Engine Noise / Ticking, Knocking, Tapping MERGED

[eric489]

All threads with vague titles regarding engine bay noises are now merged HERE.

If you honestly feel we can diagnose an internal engine problem from a poor description or low-quality video / audio sample, give it a shot.


I own a 1997 gst spyder and there is a ticking noise comming fron the engine. It comes and goes and it mostly sounds bad at idle. I have 97,000 miles on it and i change the oil regularly. I changed it about 2000 miles ago I need help to fix the problem.

 

[kleenf4i]

It alll started when i raced a cobra mustang. I did win, so thats good. Now im suffering the engine consiquences. It a LOUD knock, almost grinding sound. Car wont idle anymore but turns over just fine. Its not the sound of a rod knock. this is very consistant.It grinds and knocks at the same time. Im thinking I dropped a valve or a couple valves. Whats some opinins?
95 gst

 

[Spanky_DSM]

Check the timing to see if it jumped.

 

[kleenf4i]

timing is on

 

[undefined0000]

It alll started when i raced a cobra mustang. I did win, so thats good. Now im suffering the engine consiquences. It a LOUD knock, almost grinding sound. Car wont idle anymore but turns over just fine. Its not the sound of a rod knock. this is very consistant.It grinds and knocks at the same time. Im thinking I dropped a valve or a couple valves. Whats some opinins?
95 gst

Best bet is to get us a video so we can begin to guess for yah.

 

[Calan]

Best bet is to get us a video so we can begin to guess for yah.

No, the best bet would be to NOT keep cranking on it and guessing.

OP - If you have checked all of the timing marks and are sure it is still dead on, then do a leak-down test and see if you bent a valve or punched a hole in a piston.

 

[kleenf4i]

No, the best bet would be to NOT keep cranking on it and guessing.

OP - If you have checked all of the timing marks and are sure it is still dead on, then do a leak-down test and see if you bent a valve or punched a hole in a piston.

yeaa on second thought it wouldnt be good to start again. timing is dead on

 

[Robzone0911]

yeaa on second thought it wouldnt be good to start again. timing is dead on

Leak down test. Check your oil for debris. Where did the grinding noise sound like it was coming from?

I take it you figured out your bogging issue since you were racing a Cobra?

Upon reading your bogging thread again I assume the bogging problem was also the result of the race against the Cobra??

 

[BogusSVO]

If you dropped a valve, you will know by the time you pull the spark plug. It will be mashed up and it will be a PITA to get out the head.

Also if the timing belt is all good, and did not jump, How do you figure you hit a valve hard enough to break the valve head off dropping the valve?

 

[Calan]

Leak down test. Check your oil for debris. Drop the pan and check the bearings and bottom end. Check to see if maybe you just destroyed the turbo. Pull the VC and see if you popped a rocker arm. Etc. etc.

There are all kinds of things you can do without cranking the motor over to help figure out what damage you may have, without potentially seizing bearings or gouging cylinder walls and causing even more damage.

 

[kleenf4i]

Leak down test. Check your oil for debris. Where did the grinding noise sound like it was coming from?

I take it you figured out your bogging issue since you were racing a Cobra?

Upon reading your bogging thread again I assume the bogging problem was also the result of the race against the Cobra??

havnt done leak down yet. the sound really seems from the head. Yes the bogging came right after I raced the cobra , so here is the end result and damage. Nothing banged or blew up, which makes this so weird. Again I always seem to get all of the crazy -oddball problems. The motor was rebuilt from the p.o.x2 and had about 10k on it. I can defiantly tell it was rebuilt. Ne cam seals, balance shaft deletez( the right way) , freeze plugs new cams. so Im thinking for some reason the keepers came out of the valves. Even after my run my car was fine until i went to pull again, then i noticed it, and the sound has gotten very bad at this point. From a minorly audiable tick to a loud grinding and klunk.

\
Also if the timing belt is all good, and did not jump, How do you figure you hit a valve hard enough to break the valve head off dropping the valve?

like i said, The motor was rebuilt by the p.o. x2 so iim saying it may have bent the valve by overreving and having the keepers come out.Also because of a MAJOR loss of power. Seems as though only 2 cylinders are firing.

 

[BogusSVO]

If the keepers came outsomething really would have had to go bad wrong.

The valve spring would have to be shot to start, loss of pressure or broken.

Then the piston would have had to hit the valve, shooting it up so the locks came out of the retainer.

The other way would be that the sping tention is too much, forcing the retainer up, making the locks act as a wedge, cracking the retainer.

In either case soon as you pull the VC you will know.

Also do you know what springs and retainers you have installed in the head?

 

[kleenf4i]

i was told they are new stock 4g63 valves springs and retainers.i just cant see it being the bottom end. but i will never know until i go pull the v.c. and/or oil pan gasket

 

[c2ypt1c]

Whats some opinins?

First thing that comes to my mind is a spun bearing...

As previously stated, it's not a good idea to run the engine, but you can take advantage of other's decisions and compare...Does it sound like this?
Spun Rod Bearing 4G63 turbocharged engine. - YouTube
Obviously, every bearing failure is different so the sound will not necessarily be the same, but similar...

 

[Robzone0911]

i was told they are new stock 4g63 valves springs and retainers.i just cant see it being the bottom end. but i will never know until i go pull the v.c. and/or oil pan gasket

Is it possible you floated a valve? You do have a factory rev limiter correct?

In any case. You are going to have to get dirty to diagnose this issue without starting the car. I would start by draining the oil, and looking for debris. If you have any shavings at all I would drop the pan.

If the oil is clean, pull the VC and inspect your valve train. If all looks good with the valve train you may want to drop the pan anyway and inspect the bottom end.

Good luck man.

 

[kleenf4i]

^ thats what it sounds like. at certain rmp it doesnt make any sounds like in the video.

 

[undefined0000]

^ thats what it sounds like. at certain rmp it doesnt make any sounds like in the video.

uh oh

 

[kleenf4i]

Is it possible you floated a valve? You do have a factory rev limiter correct?

In any case. You are going to have to get dirty to diagnose this issue without starting the car. I would start by draining the oil, and looking for debris. If you have any shavings at all I would drop the pan.

If the oil is clean, pull the VC and inspect your valve train. If all looks good with the valve train you may want to drop the pan anyway and inspect the bottom end.

Good luck man.

yeah, just sucks. ugggggh I hate people who "rebuild" and have no idea how to.

uh oh

yeah. dang im more thinking its bottom end at this point. thats exactly how mine sounds. A rod knock has a distinctive sound. this is the whirling knocking, come and go. so yeah i think its a spun bearing. damn. ill pull the v.c. and oil pan tomorrow to really see. 1 Question, will a spun bearing ruin the crank? I know this is dependant on the damage but on a typical basis. Ive never delt with a spun bearing. its never happened in any of my rebuilds.

 

[Calan]

...this is the whirling knocking, come and go. so yeah i think its a spun bearing.

How long did you drive the car once this started?

Your last description doesn't really sound like a spun bearing to me. Once a bearing is on it's way out, the sound is usually pretty consistent; it just gets louder and deeper.

What you've been describing almost sounds more like a compressor or turbine wheel grinding the sides of the housing, but that wouldn't explain the (not) running symptoms, unless something else is hosed as well. Chewed up timing components can also sound like that, and will definitely cause running issues if the timing has jumped.

 

[kleenf4i]

^ 2 miles thats all.

How long did you drive the car once this started?


What you've been describing almost sounds more like a compressor or turbine wheel grinding the sides of the housing, but that wouldn't explain the (not) running symptoms, unless something else is hosed as well.

its not the turbo thats for sure. I checked shaft play. and a turbo wont give symptoms of motor knock. its for sure internal. I dont really care about the head but it will suck if its the rods/ rod bearings

 

[Calan]

How did you verify that the timing is good?

A leak-down test + dropping the pan + pulling the VC should tell you everything you need to know.

 

[Timechg]

I had a strange situation where my crankshaft broke and was knocking/grinding. It would go away at a certain RPM, but there was something definitely wrong. I was hoping that it was just a bad throw out bearing....as soon as I saw the flywheel flopping back and forth I knew it was bad.

The problem with DSMers is that we are either hopelessly optimistic or just in extreme denial.

You can at least take your valve cover off to see if you theory about valve keepers leaving, or you could even just drain the oil pan to see if you have metal shavings. Constantly turning the engine on and hoping the noises will go away is not going to fix your engine and there has been a lot of good suggestions to end the speculation.

 

[kleenf4i]

How did you verify that the timing is good?

A leak-down test + dropping the pan + pulling the VC should tell you everything you need to know.

ill have to wait until i can have it towed for the major work. But as far as the timing, #1 at tdc then check the timing marks on cams

Ok, so here's the verdict: valve cover removal showed that the head is fine. so instead of draining the oil i pulled the dipstick and it looks like i went gold mining. So its defiantly a spun bearing.I dont feel like doing the work. or tracking down the parts, so im going to sell it. Ill get another one. My lesson learned for the second time this has happened to me, is to not buy from someone who claims they can rebuild a motor. Its only been a couple months since the rebuild. So the must have messed up putting the rod bearings in. oh well, one to the next one.

 

[Archer Fabrications]

Ive got a deep knocking when there is loa on the engine from the head, 100% from head. I'm positive it's not the bottom end, I'm curious if cam journals could be making the noise, it's not very loud but it's very fast, as if it is as fast as cams turning. When i drive and rev down the engine, i do t hear it, only hear it idling sometimes from 2-3k and driving slowly 2-3k before boost and before loud exhaust notes. Any ideas? I have taken off the vc and no rocker arms were missing and everything looked stable, timing is perfect, cams are Bc 272s that were used and on a wrecked talon. Any ideas?

Car drives and boosts just fine, the sound is just annoying. Trans is a new shep stage 3 so it's not that. New sprung 6 puck clutch also.

Ive pulled the pan and the rods are solid.

 

[kleenf4i]

Sorry man. better luck next time.

Thanks man. Question: It dawned on me, if the was no damage to the crank or rod, I can simply replace the bearing after polishing that journal. Do you think this is a possibility?

 

[BogusSVO]

Thanks man. Question: It dawned on me, if the was no damage to the crank or rod, I can simply replace the bearing after polishing that journal. Do you think this is a possibility?

Doubtful. Even if the crank looks good, I would bet cash that the big end of the rod is distorted and out of spec.

You only have .0007 from Hi to low spec on the big end bore.

At a min, the head would have to come off and have that rod checked.