wolverine8490

This may not be a bad idea either. Just pull the belt and start it. Will eliminate the belt and thing accessory related.

Old Mustanger

Good idea, all those components were removed & replaced during the cam install, so ya never know what could have gone wrong.

A couple decades ago I had a friend who owned a used car dealership. He purchased a car dropped off at scrap price. It had a bad knock under the hood. The receipts in the glove compartment told a story. Knock diagnosed as bearings led to a rebuilt engine. After engine rebuild the knock was diagnosed as being from the auto transmission, so a rebuilt trans was swapped.
But the knock was still there, so out of frustration, the owner dropped the car off at the used lot and just got scrap price for it. They had spent over $2k in repairs.....
My buddy asked me what I thought about the knock. I used my mechanic's stethoscope and poked around a little, then shut the engine off, pulled out my pocket knife and cut the A/C belt, the knock was gone and everything worked and ran perfectly.
The rear bearing in the A/C compressor was severely damaged. A replacement compressor from a junk yard for $30 and the car sold at a very good profit.

Bottom like, there are many things under the hood that can knock or make odd noises, and they all sound somewhat similar. Sometimes getting a proper diagnosis is really hard to get, but using proper diagnostic tools and ruling out possible issues one by one will get you there.

How would you feel if you accepted the first person's guess and replaced your short block because the mechanic "assumed" the problem was a bearing knock? You pay $3-4k for engine work and the knock is still there???

How many people have taken your car to a dealership for a problem only to return several times before you finally get a proper diagnosis and they replace the right part after replacing the wrong part several times?

65mechanic

An excellent explanation my friend!

Old Mustanger

Thank you.

JeremyB

if you want to make sure it isn't a rod bearing, unplug one coil pack at a time and see if the sound goes away

and you will not throw the rod through the block with a spun bearing, I drove mine several times to shops getting opinions before I figured out what it was, and it only made noise after 2krpms, made no sound under that

I'm starting to wonder if they drained the oil for some reason but didn't put enough back and it has been low this whole time

Old Mustanger

I am REALLY trying to not be obsessive here, but......

The things that can "knock" in an engine that will not immediately blow it up:

Main bearing knock.
Cam bearing knock (usually due to improper installation).
Collapsed lifter or bent pushrod. Or hyd adjuster on and OHC engine.
Stretched timing chain.
Broken clutch pressure plate, or flywheel on an auto trans..
Broken torque converter.
Broken A/C compressor.
Valve to piston interference after installing an improper cam.
Bad piston slap on a cold engine.

On one hand it usually doesn't matter if you get an improper "exact" diagnosis. They will always recommend replacing the whole shortblock or longblock, so whatever the noise was, it is most often replaced the first time.

But, telling someone that they can keep driving their car even if it does have a "rod knock" is REALLY BAD INFORMATION! In a very short period of time they will throw a rod and scrap their whole rotating assembly as well as their block.

Think about it:
With an engine at idle the rod bearing will be beaten 24x a second (once at TDC, once at BDC) WITHOUT LUBRICATION! At driving speed that translates to the rod bearing being beaten 66 times a second WITHOUT LUBRICATION!
That is a fairly hard steel crankshaft beating against a soft babbit & copper bearing WITHOUT LUBRICATION! Lifespan = a couple seconds at most.

My whole life, when I rebuilt engines I prided myself on being able to 100% diagnose engine failures. The way I looked at it was if I KNEW why an engine failed, I could build better engines in the future.
Almost always when an engine had a true "rod knock" it also had a rod sticking out the side of the block and the engine was scrap/unbuildable.

Only once did I see a "rod knock" failure that did not destroy everything. That was because the driver instantly shut everything off when he heard the knock. In that second or so the rod bearing was already beaten to about 1/2 it's normal thickness. That engine was rebuildable.

TEXASx2000xMUSTANGx

sorry for the late reply, but turns out my motor decided to just take a massive sh**. Not only spun a rod, also, bent valves, scored cylinders, pistons were getting torn up spmehow, and for a reason that i cant explain, some type of liqud has been dripping onto the block and eating away at it? idk. Doesnt matter, dss shortblock, forged internals, ported and machined heads, ect. all going in next week

Hangwire

Ummm. If your engine was fine before having this work done then I think you need to send the bill to your shop because they ****ed up and your pistons hit your valves dude......

MCxQubed

Yeah I agree with hangwire. If everything was good before then obviously it would be their fault for pretty much all the damage

Old Mustanger

With this evidence, I would assume that there was a lot of crud/gunk on the internal engine surfaces (like the valve covers) when your engine was partially torn down.
Assuming this, a good mechanic would have contacted you and recommend that they pull the oil pan, clean everything up good & install a new oil pump (never, ever go cheap on oil pumps that ESPECIALLY means crap made in China!)
Barring this, it is not uncommon for the new work to loosen up the crud in the pan, then it gets stuck in the pump pick up screen and chokes the engines oil supply.
I am an Engineer, I do not believe in coincidences. This damage is directly related to the actions or inactions by the mechanic. I would at LEAST demand a refund for the mechanics labor you spent on the engine work. If they refuse, find a reasonable lawyer and have him send a "Demand Letter". They usually fold when they get this letter.

If that doesn't work, file a suit in Small Claims Court (SCC), it is cheap, fast, fact driven and it works. You can file for the cost of the new engine, but the Judge may drop it down to a number he/she deems reasonable. Look up the laws online & print them out read them and understand the mechanic's laws for your state. Make certain you read the section on damages. If the mechanic is acting like an a$$, threatening, or anything like that, the Judge can double or triple the damages. SCC is easy and non-threatening. If you do your homework you will win. Generally speaking, the person with the most/best evidence will win. Be polite and respectful to the Judge and you will be good to go, the only question will be "why" the engine failed. You need to be at your new mechanics shop while it is being torn down & take a lot of pics. Get opinions from the mechanics, if they are in your favor, get an affidavit form from an office supply store and get them to fill it out for you.

Warning! When you get your engine work done ABSOLUTELY DEMAND that any valve that touched a piston must be replaced with a new valve. You cannot visually "see" stress in the metal. You want to aim at building your engine once and you don't want to do it again in 6 months due to a broken valve. I have even heard of machine shops recommending "we can straighten those bent valves for you"...... They obviously do not comprehend metal fatigue.