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Intake valve stuck - increase performance? |
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Archangeldvm
AMC Apprentice Joined: May/13/2021 Location: Ventura Status: Offline Points: 51 |
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Posted: Aug/03/2021 at 7:17pm |
It seems that one of my intake valves is stuck on my 71 Javelin AMX 360 and I am most likely going to need to do some head work per my mechanic. Disclaimer - I have very limited knowledge in fixing engines. I have no idea what has been done on the inside of the engine in the past other than it supposedly has a mild cam. I recently changed the carb to a Quick Fuel 650 and changed to a Edelbrock Performer intake. If the mechanic is going to have to open up the heads I thought this is the perfect time to increase the performance of the motor however I have no idea what I should do or what parts to use. I really need your expert advice. I am not looking for a 400-500 HP car but want more performance than have now. Appreciate any guidance you all may have.
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troutwilly
AMC Addicted Joined: Sep/14/2007 Location: Carriere, MS Status: Offline Points: 991 |
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Riddle us a few more details of what happened: - Is it stuck open or closed? - Was it running before you added all those items? - Are they the original heads? - Any other info would be helpful. The only time I had any stuck valves was when I put 390 heads on my 304. A little dog-ear grinding at the top edge of the cylinders cured that.
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Bill O.
70 AMX |
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Archangeldvm
AMC Apprentice Joined: May/13/2021 Location: Ventura Status: Offline Points: 51 |
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Open I believe.
It was running but super lean per mechanic. So lean for unknown length of time that burnt out the header gaskets he thought. Along with the carb and intake manifold he did new plugs, new wires timing etc ran way better afterwards. Went to exhaust shop after for new headers and found other holes in exhaust so new pipes and flowmaster as well. Drive home from exhaust shop ran and sounded great. Next day very rough, shudder and stuttering when accelerating. Few backfires. Don't know if heads original. The valve covers are definitely not. The stamp inside is 3220502-1 which when I looked up is for a 401. Hope that gives you a little more info.
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mbwicz
Supporter of TheAMCForum Joined: Feb/20/2019 Location: Buffalo, NY Status: Offline Points: 1981 |
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I would estimate your budget and time requirements (when do you want to have the car back running). Is this just a fun street car or will you be doing any racing? There are some people that have very good reputations for rebuilding engines on here, or you may just want to send out your heads for rebuilding and port work.
Any idea if the rest of the engine was rebuilt, or just cam/intake?
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1970 AMX, one step forward, one step back. Both steps cost time and money.
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troutwilly
AMC Addicted Joined: Sep/14/2007 Location: Carriere, MS Status: Offline Points: 991 |
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Not knowing your level of mechanical ability, here's what I would do: - pull the spark plugs so the engine turns over easier. - pull the valve covers so you can see the rockers and valves working as someone turns the engine over, either by wrench on front main pulley bolt or by key/starter. - determine exactly which valve is not operating correctly and see if you can see why. Could be a: - collapsed lifter, - bent push rod, - loose rocker (rocker could be worn out or damaged) - broken rocker stud, - broken valve spring, - something stuck between valve and valve seat (someone dropped a screw or a nut down the intake) And don't forget to let us know what you find.
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Bill O.
70 AMX |
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Trader
AMC Addicted Joined: May/15/2018 Location: Ontario Status: Offline Points: 6755 |
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The heads are coming off anyhow and will likely need work if it's more then a simple rocker or stud. You want more performance, have the camshaft and lifters inspected and bolt on some Edelbrock heads, having your shop ensure the valvetrain geometry (lots of posts here to educate yourself on that).
The time and money spent on rebuilding 502's if not DIY is going to cost close to the Edelbrock's and not going provide any more performance. If they find the camshaft needs replacement, then your likely into a complete rebuild.
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Archangeldvm
AMC Apprentice Joined: May/13/2021 Location: Ventura Status: Offline Points: 51 |
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Thanks for reply. Budget is really not an issue to get car running like I want it but I am quickly loosing patience. Have had car 4.5 months and have had it driving somewhat normally less than a week. All the rest of time either sitting in shop getting repairs or waiting on parts.
Big issue I have no idea what was done with the car prior to my buying. Supposedly has mild cam and the carb intake I put on but no idea beyond that.
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Archangeldvm
AMC Apprentice Joined: May/13/2021 Location: Ventura Status: Offline Points: 51 |
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Mechanical skill???? I can perform major surgery but have no idea beyond routine maintanance on outside of engine. I know it is the intake valve on the first cylinder on passenger side that is current problem. I could pull plugs and remove valve cover and watch how rockers and valves working (or not). Beyond that would be lost. Should have taken more autoshop along with pre med classes
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Archangeldvm
AMC Apprentice Joined: May/13/2021 Location: Ventura Status: Offline Points: 51 |
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Thanks for reply. What exactly is considered a complete rebuild for the 360? I need to find a good mechanic near me. Most I have heard of get really bad reviews.
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motorhead_1
AMC Addicted Joined: Apr/16/2014 Location: AZ Status: Offline Points: 1000 |
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if you are in Cali, there are some good amc engine guys and some members to recommend them
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69 SC/Rambler tribute 401/th400, 68 Rebel SST LSA, 66 F100 460/c6, 88 Merkur Xr4Ti, 71 Jaguar XJ6 LS1, 08 Supercharged Tundra
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