I have another thread in the EG forum, but no one has responded, or knows the answer, so i'm going to ask you guys.

I've had a knocking noise coming from my engine only when starting my car after sitting overnight, or over 4 hours.

I adjusted my valves a few days ago (finally) and the noise went away for the most part.

Now i hear it from the exhaust manifold only, not near the valve cover. ONLY when the car is cold, and when it's in gear and i'm moving. If it sits and warms up, i never hear the noise. It still knocks faster the faster the rpm's, but goes away once the car is at operating temperature.
Would oil viscosity cause this problem? I'm running 10w30. Too heavy?

 

This is normal for Honda during cold start. It's due to piston to wall clearance call piston slap.

 

Piston slap in a stock motor?? Are u saying that the clearances are lose?? Stock motors don't get piston slap, and the clearances are very tight. If he had aftermarket forged pistons than yes but with stock pistons there shouldn't be any piston slap. Does it go away when u depress the clutch pedal?? If it does than it's something in the tranny, probably the throw out bearing. If not in the tranny than id look in to the valvetrain and oil pressure.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by leadfoot78 &raquo;</TD></TR><TR><TD CLASS="quote">Piston slap in a stock motor?? Are u saying that the clearances are lose?? Stock motors don't get piston slap, and the clearances are very tight. If he had aftermarket forged pistons than yes but with stock pistons there shouldn't be any piston slap. Does it go away when u depress the clutch pedal?? If it does than it's something in the tranny, probably the throw out bearing. If not in the tranny than id look in to the valvetrain and oil pressure. </TD></TR></TABLE>

yeah, it's got an automatic transmission

i'm thinking oil pressure too. thanks for the input both of you

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by leadfoot78 &raquo;</TD></TR><TR><TD CLASS="quote"> Stock motors don't get piston slap, </TD></TR></TABLE>
Yes, they do. It's very common with Civics. (d-series)

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Chiovnidca &raquo;</TD></TR><TR><TD CLASS="quote">
Yes, they do. It's very common with Civics. (d-series)</TD></TR></TABLE>

it's quite loud though.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AmginE &raquo;</TD></TR><TR><TD CLASS="quote">

it's quite loud though. </TD></TR></TABLE>
Some of them are.

 

I have driven two D-series and two B-series engines for over a year, never heard piston slap from any of them. I do live in Arizona so it dosn't get too cold here though.

 

I have that too. A long time ago i had a clicking sound that was fixed by injector cleaner. I might try it again to see if it goes away. Valve lash however is normal for hondas durring cold starts. I'll use my mechanics stethascope to determine where the problem is and try to remember to update this thread.

 

What year is the engine from and how many miles are on it?.. And yes, stock engines eventually end up with piston slap. I know that over at Honda, a couple customers have complained about a noise at start ups and our techs have found it to be just piston slap..

Piston slap will usually happen more if you drive your vehicle in the winter or cold weather.. When it's cold outside, say like 0 degrees Farenheit, 5w30 oil has the texture of penut butter. Thus with the oil being gooey, it can't lube the cylinder walls enough during really cold start ups.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by PnX-R &raquo;</TD></TR><TR><TD CLASS="quote">What year is the engine from and how many miles are on it?.. And yes, stock engines eventually end up with piston slap. I know that over at Honda, a couple customers have complained about a noise at start ups and our techs have found it to be just piston slap..

Piston slap will usually happen more if you drive your vehicle in the winter or cold weather.. When it's cold outside, say like 0 degrees Farenheit, 5w30 oil has the texture of penut butter. Thus with the oil being gooey, it can't lube the cylinder walls enough during really cold start ups. </TD></TR></TABLE>

112k on the odometer...


i live in houston, regardless of ambient temperature, it knocks whe i start it up.

i don't mean cold start up starting in cold weather, i mean when the engine is cold and hasn't been driven in a few hours (greater than 4 hours) it will knock.

 

I'd say as long as it goes away when the engine warms up not to worry about it. Assuming its not too violent or loud of a knock.