How long can an engine overheat without damage?
Once it reaches maximum“Hot”, you get less than a minute, before you start to do serious damage, such as seized up valves or pistons.

 

Alright first off sorry if this isn’t in the right form area or if I’m on my old form and it’s to old. Anyways I was the guy that had his girlfriends hummer with the hole in the piston, after the community told ,e to get a new engine I finally found one a month and a half ago. It looked like a dream come true it was close and fairly cheap. Anyways the guy told me he pulled it for the v8 swap. The main problem I’ve found is it’s from a 09 h3, and hers is a 07. After putting the engine in and trying to fire it I found it had no spark. I guess I should have done my reading first, I needed to swap the camshaft reluctor wheel on the exhaust side, the intake I pulled the engine again and pulled oil pan again and front timing cover removed the new timing chain and tensioner, drilled the new hole for the sensor, which I measured from the old engine with a micrometer. So I thought it was exact. Anyways got it all back in and presto it fired up, but in doing so it has codes p0340,and p0341, also has p0017 but I’m thinking it’s all in the intake sensors placement. I used my multimeter and back probed the intake and exhaust cam sensors and on the exhaust side (The good side) on the signal wire it’s fluctuating, but my multimeter has a bar graph thing that actually shows that it’s changing voltage super quick even though the voltage doesn’t refresh as quick, on the intake side the signal wire is more a constant to definitely not changing as quick or really at all.it will fire up every time but sometimes there’s a clunk and the engine stops but fires right up after like the camshaft actuator advances all the timing or something, sometimes it fires up without the clunk but everytime it takes like 10 seconds to start. After it’s fired up it runs great you’d never even know there is something wrong. It’s not misfiring . I’ve also found now today a picture of a LLR 3.7l that had no intake camshaft position sensor, but like on mine where I actually had to drill the new hole for the sensor I found on this form where this guy had a metal plate over his intake cam sensor hole and he said from the factory, but the looks of that hole it appears to be off from mine. But mine is set up from the 07’s old engine. I have the pic from the form and I can take pics of mine. I tried a new sensor today but that didn’t change it. So I’m now thinking it’s a alignment issue. Thanks everyone I got so close to having it to give back.