95civic

hey i know this might be off topic but my motor knocks at idle until it warms up should i be concerned?stock d16z6 6psi 14bwheel

Donald125

i drove it NA for 6 months then just got it boosted 2 days ago

Donald125

BTW when it was NA i would drive it really hard once a while.
it also quiets down if i kept it at high revs for a while..
then does it again after i let it cool down.

i was SO DAM WORRIED at first , i am like why does a rebuild motor knocks, but then i looked over honda tech and it seems like whole bunch of ppl with srp forged pistons has the same problem. they are saying it`s the piston to wall clearence is what makes it knocks but it is need for the piston to expend under high heat created by FI setups.

oh.oh..and i break it in the HARD way..
i basicly followed the what the motorcycle guys' web site said. then "diver it like you stole it" no problem at all. at first it burns oil for like a thousand miles then stopped.

Cadracer

Hate to say it but it done.I will bet 50 buck that the cyl walls are egg shaped.I use to work with a perfectionist when it came to building motors an he enlightened me.He told me an then procceded to show me with a dial bore gauge.I just paid 350 bucks to have this sbc block bored/decked an trued.He showed me an with the dial bore gauge,decking was at an angle wasnt even close in my book.Anyways back on the subject you need the block now honed just under the actual manufacture piston clearances an then have it plateau honed to final clearances.I bet you do this an the knock will go away.Called piston skirt rattle very few machine shops can do a good job.....Just my 2 cents.....Ask abaz i introduced him to Roger an he built jeffs zc an then he sold it.He gets his tolerances within half the thickness of the human hair.LOL

WhiteTeg24

The knock is normal for most Honda blocks with forged pistons. When the car heats up, the size of the pistons actually increases the smallest amount to seal up the cylinder. When the motor is cold, it definatly has a knock. Mine does this with Arias pistons as well. I think pretty much every motor we have built has made that noise. Never made a differnce in reliability or performance. I've even heard alot of stock Honda Acoords with low mileage knock like that. No worries. You should be fine.

HMT-Admin

Every motor I have ever built has never knocked, I have always used RollerWave pistons in d/b/h series engines without problems. However I have heard other "built" engines with Arias and JE pistons that did have a little bit of rattle (skirt rattle) when cold, but usually just goes away when warm. I've been told that is "normal" with forged pistons even though every engine I've built never does it.

If your noise does not go away when its warm, you definatly have something else going on, Do what someone mentioned above get a large screw driver and probe it with you ear until you find the source of where the "knock" is coming from.

Jeff

Cadracer

Yup you havent had the carma of an engine knock on a fresh install.just starts to knock an puck oil after you added boost huh
Just turn up the radio an only worry if you can hear it over the radio.....

quadnie

man back when I was 16 I really didn't get heavy into engines like the way I am now. I had to rely upon my dad's volvo mechanic.

What happened was I ran up on a curb and something bad happened to the front left tire, like the bearing was coming apart or some ----.. anyways I was near losing a wheel on the highway.

So I'm talking to Al of Al's Volvo and he was saying "didn't you hear the fucked up noise it was making while driving" - (me) "yeah man, I heard it then I just turned up the stereo and kept going". Man he cussed me out, it was funny to watch this old guy just go off on me for being a dumb kid.

EDIT: Had to reword a couple of things to make the story sound more complete

Cadracer

Thats awesome i got a good laugh at that one...

quadnie

Glad to share it man, back in the day (10 years ago) I was all into having a big stereo system and a slow car. I typically could not hear a pager or cell phone going off while driving. Even if I had whatever on vibrate mode I couldn't feel it from all the bass vibrations. My solution to any problem that I had no clue how to fix was to just crank the volume.. Al of Al's volvo is a ------- dick and deserves to get his shop fucked up, he fucked my dad over pretty hard and we stopped going there.. now I'm my dad's exclusive volvo mechanic so it's all good.