undetermined knock

[HondaBoy]

yesterday i started to notice a knock. it occurs at rpms of 3000-3800 rpm. i did an oil change, no metal shavings. checked the cylinder head, its not comming from it. everything on it was ok as far as i checked. thought maybe something was loose letting the cam move. nope. it doesnt sound like its comming from the bottom end, meaning not the crankshaft. it actually sounds like it is the piston skirt slapping the cylinder. so it kind of sounds like its right under the cylinder head. i may check my valve clearances tomorrow when the engine is cold. but the sounds seems to be comming from the top of the cylinder. to describe the sound, it sounds like a throaty sound but a knock at the same time. i may also drop the oil pan and take a peak. i'm thinking its got a bit of piston slap though. i'm not going to drive it now until i determine the problem. any ideas would be helpful. i may just park it and get a block built for it since the head was recently rebuilt.

[Bass Man]

I had the same knock. It's a wristpin.

Only I saw it happen and didn't do anything about it. One day my oil pressure dropped horrifically, down to 9-10lbs at idle. This was about 3 days after I changed the oil. I checked and it was full, but the pressure wouldn't come up untill about 2.5k. About a week later I started getting a ticking, then a tapping, then a clacking, then about a month after it started, I got a pretty bad knock. Pulled the engine and saw I was getting a good 1/4" of play in the #1 cylinder.

Start looking for an 88-89 LXI motor. (or start piecing a rebuild together)

[russiankid]

I have this knock you describe but its very faint. You have to listen carefully to hear it. It's been there for a while now and the car runs fine. It happens between 2k rpms and 2500rpms.

However, my situation(sound) may be different from yours. I didn't do any engine work, everything is stock.

[Bass Man]

I bet your ticking is coming from your valves or your distributor

[Civic Accord Honda]

my 3g has it to it starts at like 3200 and stops when u get past like 3800 its had it since i got it and 2 years later its still running lol

[Demon1024]

the dizzy can tick? crap i'm going to change it right now i've been considering it for a while. at 3.9k-? (never go higher now) it has a faint ticking. i figured it as main/ connecting rod bearings. hope yours is the dizzy man wish me luck.

[HondaBoy]

no definately nothing from the top end! not the dizzy, i'm damn sure. as you said, a wrist pin was sort of my guess after thinking about this whole thing. makes since. that could allow the piston skirt to slap the cylinder wall.

heres the thing, i'm going to check the valve clearances today, just to make sure. but they were properly adjusted and the valve train sounds like a new one would have. so i have my doubts on it being a valve slapping the piston top. and it honestly doesnt sound like its from down by the crank. so it really do think its going to be a wrist pin. so pretty much i can say, SHIT!

easiest and cheapest way to go if this is the case is pull the head. pull the oil pan, disconnect the rod caps, pull the pistons and see which one has the problem. and i can do all this with the engine in the car.

i've also gone the route of looking into a quick swap. found a complete LX-i engine. $350 for the engine, $450 for engine and tranny, $450+$100 for any other parts i want. so looking at $500 if i want all that. the engine looks completely original. i'd do a compression test before deciding to buy it. but i can swap my manifold onto it.

the distributor on the other hand, the LX-i dist. has three mounting holes, the carb model dist. has two. in the case i want a quick swap, could i make carb distributor work on the LX-i head? i dont remember if its possible to do so.

anyways, wish me luck in finding the cause of my lovely knock. and i was really looking foward to getting 23+mpg in the city. probably more.

[2oodoor]

don't freak out yet, sure it can rack the nerves..
but I wouldn't worry about it. Mine had that and it went away after adjusting the valves, retorquing the head, and replacing the oil pump seals. I notice that some of the rockers can walk on the rocker shaft and possibly make a resonate knock sound too. Lash adj. should keep it from geting a chace to wander

[2oodoor]

wrist pin slap can go on for years and years with no failures

unless of course you are winding the piss outta the engine to keep up with slightley modded civics anyone ?

[HondaBoy]

ok so i've just finished evaluating the cylinder head. the valves were way too tightly adjusted. so i properly gauged them. did a compression test. 170 ish in each cylinder.

proceeded to start the car, the noise was gone. left it running, revved it and there it is again. i'm pretty sure its either wrist pins or rod bearings. either or, i'd rather not have to deal with. i hate working on bottom ends. but my next day off or in my spare time i'll pull the oil pan and check for any play in the rod bearings.

what i'd like to do is buy a complete bottom end and swap my head on. i can get them from work, but i'm still going to pay $1400+. the one i looked at comes with a 3 year unlimited mileage warranty. it may be more like $1800. but is that really worth it? i'll check the prices again though, hopefully they are less than that.

anyways, i'm gonna leave the 3gee parked and not drive it so i dont fubar anything.

[greentee76]

When was the timing belt replaced last, and did the tensioner get replaced? A worn tensioner can also make a rattling/knocking sound.

[Bass Man]

unless of course you are winding the piss outta the engine to keep up with slightley modded civics anyone ?

Oooooo!!! I bet I know where that one was aimed

Yea... I didn't replace my oil pump O-rings when they went out, so that is probably why mine started acting up.

Now I CAN keep up with slightly modified Civics :P

[Rendon LX-i]

It probly your tranny man lol.....i taught i had a knock one time and it was the tranny sounded like my shit was gonna break down....a good way to find out if u use one of those doctor things lol u put on your ear and it has a rod on it and u point it on the motor where u thing its coming from you well find your problem...idk what its called i used it one time when i was in auto tech back in the day lol....give it a try

[russiankid]

When was the timing belt replaced last, and did the tensioner get replaced? A worn tensioner can also make a rattling/knocking sound.

I had this issue. The tensioner went and made a loud clack noise. If you have a long screw driver, place the tip onto the adjustment bolt for the tensioner and place your ear onto the handle. It should sound smooth with a slight "wir" sound. Mine was clacking....

[HondaBoy]

hey, i was thinking again, and yeah it could be that T belt tensioner. its at the same level that the sounds seems to be comming from. when i redid the head, i just reused the belt and tensioner that was on it. original tensioner with a belt that has about 60000 miles on it. so i'll check that

also, a mechanic today told me to check my flex plate. didnt even think about that being a problem. so i will definately check that thing out for cracks.

tomorrow will be my day off so i can poke around and check some things. i'd rather check all the little shit first before i drop the pan because its really just not very fun. makes a nice oily mess. doesnt help that the cross member is oil soaked. but oh well, its part of the process.

so yeah, i'll check the timing belt and tensioner because i did notice it looked like it had some slop in it when i would rev it, i have the top cam gear cover still off. i'll check the flex plate. if no problems there, then gotta check those internals.

i was so looking foward to driving it again, but of course some shit has to happen. its 21 years old so driving it as hard as i do i cant be surprised.

[HondaBoy]

today i took the car up to work. i let one of the older guys listen to it and said that it surely sounds like the bottom end, meaning the rod or main bearings.

what i've done so far is pulled each plug wire, started the car, reved it to the certain rpm where the knock is most noticeable. still it knocks. so without a doubt i need to pull the oil pan down.

i'm hoping for something i can see. possibly loose connecting rod nuts or main bearings nuts that have come loose. its not impossible because i've seen it before. so i'm down to this, to drop the oil pan and visually inspect things.

got a quote for a rebuild, about $1500 on average. so i may do a junk yard swap for now. i dunno, but its looking like the car will have to sit for a little while now. unless things just turn out so well for me that i can get something done sooner.

[2oodoor]

`you know.... it makes no sense to not drive it if you are going to be using another block anyway. It may not be anything to it. When is the last time the oil was changed anyway.... got an oil pressure guage? Magnetic oil plug? what brand of oil filter are you using? How much was taken off the head when you had that done recently?

[greentee76]

I'm with Roodoo on this. Drive it til it quits.
I have driven cars with a knock in them thousands of miles. A knock does not always spell immediate death.

[Ichiban]

Ha, I drove my 20R in my truck with a brutal rod knock for thousands of miles. If you were either on the gas or decelerating, it was quiet, but if you "floated" the engine (no load) or idled, well, I had to shut it off at drivethru's because they couldn't hear me over it. One oil change came out silver, and the next came out copper colored, so I just quit changing the oil. It's funny, because while I was building my 20R/22R frankenstien combo, I was stealing bolts out of the 20R and still driving it. All the oil and coolant mixed together after that, but it kept running till I pulled it out. Total lack of respect for that poor engine I guess.

[russiankid]

Here is what a bad timing belt tensioner sounds like.

[HondaBoy]

well i had it right being on the bottom end. not sure which rod or rods are torn up. but either way its fucked and i dont want to waste money fixing just the crank and whatever else. i'd rather buy a refurbished block. has new rings, pistons, rods, bearings and crank. its $380 with a $135 core charge. has a 3 month/ 4000 mile warranty. this is comming from a reliable rebuild place that i've heard of for years. my shop teachers had said their rebuilds were some of the best quality. and then recently a few mechanics had said that was who i should go with. so i think i'm going to buy a short block and keep my newly refurbished cylinder head. just considering machining the crank, boring the cylinders, possibly line boring for the crank. i'd rather just have a new bottom end and be done with it.

[Ichiban]

well i had it right being on the bottom end. not sure which rod or rods are torn up. but either way its fucked and i dont want to waste money fixing just the crank and whatever else. i'd rather buy a refurbished block. has new rings, pistons, rods, bearings and crank. its $380 with a $135 core charge. has a 3 month/ 4000 mile warranty. this is comming from a reliable rebuild place that i've heard of for years. my shop teachers had said their rebuilds were some of the best quality. and then recently a few mechanics had said that was who i should go with. so i think i'm going to buy a short block and keep my newly refurbished cylinder head. just considering machining the crank, boring the cylinders, possibly line boring for the crank. i'd rather just have a new bottom end and be done with it.

Do it.

[HondaBoy]

yeah, its the cheapest and easiest choice i have. with the cost of a machine shop and then measureing and ordering bearings, having to wait for all the things to come in and finding time to put everything together then install it. i just dont have a whole lot of time these days. so i think i will be going with city motor supply out of san antonio. i'm debating wheather or not to keep my block and have a light weight build done or just send it off as a core.

[HondaBoy]

well now i'm thinking if i'm spending a lot of money, maybe i should go forth and take an extra step and go for an engine swap. its just a though but maybe it would be closer to the performance level i want. i'd probably go with a B series, of course. i'd think the USDM 1.8, VTEC or non-VTEC would be the way to go since parts are easily available for it and not too expensive. if i do decide to go with an engine swap, it would be mated to a 5 speed manual instead of an automatic.

then there is sticking with the A20. for the short block i'm going to spend a good $400, not including gaskets and other things. it would be much easier to install. and i just cant complain about the fuel mileage it gave me. i do have the automatic so its a little sluggish. but i do love it for city stop and go driving.

i still need to pull the cylinder head and see if any damage was done to it from the piston top slapping up against it. if so i will likely go with an engine swap since i will probably need head work and dont find it worth while to go through that again.

i'll give it some thought though before i do anything.

[Josh89accord]

Honestly, I have an a20a3 in my lxi and did before, as I think back to it, I wish I would of went with a B series. If your going to be removing the engine, you might as well get a bigger one.