88' honda crx si with ZC engine. out of know where my engine starts to make this knocking noise... it only does it under load and higher rpm's. i have pretty much ruled out rod knock because it does not do it at all times, sounds to me like the valve is hitting the piston. the car runs perfectly fine, no hesitation and pulls hard (for a 1.6L Sohc). watch this video and tell me what you guys think.

Click Here for Video

 

your vid is too short to tell

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by rbjeepthing &raquo;</TD></TR><TR><TD CLASS="quote">your vid is too short to tell</TD></TR></TABLE>
its 25 seconds long.... maybe it didnt load fully, it only played for like 0.5 seconds the first time i tried to watch it. but it worked after that.

 

you got a cam in that thing? mine sounds the same way, like a diesel or something lol but it doesnt have that kocking noise

 

its just the stock cam that came with the zc engine. the noise you are hearing is the injectors ticking, thats normal. glad to hear you dont have the knocking though

 

holy hell.. what the hell is that noise.. doesnt sound good at all.

 

Take it easy man. No need to worry. If it 'pulls hard' it's something small, but that's hella loud you need to figure it out.

I'd try:

Valve adjustement
Compression test (will tell you of a piston ring failure, piston slap and bent valves, or help you in figuring it out)
Timing belt check for tightness
Waterpump bearing
Tensioner
Re-Torque the top end, something might be loose

If all those where done right and nothing needs changing, I'd pull the head. Check the valves and what not. After that, I'd yank the engine and disassemble it.

 

oh yea i forgot to mention that the timing belt and water pump has under 10k miles on it, and the belt is tight. and you can tell its coming somewhere from the head/block not any accesories. i just checked it the other day when it was making the knocking noise. i adjusted the valves to specs when i changed the timing belt, and i also rechecked them when i started hearing the noise, all are within spec. i backed the valves off a bit to see how it ran and same thing, knocking noise, adjusted them tighter than spec and same thing, knocking noise. so i adjusted them back to spec. i did a compression check, book calls for 128psi per cylinder with no more than 28psi variation. read out to be 210-210-215-215. im asuming it is higher than the book calls for because the zc engine has more compression than stock... correct me if im wrong on that. i should probably do a "leak down" test, that would be more accurate, but i dont have the equipment at the time.



Modified by QuickStyle at 7:06 PM 9/12/2006

 

in the earlier part of the video it sounds like rod bearing noise...

check oil level...

 

i also forgot to add that i changed the engine oil like a week ago after i started hearing the noise (didn't help the noise go away, and there were no metal shavings in the old oil), i put in chevron supreme 10w30, and a new filter. plus im like 99% sure its not a rod bearing, i had it up on a hoist and listened right by the oil pan, and you cant hear it as well as you can from up top. only have running time sitting in my yard, no miles since the oil change, and level is fine. i also change the spark plugs at the same time gapped at .045 i went with ac delco, i had ngk but i was changing those too often, so im trying something new.

i also misinformed about the compression test, i checked my records (yea i keep records of this kind of ****) and the test showed 210-210-215-215 in numberical order 1-4. now that i think of it, thats kinda of really high compared to specs.


Modified by QuickStyle at 7:29 PM 9/12/2006

 

change the oil...make sure there is no metal shavings in it...if there is...well...rebuild it or get another engine.
and yes it sounds like rod knock

 

that 100% sounds like my motor on the week I spun a rod bearing, mine also ran for almost a week like that before it gave out

 

Are those lines infront of the header AC lines?

Just wondering cuz today at the dealership we ahd a CRV come in with ALMOST the same noise, but it only happened in reverse.

turned out that it was an AC line hitting the ?pump? i believe. Its just an idea but check to make sure its not that.

we had the CRV up on a hoist for an hour or better, and it sounded internal (rod) or like a pulley hitting. it was harder to ehar underneath than above, Im just saying try it.

 

knocking under load = detonation. check timing

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1990si &raquo;</TD></TR><TR><TD CLASS="quote">knocking under load = detonation. check timing</TD></TR></TABLE>

True. there are a few things that lead away from thinking that...
even when i hold the throttle steady, say around 2k-3k the knocking is there, plus it sounds like its only coming from one of the cylinders more than likely the 1 and 2 cylinders, is it possible for only one cylinder to detonate? you can kind of see the timing light sitting on the car at the end of the video, i did check timing 14*. i tried putting it at 8* and 20* no difference between the two, the knock is still there, timing set back to 14*.

 

I'm putting my guess in as main bearing failure. sometimes spun main bearings won't knock unless under load. But I think piston slap from ovalized cyllinder walls is another good guess. Something like that usually doesn't happen over night though.

 

you are most likely a couple teeth off on your timing belt. My car had the same symptoms, fixed the belt and ran like a bat out of hell

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 1990si &raquo;</TD></TR><TR><TD CLASS="quote">you are most likely a couple teeth off on your timing belt. My car had the same symptoms, fixed the belt and ran like a bat out of hell </TD></TR></TABLE>
that couldnt be possible, this is a problem that started out quiet and got louder. if the teeth were off on the timing belt it would have had this problem when i first installed it, i got about 8,000 miles since i put the new belt on then all of a sudden in a matter of 40 miles this problem developes. only way i seeing this as the belt being off a couple of teeth would be if the belt slipped then tightened itself back up, dont think that could happen and if it did, it probably wouldnt be a pretty sight, and it probably wouldnt run/perform as well as it does(besides the knock). i was hoping to not have to pull the head off to check this, but it looks like i will have to, if the head checks out ok, then it would have to be something in the bottom end right?

 

Sounds awfully like rod knock. Mine sounded the same when the crank bearings were going out.

 

Blown Big end bearing,

Change them as fast as u can, else u ahve to get a new crank, '

 

does it make the sound when the clutch is depressed my throwout bearing is going out, it sounds just like that when the clutch is let out

 

its a bearing man.. metal shavings might not appear.. pull the rod caps and check it out.

 

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by SETI20 &raquo;</TD></TR><TR><TD CLASS="quote">Sounds awfully like rod knock. Mine sounded the same when the crank bearings were going out.</TD></TR></TABLE>

Mine too, Ive heard a shitload of knocks in Hondas and they all sound like that. Dont let anyone tell you different. Last time i heard one like that The motor lasted the guy a week, He was cruising on the interstate and suddenly lost pressure, needless to say the number 2 rod poped out of the front of the car a few miles later. If it hasnt been doing it long i would try to roll new Bearings in it, there not very expensive. kinda a pain to do but better than buying a new motor.

 

Have you tried a mechanics stehascope and listning to diffrent areas. That sounds just like my b16 when I spun a rod bearing. How is your oil pressure? Does the light come on at all? I would drop the oil pan and pull the rod caps off and take a look at everything. Its easy enough to do and sounds like the problem.

 

ROD Knock