r/EngineBuilding

Im rebuilding/refreshing this small block chevy its a 1970s ish block and heads rebuilt by Jasper a while ago my grandpa had it in his Biscayne for about 20k miles. Tearing it down to put in new valve stem seals I found these cracks from where new valve guides have been pressed in. THE CRACKS DO NOT GO ALL THE WAY THROUGH. They are only on the surface where it was drilled thin and new guides were pressed in but i am curious if it will be good to send it anyways. Im not too sure how it ran/if it smoked before since it has been out and non running for quite a few years.

350 SBC (.060 over), 601 heads (1.94 in / 1.50 ex)

LS firing order roller cam .480 lift (218/239)

Edelbrock Performer Intake with a 750 carb

Going in a 3rd gen Camaro

- 2500 stall

-700r4

-3:42 gears

TL;DR: bearing housing completely shattered

This is what’s left of the turbocharger on my 944 Turbo. How it happened: spirited drive through the mountains, full throttle. Water temps were raised but nowhere near the red mark, oil pressure fine.
Suddenly a huge bang, smoke everywhere and no power. Luckily it didn’t catch fire, as oil also went onto the hot downpipe.
The turbine wheel is mangled, turbine housing cracked and the shaft is bent. Bearings are slightly scratched but not seized or anything. Compressor wheel briefly scratched the housing too.
But most importantly: the bearing housing is completely shattered, so much so that oil and water actually mixed in the turbo and went into the exhaust and oil pan.
Do any experts here have an idea what happened? The seller says he never saw anything quite like it.

The Engine has about 5k miles since full rebuild. What can cause this type of wear? In picture 2 you can visually see the gap between the piston and the cylinder. I took the head off because of a high iron and aluminum count in the oil report.

*Its a 2 liter out of a 1987 Mazda b2000

I can’t find this dark blue link in the chain. I keep cranking and can’t find it. It appears to be either worn or the varnish has covered it. The timing mark also doesn’t land on a link. It just stays in between the links. Any advice?