Rod Knock?

tpunx99GSX · 01-10-2009

Ok so im still trying to figure out this Rattle. Its more of a knock so ill call it that.
The car idles PERFECT. No obsurd sounds, no shaking, really no problems.
If i rev the car to just about 2.5k rpm it makes a knocking sound, i listen really closely and it sounds like its coming from cylinder 4.
If this was rod knock, would it be only happening at 2.5k and above? Or would it affect idle?
Is there any tests to check for rod knock? Can i take off the oil pan and be able to wiggle the piston or something? Im really freakin confused, and if this is in fact rod knock, im parting out the car. But it would really like to sell this as a whole and be done with it.
Just a few notes:
New timing belt, New revised lifters bled etc, new clutch, new head gasket.
Thanks in advance. Ill try and capture the sound on video and post it.

**Goat Blower** · 01-10-2009

It very well could be. Drain your oil and look for metal particles, it could be a few things, none are good.

tpunx99GSX · 01-10-2009

Can you name a few of the things it could be, it would be very helpful. I just need some places to look? The oil is clean, i have replaced it 3 times in the past 2 months. Made sure it was clean. no metal flakes, nothing.

95talonracer · 01-10-2009

I have delt with that same sound and also occured over a bit higher rpm then idle and both cases was a bad rod bearing. Take off the oil pan and look for shavings and you should be able to grab the nut on the lower portion of the rod and yank back and forth and it will more then likely have play.

tpunx99GSX · 01-10-2009

Quote:

Originally Posted by 95talonracer

I have delt with that same sound and also occured over a bit higher rpm then idle and both cases was a bad rod bearing. Take off the oil pan and look for shavings and you should be able to grab the nut on the lower portion of the rod and yank back and forth and it will more then likely have play.

If this is the case, can i replace the bearings without pulling the block?

GnArKiLl · 01-11-2009

sure can... but the rods will need to be checked to make sure they are in spec, witch you would have to pull the head off to do

craig · 01-11-2009

it also depends if it has chewed on the crank

tpunx99GSX · 01-11-2009

im gonna try and pull the oil pan tonight and pull the bearings, ill post pics.

**JET** · 01-11-2009

Yeah, likely the crank won't be in good shape either. It sounds like you caught it pretty early though, so you might be in luck.

tpunx99GSX · 01-11-2009

Quote:

Originally Posted by JET

Yeah, likely the crank won't be in good shape either. It sounds like you caught it pretty early though, so you might be in luck.

Yeah ive been driving it really easy, no shifts over 3k. (and i actually mean that...) Plus i had been breaking in the clutch (just hit 300 miles) so hopefully all is well with the crank. Im at my wits end with this car.
After the new bearings, is there a break in period? also what do you guys suggest for the replacement bearings? And should i use some kind of lube on the bearings before putting them in or some kind of prep?

Kevin 1G Drummer · 01-11-2009

I'm using ACL race bearings in my car. They weren't too expensive, and they now have about 25k of not so easy driving on them. You will wanna use assembly lube on them when you put them in, and make sure there is no scoring on your crank. As for a break in period, you'll wanna go pretty easy on the throttle and rpms for about 500 miles, then change the oil. Then change the oil again after 1000 miles, then after that you should be good to give it hell.

**Goat Blower** · 01-11-2009

Bah, 100 miles is about all I do for break-in anymore. That 1000 mile stuff pertains to old Chevy motors.

**JET** · 01-11-2009

I am with Steve, I did about 100 miles too, but I did do 3/4 throttle at low boost after 50 miles to make sure the rings were seated. I was only fairly nice to it for the first 20 miles. I was also very picky on my clearances during assembly.

tpunx99GSX · 01-12-2009

Yup its verified. Rod bearings were the problem.
Crank and Rods look fine. The bearings still had a little copper (looking) on the crank side.
Im ordering new ones tomorrow.
On a funnier note, I found a 10mm socket in my oil pan. Not sure how it got in there.

mike55112 · 01-12-2009

Quote:

Originally Posted by tpunx99GSX

Yup its verified. Rod bearings were the problem.
Crank and Rods look fine. The bearings still had a little copper (looking) on the crank side.
Im ordering new ones tomorrow.
On a funnier note, I found a 10mm socket in my oil pan. Not sure how it got in there.

Was there alot of shavings? If so you might want to clean everything out to prevent any further damage.

**asshanson** · 01-12-2009

Quote:

Originally Posted by tpunx99GSX

On a funnier note, I found a 10mm socket in my oil pan. Not sure how it got in there.

WTF? Have you ever take this motor apart before? Or was it the previous owner who did that?

tpunx99GSX · 01-12-2009

Quote:

Originally Posted by asshanson

WTF? Have you ever take this motor apart before? Or was it the previous owner who did that?

Im thinking it was the previous owner. I havent taken the oil pan off before in this car.

it was just chilling on the bottom of the pan. Its funny though because it scared the hell out of me when i was hearing it drag on the bottom of the pan i was thinking it was something much worse. LOL

There was some shavings on the bottom of the pan, ill make sure everything is cleaned up. and do an oil change.

On the crank, cyl 4 there was a very slight scoring on the crank. I dont think it justifies replacing or returning the crank. The other 3 looked just fine. On cylinder one the top part of the bearing was broke in half. YIKES. Good thing i didnt wait any longer. Surprizingly cyl 1 does not have any scoring whatsoever.

Anyone know the torque specs for the rod bolts? I couldnt find it in my manual.

Also i definatly suggest to everyone, if you ever have your oil pan off, replace the rod bearings. its very easy to do and could fix a disaster.

**asshanson** · 01-12-2009

Free socket for you!
Sounds like you got pretty lucky. Are you going to pull the head and check everything out or just replace the bearings?

tpunx99GSX · 01-12-2009

Quote:

Originally Posted by asshanson

Free socket for you!
Sounds like you got pretty lucky. Are you going to pull the head and check everything out or just replace the bearings?

Im just going to replace the bearings, i dont think i need to check the head.

mike55112 · 01-12-2009

You really should take everthing apart and get it all cleaned, some shavings could have went through the pick up and now are in the rest of your engine/turbo/oil cooler.