Need Help Top End Knock

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Shawno

New Member

Jul 30, 2017

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Jul 30, 2017

#1

• Jul 30, 2017

• #1

hey guys My 1989 fox has developed a knock which seems to be coming from the top end. It only starts after it's been running for 10-15 min. I've checked the rockers and push rods every thing seems fine there. Just seems weird it only happens after it been running for awhile I figure if it's cam or crank it would happen as soon as it was started. Anyways any help or suggestions would be great

 

General karthief

wonder how much it would cost to ship you a pair

Mod Dude

Aug 25, 2016

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polk county florida

Jul 30, 2017

#2

• Jul 30, 2017

• #2

Welcome to stangnet.
I'll move this to the tech threads and that will expose it to some people that can offer some help.

 

Reactions: 1 user

S

Shawno

New Member

Jul 30, 2017

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Jul 30, 2017

#3

• Jul 30, 2017

• #3

karthief said:

Welcome to stangnet.
I'll move this to the tech threads and that will expose it to some people that can offer some help.

Click to expand...

Thanks

 

mikestang63

SN Certified Technician

Aug 27, 2012

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In the garage

Jul 30, 2017

#4

• Jul 30, 2017

• #4

top ends don't knock, they tap/tick
if you are hearing a knock then it is mist likely a rod or main bearing

Are you hearing a ticking or knock sound.

 

General karthief

wonder how much it would cost to ship you a pair

Mod Dude

Aug 25, 2016

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polk county florida

Jul 30, 2017

#5

• Jul 30, 2017

• #5

Try this, start the engine and let it idle, when the knock starts pull one plug wire at a time to see if the knock stops. Of course all that may tell you is you possibly have a rod bearing problem.
It could be that bad or as simple as a header gasket leaking, you could also take a long funnel and hold the big end to your ear and point the little end around header flange area and valve cover/lower intake area to isolate the tic/knock, sorry can't tell you anymore than that from a post.

 

S

Shawno

New Member

Jul 30, 2017

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Aug 2, 2017

#6

• Aug 2, 2017

• #6

Ok so it seems the knock is coming from cylinder #5. It happens when I rev it up, once I let off it had a knock. It's fine while the rpm climbs but soon as I let off I can hear it for a second or so

 

General karthief

wonder how much it would cost to ship you a pair

Mod Dude

Aug 25, 2016

25,507

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polk county florida

Aug 3, 2017

#7

• Aug 3, 2017

• #7

Pull the valve cover on that side and check for loose rockers, worn or bent push rods.