GTP Engine Knock..... sigh....

[Soeasytobefake]

2 1/2 years ago the engine in my 2000 GP GTP developed a Rod knock on rod #2, it spun the rod bearing.
Mods at the time were:
ZZP pcm 1.0
3.3" pulley
ZZP VS cam
MSD coils, wires.
Autolite XP 104 plugs
2500 stall ZZP converter, Blue.
TOG headers, down pipe.
SLP powerflow cat-back, with thrush glass-pack in place of resonator.

I used this as an opportunity to to build a better motor.
used all the mods above in conjunction with:
Stage 2 ZZP heads
JE pistons (stock compression)
Oversized SFI balancer
MLS .52 Headgaskets
balance shaft removal
double roller timing chain.

Machine work done at a local shop.

Installed the motor, and pulled again after various machine shop issues.

machine work RE-done at a different shop.

I eventually got the motor installed and running GREAT for about a month. It developed a horrid knock, and i lost that motor in a very big way. Machine shop #1 shaved material off of the tops of SOME of the rods to balance them. Making them a little thinner at the top. Rod #3 let go of the wrist-pin and tore up the block pretty good. Punched a grapefruit size hole in the block behind the starter.

Pulled the motor once again, and bought a stock used 40k short block.
I reused everything listed above with the exception of the the mangled left over chunks of aluminum piston. I left the Bottom end UNTOUCHED.

Installed the the second motor and ran the car for about a week with NO serious issues. Out of the Blue the SAME knock is back. haven't had the chance to get this thing tuned. Not sure if its rod knock, or spark knock. Ive Never heard spark knock with the 3.8L's.

Could be getting spark knock and beating the piss out of the rods? wouldn't I hear spark knock before mechanical failure occurred? I haven't been WOT with the car yet... wanted to get it tuned first.
This also makes me to question what I thought was the cause of the last failure. Not my first motor build, followed ALL torque specs VERY closely.

I was hoping this is a timing related issue... maybe a bad PCM.... Wishful thinking?

Here is a link to you-tube of my engine making this sound.
YouTube - 2000 GP GTP Knock

?????????

[blueguy]

Yup...that things toast

[Fivefingerdeathpunch]

yep its gone, you spun another bearing, I'm sorry about your luck.

[rynoman03]

That blows man. I don't get why people have such bad luck after building new motors with them not wanting to cooperate. It really sucks to put all that money into something for it to only last a week or two. So are you gonna rebuild this one or call it quits ?

[Colossus]

That blows man. I don't get why people have such bad luck after building new motors with them not wanting to cooperate. It really sucks to put all that money into something for it to only last a week or two. So are you gonna rebuild this one or call it quits ?

X2.....

[BillBoost37]

I have heard that if you don't align bore and have everything done properly these rebuilds go badly. I've seen my share of guys who rebuilt and got 200 miles out of them. Although on #3 you say you didn't touch the bottom end.

And ... you do have a ZZP PCM, most here would feel it's a liability.

[blueguy]

Well...I would say it...but everyone knows how I feel about it. Even though it wouldn't matter at idle really...have you ever had the PCM read to see what the tables looked like? I had mine align bored...and balanced...sooooo...it better work. But, correct me if I am wrong Bill but I thought that align boring was only necessary if you went with main STUDS, not TTY bolts.