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Discussion Starter #1
I took my valiant out on the road for the first time. I drove the car for only 5 minutes because when I got on it I heard a chattering sound from the motor. The motor is new and was broken in at the machine shop. I have low octane gas in the tank. Could that cause the chattering? Also I know that the kick down linkage needs to be adjusted. Could that cause the sound?
I can't see it being a bad lifter or push rod because its a new motor and it sounded fine on the dyno.
All the fluids are good.
Could it be an exhaust leak?
 

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Kickdown linkage cannot cause this issue.

Is it really a new motor, or a newly rebuilt motor? Makes a difference.

What is the octane of the gas you used? Should be 87. Is this a slant-6? If so, the valve clearance needs to be adjusted when the engine is hot and running. It cannot be set accurately otherwise.
 

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Discussion Starter #4
It is a 408 stroker with all new parts and the octane was around 87%. I just added new gas at 97%.
 

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Not familiar - is that a 360 block made to a 408? What is the compression? Hydraulic lifters, most likely. You probably do need at least 91-93 octane if compression is over 10:1.
 

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Discussion Starter #6
Yes the motor started out with a 360 block. I can not find the compression on the dyno sheets. I'm sure it is there it just he has everything broken down by inishals. The horsepower is 454 and the torq is 447. No clue on the lifters, not listed on the material slip. I can find out this information on Monday when I talk with them about this noise.
 

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The noise could actually be a small piece of garbage that was floating around inside the engine and moved through the oil galleries. Are the rockers adjustable or stock? If adjustable, it may just need to be readjusted.
 

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Discussion Starter #8
It made the noise when I was going around thirty and I stepped on it. I am going to take it out for another test run. This time stay at a constant speed. Unless you guy don't think I should drive it until I can figure out his problem?
At idel I think I hear a slight rapping. Not having any experience with a motor like this I'm not sure of what it should sound like at idel.
I could just be hearing thing.
Do not know about the rocker arms. I will have to ask tomorrow .
 

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Discussion Starter #9
Just pulled a spark plug and it completely black. It also has a strong smell of gas. Could this have anything to do with the noise?
 

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97 Octane? What fuel source company? Black plugs indicate way rich jetting. You could wipe out your new rings if you don't tune your carb better. roller tipped rockers do have some noise associated with them. You might be so rich that your fuel mix is igniting in your mufflers.
 

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Discussion Starter #11
97 might have been stretching it. I got the highest they carried. The carberator was set on the dyno test.
I had a hard time with the wiring. A lot of turn over, but no starts. Also had fuel exhaust out through the carberator. Would a poor spark cause the black plugs? Just tried to start the car. Pulled a spark plug wire and put in a spare plug. Held it to a grounded surface and I was not getting a spark.
 

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Check the plug wire itself, it may have come loose or not be firing.
 

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Discussion Starter #13
I checked all the obvious areas. The cars started on the first turn yesterday. Could the coil get burnt out or something have gone wrong with the distributor? Can all this be connected to the noise in the engine and the black plugs?
 

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Discussion Starter #14
I had the coil installed horizontal and I turned it vertical and the engine almost started. The battery gave out. Could the plugs be so fouled that they just won't work?
 

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I think you found your problem. The chattering noise was probably spark misfire at the coil, and now it's fried. I'll bet a new one gets you going.

What ignition setup do you have? Breaker point, original Chrysler electronic ignition, new aftermarket? And are you using a properly-connected ballast resistor if the setup requires one?
 

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Discussion Starter #16
A MSD distributor with a blaster two coil. No ballast resister is needed with this set up according to the MSD tech.
I had a lot of trouble figuring out the wiring. That caused a lot of failed starts and carberator flooding.
I talked with the guy that built the motor. He was not concerned with the black plugs.
I was told that with the problems I was having with the wiring, carberator flooding and poor spark that would happen.
Does this make sense to you guys? I have a lot of money in this motor and I do not want to do any damage.
Thanks for the help.
 

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Flooding and poor spark will put undue wear and tear on the new motor. I'd check the coil to see if the resistances are within spec, and make sure all of the wiring is correct.
 

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core said:
A MSD distributor with a blaster two coil. No ballast resister is needed with this set up according to the MSD tech.
I had a lot of trouble figuring out the wiring. That caused a lot of failed starts and carberator flooding.
I talked with the guy that built the motor. He was not concerned with the black plugs.
I was told that with the problems I was having with the wiring, carberator flooding and poor spark that would happen.
Does this make sense to you guys? I have a lot of money in this motor and I do not want to do any damage.
Thanks for the help.
Bob Lincoln said:
Flooding and poor spark will put undue wear and tear on the new motor. I'd check the coil to see if the resistances are within spec, and make sure all of the wiring is correct.
It looks like both of you live in the same state which is smaller than the county here in Arizona where I live. :)
 

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Betcha don't have 6.6 million people in that county, though. ;)
 

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No, but the county that I live in has almost 4 million people in it, and is still bigger than Mass... *grin*
 
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