Loud Knock - Very Scared, Need Help Immediately Options

[Nor.Cal.914]

I was just driving my car a minute ago and something very bad just happened. I had a concern about my revs earlier and how it wouldn't let me go over 4000 rpm. Well, I just replaced the coil and was trying it out to see if it helped my revs go past 4000. When I took it up there, something happened and a very loud knocking noise started happening. Another person on this thread had a post about a loud knocking noise that he heard when he started his car. Mine seems to be making the same kind of noise. I need help immediately! Any help as soon as possible would be helpful, please. Thank you very much.
-Chris

[lapuwali]

Does it knock faster as revs rise? Does it knock at idle, or only when on the gas, or only when you let off, or only above a certain rpm?

[Nor.Cal.914]

It's a constant knock. It happens at idle and driving. I didn't push the revs at all because I was really scared that something was going to happen. It doesn't seem to increase when the revs increase but I didn't push anymore than 2000 rpm when I was taking my car back. Any help would be great. Thanks
-Chris

[bondo]

I feel your pain, man. (I'm the other person) Hopefully you can get an expert to come listen to it. After Sean and Herb listened to mine, I had some guidance. I haven't acted on it yet, but soon. (IMG:http://www.914world.com/bbs2/html/emoticons/smile.gif)

[Nor.Cal.914]

Did they have any idea on what it was? Let me know. Thanks
-Chris

[bondo]

They said it was definitely valvetrain related and the problem would probably be obvious upon removal of the valve covers. I haven't done it yet because the engine is coming out of the car anyways and it'd be easier to mess with after removal.

[Rand]

I'm confused by your answer to James' (lapuwali's) question....

Are you saying the speed/frequency of the knock doesn't change with engine RPM???

[lapuwali]

If it doesn't increase with engine speed, it's likely not serious, and is more likely something external to the engine has come loose and is hitting something else.

I'd check the engine bay and see if anything is loose (airbox, battery). Make sure the engine and transmission mounts are solid. Check the rear shocks. See if you can make it clunk by bouncing the rear of the car up and down (engine off).

Check the distributor to make sure it's not loose. Check the coil you just replaced to make sure it's not loose (in fact, I'd start there).

[Mark Henry]

Real-real loud? See if your plugs are all still in...stripped out spark plug.

If not then it's bad dude...go smoke a...wait your a 16yr/old...Belay the order.

[Nor.Cal.914]

Ok I'll try to answer all questions at once. As far as the knocking noise, it doesn't "speed up" or become any louder with an increase in the revs. It isn't LOUD, but it's loud enough to hear clearly in the interior of the car. When you say "check the coil", do you mean if it's just sitting loose or if the plug wire/and wires are loose? I will go out right away and look around the engine bay and see if anything has come loose at all that I can see. I will try bouncing the car a bit as well to see if I can hear anything either. I'll get back to you guys with any new findings I have. Thanks again for your help so far. I'm going to try and take the valve covers off in a bit too, but I'll get back to you when I do. Thanks
-Chris

[Rand]

Nothing about the knock changes with the engine RPM or rolling speed of the car?

[lapuwali]

By check the coil, I meant make sure you tightened it back down again after you changed it, to make sure it's not just rattling around loose.

If it's steady in volume and frequency, it's unlikely to be loose or missing plugs (good guess though), and they're generally loud enough that you have to yell over them. Valvetrain noise will almost always change in frequency with engine speed.

Rule #14 of auto mechanics: if it starts making a new noise after you do something, check whatever it was you just did, then check everything around that. Anything you touched during that procedure is a prime suspect. Only then should you start worrying about other things.

[Nor.Cal.914]

I will definetly put the old coil back on then see what happens. The knock does not increase in volume at all when I start rolling, driving, or revving the engine. As I said before though, I did not push it anywhere at all over 2000 rpm because I was so scared that something went really wrong. But I'll go put the other coil back on and see if anything at all changes then let you guys know. I checked for anything loose and shook and bounced the car as much as I could and didn't see anything or hear anything knocking around. I'll get back to everyone after I take another look and change back to the other coil. Thanks again for the help so far.
-Chris

[Aaron Cox]

sorry to rain on your parade, but your lugging the engine at 2 grand......

[Nor.Cal.914]

Well of course I know I'm lugging the engine by only going to 2000 rpm but I was so scared to push it because I didn't want anything to happen. Ok and I'm sorry for saying the wrong thing, but I just went out and put the old coil back on and nothing changed. What I said wrong was I thought the noise didn't increase with the revs, but I just went and revved it a little and it does increase in speed a little bit. The noise level of the knock does NOT increase, but the speed of it does increase. So sorry again for saying the wrong thing, but I just noticed it now. I guess I was too scared about what happened to notice it earlier. Anymore help that could be provided would be great. Thanks again
-Chris

[914fan]

I hate to be the bearer of bad news but it sounds like it may be a nut came off of the cam gear and is flopping around. (I hope not) Check your timming. You could have changed it. (lets all hope)

[McMark]

If this happened to me, I wouldn't start it again until I crawled underneath and pulled the valve covers off. See if anything looks weird. Should only take you 30 minutes and can illuminate a lot of possible issues.

[Nor.Cal.914]

For future reference, when I get around to doing this, what exactly should I be looking for as far as something gone wrong? Is there anything obvious that would be out of place or not normal? Let me know. Thanks

[Nor.Cal.914]

I definetly won't be starting it again until I check that, I started it only to see if putting the old coil back on had changed anything. Thanks
-Chris

[bondo]

QUOTE (NeunXIV @ Dec 8 2005, 06:35 PM)

For future reference, when I get around to doing this, what exactly should I be looking for as far as something gone wrong? Is there anything obvious that would be out of place or not normal? Let me know. Thanks

Make like you're adjusting the valves, but check all the clearances instead of adjusting them. If it's valve related you'll probably find the problem.