1fastblackevo8

Hey everyone maybe someone can give some clues on why a fresh engine could rattle. First of all it has been the since the first start up and has not got any louder or worse. Sounds like something bouncing around under the valve cover. There is no rod bearing knock or anything. What ia have done so far: Changed to stock cams, different rollers, 4 sets of lifters (aftermarket and oem). The block has been through 2 engine failures. The only thing reused this time was the rods, pistons, and the block (4G64) The second failure took out the Head, crank, cams, Oil pump was the cause cause the builder decided to reuse it. I will be posting a video up soon. It does not do it at idle. I can make the sound appear and disappear just by 10% throttle under load. I have never heard of anything like this. Its not the common rattle. And im not sure if it has anything to do with it but when i put the engine together and timing on and right when i went to turn it on a 1/4 of a turn i heard a loud ping.pop sound. It was not hard to turn or anything other wise i would have not kept on turning it. I turned it about 8 full turns after that and everything was fine. No clearance issues at all. Just thought i would throw every detail i could remember in there.

The original head was a buschur stage 3 head and the cam towers were ate up from bearing material as well as the BF272 cams that were in it. I got a new head but used the vlaves, valvle springs, and retainers in the new head with brand new Tomei 280's. The new head was redone and oversized seats were installed because of the bigger valves, if the seats were installed to deep would this cause the noise that I have?

http://www.youtube.com/watch?v=KcDeg...layer_embedded

Thanks

1fastblackevo8

Mods are:
BR 2.1 motor
Stage 3 non ported head
Tomei 280 cams
Garrett GT 3582R
Exedy Twin Disk
Stock intake
Stock throttle body
DC Sports 3 in exhuast
Turbo XS 3 in 3 out intercooler
Tial BOV
Tial 38mm wastegate
2.5 inch intercooler piping
battery relocated to trunk
OEM lifters and rollers

Drifting Away

iTrader: (6)

too me sounds like a screw or something is rattling.

1fastblackevo8

Yep thats what i was thinking but i have looked all in the head and looked all around and could not find anything. What throws me off is the very small percentage of throttle the sound changes or even stops. i can make the sound appear and disappear with just 10% of light throttle. so juat say at 3100 rpm the sound will stop at 3090 rpm or 3120rpmbut if i hold it at 3100 it will rattle all day. It is the weirdest thing i have ever heard. It dont hurt performance or anything. I have logged the knock voltage between 2800-3150 rpm and i get as much as 2.4 volts. At idle its only between .1-.4 volts.

sujinX

iTrader: (22)

do u have a cat or a resonator? things rattle at certain rpm's, my broken cat rattles sometimes and sometimes it doesnt. i think the easiest thing to do IF you have a cat or resonator is to take out the exhaust and see if the noise persists.

if u can distinctly hear it from the valve cover, you should pull the valve cover off and see before it does some damage. i kind of dont think its in the valve cover. it sounds more exhaust side related. imo

1fastblackevo8

Nope no cat. Its a full 3in exhaust. I will be taking the valve cover off this evening and im going to look inside with it running to see if i see anything out of the ordinary. I will check all the exhaust all the way back. It only happens within 10% throttle at 3000rpm and its suck a small percent of movement that the oil pressure dont change and it only goes up or down about 50rpm. So thats very little of movement and its like a light switch i can make it come and go with very very little throttle. above 4500rpm though i believe its constant but cant really hear it cause of the exhaust and wastgate.

bxracer1

iTrader: (2)

did you ever figure this out? I've got the same deal going on plus another drivetrain rattle on top of it

Craig King

iTrader: (11)

Mystery rattles... the joy of owning an Evo.