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New 401 AMX

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sidefx View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sidefx Quote  Post ReplyReply Direct Link To This Post Topic: New 401 AMX
    Posted: Oct/22/2017 at 2:56pm
I have recently inherited my grandfather 1971 AMX 401 with 30k original miles.

The first issue is a cold start thud that goes away once the engine is warm. Could it be a stuck lifter or rocker arm out of adjustment?
http://youtu.be/feZIeUjiJg8 - http://https://youtu.be/feZIeUjiJg8

The next issue is really poor fuel mileage and just recently some stalling issues. I have only ~50 miles since I last filled up and have used a half tank already. I have been trying to gradually clean out the engine since it probably hasn't since over 3000 rpm in years. I think some of the 4500 rpm runs might have knocked the points out of adjustment and maybe the carb needs cleaned out.

As for the points I'm looking to convert it over to electronic with a kit from Pertronix. Should I go with either the ignitor I or II? And should I match it with their flamethrower coil?

As for the carb the stock 4300 doesn't have really good reviews out there. So I'm wondering what the best option would be for my car, its an automatic.


Edited by sidefx - Oct/23/2017 at 6:54am
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gremlinsteve View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote gremlinsteve Quote  Post ReplyReply Direct Link To This Post Posted: Oct/22/2017 at 3:06pm
Is this car in good condition
You are better off not hacking on a car that is

If it's been sitting for some time today's fuel turns to varnish type crap
It's probably going to need a new filter
A gas tank cleaning. A carb rebuild and you might even have sticking valves from it

Post pics so we car guide you in your quest
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Post Options Post Options   Thanks (0) Thanks(0)   Quote ramblinrev Quote  Post ReplyReply Direct Link To This Post Posted: Oct/22/2017 at 3:44pm
The 'knock' sounds like the very typical AMC V8 exhaust leak that sometimes quiets down after the system heats up. It's likely the 'donut' and or the 'heat riser' valve on one side of the exhaust.

Like was mentioned above, clean the tank and rebuild the carb if that hasn't been done. Show us more pics! (Though you have to have 30 posts to put pictures on here, you can put them on a photo hosting site like Flickr and put the link here).
 
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70 AMX 360 4-speed (since 1981)
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scott View Drop Down
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Post Options Post Options   Thanks (1) Thanks(1)   Quote scott Quote  Post ReplyReply Direct Link To This Post Posted: Oct/22/2017 at 4:48pm
I have Motorcraft 4300 carbs on two of my cars & love them. They are different from a Holley or Carter, so you need to know what you are doing with them when you rebuild them. I'd rebuild what you have long before I would spend the money on a different carb. If you decide to get rid of the 4300 I'll be happy to take it off your hands.

The 71 401 Javelin AMX is one of the more valuable AMC's. Don't start hacking it up with a bunch of aftermarket garbage or you'll lose value.
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sidefx View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sidefx Quote  Post ReplyReply Direct Link To This Post Posted: Oct/22/2017 at 7:07pm
I understand not hacking on the car but want something reliable. I think the Pertronix unit keeps that and maybe the 4300 can be tuned up.

Here’s some photos from cars and coffee. https://www.flickr.com/photos/28824163@N05/shares/4LUvEs - https://www.flickr.com/photos/28824163@N05/shares/4LUvEs

Edited by sidefx - Oct/22/2017 at 7:10pm
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Post Options Post Options   Thanks (0) Thanks(0)   Quote gremlinsteve Quote  Post ReplyReply Direct Link To This Post Posted: Oct/22/2017 at 7:08pm
Pertonix is fine in my opinion
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Post Options Post Options   Thanks (0) Thanks(0)   Quote amcenthusiast Quote  Post ReplyReply Direct Link To This Post Posted: Oct/22/2017 at 7:44pm
(gawking) don't try to drive it anymore; you need to find an AMC angel to help you repair all it's neglect abuse

It's not wise to damage the collector car's value.

IMO, the first thing you should do is contact the nearest AMC club and ask for someone there to help you with your situation.

Next you need to buy the books: a '71 AMC Technical Service Manuel, a Chilton's Repair Manual

I would not even sit on the seats until I knew their vinyl sides are treated to restore their flexibility. It has corduroy seat inserts? those are beautiful do you have them covered up with clean beach towels?

sheesh man don't you know coin collectors don't even touch their coins to reduce their value?

IMO you need to be looking up and reading every article you can find on 'how to revive a classic car out of storage'
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Post Options Post Options   Thanks (1) Thanks(1)   Quote Sonic Silver Quote  Post ReplyReply Direct Link To This Post Posted: Oct/22/2017 at 8:14pm
The 1/2 tank you have used in about 50 miles may be your fuel gauge or sending unit. Unless you filled it up to the top, drove 50 miles, refilled it to the top, and figured your gas mileage correctly, I wouldn't rely on a gauge reading.

   I meant to add that your car only holds 16 gallons of gas, so if the gauge is dead accurate, then that would be a little over 6 miles per gallon. I doubt you would get much over 10 around town, with some acceleration. You could easily use 1/3 of a tank in that situation.


Edited by Sonic Silver - Oct/22/2017 at 8:30pm
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sidefx View Drop Down
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Post Options Post Options   Thanks (0) Thanks(0)   Quote sidefx Quote  Post ReplyReply Direct Link To This Post Posted: Oct/22/2017 at 8:43pm
I only know 10 gallons from 1/4 tank. I should have said cold starts have to be made with starting fluid.
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Post Options Post Options   Thanks (0) Thanks(0)   Quote 73Gremlin401 Quote  Post ReplyReply Direct Link To This Post Posted: Oct/23/2017 at 12:28am
Slightly off topic - but get that car to an alignment shop.  The amount of negative camber in the front end will destroy those tires in no time.  It does look like the front end has been lowered, which is fine, but perhaps that was done and never got the camber change compensated for.
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