Help to identify top end noise

gmcman

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Ha..thanks! :thumbsup:

I didn't notice any irregular movement of the rod and pin. When I look at the RH side of the motor, my attention is drawn to what seems to be the slight slap of maybe Cyl #2.

Cyl #4 doesn't appear to jump out as far as being noisy upon first glance, but when you put your fingers on the coil pack you can feel basically a tremor when the plug fires. All the other 5 coil packs have no felt vibration, #4 is very noticeable.

I don't believe..it's a wrist pin, but this motor can make some intense sounds and can come from anywhere.

I don't know what can make that felt vibration in the coil, kinda like a shock wave.

The piston doesn't look overly caked in crud, a thin layer of carbon on the crown..not sure what the chamber looks like or how much squish is avail.
 

mrrsm

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Have you tried using the ACDelco Top Engine Cleaner or the Berryman B-12 Spray yet? (NEVER use these Powerful Solvents by pouring them into and through the Fuel Tank System). The Atlas Engine In-Line Design makes inducing this stuff into the Cylinders a BREEZE via removing all of the Spark Plugs and then just pouring it in; or better yet, using ACDelco's TEC Spray Foam Flavor to access and expose all of the upper combustion chambers and Valves enough to dissolve all of the Heavy Carbon Build-Up around the Valve Seats. The whole job will require 2-3 Cans of this stuff... and it is safely and best done when the SUV is parked out in the Open Air.

By using a sufficient quantity of these solvents to directly soak in an around the Piston Heads and upper Low Tension Compression Rings...you'd be able to get those Piston Rings to RELAX. Using this method does require pulling the Fuel Pump Relay and working with plenty of Scott Blue Shop Towels stuffed down inside of the Spark Plug Wells... turning the Motor over for several 15 Second Cycles to pump out the excess solvent through the Spark Plug Holes to avoid Hydro-Locking the Engine if the "Black Goo Mung" dissolved Carbon Slurry were left behind. Don't forget to re-install the FPR after the Spark Plugs get threaded in and torqued down properly.
 
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gmcman

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I've run this through the throttle body via spray bottle...1 oz cleaner to 7oz gas.

Screenshot_20190526-023057_Gallery.jpg

I haven't tried anything else but willing to give anything a shot. I'm not going to say chemicals will fix the issue....but surely worth a try.

The noise through the stethoscope is a sharp, hard hit...the noise goes away when I unplug the coil so it really could be anything.

What's puzzling is how pronounced the noise is with the stethoscope but barely audible without it. Either the shock of the slap travels up through the plug well and/or the chamber has deposits and increasing compression.

Would the foaming spray be the strongest? I would assume it would get into the top of the chamber easier.
 

mrrsm

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You MUST consider that regardless of the Engine Mileage and the Excellent Care you rendered with your regular Oil Changes... Once that Wear took hold ...a Conspiracy went to work to make this Bad Behavior possible. "The Legendary Mac's" @m.mcmillen 's disassembly photos show just how bad the the Piston Skirt Wear AND the Cylinder Wall Scoring and Wear can get. It will always become most pronounced when the Pistons approach Top Dead Center. This is due to the unavoidable Rocking and Off-Set Connecting Rod Procession that MUST occur to keep the "Smoothness" of the Crankshaft Rotation working as well as possible.

If the Compression Rings are impacted and literally FROZEN inside of the Mahle Piston Ring Grooves... then they are doing NOTHING to stabilize these hectic Piston Motions at the positions where the Pistons are at the extremes in the Up to Down Turnaround transitions. Add to this is the presence of High Compression and the resulting F/A Detonations from the Power of Combustion that can literally hammer each piston thusly... and so ALL of these artifacts combine to accentuate the Presence of Piston Slap.

Consider this action for possible help: If you use the ACDelco TEC (Top Engine Cleaner) Which I very much recommend in the FOAM FLAVOR... for around $15.00 a Can when available on Amazon... then the reduction in the presence of the Carbon Mass clogging the Upper Combustion Chamber will serve to restore the correct "Quench" as each Piston gets to TDC and thusly, it REDUCES the chances of Engine Knock occurring due to Pre-Ignition of Low Octane Fuel from Excessively Higher Compression than should be in there. Once the Carbon is gone... the smoothness of the "SSBB" (Suck-Squeeze-Bang-Blow) Cycles should return in all RPM Ranges. :>)
 

gmcman

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This is the can of B12 I currently have, not the spray, but not sure if it's the correct one for the job.

Screenshot_20190526-045112_Chrome.jpg
 
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mrrsm

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I used THAT very same stuff during my February to March 2019 Nissan Quest Triple Timing Chain R&R Debacle and THAT STUFF WORKS! In cases of having completely intractable Gas Gum and Baked On Black Carbon Deposits and Oil that Brake Cleaner Spray would NOT touch... THAT Stuff COMPLETELY dissolved all that mess from inside of the front of the Gummed Up Engine Block and it completely cleaned the same mess off of the Inner Timing Chain Case Cover of the Nissan 3.5L Engine.

Observe Caution...

The ONLY problem I had with this Solvent was that it has a VERY HIGH VOC (Volatile Organic Compounds) LEVEL and thusly... it Evaporated so VERY QUICKLY. This Character of its Chemistry is very unlike using the ACDelco Top Engine Cleaner...which has the very same kind of Noxious dangerous Fumes.... BUT it will give you PLENTY of time to work with the Stuff.

On the other hand... THIS material will NOT be hanging around very long. If you use it to "Clean Your Fuel System" ... you might also run the Risk of Ruining the Catalytic Converter as it tries to Burn off the Vapors of this Hellatious, Infernal Solvent. And Please ... Don't expose yourself to the Fumes this stuff creates any more than is absolutely necessary... and NEVER use it when inside of any enclosed space or Garage.

One More Precaution...

In cases of using either one of these Powerful Solvents... You will have to Change out your Engine Oil and Oil Filter after this Treatment is completed as it will pass by the Piston Rings and invade the Crankcase Oil Reservoir. The results will be that the Engine Oil Lubricity can be Destroyed AND it can also Eat through your PTFE (Poly-Tetra-Fluoro-Ethylene) TEFLON Engine Oil Seals: Valve Stem Seals, Front and Back Engine Seals, etc.; as .all can be softened or ruined when exposed to concentrated levels of these Solvents. It can also dissolve portions of the Filter and the Filter Sealants of your Inner Oil Filter and thus, allow them to break down and migrate up into your Oil Galleries where they can cause all sorts of 'Mechanical Mischief".
 

gmcman

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I warmed up the motor then drained the oil since it has about 3 hrs of idle time.

I plan on filling up the pan with some bulk oil to rinse anything that fell into the pan.

This is the crown of Cyl #4 before the B12.

Screenshot_20190526-164407_Gallery.jpg

Here's the B12 working on Cyl #4, I let it cool for awhile but the rings were likely still hot enough to boil the B12. You can see the bubbles working there way up from the rings.


This is after and now its soaking overnight in some MMO.

Screenshot_20190527-014048_Video Player.jpg


I agree the B12 is quite aggressive.
 
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mrrsm

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Marvel Mystery Oil will definitely soften up the Carbon Deposits... But in order to Completely Dissolve them...and Free Up the Stuck Compression Rings... Either the ACDelco TEC or the Can of Berryman's ChemTool you showed will be the 'Go To-> Juice...To Break It ALL-> Loose".

Here are some "Before & After" Images of my 2002 Trailblazer 4.2L Engine showing just how much Carbon can collect inside of the Combustion Chambers after 240,000 Miles and especially around the Valve Seats as well as on the tops of the Pistons and in and around the Compression Rings.

The "semi-circular' Black Rings laying on top of some of the Pistons resulted from me hammering each Head Bolt so hard...that those Carbon Rings broke loose from around some of the Valve Seats.

Conversely, you can see from the "After" Images what the ACDelco TEC sprayed down into each Cylinder after an Over-Night Soaking... The results were that the Black Carbon "Goo" Mung... wiped right off like it was NOTHING...with NO Scrubbing or Abrasive Actions necessary:

43818530771_00fe73f5a4_z.jpg42717544884_43fa690ebb_z.jpg43433659291_cef623e7e4_z.jpg43101817624_1b5065c946_z.jpg43433608921_ffc759454d_z.jpg

...and using the same Berryman B12 ChemTool stuff shown in your Video, I was able to remove ALL of the 'Gas Gum & Black Mung' off of the Outside...and most importantly...the INSIDE of this Nissan 3.5L DOHC V6 Timing Case Cover and as you can see... it came out Squeaky Clean:

32529105587_bdd8ee43c4_z.jpg
 
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gmcman

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Man....that looks like quite a bit of work...:crazy:


The rest of the pistons look like #4, with the exception of #1. I had wondered what a worn cam phaser sounded like....maybe the noise was coming from #1...lol.


Cyl #1 piston crown

Screenshot_20190527-030508_Gallery.jpg

Just so others know I'm on the same page....there's no doubt this motor has some miles on it, I figured it was either piston slap, worn bearings, possibly a wrist pin.

I'm fine with the fact it has gone 17 years and almost 300K miles and if it needs a rebuild then I accept that.

I have to dive in and cover some bases first, the rod bearings definitely quieted the bottom end a little for sure, it was bad enough I had to stop driving it.

The clogged PCV system didn't help anything, could be the major contributor. The carbon build up is either from the PCV system or just blow-by from worn rings.

I figure I'll give the rings a soak, see what happens....might knock like crazy now...lol.

This is the first time I've pulled all the plugs since I fixed the PCV system, hard to say what the ring packs look like.

Plan is to get it up and running early this week and keep an eye on it.
 
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gmcman

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The pistons cleaned up nice with the B12, I added some MMO just to get something on the rings for the start up.

This is #1, and was the worst. Would another dose of B12 dissolve the remaining deposits or just leave it be?

Screenshot_20190528-104504_Gallery.jpg

I let the MMO soak overnight, added about 1/4" above the piston....took a few hours to drain...which leads me to another question..I assume the MMO would leak past the rings?

Not sure if others have the MMO still sitting in the cyl the next day...because....mine wasn't..lol.
 

mrrsm

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As long as you are intent upon Changing Your Motor Oil and Oil Filter when these Berryman B-12 Treatments are done...go ahead. Just know that MMO may be shielding the Carbon Deposits from the Full Chemistry of the Berryman B-12 Liquid... so perhaps by not "Mixing your Medicinal Metaphors" it can do a much better job at dissolving that stuff.

While you are at it... consider coming up with some imaginative ways that you could induce that spray upwards towards the Combustion Chambers and Valves in each Cylinder. This is why I like using copious amount of ACDelco Foaming TEC...because invariably... it can expand its volume inside of the confined Cylinder Spaces and gets exposed to those otherwise unreachable areas.
 
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gmcman

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I drained the oil and have some cheap oil I'm going to run through it after the cleaning.

I ran the MMO in the cylinders once to see how it would work. Pretty much I've done 3 cleanings with the B12, and I picked up 3 cans of GM top engine cleaner today....working on 2 cyl at a time at TDC.

I fabricated a tube to get the chemical into the cylinders with the can upright.

The carb cleaner can had a smaller nozzle so I used a drill bit in my hand to open the tip to 5/32 then secured a 1/8 ID tube that goes into the cylinder with a 1/4" ID tube around a piece of R/C fuel line...this way I can hold the can upright.

I agree with others...I don't know why they didn't allow a straw or something to be attached to the tip of the engine cleaner.
Screenshot_20190530-173840_Gallery.jpg

Screenshot_20190530-173806_Gallery.jpg

Screenshot_20190530-174100_Gallery.jpg

Screenshot_20190530-172856_Gallery.jpg
 

gmcman

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I have a lot to follow up on, sorry to not update sooner as my work schedule changed last week.

Quick pic, this was the worst...cyl#1, in regards to carbon build up. I did two overnight soaks of B12 then two overnight soaks of GM top engine cleaner. The cleaning was also for the piston crowns, primarily for the ring packs.

I have run two tanks of Costco 87 along with a bottle of Amsoil Pi, I checked cyl #1 today and the results are quite good.

From start to finish.

Screenshot_20190613-144838_Gallery.jpg


After overnight soak of GM TEC.

Screenshot_20190613-144758_Gallery.jpg

Shop vac used through Mityvac liquid container.

Screenshot_20190613-144744_Gallery.jpg



After two tanks with Amsoil Pi

Cylinder walls aren't black, that's the reflection of residual carbon on crown.

Screenshot_20190613-144609_Gallery.jpg


As discussed earlier, the wear of the piston skirt is long term, mainly trying to extend life of engine.

Overall the noises have subsided quite a bit, the ring and piston cleaning have helped dramatically. I'll try to get a other video this weekend as I'm on vacation next week.
 

gmcman

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Sorry for the delayed response super busy and the motor has been through a series of taps and knocks over the last 2800 miles.

I'm sure the main culprit is #4 being slightly loose but overall given the circumstances, if all stays the same I will live with the noise for awhile.

The carbon could have been an issue, what's odd is the felt tap on the top of the #4 coil pack is now gone with the new coils. I haven't looked inside the cylinders in a few weeks, but will check the piston crowns again soon.

When I started driving it again, I used Pennzoil Ultra Platinum 5W-30 for 1100 miles and started hearing a light tap and could have been a manifold bolt working itself loose. Either way, my thought was to try a thicker oil anyway sonic drained the PUP 5W-30 and went with M1 0W-40 Euro and M1 15W-50, 6 qts 0W-40 & 1qt 15W-50.

Wanted the added Magnesium of the 15W-50 and have had that in for 1600 Miles. I'll post up some oil analysis' when I get them back.

So here's the engine noise now after a warmup, not too bad with all considered. Has been getting quieter and quieter but not sure if the light piston slap will go away...but at least trending for the better noise-wise.

 
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mrrsm

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Well, Brother... Congratulations... and Serious Props to YOU are In Order. You've definitely taken this issue from the Concept Board... right outside into the "Real World" as far as trying to De-Carbon the Engine Top End, with remarkably decent results coming from all of your determined labors.

If EVER there was a "Sticky"-Worthy Exemplar Thread for the Positive Outcome from using a Combination of Chemical Carbon Busters like Berryman B-12 and ACDelco Top Engine Cleaner... THIS one is THE Signature Thread worth following. :>)

Incidentally... I neglected to mention a Third Player that is also another powerful, totally Non Toxic and "0" VOC Carbon Busting Chemical that unfortunately must be watched VERY CLOSELY when being applied to anything made of Aluminum:

Purple Power

1563849498987.png



Were it not for the fact that when exposed to Aluminum Metal Surfaces for periods of just a few hours... the Chemistry of Purple Power WILL cause Aluminum Bearings and Pistons to Leach out Crystals
of Aluminum Oxide and corrode their surfaces dramatically.

But... If you even wanted to "De-Carbonize" your Oven and Stove Top Burners...and NOT have to invest in any "Elbow Grease"... Purple Power Spray WILL dissolve every last bit of Carbon and Grease...it right down to Clean Porcelain surfaces without having to lift a Pinkie Finger to scrub those surfaces in the slightest...just wait a few hours...and then wipe up the Black Carbon "Mung" Sludge left behind afterwards:
 
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gmcman

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Thank you for the good words..:thumbsup:

I received my first UOA from Blackstone today, This oil sample was taken 1,100 miles after the rod bearing replacement and the top engine cleaning.

Before I drove on this oil, I idled some left over new 5W-30 through the engine for about an hour to remove any cleaning deposits that may have been left.

I have another sample coming soon, as this oil was drained at 1,100 miles being unsure of shear and was worried it may have thinned if the blow-by was bad. Mainly because I heard a louder tap when warm and didn't want to chance anything...that noise has subsided quite a bit.

Turns out it faired well, I was worried I would see more wear metals but I was surprised at the results.

They mentioned the silicon and I didn't notice at this sample or the following sample, but my fresh air supply for the PCV has a crack at the large nipple on the intake resonator...could be from injecting some dust. I have since repaired that with a spare Intake resonator...I'll mention that to them.

Here's the Pennzoil Ultra Platinum 5W-30 1,100 miles after getting it back on the road.


Screenshot_20190724-210443_Drive.jpg
 

mrrsm

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It would not surprise me that Silicon would show up in the Motor Oil Sample so soon after your Mains and Connecting Rod Bearing replacements (if both were necessary) due to the composition of the Aluminum-Silicate Bearing Materials versus the Original Tri-Metal Bearing recipe of Lead, Tin, Zinc Babbitt Materials... the former being identified as Al2SiO5. This chemistry is meant to Increase the Durability of the Bearings Surfaces...without becoming so hard as to eat into the Nodular Iron Journal Surfaces over Billions of Rotational Cycles.

There would certainly be some immediate "Break-In" adjustment where the New Modern recipe for those AL-Si Babbitt Bearings WOULD experience some changes while a conforming 'wear-in period' was happening on a less than Pristine or Re-Ground Crankshaft. So... I would not worry about that odd chemical signature... and the present "Well Behaved Engine" speaks Well (as well) for the Quality of Your Repair. :>)
 

gmcman

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It would not surprise me that Silicon would show up in the Motor Oil Sample so soon after your Mains and Connecting Rod Bearing replacements (if both were necessary)

To clarify, I only replaced the rod bearings, mains are still original. The rod bearings definitely needed to go.

and the present "Well Behaved Engine" speaks Well (as well) for the Quality of Your Repair. :>)

Thanks!.

I agree, it's too early to tell but the new bearings will surely skew the results.
 
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gmcman

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Here's the follow up oil analysis of the Mobil 1 0W-40 Euro/15W-50 mix @ a 6:1 ratio. 6 parts 0W-40 to 1 part 15W-50.

In the report, the Pennzoil Ultra Plarunum is on the right of the grey column, and the M1 mix is on the far left.

The M1 is still in the engine, will sample again at 2,400 miles. Current M1 oil was at 1,200 miles, the Pennzoil was sampled at 1,100 miles then drained.

I gave a virgin sample of the M1 mix and I didn't take the oil from the same new containers. Not sure what went wrong but the VOA was way off, not displayed in this report though but explains some of the above text in the report.

Edit: Had to change pics, last one didn't show TBN

Screenshot_20190727-012710_Gallery.jpg
 
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gmcman

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I didn't see their email until late last night, need to question the sample as those oils don't normally show that high of moly...usually much lower as a virgin sample.
 

gmcman

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Just another follow up, this is 3,500 miles from when it was back on the road, 2,400 miles on the 0W-40/15W-50 mix.

I will likely change it out at 3,500 miles on this oil. Overall so far so good.

The 1,100 mile column shouldn't be there, that was the Pennzoil Ultra Platinum 5W-30 which was changed out at 1,100 miles.

I'm curious as to how the Magnesium, Zinc, and Phosphorus levels increase.

20190909_161502.jpg
 
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gmcman

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I wanted to update this thread. I tried Blackstone and gave them well-labeled bottles of virgin oil, and a few bottles at different mileages. My results were all over the place and they had mismanaged the samples, when trying to fix the screw up it was even more mixed up. This is why I haven't updated any samples.

I'm at the 20K mile mark since this ordeal and the engine is running well. You can hear the piston slap from #4 when the engine is warming up, likely right when the cylinder has expanded a bit more than the piston. This seems to almost completely go away when warm, you have to really listen for any noise.

I'm.going with Polaris labs on my next sample, I used Amsoil 15W-40 Diesel oil for my last oil service and the same this time around.

Screenshot_20200830-194003_Chrome.jpg

My thinking is some good protection for the piston skirts, might swap during winter or may try a lighter oil but going to see how the oil samples first.

Has quieted down over the last 10K miles, no complaints. Tiny bit of noise but nothing serious, hopefully this breathed some more life into her.

Noise update 20K miles after deep piston cleaning and rod bearing replacement.

 

mrrsm

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Man...I just re-read this Thread 'From Cover To Cover'.... WOW..., Dude... The expansive repair ground you covered by leaps and bounds here on your Engine REALLY deserves having a Title more worthy of all your successful efforts:

Achieving 20,000 Additional Miles on your Atlas Engine and still going strong should really be Marked and Memorialized with a Title much less vague than being about mere "Engine Noise..." ...and more towards prompting interest in all of the hard work and all the solutions you came up with.

Man...Think about it... YOU REALLY SOLVED.jpg some VERY Hard Problems Here!
 

gmcman

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@MRRSM Thanks again for the good words. I hope it works out, seems to be ok and I understand I can only slow the wear and not make it better. If the rotating mass remains healthy and we have hopefully slowed any more wear to a minimum then I'm fine with that.

If I can come across an 02-05 motor cheap I might start a slow rebuild in case anything goes south with this one. Would love to get an 06 head on an earlier motor if possible, but that's a project that will have to wait for now.
 
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zaid3ssaf

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I found that WD-40 attachment nozzle works very well.

1607730239122.png

I tried soaking with TEC (non-aerosol) then run for 200 miles, soaking with MMO only then run 200 miles, and finally soaking with TEC (aerosol).

TEC liquid works well but doesn't reach the valves much. The Aerosol probably works better for that purpose. Finally MMO was the worst. It actually made the piston crowns dirtier. Though, none of the treatments helped with my top engine noise.
 

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A Strange Question, perhaps... But What Brand and Part Number of Spark Plugs have you been using?
 

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gmcman

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@zaid3ssaf I had another noise not long ago, was somewhat faint but came from the valve cover.

I could feel what seemed like a rap on the ignition coil bolt when running, only on one coil. This was different from the other coils where you could sense the combustion process, but this felt like someone was tapping it with a hammer.

I thought it could be carbon knock or worse, but I took a chance and replaced the coil and all is good. Was quite odd that it was a sharp rap that was felt through the coil bolt, spark plug looked fine.

Just a thought.
 

zaid3ssaf

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@zaid3ssaf I had another noise not long ago, was somewhat faint but came from the valve cover.

I thought it could be carbon knock or worse, but I took a chance and replaced the coil and all is good. Was quite odd that it was a sharp rap that was felt through the coil bolt, spark plug looked fine.

Interesting indeed. Unfortunately, I replaced all ignition coils about 5000 miles ago.

A question, did you get better results with chemtool B-12 or GM TEC? I have a second can of GM TEC and I want to soak the pistons for a whole week but I'm not sure if that would harm the head gasket.
 

mrrsm

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Not to worry. The GM 4.2L LL8 uses the MLS (Multi-Layered-Steel) inorganic style of Head Gasket. Regarding your thoughts on using the remaining can of ACDelco TEC Solvent for a Week Long Soak of the Pistons and Compression Rings, double check the Cautions on the Can Label. IIRC from the GM TSB ...the recommended Time Limit for the soaking period should be kept to around Three Hours.

If you use this Liquid in Quantity inside of the Six Cylinders, before re-installing the Spark Plugs, be sure to Plug up the Spark Plug Wells with Scott "Blue" Shop Towels and after pulling the Fuel Pump Relay... Rotate the Engine for 2-3 Ten Second Cycles to flush out the remaining ACDelco TEC. Don't Skip this Step...or you'll run the risk of Hydro-Locking the Engine and Bending the Connecting Rods.

I agree with you about choosing the Foaming variant of the ACDelco TEC for this task as being much more likely to make direct contact with the thickly built up Carbon deposited as sticky rings surrounding the Valve Seats and be able to loosen and dissolve more of that Black Mung that can be clogging the upper Combustion Chambers.

This also Bears Repeating as a WARNING:

Please ...Avoid using the
Berryman's B-12 Chem-Dip or Chemtool for the Installed Engine Piston Soak as its Carbon-Busting Chemistry is Different and may dissolve the Graphite Coatings along the Piston Skirts too, making the problem with the Engine Knock Noises increase... or worse yet, cause the Pistons to Wear Out MUCH Too Soon...

GMMAHLELL8PISTONS4.jpgGMMAHLELL9PISTONS5.jpg
 
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zaid3ssaf

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the recommended Time Limit for the soaking period should be kept to around Three Hours

The old style bottles shows CAS numbers for all the chemicals in TEC. It would be interesting to see if the three hours soak time is based on chemistry or speculation.
1607966378396.png

Rotate the Engine for 2-3 Ten Second Cycles to flush out the remaining ACDelco TEC

Indeed. I use a brake bleeder pump to suck out residual fluid in addition.
 
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gmcman

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A question, did you get better results with chemtool B-12 or GM TEC? I have a second can of GM TEC and I want to soak the pistons for a whole week but I'm not sure if that would harm the head gasket.

@MRRSM sounds confident with the head gasket, I would agree.

As far as effectiveness, the B12 worked very well, I believe I let it soak about 3 times. I also used a shop vac with a PC cleaning attachment, connected to a clear hose to get inside the spark plug hole and cleaned out what residue I could.

I followed up with a can of BG44K once it was running.

These pics were from the B12.

20190527025927.jpg

20190527021458.jpg20190601125345.jpg20190701141653.jpg
 

zaid3ssaf

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Looks like you had good success in most of them. In a similar fashion to what you have, my cyl 1 still appears carboned up on the crowns. I am trying to rig a soft brush that would fit into the spark plug holes.

Did you have to 'lubricate' the cylinder walls after the chemical treatment, especially that the thin layer of motor oil on the walls would've been removed?
 

gmcman

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Did you have to 'lubricate' the cylinder walls after the chemical treatment, especially that the thin layer of motor oil on the walls would've been removed?

I did add a small amout, maybe half an ounce, not sure exactly, then cranked the engine over before reinstalling the plugs.
 
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mrrsm

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The Factory GM OEM Mahle Piston Set appears to have some sort of Gray Opaque, Glass-like Substance Coated or Baked onto the ENTIRE Pistons Surfaces ...as well as having Impregnated the Major Side-Skirt Areas with Pure Graphite for the purposes of Friction & Noise Reduction.

Perhaps THIS is where the GM concerns mentioned in their TSB originate from for Avoiding Excessive Chemical Soaking Periods and Exposure Times. Take a look at what these Pistons look like, right out of the Mahle Factory Shipping Box Brown Paper Wrappings... and draw your own conclusions:

GMMAHLELL8PISTONS1.jpgGMMAHLELL8PISTONS2.jpgGMMAHLELL8PISTONS3.jpgGMMAHLELL8PISTONS4.jpgGMMAHLELL9PISTONS5.jpgGMMAHLELL8PISTONS6.jpg

I would be cautiously concerned though with using any Electric Vacuum Cleaner to evacuate Highly Flammable Liquids-Fumes out of the Cylinders, lest the Risk of Explosion or Fire occur from getting exposed to any unsealed, or unprotected Sparking Commutators in the Electric Blower Motor.
 
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mrrsm

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Just touching base on this very useful Thread with an attachment of the Official GM Instructional Service Bulletin PDF on the use of the ACDelco Top Engine Cleaner along with the requisite Tools and Procedures involved, including the Important Product Warnings here as well:


Please note the broad range of GM Vehicles covering many different Makes & Models of Trucks and Passenger Vehicles and includes all engines as per those presenting with P0300-P0308 Codes and other symptoms for the Vehicle Years 2000-2018:
 

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