Engine knock

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Oct 17, 2011 | 08:09 PM

Mel07

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4th Gear

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Engine knock

Hi I have a 68 454- drove it a few times this summer and the last time out it started knocking about a mile from the house. It knocks LOUD when idleing and faster when pressing on the accelerator.
Any idea what this might be and a possible fix without a mechanic?

Thanks!

Oct 17, 2011 | 08:12 PM

l88rocket

Melting Slicks

Joined: Feb 2006

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From: Mo

upper end or lower end?

upper end is a bad lifter, dropped valve etc,
lower is a rod knock and needs the short block rebuilt

You can start it take a stethoscope and listen around the engine

Oct 17, 2011 | 08:19 PM

LB66383

Drifting

Joined: Dec 2002

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From: Long Beach CA

As he says, try to locate the noise with a stethoscope. You can also, with the engine idling, pull off the spark plug wires one at at time (carefully, there's a lot of voltage there!). If the noise goes away or diminishes, that'll tell you which cylinder it is -- usually indicates a bad rod bearing.

Oct 17, 2011 | 08:20 PM

Mel07

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What do you mean by lower end or upper end. Sorry, I dont know much about the engine

Oct 17, 2011 | 08:48 PM

DRIVESHAFT

Drifting

Joined: Aug 2005

Posts: 1,682

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From: League City TX

Quote:

Originally Posted by Mel07

What do you mean by lower end or upper end. Sorry, I dont know much about the engine

Where do you hear the knock coming from?
Is it in the bottom part of the engine, or the top part?

Oct 17, 2011 | 11:07 PM

l88rocket

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From: Mo

lower end is crank, rods, pistons,
upper end is heads, cam, lifters, all the valve train componets

Oct 18, 2011 | 08:48 AM

69 Chevy

Melting Slicks

Joined: Aug 2008

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From: Lehigh county Pennsylvania

Quote:

Originally Posted by Mel07

Sorry, I dont know much about the engine

Here's a fact: no 454's were produced before 1970.

Oct 18, 2011 | 09:07 AM

ZZ71S

Racer

Joined: Mar 2008

Posts: 315

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From: KY

Is there oil in it?

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Oct 18, 2011 | 09:56 AM

63split63

Burning Brakes

Joined: Mar 2005

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From: Ontario

Quote:

Originally Posted by Mel07

What do you mean by lower end or upper end. Sorry, I dont know much about the engine

After you check the oil level have an expierenced mechanic listen to your engine . The older he is the better.

LMO Bill

Oct 18, 2011 | 11:22 AM

#10

Easy Mike

Team Owner

Joined: Jun 2000

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From: Southbound

Cruise-In II Veteran

Quote:

Originally Posted by ZZ71S

Is there oil in it?

I'll go with a quart low.

Oct 18, 2011 | 11:25 AM

#11

vanice

Advanced

Joined: Oct 2011

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From: whiting NJ

Automatic? Check the torque convertor bolts

Oct 18, 2011 | 11:48 AM

#12

forman

Melting Slicks

Joined: Mar 2010

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From: Randolph nj

Do yourself a favor and have someone qualified look at your motor

Oct 18, 2011 | 12:10 PM

#13

Mel07

Thread Starter

4th Gear

Joined: Oct 2011

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Quote:

Originally Posted by 69 Chevy

Here's a fact: no 454's were produced before 1970.

Sorry.. yes 427

Oct 18, 2011 | 07:50 PM

#14

63split63

Burning Brakes

Joined: Mar 2005

Posts: 1,231

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From: Ontario

Quote:

Originally Posted by Easy Mike

I'll go with a quart low.

It would need to be more than 1 quart low to cause a knock .

Bill

Oct 19, 2011 | 11:59 AM

#15

Mel07

Thread Starter

4th Gear

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Thanks for all the input. Its not the oil, that is where it needs to be. I am having it towed on friday to a professional. Fingers crossed it doesn't cost a fortune!

Oct 19, 2011 | 06:57 PM

#16

Indiancreek

Drifting

Joined: Jun 2010

Posts: 1,781

Likes: 15

From: Oxford Ohio

Put a timing light on it. Move it from one plug wire to the next until the flash matches the knock and that will locate the cylinder. The the timing of the knock will tell you it it's in the valve train or the bottom end.

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