Originally Posted by ray42

Patwac,

Those pix are pretty good, for a new borescope ace.

From here, I'd say that you have dodged a bullet. I'm guessing that you believe only one cylinder bank has a problem, which is usually correct. You have "scratches" and cross-hatching going around the cylinder walls, which is very good news at 148k miles. That engine probably spent a good portion of it's life running with full-synthetic oils, also good news. Gouges going up and down the cylinder walls would be bad news, and I don't see much of that (so far). Obviously, once you have seen all around inside each odd-numbered cylinder with a borescope, you would want to pull that head first, and let in some daylight for a better look there. At that point, I'd want some local experts to give it a second look, in person. Buy dinner, for their expert advice. You can get a lot of valuable tips, over a good meal.

So far, it all looks encouraging. The condition of rod bearings, end bearings, and main bearings would be guesswork from here, and you would need to look at them physically to be sure. The oil pressure gauge would give you a clue (if it runs healthy and steady), but that is not much to go on. If the coolant you have in the engine is mostly water, not antifreeze, you may dodge another bullet there, also. It's your call, on the bearings. Local experts may be helpful, there.

If new head gaskets and fresh oil does not get your Z running smoothly, you may have a problem in the Optispark. The LT1 Optispark does NOT like antifreeze (or even water). If coolant got in there, that could explain the hard starting and rough running, or maybe it was just the water in the cylinders, earlier. The Optispark is the Achilles heel of the LT1s, IMO. They are expensive to replace, and there is junk being sold new, so if needed, purchase by reputation, not by prices. Check for traces of coolant in or around that thing. You have a newer version there, with better sealing against coolant damage, so it may be okay anyway. Checking the Optispark's electrical operation needs gear that you and I do not have, but you can probably drive it to a good shop for that check.

Best wishes.

Originally Posted by patwhac

As far as local experts, I am very skeptical about the knowledge of most mechanics, so I'd have to do some digging to find someone suitable. Kinda the reason I joined this forum haha Are the fasteners on these engine metric (head bolts, exhaust manifold bolts)? I'm used to everything being all SAE . . .Thanks again!

Originally Posted by Injuneer

Guide to some of the hardware, from Shoebox:

4th Gen LT1 F-body, Fastener Torque and Spec Matrix

Head bolts are SAE. Can be either 1/2” or 5/8” head.

Already provided the factory service manual download link.

Originally Posted by Injuneer

If it’s been seriously overheated, I would do both sides.

Originally Posted by patwhac

I was able to sneak in a couple of hours on the Z after work yesterday, and was working on removing the passenger side plugs when I did something stupid! I let my socket wrench touch the power stud on the back of the alternator (which was uncovered for some reason) for a couple split seconds and made some sparks. Naturally I disconnected the battery ground and kept working. When I reconnected the battery and went to try and bump the engine over to get the borescope a good view, the engine now will not crank. I have dash power, battery is still charged, fuses in the dash and under the relay box are all still good . . . What did I blow that's preventing the starter from cranking?

Originally Posted by ray42

Patrick,

Did the engine crank, before the sparks? IOW, is the car in gear now? Clutch pedal depressed? Without the right schematics here, my guess is that there is a fusible link blown. It looks just like any electrical wire, but it acts as a fuse. It may be marked as a "fusible link" on the insulation. Trouble is, you usually can not see if they are blown or not, by looking. A voltmeter, measuring voltage at each end of the fusible link, will tell the tale. I do not know where they are located on the Z28, but typically on cars, they are located (electrically) between the battery and the fuse boxes. A loose or dirty battery terminal can also be the problem, not carrying enough power to crank the starter.

On the basis of "one disaster at a time," the immediate problem is to rotate the crankshaft. With all of the spark plugs removed, you should be able to turn the crankshaft with a wrench (or strap wrench) on the lower pulley.

Originally Posted by patwhac

I did something stupid! I let my socket wrench touch the power stud on the back of the alternator (which was uncovered for some reason) for a couple split seconds and made some sparks.

Naturally I disconnected the battery ground and kept working. When I reconnected the battery and went to try and bump the engine over to get the borescope a good view, the engine now will not crank. I have dash power, battery is still charged, fuses in the dash and under the relay box are all still good . . . What did I blow that's preventing the starter from cranking?