"Pinging Sound"
 

Hey everyone, I'm hoping I can get some advice with what to do with a 3400 thats giving me a pinging sound:

History -
02, 3400 - 120000KM on it, buddy called me up said the engine "blew". Took it down to the heads, No. 6 cylinder area was warped (determined this was due to cristalized dexcool in the coolant vessels). We had the heads redone, all good to go. Put it together, had a banging sound that eventually went down to a subtle clicking sound.

Tried thinner oil, tried thicker oil. When the engine is cold, no pinging sound. When it warms up, it's back. Same place, right around the No. 6 cylinder. Took the heads off again, retorqued everything to the specks that were given for the 3400... can't get rid of it.

Engine works fine. Loads given, taken from slow idle to a steading increase until the governer kicks in, no damage is being done, no power is missing, just keep getting that constant pinging sound.

Any advice?

rockers torqued correctly? Is it standard lifter tick? Or possibly piston slap?

Rockers are torqued correctly, a number of times now...
I'm doubting its piston slap, doesn't sound like it at all. I'm leaning towards the lifters...

ok, umm... were the heads disassembled? Are the valves, springs and retainers seated properly? Lifters pre-lubed, im pretty sure they need that. I wish i could be of more help, im not the greatest diagnostic person, im just kinda bouncing ideas around.

Lifters were soaked and lubed with moly-urithane ("moly grease"). However, we are starting to lean towards piston slap, due to a collapsed piston. Any advice?

I'm thinking, if this is the case, hitting up Mantapart for the billet rods and new piston heads for all 6 cylinders...

god i wish i could tell you. Last i heard GM didnt even have a fix, my roomates girlfriend's 3400 monte got it and the replaced the piston under warranty so i dont know what to tell you. I would consider calling a dealer and talking to a mech for advice unless BJ or someone more knowledgable than i checks this out soon.

You know you can just narrow down a set of 5.700" small block V8 rods and use them instead of some high-priced V6 specific ones..

Cliff, can you give me more info on using down the rods you speak of? And in using them, what else needs to be done?

I don't have it right in front of me right now. I'm sure you can find info at www.60degreev6.com

check your rod bearing clearance before buying all the rods and pistons just in case there isnt any play....and make sure you get hypereutectic pistons...they are a lot stronger

Have you done a compression test? If it's piston problems, a compression test should show lower on the faulty cylinder.

my buddy got a 3400 from bucks autoparts for $325 out of an alero that was totaled. has less km than mine and its going into a 91 Z24. try a wrecker and get a new one.

Done and done... we checked the compression of cylinders, and yes, showed us that it's the no. 6 cylinder, as we figured. But, good confirmation. 900 CND for a 3400 with 16000km on it. Made us happy. This one that's there is going to be ripped right down until we find the issue with the knocking.