Knocking during start up...

[Dirky]

Hey guys, how goes?

Got the 77 out now, runs good, looks good too...

For some reason, when I go to start the motor cold, It knocks for about one second after it fires, but why? The motor is strong and runs good, I have no problems with it. Almost sounds like a rod knocking, but just for a second. When the engine is warm it won't knock when I start it. Motor probably has around 50,000 KM on it since the rebuild.

What's the deal?

Thanks

 

[LEB Ben]

Man...that's not many miles on the rebuild, so it's kinda got me stumped...you sure it's like a rod knock and not a sticky lifter? Maybe throw some Lucas in there and see if that helps with the dry starts.

 

[Dirky]

Man...that's not many miles on the rebuild, so it's kinda got me stumped...you sure it's like a rod knock and not a sticky lifter? Maybe throw some Lucas in there and see if that helps with the dry starts.

I'm quite sure it's not a sticky lifter. It would sound more like a click, and what I'm hearing is a knock. Knock, knock, knock, then it stops. I can't say its a rod knock, because I don't really know... But the sound is similar.

Hmmm, I think I will give the Lucas stuff a shot... Doing an oil change on her this sat. too, so might as well do it then.

 

[LEB Ben]

I'm just shocked you'd have a rod knock after so few miles on the rebuild...so I'm just trying to think of what else it could be. Busted flex plate maybe...those usually sound the same, and wouldn't be outside the realm of possibility.

 

[73F100Shortbed]

If flex plate was busted would the noise go away when warming up? Try the lucas first like Ben suggested. I would only suggest half of the bottle though honestly. It is really thick. I used alot trying to get my old motor to smoke less. The stuff was stuck to the tops of my valve covers.

 

[LEB Ben]

Shoot...forgot about the part that the knock went away.

 

[surewhynot]

What weight oil are you using? I wonder if it is too thick to instantly flow when cold.

 

[hollenjoe]

hmmm knocking on start up could be pinging... but it usually happens after the engine is hot, when the engine is too advanced the spark could ignite a single or few cylinders earlier than the rest... try retarding it a bit..

 

[Dirky]

Thanks for your help guys... I think the timing may be advanced a little much, I am going to try and dial it in tomorrow.

 

[LEB Ben]

Good luck...I hope for your sake it's just that easy.

 

[89frankenford]

simple thing, are you using a motorcraft oil filter? i have the same problem with my truck (4.9L) if i use any other filter other then the motorcraft one. i still dont know why but it works, no knocking once so ever, its a cheap enough to replace and see what happens