Happy Thanksgiving! Looking for some help regarding a pronounced engine tick/knocking.

I had my car at the shop for the last two weeks doing some suspension work and while it was there the mechanic did a smoke test and repaired a number of air leaks. After completing the work he then proceeded to start the engine and now there is a pronounced knocking/ticking noise. They pulled the oil plug and found small metal fragments attached. They also tested the cylinder compression and all is within spec and their camera showed clear cylinders. He suspects that the issue is at the bottom of the engine and is likely a spun bearing or rod issue on the 4th cylinder. (The car has 150,000 miles).

My question is that the car drove fine when I dropped it off two weeks ago and now on startup, clearly something is wrong. Is it possible that this is just coincidental timing? The technician rechecked all of his work and is confident that nothing was dropped into the cylinder accidentally. I don't have a video of the loud knocking that is currently there but the video below is prior to dropping the car off. Is the ticking in this video normal rocker tapping or indicative of the problem I now have? Obviously this is terrible news and will likely require a rebuild but trying to determine if it was only a matter of time or if there is reason to suspect the shop did something incorrectly.

Thanks in advance for your help.

 

Bearing material isn't magnetic - you'd have to do an oil analysis to figure that out.

Hard to tell from the video... might just be lifters or an exhaust header leak?

 

Thanks Van. The tech said he is going to send the oil sample out for analysis but the current knocking/tapping is much worse, definitely wouldn't feel comfortable driving it. I can't help but think something was screwed up while they were in there.

Hopefully I'll have an update next week but he said the engine needs to come out.

 

The ticking in the video just sounds like the normal injector tick. Mine sounds exactly the same.

Got a video of the louder current knocking/tapping?

 

I wish I recorded a video when I was at the shop. Definitely much louder tapping/banging. The tech was apologetic and told me he'd work with me on the repair cost but I really can't help but think everything was totally normal when I dropped the car off and the only scenario where this could happen overnight is if something was left behind in the engine when they were repairing the air leaks. It just doesn't add up that a rod or piston would go spontaneously upon startup.

 

That is quite strange indeed. I wouldn't take an engine out without first finding exactly where that noise is coming from though. It could be something simple like a loose belt slapping against the cover, worn water pump or pulley bearings or like Van said lifters or exhaust leak . Sending the oil out for analysis is a good idea though, as that will help determine if there's a spun bearing or not. In the meantime, you can also run the engine and pull one spark plug lead at a time, if the noise is decreased when you pull one lead, then it's likely the noise has something to do with that specific cylinder eg; that rod bearing is knocking.

A good way to pinpoint weird noises is to hold a hose to your ear and then move the other end around to where you think the noise is coming from. I had a pretty weird knocking noise, which I was having trouble pinpointing, but using a hose I was able to discover that the alternator pulley bolts had loosed off a bit and it was banging against the balance belt pulley.

 

A rod bearing can go without warning. Especially on a 150K motor depending on its history. The earlier suggestion of pulling sparkplug wires and see if the noise goes along with using a mechanics stethoscope will go a long ways. If the noise is coming from a cylinder and changes markedly when the sparkplug is shorted then the oil pan has to come off for a look see.

 

This is rodknock.

 

 

Yep... that's definitely the sound I was hearing.

Full engine rebuild?

 

the only thing wrong i hear is that your balance belt is way too tight.

 

I might have gone full retard.

I found the QRPV valve half stuck, so no oil to rod 2..

Voith sold me a nice crank.
H-rods
Wiseco pistons
LA Sleeves
And all other moving parts.
Ian at 944 online sold me a nice package with pumps, valves, seals,bearings ++++++

Take down the oilpan and check the rod bearings.

 

Any update ?

 

Spoke with the mechanic and was able to get my car the hell out of there - after he immediately resorted to a $6-8K rebuild for next steps. I researched favorable mechanics in the Philly area and ended up having the car towed to Possum Hollow motorsports (now Zeilger Exotics). I met the owner, Frank and explained to him the scenario where I dropped off the car in fine running condition and asked them to clear up any vacuum leaks and then when they started the car up the loud engine knocking began.

Frank and his team took a close look with a borescope and showed no cylinder scoring and no compression issues. After draining the oil, he also didn't find any metal shavings. He said the original shop used the wrong oil in the engine, incorrect injectors and plugs and it's possible one of the lifters was sticking causing the noise but he also mentioned that all of the screws on the airbox and intake manifold were finger tight and ready to cause major damage if the car was driven. They went through the entire car and fixed everything that needed attention based on the previous shop's work (diagnostics, belt tensioning, new oil seal, cam sensor) and he even aligned my headlights, did a smoke test and went over my suspension and exhaust - at no cost to me.

The car should be ready for pick-up tomorrow and I can't wait. He said the engine is running much smoother with all the kinks worked out and the belts re-tensioned.

I'll post an "after" video of the motor once I pick up the car. He tells me it's a night and day difference. Can't recommend this shop enough based on my experience thus far.

 

You should share a review of your experience with the first shop (Yelp, Google, etc.), maybe save someone else from a similar disaster. Why the heck did they do all those other things when your post said it was only there for vacuum leaks? Why isn't the second shop charging you anything?

cheers,
c