strange knock when cold

[rslayerr]

heya to all..
got a cutlass 91 with 3.4dohc,210 000km on it...
question is...when the car is cold,their is a "knock"coming from the crank-piston area(front-right near oil cap section,if you understand)..but the knock goes once the car is at normal tempertaure..(still there,but almost inaudible)...what can it be causing that.??its not the heads...thats for sure...is it possible a bad timing doing this.??.any kinda help would be greatly appreciated...beside...depending on the cause,,what can i do for it??
tks all..
ps--i know the car is not new at all(210000),but it running very good(not the fastest,but i have try worst)
this is the best w-body site!!!
now 2 years that i read all you guys info..very informative...

[TheProfessor]

piston slap
when its cold the piston rocks back and forth slightly at the top of the bore
then as your engine warms the piston expands taking up the clearence
if you dont beat on you motor and its not really bad then you should be cool for a while

[Lyle's GTP]

It could also be a collapsed piston skirt. That is a classic problem. But I don't know if it is a problem with our style of piston.

Lyle

[rslayerr]

hmm

colapsed piston skirt??hmm...
piston snap is my first guest,so i guess the only remedy for this is to rebuild engine in new?
what the worst thing that can happend with piston snap???piston wll self destruct enventually.??broken head with it?should i be worried alot by it|?
is there anything i could do to help that??(special oil,treatment etc).?
look like it will be time to rebuild and boost that engine now!!!
HO YEAH!

QUICK QUESTION...anyone know a place in montreal(yeah i know)that do good job at rebuilding that engine??should i do it in gm dealer.?(if fesable)...any hint greatly appreciated...
tks for the response guys!

[TheProfessor]

like i said you can probably drive the car for a while yet if its still running alright
but dont rag on it just baby it and use for transportation
yes the only thing you can do to get rid of it is rebuild but if your intent on not doing that yet some 10W40 would be the best thing to kinda cushin it till you do
and personally a dealer would rape you on a rebuild and wouldnt do anything other than stock most likely

[rslayerr]

hmm

well tks for the advice...1 question is bugging me,,you said that i should put 10w40 in it to help....but the point im a bit incomfortable with is where i am,whe have very very cold winter(-40)..and using oil that grade(10w40),wont it be worst for it??im mean its thicker,so would it be tougher to warm it,less flow-worst damage?
since our motor are rate for 5w30..?wont it damage oil pump?or clog more easily oil passage?
sry..i know its not specific to 60*engine,but more general..
tks again

beside..one note for all...what yu guys think about the high mileage oil that they have start to sell.??good.?not?

[TheProfessor]

well if you are in a very cold place with temps like that then dont use 10W40
wouldnt be a good idea
valvaline maxlife is very good i put it in all my high milage cars (100000+ miles)

[wiserocz]

Is it possible that your knock could be a exhaust leak? I thought I had a little knock but when I get under the hood it disappears and can only be heard in the car. So now I'm looking at heat shields and exhaust. I think your best bet is to get a stethescope and see if you can pinpoint where it's coming from.