b20vtech

motor knocks when i start (cold) then stops when it warms up..any advice?

HYBRID_H@TCH

piston slap..

not much you can do but over bore it (new pistons) and set the piston to cyl wall clearance correctly..

clemsonteg

mine does the same thing, I was told it wasnt a problem, thats what you get for having low silicone pistons, I was told just to not drive it until it warms up, other then that it should be ok, but someone else would be able to tell you better

Tooned

Dude above is right. It's piston slap mine does it until it until it's warmed up temp. My clearances are a little loose. That's how it was built. It's normal.

b20vtech

so that knocking noise shouldn't be a problem?

wantboost

iTrader: (2)

nope

AlphaQup

Mine does the same thing. But I was thinking it was my LMA's.

People who've replaced their lma's before, does the knocking continue even after the car is warmed up, or does it go away as well?

SiKid86

once the pistons expand (car warms up) it should go away

HYBRID_H@TCH

mine has a very slight slap when dead cold but I set mine a little looser due to the rpm and power mine see's..wont hurt anything as long as you warm it up..

clemsonteg

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by AlphaQup &raquo;</TD></TR><TR><TD CLASS="quote">Mine does the same thing. But I was thinking it was my LMA's.

People who've replaced their lma's before, does the knocking continue even after the car is warmed up, or does it go away as well?
</TD></TR></TABLE>

LMAs?

AlphaQup

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

LMAs?</TD></TR></TABLE>

I guess you've never heard of lost motion assembly?

clemsonteg

no I havent, I have never actually built a motor, so I know the basics, rods, bearings, mains etc. but I have never heard of lma's, where are they located and what are their purpose?

AlphaQup

check the archives dude. There's plenty of info on lma's.

BiG Chris

ive got the same thing in my chevy tahoe, when its cold it has a good slap to it but once warm it goes away, due to the work that the motor has to do it helps when your under load or boost

b18a1ef9

i have a wrx and it has piston slap from the factory, i guess wrx's all have some piston slap when the car is cold. as long as it doesnt slap when its warm i wouldnt worry about it.

turbotime

piston slapparoo

my built engine does this too- its just cause the pistons arent warm and havenbt expanded

Tooned

LMA's are in the head under the middle rocker arm.
Their purpose is to keep the middle rocker arm from flopping around widely when the motor is not in vtec and keeps a little pressure on it