hello.

i have a 94 civic with b18c1. lately the motor has this metal noise at cold starts. you hear it about 1 minute after initial start up and it goes away after you drive about 5 miles. you can hear it is from somewhere inside the motor. i checked for any loose objects outside the motor for any possible rattling but there are none.

the sound comes from somewhere on the intake side. the noise isn't too loud but it can be heard. the thing that stumps me is that the noise is not consistent.

any thoughts?

thanks
dustin

 

what kind of metal noise?

 

after 30 seconds of firing up, you hear this rattling/flapping/tapping noise. not sure if it's metal/metal or metal/hard plastic contact; but i'm sure it's from somewhere near the alternator/timing belt area.

when that goes away when the engine is warmed up, you hear this metal beating sound come and go inside the engine. it sounds like "clack.. clack..". very inconsistent. i took the car to carboy in houston. this is what the chief mechanic say:

"we can't fix this. it's not consistent enough for me to tell what it is. must be outside the engine.."

the noise goes away after the engine is totally warmed up to normal operating temp.

help!

dustin

 

any mods? how many miles? when was the last time you did a valve adjustment?

 

a ghetto intake. USDM R pistons. and an exhaust. that's it.

the motor's bottom end is fully rebuilt. the head is off a motor with lesser miles.

the noise comes from the top half of the engine.. so i assume the bottom end is okay.

as far as valve adjustment goes, wouldn't the noise be more consistent? it's the inconsistency that's giving me a headache as to where to look for the problem.

dustin

 

what it sounds like how your describing is maybe a valve clearence problem because the lifter will make some noise when cold and as it warms up the clearences get tighter so it will go away. my brothers SOHC civic engine does this too......it's in need of a valve adjustment.

OR since you said the bottom end was rebuilt maybe the piston-to-wall clrearences are a little on the loose side so on a cold start you will get slight piston slap for the first miniute or two until the piston expands enough to quite down.....

try re-adjusting the valves anyway.......if it doesnt go away see if you can ask your machine shop what piston-to-wall clearence they used when measureing each cylinder/piston.