70 challenger 318 weird noise camshaft area need advice

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Hay Ed

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Hello all I just purchase a 70 challenger with a 318. When I bought it the previous owner had just installed an Edelbrock 1406 carb. (Not sure if it’s tuned right) but when I give it some gas there’s a weird knock in the engine almost sounds like in the middle of the intake. Here’s a video of how it sounds on YouTube
 
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The video makes it hard to tell. I'd start by pulling the valve covers and looking at the rocker arm/push rod preload.
 
That sure doesn’t sound good. How’s the oil pressure?
 
If it has an automatic transmission check the flex plate to converter bolts.

If one or more come loose, the bolt heads can hit the webbing at the back of the block.

When that happens, it sounds similar to a rod knock.
 
If the harmonic balancer comes loose, it can also sound like a rod knock.
 
Alaskan_TA said:
If it has an automatic transmission check the flex plate to converter bolts.

If one or more come loose, the bolt heads can hit the webbing at the back of the block.

When that happens, it sounds similar to a rod knock.
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It has a manual in it the 3 speed
 
Sounds like a rod knock. You can pull the plug wires off the cap one at a time and see which cylinder it is.
 
Hey, what that guy said about the flexplate! Seen this happen many times and it can trick you into thinking rod knock. Anyways, sounds more like bottom end to me than up top. Check the flex plate first, its quick and easy. I use a mechanics stethescope to pinpoint stuff like this. Works like a champ.
 
MoparMike1974 said:
Hey, what that guy said about the flexplate! Seen this happen many times and it can trick you into thinking rod knock. Anyways, sounds more like bottom end to me than up top. Check the flex plate first, its quick and easy. I use a mechanics stethescope to pinpoint stuff like this. Works like a champ.
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3 speed has no flexplate..
 
Hay Ed said:
Hello all I just purchase a 70 challenger with a 318. When I bought it the previous owner had just installed an Edelbrock 1406 carb. (Not sure if it’s tuned right) but when I give it some gas there’s a weird knock in the engine almost sounds like in the middle of the intake. Here’s a video of how it sounds on YouTube
Click to expand...

By the way, welcome to the site!!! :)
 
Hay Ed said:
I have not checked the oil pressure. Where should it be at?
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If it does not have an oil pressure gauge you would have to add one. If it doesn’t I would drain the oil and look at it carefully and run a magnet through it to see if it picked up and pieces of metal. Toolman mikes suggestion to pull a plug wire off of the cap one at a time to narrow it down is a good one but be careful, it will shock the crap out of you.
 
I have heard of (but never experienced it myself) of a fuel pump pushrod or cam eccentric making a noise similar to a rod knock. If you do drain the oil and it looks ok maybe refill it with a heavier weight oil and see if the sound changes.
 
Oooh, 318 3-speed. Awesome, I have one also.

Check the easy stuff first, check to see if the harmonic balancer & bolt are tight.
 
Sounds like a rod knock to me, start with pulling plug wires one at a time and see if you can isolate it.
 
Sounds like a rod knock to me. Drain the oil and filter and check for anything metallic in it. Does it make more noise a few seconds after it starts then quiets down some? I would venture into it having bad rod bearings.
 
X2 that sounds deep like multiple rods knocking.
 
Driver side valve cover has a push rod that ain’t movin at all I’m assuming this is what is giving me my knock. The engine does not knock at all on idle. Only when it give it brief idle
 
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