Rod Knock

[4GZChatch]

Guys, I am serious trouble here. I have a ZC motor that has developed a rod knock. I know that it means bottom end problems, but what are the most common? I have heard people say things about spun bearing and wrist pins, but I don't know what most of it means. Can anyone put it in real plain english? Moppie, are you out there? I know that you know everything about Honda's. I could sure use a little help! :help:

[Moppie]

I know everything about Honda's? :huh: cool. :smoker2:



Ok, by rod knock I assume you mean theres a knocking sound coming from the bottom of the engine.

Its normally a good sign a big end bearing is gone.
Easy way to check, get under the car, take the exhaust off, and take the sump off. Then take the caps off and check the bearings. (just remember to torque the back down if thier OK, and to put the cap on the same way round you took it off.)

You'll know pretty quickly if the bearing is worn. And once the sump is off you can replace them in the car.
While cap is off you can also twist the rod while holding the piston and feel for any movement in the wrist pin.

Good luck.

[4GZChatch]

See, I knew you would know. Thanks a lot for the help! Are there any serious problems that can go along with the bearing problems? Is there any other possibility for what is causing the knock? Thanks again!

[Moppie]

Well if you keep driving it you can say bye bye to your crank.
And its not kind on the bore either. Or in fact any other internal part if the bearing shell comes apart. That soon equals bye bye motor.


As for other things it can be?

Broken ring land on a piston.

Worn wrist pins.

Damaged valve, or valve gear.


Or like an alfa we just fixed at work it could be something has found its way down the intake and into the cylinder.
We even found a badly worn rod bearing, replaced all of them and it still made the same noise. So we whipped one of the heads off, and a tiny little piece of metal fell out. About 3mm long and 1mm wide.
The cylinder it come out of has scratchs and dents on the head, and piston face.

[4GZChatch]

Ok, well, I'm not driving it. It's just sitting until this semester is over at the university. I guess I'll start by taking off the oil pan and checking the bearings. Do you think that's a good place to start? That way, if it is simply a work bearing that needs replacing, I won't have torn down the whole engine. Do you think that makes sense? Are there any other things that I should look for while I'm in there?

Also, what exactly is meant by a "spun bearing"?? I was under the impression that the bearing is entirely covered by the rod, and doesn't really move at all, except in relation to the crank. Is this right?

Thanks for all your help man!

[Moppie]

Yip, 90% chance its a bearing thats gone. So starting with the sump off and having a look at the big ends is the best place to start.

Just remember that you have to torque them back up to spec, and that if only one is worn, you still need to repalce all 4.


The phrase a spun bearing is just a pharse I think.
After all its going round and round, and spinning.



Have you ever opened up an engine before?
If not then its a good idea to have someone whos knows what thier doing handy, or if you can get hold of a digital camera you can take photos and we can talk you through it.

[4GZChatch]

I have had an engine opened up before, but only from the top. I've never really messed with a bottom end before, only replaced a head gasket and done a very small amount of head work. However, I have a friend who is willing to help, who knows what's up. Do you know what bearings will fit a ZC, or are they all the same for D-series motors?

Also, what do you mean by the "big ends"? Just a little jargon illiterate, I suppose. Thanks again!!:flash:

[sastanley]

My research on the Internet has led me to believe that if you buy 91 Civic Si (d16a6) parts for the bottom (block) and 89 integra parts (d16a1, right marked001?? ) for the top (head) you should be safe.
I just spent about $500+ buying bearings and rings and stuff for my ZC and bought d16a6 parts. Be careful, each bearing is custom fit and could be different sizes. They are differentiated by color swabs on the edge of the bearing and such, and the stampings in the block and on the rods...I would HIGHLY recommend a service manual.

[Moppie]

Originally posted by 4GZChatch
Also, what do you mean by the "big ends"? Just a little jargon illiterate, I suppose. Thanks again!!:flash:

Just Jargon.
Little end, Wrist pin, Piston bush,: If the pin that holds the piston into the top of the rod.

Big end, Rod end: Bottom of the Rod where its attached to the crank.

Mains: Big bearings and end caps that secure the Crank into the block.



Its important to have someone who knows what thier doing handy.
Things like replacing the end caps the same way round they came off, and back onto the same Rod end are not always common knowledge.
If you put the wrong end cap on the wrong rod it could be a very short time before your rebuilding the bottom end again.

As for what bearing set to get Im affriad I have absoluty no idea, we can get genuine ZC bearings down here, so messing around with parts from other engines isnt a problem.