Very Loud Sound is it a Rod Bearing?

[X-Lr8]

88 LXi making a very loud sound very metal on metal kinda sound kinda like a rod bearing but it dosent allways happen when the car first starts it does it then goes away in like 2 seconds also when driving the car it does it at the top of each shift or when im going fast and suddenly let off the gas. i found that if i remove the plug wire from Cyl 4 the noise stops. also the noise isnt really a constant banging like one right after another its kinda wobbely sounding. so im not sure whats wrong. the car idles fine and aside from the horrific sound it seems to be working fine.

any ideas

Thanks

[86LXItooFAST4me]

i bet its kind of a rattle sound isnt it? its called "spark Knock"

basically check your timing and/or do a tune up (plugs, wires, cap & rotor)

[Oldblueaccord]

Can you pull that plug and look at it. Sounds kinda like a broken piston.

wp

[X-Lr8]

i pulled the plug and it looks fine just like a normally worn plug to me no mechanical damage.

[86LXItooFAST4me]

have you moved your distributer at all? as in have you tried to advance or retard the timing? and you might wanna check your timing belt.

ive never heard of a broken cyl in a 100 HP 4cyl, let alone one running that way....

[X-Lr8]

Hmm havent changed timing recently i had the belt replaced 6-8mnths ago. my distributor died about 3mnths ago and i got a used one. seems to be working fine other then the noise its so strange

[Oldblueaccord]

Another easy thing you can do is pull the valve cover and look for any damage up there. Might have a valve thats not adjusted right or is bad.

You say its at start up and the top of each shift meaning high RPM?

Start up might be a little bit of low oil pressure cold,worn bearings, or oil pump is weak. I changed my pump at 150k miles I had rattle at start up cold and it fixed it.


I little rattle especially over 5k shifts is normal on older cars.

I think if its a rod bearing they go bad quick. You cant keep driving it.


wp

[X-Lr8]

checked under the valve cover there isnt so much as a scratch. man this is driving me crazy i dont want to scrap this engine..

[86LXItooFAST4me]

you said in another post that you can "spin" your rotor on your dist. can you really take off your dist cap and turn your rotor all the way around??

[X-Lr8]

umm yeah if you take off the distributor mounting bolts and pull the distributor away from the engine.

[Oldblueaccord]

Any chances of like its an exhaust rattle or somthing. Maybe you put a big fart can on there and the clothes hanger is loose. :bowrofl:


I dunno what else to tell you I still think could be a broken piston or bad valve.

Worse you need to take the oil pan down and take a look. Check the bearing and look at the piston.

wp

[HondaBoy]

heh, my exhaust is like too big or something and rattles on the heat shield. no fart can though. it would be interesting to know exactly how that sound goes, like to hear it in person, its hard to tell you what could really be wrong.

[89T]

you spun a bearing....i had the same problem.

drain oil using a screen over your drain pan look for metal chunks..

[X-Lr8]

OK it looks like i will be taking the oil pan off and checking my rod bearings i will see if i can record the sound for you guys its really really bad sounding ;)

[SHURIK]

BEFORE U DO ANYTHING CHANGE UR OIL AND FILTER GO TO HONDA AND GET AN ACTUAL HONDA FILTER AND IF THE MOTOR HAS REALLY HIGH MILEGE GET THIKER OIL LIKE 10W40 15W20 MY OLD BS MOTOR LOVED 20W50 BUT IT HAD ALMOST 600,000 KM AND WAS STIL GOOD TILL THE CARB HEATER LINE BROKE OFF AND I OVER HEATED IT AND KILLED THE MOTOR I WAS SO SAD TO SEE IT GO :sad2:

[racerx]

it might be a compression problem. you could check your compression, and if it's low (or if there is more than 25psi difference between cylinders) that could be part of your problem.

my best advice would be to rebuild the motor as long as you're going to be checking bearings. It's not too hard to pull the head, as long as you've got a friend to do it with. I've done it 3 times. The worst part is the intake manifold bolts, but I guess some people just leave that on, and pull the head with it.

anyway, if you want parts, there's a $300 rebuild kit (shipped) which includes your choice of stock or oversized pistons, and all the other necessary crap like rings, bearings, main bearings, belt, etc.

Let me know if you're serious (or if anyone else is interested) and I'll find the link again.

EDIT: Also, I wouldn't count on the problem totally being a rod knock. My dad had a rod knock in his jeep and the noise it made was a ticking, or tapping. *tap tap tap tap tap tap tap* It got faster with higher RPMs, and it never went away until we rebuilt it.

[racerx]

found the site:

$279 + shipping for full rebuild kit (includes oil pump). over-sized pistons, rings and bearings available AT NO EXTRA CHARGE.
http://www.importperformanceparts.net/imports/topekits-honda2.html