400 motor probs
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New User
Joined: Apr 2004
Posts: 3
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400 motor probs
Ive got a 79 ford truck with a 400 in it,I bought it a few weeks ago and noticed that the timing was WAY OFF the truck ran very good,so i set the timing and it ran good at ideal but when you rev it up it has a rattling sound,you cant hear it when its at ideal,only when you rev it up or going about 50mph down the road,I thought it was a timing chain so i pulled it apart and it was so loose i took the chain off without unbolting the gear,put all new timing chain on but still the same noise,there is a bearing on the front of the timing gear that runs the fuel pump,I thought it might be that making the noise so i pulled the fuel pump off and blocked it and installed a electric fuel pump, but still the same noise,could this be a piston wrist pin? Thanks for any help,This is driving me up the wall,dang fords lol
Freshman User
Joined: May 2003
Posts: 34
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From: Fernandina Beach, FL
In your your first post, you stated you bought it, it ran good but the timing was off, correct? Was it after you changed the timing that the noise started? What are you hearing, as in noise? My first thought was that by you changing the timing you created the noise... More input please, more than willing to try and help... 
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Lead Driver
Joined: Mar 2004
Posts: 8,922
Likes: 153
The "bearing" on the front of the cam gear is called the fuel pump ecentric. It wont make any noise. Whats your oil pressure ? Sounds like a rod bearing to me. Take your oil filter off and cut it open and see if there are any shavings in it. 
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I had a similar noise under load/no load at around 2000 RPM... You could only hear it while accelerating.... I could find the sweet spot in the RPM to make the noise more distinct... Try pulling one plug wire at a time until you find one where the noise goes away... If it does, it is probably the rod bearing... I just tore down my motor after making this determination and found a large groove in the number one rod bearing... Good thing I shut her down and took a look, I might not have been on the road for much longer...