Engine noise- stuck lifter?

[Tim555]

While warming my car up on an easy drive to troubleshoot a hot start issue it abruptly started making a loud ticking noise. This happened off throttle going down a hill at 30mph in 3rd gear. The car was fully warmed up at the time. Oil pressure seemed normal before and after. The engine seemed to run rough for a few seconds and the noise got better, but was still loud. I drove it 1/4th mile, took this video and shut it down. I have not attempted to start it. It sounds like a lifter, but some people on fb suggested it might be a chain tensioner or a coil pack.

https://youtube.com/shorts/bMqIPn26riE?si=62JLZIm1N9ZcjiIc

[KPW]

Useful when troubleshooting to be able to prove things out quickly so the true issue can be found.

I can?t comment on lifters or chain tensioners so I?ll leave that to more qualified folks here.

That said, I do have experience with a coil pack failure.

Coil packs can be checked pretty easily with no real tear-down by getting resistance readings through the spark plug wire ends. They should all read similar ohm values.

Plug pairs per coil are:
1/6, 2/3, 4/7, 5/8.

When it happened to me the car got really loud on the exhaust note and idle was super rough. Turned out I had open circuit on one of my coil packs.


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[Tim555]

Update on this. I pulled the left side spark plugs and put a borescope down the cylinders. The plug from the rear cylinder seemed to be a little wet and dark. Picture is attached. Hopefully something didn?t get into that cylinder and bounce around. The bore scope showed a wet piston with carbon buildup. There are reflective spots that can be seen and I can?t tell if that?s glare or if it is actually shiny metal. I put everything back together and fired it up and the noise wasnt as loud. I then pulled the plug again and had a look down. No real changes. I started it back up again and revved it to about 3k and the noise seemed to almost go away, and stay away. The oil was changed in February but it looked like there was some sludge on the bottom of the dipstick. I was told the car sat for several years before that. Is it possible something just got into one of the lifters and temporarily affected the oil flow? The next step is to change the oil again.
https://youtube.com/shorts/qtXyKD6Wmhg?si=VznlxeizijrzQ7Db

https://youtube.com/shorts/JgwCl0OcePk?si=iF79X1G6zw8v4KE7

[HAWAIIZR-1]

Another vote for failed coil pack.


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[Tim555]

Another vote for failed coil pack.


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Is that driver side back cylinder #7? Do I just test for resistance between the ends of the 7 and 4 spark plug wires?

[HAWAIIZR-1]

Is that driver side back cylinder #7? Do I just test for resistance between the ends of the 7 and 4 spark plug wires?

Here is what I could find. It was the same problem I had years ago and thought the worst and it was just a coil pack. I hope same for you.

https://www.corvetteforum.com/forums/c4-zr-1-discussion/1403245-how-do-you-test-the-coil-packs.html

[Tim555]

Here is what I could find. It was the same problem I had years ago and thought the worst and it was just a coil pack. I hope same for you.

https://www.corvetteforum.com/forums/c4-zr-1-discussion/1403245-how-do-you-test-the-coil-packs.html

Thanks for the link. I hope so too!

[HAWAIIZR-1]

Thanks for the link. I hope so too!

YW. 🙏🏼 🤙🏼

[WARP TEN]

Lots of good advice here, but I would be remiss if I didn't once again post my idea for the strange ticking sound. --Bob

[phrogs]

Maybe that's my ticking sound as well, shows up out of nowhere and I can't figure out where its coming from sounds like its under the plenum on mine as well.

The problem is I just replaced them damn coil packs last summer.

[phrogs]

haha Not for me My tool control program is on point.



Lots of good advice here, but I would be remiss if I didn't once again post my idea for the strange ticking sound. --Bob

[HAWAIIZR-1]

Lots of good advice here, but I would be remiss if I didn't once again post my idea for the strange ticking sound. --Bob

😂

[WARP TEN]

haha Not for me My tool control program is on point.

Watch out Johnny--this soon could be you....Bob

[1991 Corvette ZR-1]

Just armchair quarterbacking the issue, but the rev to 3K rpm seemingly resolving the issue, to me, indicates an oil pressure or quality issue. The result is a ticking lifter or lifters. Does the actual drivability of the vehicle seem different? From a cruising perspective, or moderate acceleration, a failing coil pack will not allow you to maintain anything close to the performance you were familiar with before the issue developed. Unhappy ticking valvetrain will, it will just sound like a sewing machine from hell.

A bad or failing coil pack?s performance should not improve with increased demand in revolutions from air, fuel and now the significant increase in spark production demand from idle to 3K.

Furthermore, the heat generated from a cold idle time to a fully heat soaked motor from idling while diagnosing the issue should have an adverse impact on the failing coil capability to clear up when revved. You mentioned sludge on the distick, despite newer oil being changed in. If you can ohm the coil packs cold and hot and they check out, an oil change may be an easy option for next step.

With fresh oil, a few short drives SHOULD completely resolve the ticking lifter. If that is the case, something is in that pan that is compromising any oil put in over time and the valve train is not happy.

[Tim555]

Update on this. I checked the resistance of the coil in the affected cylinder. It was 21.3k ohms cold and 22k ohms hot. I did notice that I can hear a noise under the car as well, and can feel an exhaust leak where the header connects to the rest of the exhaust on this side. The sound seemed more substantial than an exhaust leak ticking, and I don?t know if that leak was there before I started hearing engine sounds.

The cylinder for the engine that I thought was making the noise seemed to be a bit cooler than the others. An infrared thermometer on that part of the header showed temps 60 degrees cooler on an idling engine. Seems like the exhaust leak may be unrelated to the other noise I have, but the sound is also apparent when you stick your head under the car by the drivers door.

[Tim555]

Video from under the car

https://youtube.com/shorts/sTq_7Pym044?si=xPvOYoK-Qcm1TaNr

[Matt B]

I tend to agree that it's not a coil pack issue. I had a faulty coil last year, one cylinder was down to no spark, and there was no noticeable noise but a MASSIVE loss on power. Car was merely driveable at all.
Which is interesting by the way, as in my early ZR-1 days I accidentally drove a short stretch with one spark plug wire plugged off - and didn't even realize it for a while.

So, for whatever reason a bad coil has a much more severe impact.

[Tim555]

Update on this. The noise seemed the go away. I was concerned about the sludge at the bottom of the dipstick so I changed the oil. It was pretty dirty despite the dealer saying it was changed in February (1000 miles ago, or so). I am very concerned about metal that appears to be in the oil. See photo. It looks gold. The rattling/lifter noise a few weeks ago sounded like lifters on a dry start, and then just a lifter tick.maybe a momentary disruption kn oilmto a lifter. Would this produce metal? I should mention I did have to drive a screw driver through the filter to get it off, but I don?t think this is from the filter.

[WARP TEN]

Did you save any of the oil? If so, you could send it out for analysis to one of the companies which do this. I don't know specifically who does it but others here have that information. --Bob

[Tim555]

Did you save any of the oil? If so, you could send it out for analysis to one of the companies which do this. I don't know specifically who does it but others here have that information. --Bob

I did save some. I?ll send a sample out when the blackstone oil sampling kits come in. I looked in the oil drain pan this morning and there was lots of glitter.

[Tim555]

Cut the filter open today. This is what I found. Some small silver particles. No gold ones like were in the oil drain pan.


https://youtube.com/shorts/kakxFT_zqoM?si=ZMQastpxuNvXhddD

[Tim555]

Results are back from the blackstone oil analysis. They didn?t seem too concerned. It doesn?t seem like the bearings are wearing, but there is a lot of iron and aluminum. Could one of the lifters collapsing, which may have caused the an engine noise, resulted in a cam lobe or lifter itself getting beat up?

? Using a fuel additive before sampling can result in a low flashpoint, but not in this case. No
water showed up either. Aluminum (pistons), iron and nickel (steel parts) are high compared to averages,
which are based on a 2,400-mile run. Copper looks fine on a microscopic level, but if you find more visible
metal next time then there might be an issue with brass/bronze parts - let us know if you find more metal
next time. The slightly low viscosity isn't a concern. Check back in 1,000 miles to see how metals are
trending?

[A26B]

......... Some small silver particles.........
https://youtube.com/shorts/kakxFT_zqoM?si=ZMQastpxuNvXhddD

See if they stick to a magnet.

[Tim555]

See if they stick to a magnet.

They do

[Tim555]

When changing the oil I noticed this part appears to be loose. It looks like the timing chain tensioner. See the video linked below. It also looks like the chain is rubbing on something. There are rub marks visible. Is this normal?

https://youtube.com/shorts/lVDWThbNe48?si=uYVWj6Dx96yDdgfn

[A26B]

The video looks like the facing for the top chain guide (attached to the cam cover) has come loose, broken or detached. It is not a common thing but has happened before.

The Cam Cover has to come off & the wear strip attached. It snaps onto the guide. The Guide is simple, just a flat plate, about 1/8" thick, with notches on each end.

[Tim555]

The video looks like the facing for the top chain guide (attached to the cam cover) has come loose, broken or detached. It is not a common thing but has happened before.

The Cam Cover has to come off & the wear strip attached. It snaps onto the guide. The Guide is simple, just a flat plate, about 1/8" thick, with notches on each end.

Thanks for providing that insight. Do you have those wear strips in stock? What are they made of? Does the chain always rub that much on them? In wondering if they?re the culprit for my shiny oil and high iron content that blakcstone said was in my oil.

[A26B]

Thanks for providing that insight. Do you have those wear strips in stock? What are they made of? Does the chain always rub that much on them? In wondering if they?re the culprit for my shiny oil and high iron content that blakcstone said was in my oil.

You are welcome.

Yes : https://www.jerrysgaskets.com/facing-top-guide-cam-cover-new-90-95-1f4/

Plastic:

Not much if the chain tensioner is working properly.

I don't think so, as long as the guide facing is still in place. From the photo, looks like to be detached only on the end you are looking at and maybe laying down lightly on the chain. It is hard to tell from the picture. You can probably tell better looking at it with a good pen light.

[Tim555]

You are welcome.

Yes : https://www.jerrysgaskets.com/facing-top-guide-cam-cover-new-90-95-1f4/

Plastic:

Not much if the chain tensioner is working properly.

I don't think so, as long as the guide facing is still in place. From the photo, looks like to be detached only on the end you are looking at and maybe laying down lightly on the chain. It is hard to tell from the picture. You can probably tell better looking at it with a good pen light.

Is the only way to get that end reattached to pull the cam cover?

[Tim555]

I was able to remove the passenger cover so far. The chain guide was still firmly in place. There was writing on the inside of the cam cover as shown in the photo. Is this factory, or has someone been in here before?

[bob@tradeshowconsulting.c]

Been following, interested in several pics of the chain Gude since you have the cover off.. and if it firmly in place...what was the loose piece you originally showed ? what condition was the plastic on the guide and will you replace ?

[Tim555]

Been following, interested in several pics of the chain Gude since you have the cover off.. and if it firmly in place...what was the loose piece you originally showed ? what condition was the plastic on the guide and will you replace ?

It was firmly in place. The loose piece was the chain guide that is attached to the top of the cam cover. The plastic seemed fine and didnt have much wear. I don?t plan on replacing it. I?ll take some pics and videos of it when I?m home in a few days.

[Tim555]

I got the other side off by drilling out the two stuck bolts. I was then able to free them up with heat once the cover was off. What a pain in the ***. I did not find anything obvious that would be the cause of any noise or metal in the oil. Is it safe to pull the fuses for the fuel pumps and injectors and crank the engine over? Spark plug wires are also removed and plugs loosened.

[bob@tradeshowconsulting.c]

Tim,

I have removed the fuel pump fuses many times without a problem,
sometimes after a month or more of storage , I pull them to crank the engine to build oil pressure .. before starting

[Tim555]

Here are some videos of the noise with the cam cover removed.

https://youtube.com/shorts/QLG1ntYRF-I?si=0W3_FwigdtHKd5Hz

https://youtube.com/shorts/FWlOfSDEsds?si=dJwdCUexmoP6U_Cw

[Jagdpanzer]

A word of caution.
The camshaft retainers that are installed under the cam covers are meant to hold the cams in place to facilitate the installation of the camshaft cover. They are a very loose fit on the camshaft. The smaller ones are not that strong and have been known to break if used by themselves to hold down the camshafts while rotating the engine. This is purpose for installing the 16 temporary camshaft retainers found in the Kent-Moore LT5 service tool kit.
20654


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[A26B]

Camshaft Retainer Set also found here.
Can be rented or purchased outright. See ful description for details.

https://www.jerrysgaskets.com/tool-set-temp-cam-retainers-for-cam-timing-14b2/

https://cdn10.bigcommerce.com/s-nkg90o/products/980/images/2475/ST-10197303__76259.1528764739.220.220.jpg?c=2

[A26B]

It was firmly in place. The loose piece was the chain guide that is attached to the top of the cam cover. The plastic seemed fine and didnt have much wear. I don?t plan on replacing it. I?ll take some pics and videos of it when I?m home in a few days.

If I understand you correctly, the steel guide was loose from the Cam Cover?
https://cdn10.bigcommerce.com/s-nkg90o/products/297/images/1690/10110932_N__52640.1443363294.220.220.jpg?c=2
If so, I suggest you remove both screws, clean the screws & the tapped holes with brake cleaner & blow dry before reinstalling with Loctite 262 (red high strength) You absolutely do not want it to come completely loose & get caught up in the timing chains. It has happened before.

Otherwise, I understand the plastic facing was firmly attached to the steel guide. Correct?

[Tim555]

If I understand you correctly, the steel guide was loose from the Cam Cover?
https://cdn10.bigcommerce.com/s-nkg90o/products/297/images/1690/10110932_N__52640.1443363294.220.220.jpg?c=2
If so, I suggest you remove both screws, clean the screws & the tapped holes with brake cleaner & blow dry before reinstalling with Loctite 262 (red high strength) You absolutely do not want it to come completely loose & get caught up in the timing chains. It has happened before.

Otherwise, I understand the plastic facing was firmly attached to the steel guide. Correct?

It could be moved slightly, side to side, but I can?t get it off with just my fingers.

I did take a look at the timing chains and noticed something very strange. On the passenger side there were all these scrape marks on the side of the head. It was hard to get a picture of, but I attached a few that turned out ok. Is it possible for the chain to move this much with a bad tensioner and cause that? That would explain the metal in the oil and the elevated aluminum and iron that the used oil analysis showed. That cam cover did have 9/14 written under it in sharpie while the other side was blank, so maybe it?s old damage that was repaired?

[Tim555]

Pics didn?t attach. I?ll try again

[Jagdpanzer]

My heads have those grinding marks too. They are from the finishing work done at the factory to remove casting flashing during production. From what I can see nothing to worry about.


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[bob@tradeshowconsulting.c]

When changing the oil I noticed this part appears to be loose. It looks like the timing chain tensioner. See the video linked below. It also looks like the chain is rubbing on something. There are rub marks visible. Is this normal?

https://youtube.com/shorts/lVDWThbNe48?si=uYVWj6Dx96yDdgfn

Please confirm that this loose chain guide in the video is not supposed to be loose ..? and how did you tighten it ?... because the wear strip is a separate piece and ......was it damaged? what caused the marks on the chain ? etc...

And ultimately was this the cause of your noise? or just additional issue ?

Hoping you find answers and get it resolved

Thanks

Bob

[Tim555]

Please confirm that this loose chain guide in the video is not supposed to be loose ..? and how did you tighten it ?... because the wear strip is a separate piece and ......was it damaged? what caused the marks on the chain ? etc...

And ultimately was this the cause of your noise? or just additional issue ?

Hoping you find answers and get it resolved

Thanks

Bob
It wasn?t really that loose when I took the cam cover off. I did not figure out what the cause of the noise is. I?m in the process of putting the cam covers back on. The passenger side is very difficult to get back on!

[bob@tradeshowconsulting.c]

did you re-secure / Tighten the chain guide ? is it bolted in or screwed in ?