hi all,
it's my first post here. i have come up with a problem that baffles me. hopefully it is common enough that someone knows what's wrong..
I'm working on a 1989 honnda prelude with a 2.0 L engine. it has 120k miles and runs fine everyday.
one day, the valves all began to clatter when the engine returned to idle after driving.
the oil pressure light works. it turns off when the car is started.
there is fresh oil in the engine.
As the idle is raised to 3000 rpm, the valve clatter dissappears completely.
the engine runs evenly on all 4 cylinders, even while clattering and behaves normally except for the noise.
It sounds like every lifter has collapsed...it is really loud (are lifters called lost motion devices on this car)
i inspected the cam and rocker arms and nothing was obviously wrong.

I'm guessing that perhaps the oil pressure is low due to some oil pressure regulating device having suddenly failed...but that it's not low enough to leave the oil pressure light turned on. Anybody have any advice?
thanks
ray

 

The very first thing I would do is a valve adjustment. There's a good chance that's what it needs.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rayatbhf &raquo;</TD></TR><TR><TD CLASS="quote">It sounds like every lifter has collapsed...it is really loud (are lifters called lost motion devices on this car)</TD></TR></TABLE>

Lost motion assemblies (LMAs) are only on VTEC Honda engines, all you have are rocker arms, valves and cams.

You might also try to hook up an oil pressure gauge and find out for sure if the pressure is low.

 

is it a misfire? or timing?

 

Hawkze:
It looks like the rocker arms are sitting on the equivalent of a lifter on one end and on the valve stem on the other end.
I was assuming there are hydraulic lifters that pump up and remove the valve lash when the engine is revved up. Is all that wrong?
Also, i'm willing to try readjusting the valves, but last night, when i had the valve cover off, i checked them (albeit without a feeler gage) and they seemed close enough, but either way, I am having a hard time figuring how all the valves would all be fine and then suddenly all need to be readjusted.
I was reading a manual for VTeC engines last night...in order to check the oil pressure, in those, it was necessary to remove the axle. Do you know if that's the case with teh 2.0 L, too? Do you know wehre there is a manual on line that i can view?

TKevin:
I'm thinking that the even steady idle on all 4 cylinders and otherwise good response of the engine means that it is neither misfiring nor out of time.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rayatbhf &raquo;</TD></TR><TR><TD CLASS="quote">Hawkze:
It looks like the rocker arms are sitting on the equivalent of a lifter on one end and on the valve stem on the other end.
I was assuming there are hydraulic lifters that pump up and remove the valve lash when the engine is revved up. Is all that wrong?
Also, i'm willing to try readjusting the valves, but last night, when i had the valve cover off, i checked them (albeit without a feeler gage) and they seemed close enough, but either way, I am having a hard time figuring how all the valves would all be fine and then suddenly all need to be readjusted.
I was reading a manual for VTeC engines last night...in order to check the oil pressure, in those, it was necessary to remove the axle. Do you know if that's the case with teh 2.0 L, too? Do you know wehre there is a manual on line that i can view?

</TD></TR></TABLE>

mmm... no hydraulic stuff, just a ball-stud that the rocker sits and rotates on. You have to do a valve adjustment with feeler gauges because no one can tell the difference between .005" and .007" with any of their senses.

I'd try to get a manual from http://www.helminc.com (if they have it) and go from there. It's hard to explain things like this in text because there's to much going on in there.

Also, http://www.preludepower.com is a big 3rd gen site.

 

There did appear to be a ball on which the rocker sits. I assumed they must be hydraulic lifters because it seems impossible that all valves could suddenly go so far out of adjustment. As I remember, the sticker on the hood said to adjust the intakes to .011 and the exhust to .018 or some such. I'll give it a shot.
I couldn't believe that such a clatter could develop on so many valves so suddenly. I wonder if the cam shaft has come loose...I'll check that, too.
thanks for the prompt responses
ray