How A Few Tiny Plastic Chips Almost Had Me Junking a Perfectly Good Engine
Sometimes it takes a long time to find a small problem – but patience pays off with car projects!
After buying a used engine for a 2008 Hyundai Tiburon, then realizing it was full of rust and water, I went back to the scrapyard to exchange it and try again. I got another engine, this one wrapped in plastic. I even turned the crank about a full rotation. But I still had a heart-stopping problem.
Christmas Eve was the next day and I, like every other American, had mentally checked out from work. I wanted to go home, and enjoy some holly-jolly or whatever the hell we do on Christmas. I mean, I looked over the engine. It moved freely, and it seemed like everything was good to go. But it was still going to be a pain in my ass.
Nah, nothing is ever that simple with my projects. Ever!
My mechanic, we’ll call him Tu, was moving a bit slower than usual on account of the holidays. No one wants to work on a dirty, greasy car, in a garage that smells like burnt oil and exhaust fumes on Christmas day, or New Year’s Day for that matter. But after January 1, he got cracking back into the car. I took a quick break from writing stuff here at Car Bibles and ran over to drop off the wheels outside his door, not wanting to bother his work.
Not even five minutes later, he calls me: “Hey, can you come back? I can’t tell what the F is going on with this engine…” Oh god. Did the yard give me a bad engine again? I shuddered at the thought. When I arrived back at the house, my mechanic turned the crank pulley by hand. He got nearly a full rotation… then couldn’t turn it in any further.
“Man, I dunno what the F this motor is doing,” he said.
“It looks like it might be out of time? I can’t really tell, the alignment marks are slightly off but not really,” He said.
The intake manifold was off, and the timing belt cover was still attached, at least the lower half. The upper part of the timing belt cover had a big hole in it. Nothing serious, but still, it was cracked. Sometimes junkyards bang stuff around a little, and a plastic timing belt cover is mostly only cosmetic.
The Hyundai/Kia 2.0-liter Beta engine is what is known as an interference design motor. This means that the pistons and valves (when open) occupy the same space. Engine timing makes sure that they don’t occupy the same space, at the same time. If engine timing is incorrect, the pistons can hit the valves, damaging them.
A visual inspection of the exhaust valves showed that they were in fact moving when the crank was turning. But once again, a full rotation of the crank would lead to the engine mysteriously not turning all the way.
“Oh my god, are the pistons hitting the valves and stopping the damn thing from turning?” I asked.
“Yeah, they might be,” my mechanic replied.
I had to reckon with the fact that the junkyard, a place I had shopped at quite a few times, had seemingly given me two bad engines in a row. The yard was kind about taking one engine back, but would they take back a second one? Do they even have a replacement engine for me? Would their replacement be just as bad?
I called my roommate, Garrett. The two of us have several friends that have 2001-2006 Hyundai Elantras, which use the same engines. He’s done several timing belt jobs on this engine, so he’d know more than me, or my primarily Honda-oriented mechanic.
“Sometimes these things have oil in the cylinders from sitting, or they don’t want to turn because compression builds from turning. There may be too much pressure, not allowing you to turn any further. Pull the spark plugs, let that pressure out, and then try again,” Garrett said.
That sounded reasonable. About a minute later, the spark plugs were removed, and we tried again to turn the crank.
“Dammit, I guess I gotta crack into this motor.” Tu took off the valve cover, so we could get a good look at the cams. They looked good, no rust or water. The chain tensioner that keeps both cams in sync looked taut.
Eventually, Garrett came to my mechanic’s shop – to help both of us figure out why the hell the engine is binding. Interestingly, he was able to strong-arm the crank to do more than one full rotation. It took a lot of work, which is bad, but it did turn!
I started off first: “Could it be, say, a rust issue or something? These engines are mostly iron, so like, maybe it’s been sitting awhile and there’s rusty something or other that needs a bit of lubrication?”
“Nah, it’s more likely to be a rod bearing with too much play, laterally. Might be intermittently rocking back and forth, binding the whole crank,” said Garrett.
“Yeah, if that’s the case this motor is effed,” said Tu.
I knew that if I pushed forward anyway, installed a motor with bad rod bearings, it would make itself known with a hard and ugly knock. No one wants to buy a car with a knocking engine, except me, maybe.
I was not looking forward to having to lift this engine up in the back of a Scion xB for a third time. The junkyard took my other engine back, but I wasn’t confident they’d be willing to give me a second replacement engine. I didn’t want to try and go full Karen and demand to see the manager.
“I’m not convinced this engine is ruined,” I said.
In a last-ditch effort to confirm if this motor truly was toast, we removed the oil pan, so we could check out what the rod bearings looked like. They looked great. No play in any of them. The oil looked old, but not in a bad state. Even with the oil pan off though, the engine would bind every other rotation. A borescope revealed that the cylinder walls, pistons, and valves looked fine, too. What the hell was causing the binding?
Mentally, I was distracted, already gear up for a potential fight with the scrapyard. I didn’t want to ruin my relationship with them, they were always nice to me, and even sometimes would cut me a deal on parts because I came there so much. But, I know they wouldn’t be too happy about a third engine for the same project being bunk from them.
“Let me check down in here,” said Garrett. The bottom half of the timing cover was still on, held on by the crankshaft pulley. “What the hell is that?” he exclaimed. Without another word, my roommate zapped off the crank pulley and removed the bottom half of the timing belt cover.
There, some plastic pieces from the shattered upper half had wedged themselves between the crankshaft gear, and the engine block.
(The timing cover plastic is brittle enough to be punctured but strong enough to block the crank pulley.)
What a relief; this engine was totally fine. We removed the plastic pieces, and sure enough, the binding went away. After leaving, my mechanic texted me “yep, this engine is in time now, and good to go.”
Crisis averted. Onto the next!
The moral of the story is: Don’t throw in the towel until you’re sure you’ve checked every potential problem area. And if you find yourself diagnosing a similar situation to what I described above, maybe some of the techniques we described running through will help you find the problem even faster than we did!