wierd engine knock 302 ho ford

Old 09-21-2009, 10:53 PM
  #1  
altune
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Default wierd engine knock 302 ho ford

I have a wierd engine knock towaed the back of the block.
I had removed the pan and replaced the rod bearings ( they had wear but not too bad ) and restarted the engine. Knock was still there, no difference.
I started the car on the rack and listened from the bottom, sound was not any louder from the bottom, it soundes like it is coming from the top of the engine.

I killed it and a friend suggested I make sure the torque converter bolts were all ok, they were but when turning over the engine to check them, I felt a small gap in the crank between forward and reverse ( I know you are not supposed to turn them back wards ). The gap is maybe a 1/4 on an inch when I pull on it.

I am wondering if this could be the timing chain or possibly a burnt piston pin bearing , need some expert help on this one.
Please help.
Al
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Old 09-21-2009, 11:01 PM
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DirkaDirka
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How many miles is on this engine? As you speed up the rpm's does it make the noise louder and faster??
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Old 09-21-2009, 11:27 PM
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cepx111
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Default Re: wierd engine knock 302 ho ford

Originally Posted by altune
I have a wierd engine knock towaed the back of the block.
I had removed the pan and replaced the rod bearings ( they had wear but not too bad ) and restarted the engine. Knock was still there, no difference.
I started the car on the rack and listened from the bottom, sound was not any louder from the bottom, it soundes like it is coming from the top of the engine.

I killed it and a friend suggested I make sure the torque converter bolts were all ok, they were but when turning over the engine to check them, I felt a small gap in the crank between forward and reverse ( I know you are not supposed to turn them back wards ). The gap is maybe a 1/4 on an inch when I pull on it.

I am wondering if this could be the timing chain or possibly a burnt piston pin bearing , need some expert help on this one.
Please help.
Al
It could be that your feeling the slack in the timing chain.

Have you checked the flywheel itself? Make sure it's not cracked before proceeding.
If it is cracked, it will sound just like an internal engine problem.

Goodluck, Cp
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Old 09-21-2009, 11:28 PM
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altune
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Engine was a transplant so I am not sure of the milage. But the con rod bearings were worn to the copper a bit on some so it must be pretty high.
the sound increases with rpm and gets less noticable at higher rpm but it is still there. ( maybe you just cant hear it due to ehxaust )
what is maximum piston to bore clearance?
I may pull the heads and see if there has been contack with piston.
any help appreciated.
Al
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Old 09-22-2009, 06:24 AM
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fbodyjunkie
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I had a buddy 1 time with the same problem in a 79 malibu. Turned out his bellhousing bolts wasn't tight and the bellhousing was smacking the motor. Sounded like a piston hitting. Tightened them up and drove the crap out of it. Something you might check.
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Old 09-22-2009, 09:45 PM
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altune
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I spun the flywheel, plate and could not see any crack, not sure about the bell housing though , I will give it a try and see. The problem was happening before but very slight tapping noise, though it was just the valve adjustment.
hmm
If I dont find anything by tomorrow, I will need to pull the heads and check the bores.
Al
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Old 09-22-2009, 10:06 PM
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OneBadGMC
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You checked the converter bolts, but did you check the flexplate bolts in the crank?

At idle and light load with a lopey cam, it'll sound like a rod knocking.
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Old 09-23-2009, 06:41 PM
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altune
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I'll have to pull the transmission to check that. The cam is not lopey at all , just a street camshaft on this one.
I will see what the customer wants to do. maybe a second opinion is needed. ( someone to listen to it )
Al
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Old 09-23-2009, 07:20 PM
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OneBadGMC
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You shouldn't need to pull it... Especially if there's a motor plate back there.

You should be able to shine a flashlight up between the converter and flexplate and see any REALLY loose bolts. Assuming the threads were clean when it was assembled, you may be able to use a long straight screwdriver and turn a loose bolt as well. You could also try and wiggle the flexplate fore and aft. If a bunch are loose, you'll feel it 'tick' back and forth on the bolts.
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Old 09-25-2009, 03:51 PM
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altune
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I'll give it a shot and see what is going on. What are the chances of a really worn upper rod bearing?
When I had the rod bearings out, I pulled and pushed on the free rods but I could not feel any play.
The pistons though at bottm dead, when I pushed on them they moved back and forth ( like rocking ) in the bore. Not sure how much is too much.
If anything, I think I will have to pull the engine and take it apart.
Al
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