As some of you may remember, I burnt a couple of pistons back in mid August. I pulled the engine, tore it down to a bare block, took the block and had it cleaned, machined and checked along with the crank. Kept the same bore and crank was good. Ordered new Wiseco pistons, Total Seal AP series file to fit rings Swapped out the triple 12 cam , put in a Summit stage 2 turbo cam. Swapped from my PRC stage 2.5 heads to some RPC heads(supposedly thicker decks), Put it all back together using new LS7 lifters, Cometic head gaskets.

So I got it running a week or two ago. Fired up on the first attempt. Idle was smooth as can be expected with that cam. Seemed to run well, no noises with the hood up at idle. After checking for leaks, etc, took it out and put about 50 miles on it but on the way back I started noticing a strange noise that seemed to be in time with a cylinder BUT only on trailing throttle. If I had a load on it(going up a hill or just accelerating, no noise. It's not a tick or a knock when driving on trailing throttle, it's more like a 'tsk, tsk'. My first thought was perhaps I didn't tighten one sparkplug all the way. But when it cooled down, I checked them all and all were tight.

After that, I again opened the hood , got in and started it, fires right up and idles fine. I go out to the front of the car, going around the perimeter of the engine bay and listening. I don't hear the noise. So then I grabbed the throttle body bracket and rotated it to make the engine rev up, just quick throttle blips. Now, I could hear something like a metallic click as the engine hit a certain RPM level but it would go away as the RPM went back in the direction of idle.

I checked the oil, no glitter. Coolant temps stay just under the first quarter mark, Startup oil pressure is 85psi, warm idle is 40 psi.

I'll do a few more checks (compression tests, bore scope) before pulling it out and tearing it down again,

 

Double ck for an exhaust leak, those things can drive you crazy.

 

Will do. Thanks!

 

Flywheel bolts loose?

 

I definitely torqued all of them to spec. Thanks though!

 

Replaced both gaskets but the sound is still there. I borrowed a bore scope and will check the piston tops and cylinder walls after she cools down.

 

Replaced both gaskets but the sound is still there. I borrowed a bore scope and will check the piston tops and cylinder walls after she cools down.

 

Well, the bore scope showed that a wrist pin has walked and was scuffing the cylinder wall. I must have mis-installed that spirolock. I took everything off and will finish dropping the engine/trans tomorrow.

 

Thats unfortunate but good catch!

 

Good early catch. Hope the cylinder checks out ok. Hate those damn spiro-locks.

 

Bummer, but I guess if it had to happen better going into winter as opposed to spring.

 

Yeah. Thats my feelings too. Got the engine/trans dropped out. Was only able to get the intake off before the wife called to tell me to come home. I sourced another complete engine for $250 (200k engine, std//stock bore 5.3) that I'll pick up next Saturday. I just want the block more than anything. I weighed the possibilities of

1. Boring my existing block to whatever oversize it would take to clean up the scored cylinder wall, buying new pistons(remember I just bought a brand new set of 3.810 Wisecos for THIS engine and Total Seal AP series rings($2xx a set). Have it all balanced
2. Or buying a standard bore block , bore it to 3.810 , use my existing pistons/rings, bore the scored block to whatever size it takes to clean it up, set it aside for future use, I'd swap the rotating assemblies so I don't see any reason to rebalance it.

I've decided to go with option 2.

 

thats sum bad luck right there