Follow up, and some insight on the Hyundai Gamma T-GDI engine.
Confirmed one exhaust valve slagged, also this wear at 6:00 and 12:00 on all four cylinders - probably why these engines have such bad oil consumption issues. After getting it back together and driving a little bit to shake it down, I discovered it's tuned to stay under 2,500 RPM unless you really hammer on it. Even climbing a relatively steep hill at 65 MPH it knuckles down and stays locked in 7th gear at 2,000 RPM rather than downshift - which makes it feels powerful but means it's boosting hard to make that kinda low speed torque. I'm going to go out on a limb and say very short pistons without a full skirt in such a small, undersquare, boosted engine running in an RPM range considered lugging for most other small 4 bangers, all combines to cause really bad ovaling of the cylinders. Once you get the intake and rats nest of wires and hoses off the front and driver's side of the engine, the rest of the process to get the head off really isn't that bad. Timing chain and cam marks are easy, and there's an oil jet pointed directly at the chain right above the crank sprocket. Valve clearance is by bucket shims so that makes a valve job more laborious. None of the exhaust manifold hardware was in visually bad shape but one turbo>downpipe (cat) bolt was snapped off and missing already, another galled up and snapped during (gentle) removal, and upon reassembly one exhaust manifold stud finished breaking>pulled 2 threads out of the head.
I feel like shorter OCI's alone can't prevent this wear, eventually - maybe a tune favoring slightly higher RPM at medium and higher load would help, but there's still just apparently poor material quality throughout. Is what it is; at least I now have some first-hand study of this brand+era to relay to anyone considering buying one.
Confirmed one exhaust valve slagged, also this wear at 6:00 and 12:00 on all four cylinders - probably why these engines have such bad oil consumption issues. After getting it back together and driving a little bit to shake it down, I discovered it's tuned to stay under 2,500 RPM unless you really hammer on it. Even climbing a relatively steep hill at 65 MPH it knuckles down and stays locked in 7th gear at 2,000 RPM rather than downshift - which makes it feels powerful but means it's boosting hard to make that kinda low speed torque. I'm going to go out on a limb and say very short pistons without a full skirt in such a small, undersquare, boosted engine running in an RPM range considered lugging for most other small 4 bangers, all combines to cause really bad ovaling of the cylinders. Once you get the intake and rats nest of wires and hoses off the front and driver's side of the engine, the rest of the process to get the head off really isn't that bad. Timing chain and cam marks are easy, and there's an oil jet pointed directly at the chain right above the crank sprocket. Valve clearance is by bucket shims so that makes a valve job more laborious. None of the exhaust manifold hardware was in visually bad shape but one turbo>downpipe (cat) bolt was snapped off and missing already, another galled up and snapped during (gentle) removal, and upon reassembly one exhaust manifold stud finished breaking>pulled 2 threads out of the head.
I feel like shorter OCI's alone can't prevent this wear, eventually - maybe a tune favoring slightly higher RPM at medium and higher load would help, but there's still just apparently poor material quality throughout. Is what it is; at least I now have some first-hand study of this brand+era to relay to anyone considering buying one.
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