checked via magna flux and the builder said there was no cracks. 
The rocker arms and shaft I suppose are old and reused, he didn't tell me anything about that so I figure that part is old and no new one was used. 
I asked for a detailed receipt but he didn't give me one, so I don't know alot about what he did. 

So other then a few mechanical things that I don't have alot of knowledge about, and also maybe something stopping exhaust gases from leaving the engine cleanly, like maybe something stuck in the exhaust pipe during all the time the exhaust pipe that attaches to the exhaust manifold was sitting open in the engine compartment before the engine was installed, I'm asking what ideas the forum has as to what could be causing an engine with this description to have this type of intermittent sound and cause the engine to shudder? 


Edited by 1958 rambler super - Feb/03/2023 at 3:13pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1948kaiser Quote  Post ReplyReply Direct Link To This Post Posted: Feb/03/2023 at 2:45pm
did you change the fuel filter?
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1958 rambler super View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1958 rambler super Quote  Post ReplyReply Direct Link To This Post Posted: Feb/03/2023 at 3:14pm
Yep, new Fuel filters at new elec fuel pump and also new fuel filter infront of carb, new carb too. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sweatlock Quote  Post ReplyReply Direct Link To This Post Posted: Feb/03/2023 at 3:27pm
When does it make this sound - during warm-up/while cold or when at operating temperature? At idle, during acceleration, or when cruising? Is it an automatic or a manual? If manual, does it make the sound in-between shifts? 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1958 rambler super Quote  Post ReplyReply Direct Link To This Post Posted: Feb/03/2023 at 3:30pm
The car is not driveable yet, so no shifting is involved, but the engine has this behaviour at all times and never goes away, at first start up, warming up, warmed up, fully warmed up and at operating temp. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Feb/03/2023 at 3:55pm
If ignition is fine, it would likely be fuel. 
At idle, low fuel pressure or low float would likely stall, so high fuel pressure or high float should be looked at. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1958 rambler super Quote  Post ReplyReply Direct Link To This Post Posted: Feb/03/2023 at 4:03pm
Hi trader, I don't get what you mean, you mean the float being set too high could be a problem? 

No matter how much the throttle lever is being turned the problem is still there.

Also, the wires in the car are old, last year tomj suggested this problem/ a misfire I was trying to solve could be the old wires. 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote bigbad69 Quote  Post ReplyReply Direct Link To This Post Posted: Feb/03/2023 at 4:16pm
Originally posted by 1958 rambler super 1958 rambler super wrote:

Also, the wires in the car are old, last year tomj suggested this problem/ a misfire I was trying to solve could be the old wires. 
That could very well be the problem. It sounds to me like you have an intermittent misfire.

If a new set of wires doesn't fix your problem, I suggest you post a video so people can hear what's going on.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 1958 rambler super Quote  Post ReplyReply Direct Link To This Post Posted: Feb/03/2023 at 4:41pm
So the wires I would be replacing would be the ones going from the ballast resistor to the coil, and also going to thier origin?

 Would the wires leading away from the starter also be wires I should replace?
Could loose battery cables cause the misfire too? Because those are lossley slipped onto the battery posts, as they are taken off quite a bit due to ongoing maintenance 
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Post Options Post Options   Thanks (0) Thanks(0)   Quote Trader Quote  Post ReplyReply Direct Link To This Post Posted: Feb/03/2023 at 5:11pm
Aside from the wiring issues you may have, too high a float level can cause fuel to spill down the carburetor and that cough you hear and shake may be a small backfire when that fuel ignites in the intake or head. 
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