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How do I tell if it is a rod knocking?

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Old 01-05-2011, 10:06 PM
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Default How do I tell if it is a rod knocking?

Well I have noticed a ticking coming from my 01' LS-1 that at first a few days ago I was thinking that I must need new header gaskets.

However today it has started to get allot louder and is sounding more and more like a rod knock from a spun bearing.

Maybe I sprayed the car too much last summer? The motor and car only have 45K miles but I drive it hard everyday with the cam and all the other mods in my sig.

Is there any way to tell if it is a rod bearing? I assume a compression check wouldn't hurt, but it won't tell much. If it is a rod bearing is there a chance I can just change bearings and rods and not have to do anything to the crank and pistons etc... ?

Where should I go from here? I guess I could pull the lifters and make sure I didn't collapse a lifter?

it was low enough to turn the amber add oil light on the other day (it was only a qt. low though)

Anyway what would you do now if you were me
Old 01-09-2011, 04:07 PM
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Originally Posted by adrynalinjunkie
Well I have noticed a ticking coming from my 01' LS-1 that at first a few days ago I was thinking that I must need new header gaskets.

However today it has started to get allot louder and is sounding more and more like a rod knock from a spun bearing.

Maybe I sprayed the car too much last summer? The motor and car only have 45K miles but I drive it hard everyday with the cam and all the other mods in my sig.

Is there any way to tell if it is a rod bearing? I assume a compression check wouldn't hurt, but it won't tell much. If it is a rod bearing is there a chance I can just change bearings and rods and not have to do anything to the crank and pistons etc... ?

Where should I go from here? I guess I could pull the lifters and make sure I didn't collapse a lifter?

it was low enough to turn the amber add oil light on the other day (it was only a qt. low though)

Anyway what would you do now if you were me

Ok first off. Can you get us a video of the sound? If its a exhaust leak you can pin the spot to one spot, or at least I could on my truck. Personally I would drain the oil and check for metal shavings. Next would be to pull the pan if you can and look at the bearings. If you did spin a bearing I would recommend turning and polishing the crank. When you pass metal between the bearing and the journal you can score the crank that the new bearing wont like.

Good luck with it. IF you can get a video it would help.
Old 01-09-2011, 05:22 PM
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Pull the plug wire one at a time on that side if it goes away on that cylinder then you have spun one......,
Old 01-09-2011, 05:24 PM
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knocks are usually pretty loud like metal hitting. itll get louder too over time. its a pretty violent sound.
Old 01-09-2011, 06:25 PM
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Here is mine with a rod knock;

http://www.youtube.com/watch?v=haPyFvU0r7Y

and here was the damage to the crank;



If yours is a rod knock, you'll know it. Kinda hard to miss that distinct sound, haha!
Old 01-10-2011, 10:51 AM
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Originally Posted by TechCam97
Here is mine with a rod knock;

http://www.youtube.com/watch?v=haPyFvU0r7Y

and here was the damage to the crank;



If yours is a rod knock, you'll know it. Kinda hard to miss that distinct sound, haha!
YUP!! ... I spun a bearing 3-4 years ago in my original motor. Sounds just like that! Sux!! I wish I still had the fouled bearing still to show a pic but it basically took the 2 halves of the bearing, shifted one on on top of the other and then fused them together. ... It was pretty bad. ... Had to junk the core. I guess I completely warped one of the cylinder walls in the madness, to the point that that sucker was past the point of saving! ... If it is a spun bearing, STOP cranking the motor 20 frig'n times over to get a "friends opinion" .. Its like kicking your family member in the ***** when he's already on life support

araber89 called it! .. Drain the pan!.. Look in the oil for metal shavings. .. If your having trouble identifying it, hold it up to sunlight if you have it in a pan. <-You'll see a "metallic rainbow" in the oil. ... You can also just run it through your fingers.

BTW, if it IS a spun bearing, now would be a great time to go with forged internals! Look at it from the most positive side possible before you start cursing your birth!

Last edited by WS6 Rampage; 01-10-2011 at 10:57 AM.
Old 01-10-2011, 01:02 PM
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Originally Posted by WS6 Rampage
.....I wish I still had the fouled bearing still to show a pic but it basically took the 2 halves of the bearing, shifted one on on top of the other and then fused them together. ... It was pretty bad.....
That's basically what happened to mine except they two bearing pieces didn't fuse together, they just interlocked. I still have them out in my tool box somewhere, they are a nice conversation piece for other car guys.

Originally Posted by WS6 Rampage
.....If it is a spun bearing, STOP cranking the motor 20 frig'n times over to get a "friends opinion"..... araber89 called it! .. Drain the pan!.. Look in the oil for metal shavings. .. If your having trouble identifying it, hold it up to sunlight if you have it in a pan. <-You'll see a "metallic rainbow" in the oil. ... You can also just run it through your fingers.....
Yep, stop cranking it or else your crank will look like mine. My crank was trash, but I was lucky and my block was perfect. I just had my block cleaned and looked over a local shop and they said it was good to go. Mine also had the metallic rainbow and felt like sand was in the oil, very nasty. If it turns out that it is a connecting rod bearing that is out and you're looking for a cheaper alternative, look into a 5.3. The 5.3 shares the same crank and connecting rods, they just have a smaller piston. I got a complete 5.3 for like $400 and had a shop swap over the pistons from my LS1 onto the connecting rods out of the 5.3. I then just used the crank out of the 5.3 and I had complete rotating assembly for just a few hundred dollars. I ended up selling the 5.3 block and heads as well, so that helped my wallet. If it is a spun bearing and you can do most of the work yourself you can fix it for pretty cheap as long as you're patient. Take the motor apart and bring the parts to a reputable machine shop and they can tell you what is good to be reused and what is now junk.
Old 01-10-2011, 02:50 PM
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Don't run the engine anymore...pull the pan and check. Rod knock is very distintive...mine gave up the ghost a few years and before it did I lost oil pressure...here's my favorite pic.
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Old 01-14-2011, 12:27 PM
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Wow you guys rock! I have been driving my truck and haven't checked this thread in a few days, but I have been missing the 400 RWHP ALLOT!

Here is a update, I drove it around the block and it ran great but had the knock or tick from idle to about 2800 then it seemed to stop. I didn't get on it though so 3000 grand easy was about all the tach saw.

I then put it up on the car lift and took off both the Ac belt and the main accessory belt and I didn't have any change in the knock when I ran it with no accessories. I then pulled one weather head at each coil pack as was suggested and couldn't find a smoking gun cylinder with that test either.

I raised the car up oin the car lift and listened with my stethoscope and it definitely sounds like it is coming from the engine. It seamed a little louder with the stethoscope on the heads than when it was on the oil pan, but it was allot quieter with the steth on the T-56 tranny.

Next I did a compression test on the motor when it was warm fro the first 6 cylinders then I had to go inside and take my turn watching the 1 year old boy and my little girl.

The next day I did a cold comp check on #6 and still got 185# however I only got about 175#'s in #8 All cylinders would hold at around 180 PSI or better for a few minutes.

I did find a small hole (maybe 3/16" dia)in one of the exaust welds were a speed bump hit it the other day. Should I weld that hole shut and put plugs back in it and put all the coil packs back on a fire it up again? Or should I just pull the motor?

I was going to go out and pull the cam and check the lifters since I heard the noise a llittle more on the top of the motor.

(I will go drain the oil in a clean plastic pan now and pull the pan (beauty of a car lift)

I did smack that speed bump hard enough to dent the 3" pipe and make that 3/16" hole in the weld joint. I can't believe that would cause a knock like this but maybe.

I will update this after I go drain the oil and pull the pan.

Thanks again for all the help and posting the vid. I will shoot a vid if I do put it all back together and try and run it, but at this point I think I should probably just pull and disassemble the motor.

Can I safely get the caps off the rods without any special tools or do I need a rod splitter?
Old 01-14-2011, 12:30 PM
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BTW

It did have 45 psi or so at a idle and 65-70 psi when driving below 3K RPM's so I would say oil pressure is normal.
Old 01-14-2011, 07:44 PM
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I just drained the oil and it is damn black for only having around a 100 miles on it.

This car didn't have a air filter when I bought it last February, did I mention that?

The Haynes manual is talking about having to lift the motor 3" up and unbolting the steering linkage and all this other junk so I think I am just going to pull the motor tonight.

I looked at that exhaust pin hile and it is much smaller like 1/64th inch Dia. and you can see it is where I stopped and started beads so I drought that is the knock.

I did take all the bolts out of the pan and one of the rear bolts had some clutch plate dust and engine oil! I hope that new Monster stage 3 clutch is OK, I am going to pull the tranny after dinner and see if my Monster is OK. I will try to get the motor out tonight.
Old 01-14-2011, 07:47 PM
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Originally Posted by TechCam97
Here is mine with a rod knock;

http://www.youtube.com/watch?v=haPyFvU0r7Y

and here was the damage to the crank;



If yours is a rod knock, you'll know it. Kinda hard to miss that distinct sound, haha!

Yeah it isn't that loud yet but that is what it sounds like.

Time to put that engine stand and hoist to work, that I bought 5 years ago!
Old 01-14-2011, 08:20 PM
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get 'er done
Old 01-15-2011, 08:51 AM
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When you changed the oil did you save the filter? Cut it open (in half) and look in the pleats for bearing material. However if yours sounds like the motor in the video, I'd say yes your goose is cooked. Stop running the motor and pull it. Do a teardown and see what you are up against.
Old 02-14-2011, 09:08 PM
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UPDATE

I pulled the motor and pulled all the rod caps off and NOTHING !

I installed new Ketech bolts (katech said it was OK that I took both rod bolts off and separated the cap from the rod because they are cracked cap factory rods so they will allign easily)

I then found several lifters that seamed to have weak springs. I submersed them in oil and pump them with a push rod while they were under oil and they never got stiff like the other 14 lifter were.

The week lifters would pump up that is why the knocking sound would stop above about 2600 RPM. I f ing rod knock would not have gone away at increased RPMs !!! OH well hindsight is always 20/20

Lesson learned is, if you are running a big cam your stock lifters will wear out and start this knocking or clicking around 15,000 to 20,000 miles after the big cam install.
Old 02-14-2011, 10:00 PM
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Nice update!!! Could have been worse

I would check lifter preload because a big cam alone won't kill lifters that quick.... I know guys with 50K plus on MS cams and I went 30K plus on my last .600+ cam with LS7's....
Old 02-14-2011, 10:26 PM
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Well now you'll have peace of mind when you put it back together again!
Old 02-15-2011, 07:34 AM
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Originally Posted by SOMbitch
Nice update!!! Could have been worse

I would check lifter preload because a big cam alone won't kill lifters that quick.... I know guys with 50K plus on MS cams and I went 30K plus on my last .600+ cam with LS7's....
THese were the crappy discontinued LS-1 lifters, hopefully the new LS-7 do better. I will check preload, I am shimming a lifter to make it solid to get a very acurrate measurment.
Old 02-15-2011, 08:25 AM
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Originally Posted by adrynalinjunkie
THese were the crappy discontinued LS-1 lifters, hopefully the new LS-7 do better. I will check preload, I am shimming a lifter to make it solid to get a very acurrate measurment.


Smart move
Old 02-15-2011, 09:08 AM
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As stated earlier, you're lucky it was just lifters. Glad to hear you're back in business.



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