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I ended up not working on the car the last 2 nights had to get some other things done around the house. I should be back into it tonight and will post more updates as i go
Recently my 2003 Z06 started to make a knocking noise from under the hood and I'm having a hard time pinpointing it.
Long story short, the harmonic balancer failed and the car sat for 2 weeks while i collected parts/tools/research before tackling the job. Got it all buttoned up and started it for the first time in 2.5 weeks and was greeted with a very loud knocking noise that seem to be coming from cylinder 1 and 3. I used a stethoscope and the noise is definitely louder on the valve cover, than on the cylinder head at 1 and 3. . It was not doing this before replacing the balancer, so it seems odd to me that it would be rod knock. A collapsed lifter would make the most sense, however i dont feel the noise matches that diagnosis. I have pulled the valve covers and cranked the engine (fuel pump relay removed) to watch everything in the valve train. All appears to operate correctly and there is no noise at cranking speed. I have also tried pushing on the push rods to see if i could locate a collapsed lifter and none budge... I also pulled the push rods on 1 and 3 as that seems to be where the noise is most prominent but they look great. I think this is way to loud to be piston slap, but i have not let it run long enough to warm up as i do not want to cause any more damage. I don't think it is an exhaust leak as i have not messed with that system but i suppose anything is possible...?
There is no CEL, and there are no stored codes in the DIC
Does anyone have any suggestions to help isolate the issue before i tear anything down?
I have seen countless 5.3 liter engines start knocking from worn out cam lobes that damage the lifters. Replaced many of engines in Chevy trucks on account of this problem.
The lobes of the cams would literally have pits and chunks missing!
I haven't posted any progress updates for a little while and figured i would share where i am currently.
Heads removed as well as all the front accessories and water pump. The steering rack has been removed, which by the way is WAY easier to remove with all the accessories out of the way, compared to pulling it from the bottom
With the pistons exposed i rotated the crank by hand, watching each piston move. I rotated the assemble around until each piston was on the downward stroke then stopped. I wrapped a wrench in a shop rag and pushed down on the pistons that were in the downward stroke to check and see if there was any slack. Piston 3 and 4 both moved a few mm and made an audible clunk. The rest were snug. This would lead me to believe 3 and 4 have spun rod bearings. When on the downward stroke, the crank would be "pulling" the piston down with the bottom of the lobe, if there is freeplay in the bearing pushing down would change the contact point to the top of the lobe and would make a noise. (at least that makes sense in my head)
Anyways on to the pictures:
As it sits now. Both heads removed
Driver side of the engine
Steering shaft removed from rack and rack removed
Rack removed. Finally getting to detail clean all the grime in the engine bay that i couldn't get to otherwise. Also going to take care of the leaky front cover while its out.
Passenger side of engine
Passenger side. AC compressor removed. (Pro tip.... the upper left nut is threaded onto a stud. The stud can be removed by small socket on the tip. that is the only way to remove the compressor with the engine in the car still) took me a while of pondering to figure out.
Both side mount bolts have been removed. the only thing left to do is to remove the bell housing bolts and i should be good to start removal. I am going to order a top plate puller from Amazon when i get paid Friday so progress will stop until i get that.
Last edited by ezstreet; Aug 15, 2016 at 12:35 PM.
All bell housing bolts removed, remaining wiring clips/connectors ect have all been removed.
Ready to pull the block. Any tips or suggestions to separate the bell housing from the block? I have a jack under the bell housing to get enough angle to clear the crank pulley to cradle. just cant seem to wiggle it free from the input shaft.
I haven't removed it from the top. The drive shaft has a few inches of spline shaft that the engine needs to slide off of.
I'm assuming that you are looking for a rotating assembly that will work better for supercharging. The guys on the forced induction section may have more ideas for this in specific.
In the pic the motor mounts are still in. I pull the entre mount and bracket out. I assume you have the front cradle lowered off the mounting bolts. The rest is keeping the angle of the motor and torque tube even. With a jack and some wood under the torque tube and the motor on the lift pull the lift and motor to the front.
As for a short blocks I liked Texas Speed. They had options so you could build whatever you wanted or your pocket can handle.
I had forged rods and pistons but needed a crank and block so I ended up buy parts not an assembly. TS has a good rep.
did you let your oil warmup before going over 2k rpm on a cold engine?
Warm up to what temp?
Cold engine as in freezing temps, or while sitting in my climate controlled garage overnight?
I do not get deep into the pedal before its at normal operating temp, but I'm sure it has crested 2k on more than several occasions before hitting operating temp.
Cold engine as in freezing temps, or while sitting in my climate controlled garage overnight?
I do not get deep into the pedal before its at normal operating temp, but I'm sure it has crested 2k on more than several occasions before hitting operating temp.
i dont go past 2k rpm until my oil reaches 170 degrees, doesnt matter if its in a garage or freezing outside. oil should be at 170 or higher for engine to operate at over 2k rpm. at 170 degrees everything is nicely warmed up and engine is expanded to proper clearance.
Last edited by RomanNYC; Aug 24, 2016 at 01:17 PM.
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had to get some other things done around the house. I should be back into it tonight and will post more updates as i go
You are absolutely correct! I don't do FI so, it didn't immediately hit me. Yes,, It could cause it to pop out!
