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Discussion Starter #1
I picked up this 83 with a 351W at an auction. I had a hell of a steal for about two months until I start hearing this knocking. I take it to the local ford dealer and they say that it was FOUR QUARTS LOW!!!! They filled it up and it still is knocking. There was no huge puddle on the driveway or any sign at all of this problem. Even the mechanic said he did not see why it was that low. This truck had every service record back to the purchase date in the glove box when I bought it. All the records showed a new 351 in 2002. The knock is quiet in park but when you pull her into drive and accelerate it gets louder and faster as you go. Any ideas on what is wrong or some alternatives for me? Is it top end or bottom end? Thanks:banghead :banghead :stupid
 

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Discussion Starter #3
Hey crazed thanks for the info. So It will get worse if I keep driving her.? I will take her home and park her then. Do you think that the heads are still O.K.? It was just rebuilt, so I want to keep as many parts as I can off this motor. I saw your recent rebuild, how do you like the 351? It looked awesome. Well I am sure I will have more questions later.
 

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CheeseBurger Milkshake!!
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Sounds like a rod knock. Park it before you have unwanted crankcase ventilation.

While the engine is apart, it would be a good idea to inspect the cam lobes and cam bearings. Also, replace the oil pump and timing chain/gears........cheap insurance.

Hopefully the crankshaft isn't FUBAR.

Good Luck!
 

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If it a higher pitched knock that rapidly accelerates as rpm increase (think snare drum), its a rod knock. If it is lower and stays more consistent it is either a main bearing or a main thrust bearing. Either way bottom end needs new bearings, should be driven, at least very long or very fast.
 

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Stuck like a MoFo
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i bought an 88 that had a 4.9 and aa slight knock at idle but it had 250,000 abused miles.....i put 20w50 in it for about 20,000 miles when i had time to put new bearings in it. If i were you and were going to buy new bearings to put in the motor first take off a couple of mains and rods and plasti gauge it so you know what size to buy....i bought standard the first time and it still lost pressure after it got warm and knocked. I plasti gauged it and found i needed to put .02 oversize in them....could have saved me a 100 bucks if i would have did that the first time..:twak ..mains are a pain in the arse to replace while the motor is in the truck.....have fun :smash
 

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Stuck like a MoFo
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3,450 Posts
almost forgot

:duh you also need to get the clearance specs .....not sure of them off the top of my head that way you can use the information you gain from the plati gauge....there is an online chiltons manual if you don't have one that has all the information..
 

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That SmackMyB$tchUp Guy
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Don't drive it until you pull it apart.

I had a terrible knock develop in my GMC ('91, 350) and when I got into it I found that the flywheel was cracked!! Not saying that is your problem but..just saying you never know.
 
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