View Full Version : Rod Knock??

November 9th, 2005, 07:59 PM
I know Ive searched but I couldnt find what i was looking for. I know that the typical rpm range where rod knock is audible is between 2500-3000 rpm and the car makes the sound both in nuetral and while in gear. When I feather the throttle in nuetral I can hear it when the car is reving up, but not when the revs are coming back down. I can also hear it when I am accelerating in 1-3 (not in 4th or 5th, but I think that is due to the fact that there is so much other noise I just cant hear it). Ive found a couple of sound clips but one was of an MR2 which sounds nothing like mine and one of a GTE that sounds like its about to fall apart and also sounds nothing like mine. The sound my car is making is more of a rattle than a knock and sounds like its coming from somewhere near the front of the engine. Also the sound has not progressed down the rev range like many have said that it should instead its creeping further up the rev range.

I do have a problem with the h2o pump though the seals on it are dumping fluid out left and right, to the point where I have to fill up the overflow bottle on a daily basis. Would the bearings in the pump taking a crap make a rattling sound? Hopefully I can get a sound clip in the next couple of days, but in the meantime, does it sound like I have the dreaded knock?

November 9th, 2005, 08:08 PM
I think I read somewhere long ago that if you remove a spark plug wire to each cylinder and then stop hearing the sound from a particular cylinder, that would indicate where the knock is coming from...if you do indeed have a spun bearing.

November 9th, 2005, 08:10 PM
great, Ill try that. Thanks!

November 9th, 2005, 10:21 PM
Also, if your water pump was that far gone, it would have some serious issues by now - like letting the fan wobble enough to tear the snot out of all your belts and your fan shroud, for starters. I've had this happen to me, it was more than a little bit annoying.

All Rod Knocks are not created equal - some deteriorate very fast, some take years to get any worse. Try Tony's advice, that should pinpoint it - unless you have the rare case of TWO fried bearings.

By the way - LOUD knocks, or ones that deteriorate fast are usually spun. The one that you are describing sounds more like a bearing that is barely fried - I've had two of these, both lasted a good long time, and never really got any worse, I just got annoyed and fixed them eventually.

November 10th, 2005, 08:16 AM
I have a friend that is a supra connieseur (spelling?) and he has given me tips on what to do if you have rod knock, and cant fix it right away, and want it to last.

1. Drive smoothly, the knock is usually worse when changing engine loads.
2. Keep your foot outta the boost (if so equipped), and dont beat on the car.
3. Use thicker oil, and/or lucas oil...this is SUPPOSED to help it keep from getting worse.
4. If it gets louder, or worse in a short ammount of time. Stop driving. Even if you have to rent a car, it'll save you money in the long run by not having to buy a new engine for your car!

Just thought id share

November 10th, 2005, 02:20 PM
Well just a mini update, I had time to pull the front and back two wires and listen for the noise. Its na so its a bitch getting to the middle two, but so far its still present and just as loud. It does seem to be coming from the head right around the #1 cylinder and not the block though. It still worries the crap outta me, if I hadnt fixed the fan I would have never heard it. Atleast now I know there is another issue.

I dunno, Im just gonna start saving for the swap now I guess. Ill also check those two middle cylinders and see if that changes the sound as well once I get a chance. Thanks guys!

Nick M
November 10th, 2005, 03:20 PM
Typically on any OHC, the cams starve before the crank.

November 10th, 2005, 04:03 PM
It's much easier to disconnect the wires from the distributor. :D

November 10th, 2005, 05:15 PM
sure its not your valve spacing, i have it, it kind of sounds like knock but its coming from the top end more than the bottom but still sounds like hammering/ticking.

November 11th, 2005, 01:57 PM
It's much easier to disconnect the wires from the distributor. :D

Dude, once again you point out the blatantly obvious to me, I dont know why I always have to make things difficult, lol. Thanks again!

Im not sure if the valve spacing is off or not. How would I check that? I know that means taking the valve covers off, but are there any special things I need to know about or any special tools Ill need?

November 11th, 2005, 02:03 PM
you need feeler gauges to check the clearances on the buckets... generally they sound like a TICK TICK sorta similar to injector ticks