My First Engine Build FAILED - What We Found...
HTML-код
- Опубликовано: 3 июл 2023
- Well we discovered the problem. After our 300+ mile roadtrip up to the Sierra Mountains, my 6.0L LS started knocking. We pulled piston # 2 and sure enough... the engine needs to be rebuilt.
Авто/Мото
Took the engine to a very well-known engine builder for a professional opinion.
He has seen that specific wear on the skirts before and believes injector # 2 was firing intermittently / not fully plugged in or perhaps not flowing at the same rate as the others, causing that cylinder to run very lean. He also believes the piston to wall clearance was on the tighter end of the spectrum but not tight enough to hurt the piston the way it did.
Lesson learned. The block will be honed and clearances measured. I will be replacing the # 2 piston, the ring set, all the rod bearings (just to be thorough) and have the injectors flow tested.
Going to be monitoring my AFR a lot closer when we tune the car.
I don’t believe I’ll make another engine building video as filming takes a lot of time and I want to really focus and enjoy the engine rebuild process. Appreciate you guys tuning in and supporting my dreams. This was my first engine build and certainly not my last!
well jjst make sure the block is magged, make sure the deck is proper even if it's detonation there was undue friction which is of course gonna cause excess heat. Also get the head xrayed, I noticed they are AFR heads I'm not 100% sure but I've heard they are decent to work with, have them spec the heads for you, it's in their interest your giving free advertising in a way, maybe not at their behest but you are definitely not hiding the emblems and are forthcoming with brand names and details. Ask dont imply it's most likely a simple mistake in assembly or tune, no fault to anyone shit happens. But do not assume any if the parts are 100% without complete inspection. Too much money to throw hand over fist at repeated engine failure. Anyway blah blah, glad you got answers and have found a builder you trust.
Anyway, "stay sideways and keep it between the ditches.
I was just surfing through videos and seen this, first thing I wondered is, why is #6 in the #1 position and others not in the right hole? Maybe it was pieced together from used parts and re-balanced in that orientation? I would definitely get a 4-5" micrometer and dial bore gauge to check PtW clearances, 2618 grows a lot more than one with a higher silicon content. The bottom tips of the skirts will not grow as much because the heat is more oriented to the top of the piston and because there is no bracing behind that area, if you look at the wear pattern it's where there is solid bracing behind it all the way across the piston because the growth from the heat has no where to go but out. Clearance depends on a lot of things, material, size, full round vs fsr etc, purpose/application and so on. I like 5 thou for a 4" 2618 at the minimum. Piston manufacturer should have specs for a certain piston in whatever application your running, be it NA, nitrous, turbo or whatever. If you know your gonna beat on it hard go for the middle to far end of the spec, gives a little wiggle room for those occasions that cause extra heat, be it lean or whatever. With heat comes growth, make sure you have enough room or your gonna bust out of it. It's good to idle the engine till the pistons get some heat in them and grow, which it's good for any engine to reach operating temperature before its put to work. The chamfer side of the rods always go towards the fillet, the reason for the chamfer is to clear the extra material in that radius(most aftermarket cranks add material here because it strengthens the crank tremendously and you usually have to run narrower bearings because of it) where the journal meets the side, down in that corner. Just my opinions, I'm definitely no expert.
I believe the software can monitor and control the AFR millisecond by millisecond. If the AFR goes to lean the LCD display I believe can show a warning. The best way is to control the AFR ALL THE TIME using the EFI computer, that way it will never lean out. I'm by no means an expert so, I'm assuming the EFI computers PCM can control the AFR. Thanks for telling us what happened to the engine. One cylinder damaged is a lot better than eight!
Yeah Mike Finnegan of Roadkill ran into that same problem with his hemi, the damn fuel injectors, one of which was new, was clogged and not working right, and burned through a piston, like he has a whole video and series on it, so check all before putting them in and get a machine to test it first
also with the pistons check the weight per piston, the weight can actually be off on all the same casting, its an issue that both a Miura and Nick from Nick's garage ran into on his challenger when he was building a new motor for it, with the same pistons he had on his test one that ran better
so sometimes the motor can be out of balance even when you do everything right
and I gotta say while its an LS, sometimes an accusump can help with keeping the thing oiled if your doing some spirited driving, especially up a mountain where back in the old days you would change the fuel to air mixture manually via the points and plugs before a trip such as that,
and its something some of the old muscle car guys do when autocrossing their cars now
and apparently the forerunner of the LS needs it, although he was the only one to ever say he had seen Corvette Gen 4's failing at a track, so I dont know how legit that is, but its one of the ideas I had for building a super vette
as if their are three things GM's fail at its forethought, Build Quality, and High Reving Motors that are balanced properly
and making sure the magnet for the flywheel on the 3.6 liter V6 is actually mounted properly and hasnt come off again, which actually happened to a guy on here who bought that chevy cavalier they turned into a luxury car
dont think he saw my message though so he's gonna be chasing parts on a 12K mile surivor that someone already replaced a ton of parts on trying to find it till he finds it.
all because GM thought the best way to have the engine speed sensor talk to the computer was by literally gluing a magnet to the flywheel
@@robertyoung. wasn't it in the #1 hole? Without going back and looking I was thinking it was the first rod from the front. Seemed like I saw #2 somewhere in the middle, you was probably like me "what in the heck" lol somebody numbered them and they're still all outta wack.
Great information and analysis.
And without Dark's knowledge or the knowledge of a LS engine builder, chances for success are very slim. Take the engine to a LS builder and have it set up properly. If you want to learn and engine building is a science unto itself, ask to participate in the build process.
Seems like it would be hard to compress and get in the hole if the expander over lapped because the scraper rails rest on top of the side of the expander and the scraper would probably protrude out more than the piston to wall clearance. I've had it happen several times installing rings and it's easily noticed when you check to make sure the rings seat in their grooves.
@@jason3211 I can't say I've ever weighed std pistons vs the over bore pistons, 10, 20 or 30 over isn't much at all and might be very close if they were the same type, same manufacturer. Different type or manufacturer they could be drastically different, lighter or heavier. I would definitely want it balanced, if not then those pistons better be weighed and dang near weight matched to the previous pistons.
better view at 15:58
That’s called a four corner seize. This is indicative of a lean mixture.
When setting bore clearance for a typical piston you measure about .500” up from the longest part of the skirt straight across the piston. This will be the largest area.
If you measure diagonally across the skirt of the piston, the area where the seizure occurred, you will find that the piston is much smaller in diameter at these points by design. The area that seized in the bore is likely to have .015-.020” clearance at those points. So the bore size of the cylinder is not the issue here. Excessive heat is.
The connecting rod offset described is correct. Above all else, numbers on the rods, or any other outside visual references, the bearing offset machined into the connecting rod must be considered.
You will be able to see a very clear offset of the bearing when it is installed to the rod. One side of the rod will have more overhang and hopefully a nice radius or chamfer relative to the bearings, the other side will have less.
Also note that with those rods and bearings there will likely be a top and bottom bearing. Upper, lower to accommodate the crankshaft journal radius fillets.
By the looks of those bearings you guys did a very clean assembly job and assembled the engine correctly.
I would closely scrutinize the number 2 injector if not replace it and make sure you do not have a vacuum leak anywhere going into number 2 cylinder. Vacuum ports etc. I doubt there is a vacuum leak because of the consistency of the burn marks on top of each piston. Number 2 was firing. Evenly with the rest most of the time a vacuum leak will be more consistent.
This is intermittent and should be closely monitored and scrutinized.
This would be a case where I would pay a reputable engine dyno fee. This way they can hook their headers up with thermal couples on all 8 cylinders and dial them in. If there are any problems with fuel enrichment. The dyno operator will see it immediately and it can be repaired much safer and quicker.
That or thermal couple all eight cylinders but I don’t believe that is cost effective.
JMO based off of my profession.
100% Hugh. Then it pushes aluminum skirt material into the oil control rings, seizing them, marking up the cylinder. Good on them for shutting down as quickly as possible, limiting the damage.
Glad to see it wasn't a total catastrophe. Keep up the good work, it's a learning experience.
The smartest thing you guys did was noticing something was wrong and not running anymore than you had too. I have had motors go bad too and you just need to learn from it. The cylinder might need to be board out, honing it might not remove all the scratches. You did a good job on it and you can fix it. Now let’s talk about putting a 455 Pontiac it there.
No try a 428 instead.
It’s junk.
Posted hear because your first in line. OMG! "Put your rods any way you want!!!!!? You have the piston rod assemblies orientated wrong. Passenger side front cylinder 2 should be mated with Drivers side front cylinder 1 NOT 6. BUY a service manual. NEVER TRUST the keyboard warriors. Author Chris Werner "How to rebuild LS engines." PAGE 113 Piston and connecting rod orientation RULES.
Great post. We caught a damaged push rod just recently before it went catastrophic in a 20k big block. This was just recently. Instead of chancing things it was completely torn down. Sometimes you learn the most when something goes wrong. Just hopefully they aren't really costly over looks unless there is coverage. $h!t happens. I don't call these "mistakes" because she has the right attitude to benefit from it in the long run. By picking up on valuable knowledge.
@@potsy9973 ,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,,AMEN..................................................................................................................................
I am glad you are sharing all of this because I am yet to built my first LS and though its a head scratcher its great to have caught it before it destroyed itself
Sucks that that happened, but that's the way it goes sometimes.
The good news is, it looks like it is fixable, and you don't have catastrophic damage to the block.
I'm sure you guys will get it up and running soon.
Great video.
The Good, the Bad, the Ugly. Thank you for taking us on this journey.
How to get better, ………learn from experiences,good or bad! Life is one learning experience after another.
You have this , you are both super intelligent,have great attention to detail!
Can’t wait to find out the actual cause of the damage.
Keep up the great videos👍
Dont feel bad. The first engine I rebuilt was for my '71 Fiat 124, 1.6 liter 4 banger. I failed to stagger the ring gaps, even though I was aware that it needed to be done. Just working in a hurry in my driveway with primitive tools. It sent out blue exhaust smoke like a 2 stroke. Had to take it all apart again. There are a lot of little details with engine assembly.
So sorry to hear about the engine! Good news on the trans warranty! I’m not an expert engine builder, but I used to build short blocks at Caterpillar in their engine plant 20 years ago. It was assembly line work. My 2 primary work stations was crank install and crank torque. Right after I torqued the crankshafts, the pistons were installed. We did about 200 6 cylinder diesel engines every 8 hours. 65 second cycle times. Later I operated CNC machines making ring gears for transmissions and differentials. But that aside, I wonder if the cylinder wall was out of round or the piston wasn’t in round. Seems you had a rub issue. It was nasty too! Hopefully you can rescue that one hole! Good luck!
I remember my first engine rebuild i did myself it was a big block Mopar. I disassembled the engine and sent it to the machine shop and reassemble it myself after the machining. On first start up had no oil pressure. I talked with the machine shop about possible problems i disassembled it checking everything put it back together and still had no pressure. I finally found a small oil plug in the front of the motor that was missing put a plug in had oil pressure. Still to this day years later it bugs me that I missed a tiny plug. Good luck on your motor and don't let it get to you. Wishing you all well Take Care
Clean shop. Hope to see you do some more videos. It takes broad shoulders to show a teardown that could reveal mistakes. Most would not expose themselves like that
Good response to adversity. That’s the difference between success and failure. Always positive!
great scott, you two make a great team! wish you much luck and fun now, and back in the future..!
I would be checking the piston to cylinder wall clearance most likely too tight , its always good build practice to double check and make sure all the clearances are in spec even if the machine shop is good some times things can get over looked . The last small block I built I had to send a rod and piston back to the machine shop because they pressed it on backwards , we can all have a bad day good luck with the new build 🤘🏁
I only built a couple of engines. My first was a 283 Chevy for my 57 Chevy back in 1978 when I took an engine rebuilding class in college. I checked the clearances on every piston/bore to make sure they were in spec. Checked all bearing clearances too. I even rebuilt the heads myself including lapping the valves, etc. That engine ended up running for more than 10 years before I got rid of that car. Definitely check everything carefully when putting the engine together.
I did not build many engines, because I ended up going into the computer field instead.
Pause at 14:38. I was thinking the pistons are way too small lol. Is that the ring visible in that huge gap?
Yeah i was thinking maybe a piston fittament issue. It doesnt take much.
@@oldtc3615 Yeah, those pistons are WAY too small for the bore. .004-.005 is all you need and that looks more like .250 This large gap is causing piston slap.
And thats what I think happened here; the major and minor thrust side were switched and the piston was installed with the wrong thrust side orientation.
The spark plugs will tell you if it ran lean or rich. Dimples on the piston go towards the front of the engine no matter what side.
My props go out to you girl.. I'm glad that you are willing to figure it out and keep moving forward with the build instead of shipping it out..
Thank you so much!!
It took me years to restore my 64 Pontiac.
I love your videos ❤
Great video guys Thanks again for sharing with us 👍 from Alabama 🇺🇸 watching 👍
Well hopefully you can fix it. Good luck you guys. I'll be watching.
Keep your head up! Happens to the best of us!
Haha yeah why mess up your shop floor when you can wash down the ditch ! Thanks for taking us on this journey
Also make sure you oriented the pistons to all point forward. Because piston wrist pins aren’t exactly in the center, they are slightly off center, to reduce piston rock. Also since the rods were scribed you can’t even make a mistake with rod orientation unless you put them in a different cylinder, which somehow happened.
While it's not great to be tearing it down it's good that you caught it early, besides detention I don't know what could do that, I've seen what too tight ring's can do and it's not that, that piston was slapping around in the cylinder and none of the others were so I'm confident you'll be able to figure this out
Also, @11:18 you can see cylinder 2 appears to have its rod cap on backwards. Cracked rods will not have a perceptible seam when clamped together and this one has a seam. (unless you disassembled it off camera)
That too stood out to me...
GM uses the "Fractured Rod" technique in these LS Engines. And YES, that rod cap is CLEARLY on backwards. You should NOT be able to see the seem of the fracture very easy when the caps are torqued down and on to the the crank like it is here. There is also a clear issue with the AFR (Air Fuel Ratio) on this cylinder. Likely a injector issue. And when you got it up in that thinner air is when that cylinder shit the bed. Thin air with a existing AFR can be DEADLY to a engine like this.
If the video is in chronological order, she did remove the caps earlier and put them back @8:16. She could have simply put them back haphazardly just to keep them together.
Another great video, if I had to make a guess what happened, it's either piston to bore clearance, or a deformed piston or bore out of round, of course they're only guesses not being there, you'll find the trouble I'm sure, keep pushing on ❤❤
To me it looks like it got really Hot. That is what I call a seized piston. Check the cooling holes in the block for that cylinder. The piston melted. You can remove melted aluminum from the cylinder walls with acid. I can't remember which...muriatic I think. It melts aluminum but not iron. The piston should be replaced with a new one and new rings. You can probably reuse the rings on all the other cylinders, just clean them up. Shoot anyhow this happened. You sure have a NICE shop to work in!!!!
To me it looks like the piston to cylinder clearance is not correct. You might also check the little port that oils that bore.
To me that was caused by piston to cylinder wall clearance, when you go back together make sure all cylinders have good clearance.
I guess in the end you guys will be better engine builders, that sucks that happened after all that work. Great content. Thanks for sharing.
The piston skirt was definitely touching the inside of the cylinder bore. You can tell because the score marks are the exact width of the piston skirts. I’d start by looking at the rings and ring installation. They should be able to move freely when you spin them. If not, they can cause the piston to snag on the cylinder walls. Also, lubrication. If there’s a problem with lubrication, the same thing can happen. The piston will snag on the cylinder wall and as the piston rocks on the rod axis, the skirt will touch the wall. Piston rod orientation is important but only if the design calls for it. If the manufacturer doesn’t specifically say there’s a bias, it’s usually not an issue.
As others have said, you guys absolutely need to completely tear it down to the bare block, identify where the metal came from in the bottom of the oil pan and thoroughly clean and inspect everything. Especially all the oil galleries and passages in the block, oil pump and pickup tube. When you think it's clean, clean it some more. Good luck. Looking forward to seeing the Tempest back on the road.
If you look at the underside of the piston you can see the wear is aligned with the cross webbing. As the piston heats up and expands it is not uniform so a slow warm up is needed. We see this with high performance 2 stroke engines when first started and revved cold the pistons swell up faster than the cylinder expands and they bind. Since this only happened on cylinder #2 its possible you had a lean condition which ran that cylinder hot and then pushed the engine before it was fully warmed up or as others have said the piston to cylinder wall clearance was a bit to tight seeing the wear was 180 degrees apart. Good job and thanks for posting.
I just found your channel I watch the whole video. I love the two of you. How are you explain things and try to figure things out. It’s just my speed. I am now subscribing to you.
You two work so well together and make a great team. I'm sure you'll figure it out and it will be okay the next go around. We'll be watching to see how it turns out.... peace
Right, why can't I find a woman like her? Life would be great.
At 16:45 the reason why it looks that way is because pistons are not perfectly round and are tapered. This looks more and more like that piston belonged on the other side of the engine. It looks as though the minor thrust side was where the major thrust side should have been and the piston was slapping. Hold a piston by its rod as plumb as possible and the piston will fall to one side, thats the major thrust side. When viewing the engine from the front (non-traditional way) as the engine turns clockwise the major thrust side is to the left side of all cylinders. Now look what happens to a piston as you walk it around to the other side of the engine: the major thrust side is opposite and the piston will be weighted to the right. This will cause piston slap.
i rebuilt and ls1 and had the bearnings wiped a week after building an engine is a learning experience and rarely goes right your first time good job on the car...
i use to work on high performance 2strokes with my father and yea ive seen this lots of times. one cyl would score and the other looked great. generally caused by one side of the motor getting hotter than the other just due to cooling issues. one cyl would just run hotter because of air flow over the fins, cooling port locations, the polaris 3 cyl's often had a different jet in the center cyl carb. it was quite often we would jet the carbs differently to compensate for how hot each cyl ran.
Hi, hope this is okay I think the engine pistons nipped up due not enough piston to bore clearance.
Best way forward is to have the bores honed to see if the scoring can be removed and what the finial bored diameter is then see if replacement pistons to suit are available.
Planets on a 4l80 should never be noisy. Good catch getting it handled while still under warranty. Hope the replacement is perfect. Sucks to do it twice but better than paying twice.
I had the same issue with a 418 stroker making a bunch of racket when running but when i pulled it apart everything seemed fine. It turned out to be a worn wrist pin bushing had to much play in it.
While waiting for the engine. Order one of the 25 buck injector cleaning kits that has transparent sleeves to hook a spray can to the injector top and it has a box to pulse the injector windings. Lets you compare spray patterns to see if the number 2 injector was not spraying as much.
You learn from everything, it isn't a "fail" if you learn from it. I'd personally send it to machine shop, at the very least for a thorough cleaning. Invest in some good dial calipers and bore guages. Double check your parts as well as your machine work. But it's no biggie, a good mechanic learns from each experience.
My first build was done by machine shop one....multiple issues. Pulled it after 3000km. Three bores had score lines and slight wear on most piston skirts. Was told all was good and why did i strip it???
2nd machine shop has been way more helpful, went foged Carrelo pistons and spool rods. 4000km now and still running, so hopefully all good. Expensive lesson. But we learn from it.
The experience you gain will be invaluable in the future.
I use a pressure tank with oil in it to prime my engines before starting. Just hook it up where the oil pressure switch goes and it works great.
It would be better to put it in the port next to the oil pump
glad you are having everything check. but i still dont believe that is the noise, take the heads apart check the valve springs, also check the cam and lifters, not sure is your heads have pressed in studs for the rockers like some chevys,just something else to check. sound like you have some great help, good luck ,brad
The rings have pinched due to the heat which may be due to bore wash and the fuel washed the oil of the bore walls. Run the motor in on mineral oil as this will allow the moving parts like rings to contact each other and bed in and then switch to a semi-synthetic or fully synthetic to get the better metal to metal protection, as synthetic is too good and will not let the rings bed in and you will get blow by from the start. This issue was common when Mobil 1 first came out and an engine builder I know had a top spec rally engine come back two times after emptying its oil out during it first two events and when stripped down they could not find out why. Lucky for the builder this issue came to light and as the owner specified this oil he got paid for the rebuilds. Good luck with the rebuild.
I’m sure you will learn a lot from this experience. That’s the biggest takeaway.
The first thing I noticed was when you pushed out the piston it didn’t look like you placed the end gaps of the two top rings over the center of the skirt. They should be 180 degrees from each other and rotate the oil ring end gaps too to retain maximum compression.
Finding where the gold material should be easy to spot since you should see where that colored material is in the motor. Are you using a bronze distributor Drive gear.
I’m a mopar guy so we know that the bearing tabs go in the same side and the groove on the rod cap once installed faces the opposite cylinders for oiling.
Either the clearance was wrong, the ring end gap was wrong ( which doesn’t make sense because the other pistons are rings were fine) or the bore was not the proper size.
When you installed the pistons and rings did you lubricate them?
Did you overheat the engine during break- in? Did you use the proper oil and break-in process?
Something could’ve fallen into the cylinder via plug hole.
The best way to rule out possible problems is to know all clearance specifications were checked before installing the crank, rods, bearings rings. The ring instructions should have told you what ring end gap.
Even brand new cylinder heads have to be disassembled and checked before installing.
Don’t trust anyone to do it right for you and check everything!
The motor has to come out and cylinder bored over. That’s the time to measure and compare everything.
It’s possible that the copper color is from something that got sucked into the intake and landed in that cylinder only to be chewed up. That could cause a problem for sure. It happens!!
My friend had a problem on start up because the head overheated because the cooling passage was blocked by one cylinder. Check the head gasket and make sure you’re getting coolant and not overheating by that cylinder.
Good luck and don’t give up!
Welp…bad news, good news, huh. Not catastrophic, great call on bringing ‘er home. I’m sure y’all will get ‘er figured out n’ back on the road. Just consider it ‘bonding time’😉. I know we’ll be watching and rooting for you and Danny! Danny…stop with the “sell it!” 😊
Sell it!!!!😂😂😂😂j/k
My first three engine rebuilds were the same engine. 😂. But in the end I learned a lot and it worked out. it’s been my sons daily driver for the last year now.
Great channel, very cool car and build, regarding this engine failure it appears that side of the engine and specifically that cylinder got very hot and the piston grew in size and scuffed the cylinder wall, one possibility is that the head gasket was installed facing the wrong direction blocking the coolant passages for only that cylinder. The fact that the valve cover gasket grew in size supports this theory. There also appears to be some unrelated bearing damage as evidenced by the flakes in the oil.
Did you use a stress plate when setting up the bores ?? Did you keep a build sheet containing all measured clearances vs target clearances.. coolant flow ??
Also, the whining noise in the transmission; make certain that transmission is not overfilled, even by a little. The 4L60E planetary can churn up fluid and it can make a moaning or humming sound. It didn't look air bound when you drained it but i don't know how long the cold soak was.
It aways hurts specially when it's your first, you will be back up and running again, better you guys got this
That piston was really scratched up. Glad you shut it down and towed it back. Building a engine is a learning experience. It will be great the next time.
A lot of good comments here, I think you should closely inspect the oil ring expander to see if the ends are overlapped. If so, as someone else said the oil rings will not work properly. I didn't see anyone mention oiling to that cylinder. Each cylinder is supplied oil thrown off by the crankshaft. For this to happen correctly there must be a minimum side clearance between the rods. Too little clearance gives too little oil. Even if the oil pressure is good tight rod side clearance could starve this cylinder of oil. It's also a good idea to run the oil pump for several minutes before you start the engine to fill all of the oil passages with oil before the engine starts. I also like the suggestion to break in the engine on a dyno to see all of the variables as the engine warms up.
Good Luck with your rebuild!
rod big end chamfer should go the crank side. the chamfer accepts the radius on the crank journal.Using numbers and dimples is risking that someone didnt mess up at the factory. always orient based on the rod characteristics.
that piston was seizing. this was a bore size issue
also a heads up, IF your piston skirts drop out the bottom of the bore make sure the bottom of the bore is chamfered/smoothed. if you drag your hand against the bottom edge of the bore and its sharp or rough, your piston is getting that too this only applies if your skirts drop out the bore bottoms (common on stroked engines)
I use to be a transmission builder and the 4L80 is a little louder by design as the low planetary gears aren't cut as hard of an angle due to being a heavier-duty application so some whining is completely normal.
actually really good to see a genuine "why did this happen" video, also really good to see a woman oon the tools, it doesn't happen too often and it should! FYI higher elevation is less dense air so fuel runs rich, but if it's already too lean, it'll run hot and expand things more. short piston means heat in the gudgeon pin and that'll have less than required clearance so will semi seize and flip flop. On Rover engines the conrod dots face each other so forward on rigth bank, rearward on left bank. As it's an old Buik lump, it would make sense that yours may be the same... but the other cylinders would verify this.
Looks like a piston to cylinder wall problem. It happened to me due to one cylinder bored too small ( not enough clearance when hot and run hard) If the block was bored, check cylinder diameter compared to the others possibly use ring gap comparison with the other cylinders, Do your rods have an oil squirt hole to oil the opposite cylinder? If so that could answer the question about rod orientation.
Lack of clearance or a distorted bore is my call. Clearance causes scuffing on the thrust side where as overheating tends to be on the pin side. Bore distortion is wherever the bore is distorted and tight. Of course these are "typical" situations and not all.
I agree with the builder on this that you had a lean cylinder and it was probably on the tight side. I think your solution is spot on too.
When going back together make sure everything is clean. When you are 100% positive it's clean - clean it again. Then clean it again just to be absolutely sure. Especially after any kind of machine work.
Curious, what happened to the OHC6?
A couple of engines I built wound up failing in the strangest ways. Like the lower wiper oil ring being bent in the downward position toward the piston skirt. this was where the ring end is. I still to this day haven't flgured out how I even was able to manage to install it without having to actually beat it in with a hammer. It wore a groove so bad i had to junk it. yours is a real mystery though.
Make sure the rods aren't hitting the windage tray and throwing debris. Or, it could be ring end gap or scoring from not chamfering the ends of the ring enough after filing the gap. If the ring got hot enough and the gap wasn't correct - it could have expanded in the bore and scored it like you are seeing. Possibly the tune? But isn't Holley EFI self-tuning to an extent? Clean out your oil passages with soap and water and those extra long bottle brushes. Was hoping this was torque convertor bolts. So sorry to see this. Hugs!
Bore sizing and ring gap is the answer. If ring gap is too tight, it will bind and cause the piston to put excessive force on the side walls as it forces up and down. You'll end up with both sides being wiped out due to the rod acting on either side of the piston.
NO SUCH THING as FAILURE-- only DATA!!!! YOu have valuable experience, learning- and information that make your future MORE successful that had you not had it!!!!
Will that's what it sounded like when you started having problems gauling and piston slap on one cylinder was typical sound produced by piston thrust over. Large chamfer on rods and bearing always go to radius on journals. You did good work liv.
Check the bore in 3-4 locations to see if it went oblong.. set a new ring in and look for odd clearance.
also the piston may not be made right and the rings are jamming in the grooves.
That might not be caused by running lean, that looks like the wrist pin to con rod clearence was not correct to much slop. That allowed the piston to have more movement in the cylinder to let the skirt smack the cylinder wall. detenation maybe, but I'm thinking it was the clearence of the wrist pin and con, rod thats what it looks like to me.
Piston to wall clearance, proper ring gap, fueling system health, tune, cooling system properly bled. Your rod bearings like great, I like to orient the LS factory rods dots towards the flexplate, but your problem is not the rod orientation. Block at least needs a touch up on the bad cylinder, otherwise clean everything best you can and check heads and block are still true. Wishing you the best of luck on round #2, take it slow and double check all the machine shop measurements / work.
What’s your piston to cylinder wall clearance ? I’m guessing .004-.006 in power adder application . Looks tight .
grandfather, father and i all raced VWs back in the 90s, breaking is part of racing. spending time with family building your car, a win. just the fact you're in the game doing something, a win, the good always outweighs the bad. good luck. be safe but have fun.
It's so amazing to see a female get so deeply involved in engine building and now diagnostics of a failure. At the very least you will come out of this more knowledgeable in many aspects! Everyone goes through this and those that don't, will eventually.
sucks this happend to your first build Liv, but iam sure youll get it fix and have the tempest back in no time!
Heat deformation. heat makes the edges move outward. I had that happen on several Porsche powered desert racers. But our damage was always on the middle cylinder.
As an engine builder for 50 years here in the UK..Rule of thumb ,the piston to cylinder wall clearance should be at least 10 thou of an inch that would make 5 thou when centre to centre when the piston is installed..Looking at the footage of the damaged piston ,it looks as if not enough clearance was had.
I love the way she is still smiling, calm and cool as they were trying to diagnose what happened. I wouldn’t have handled it that well. Nice vid, thanks for taking the time make it.
If it is normally aspirated and you go to elevation there is less air so the engine runs rich. Hope that helps.
Looks like a lubrication isssue, I can’t see close enough to identify a particular problem. I would pull the block fully apart and have it cooked out, replace the oil pump, filter housing etc to ensure everything is clean. You could contact the rod manufacturer to get their recommended position.
I was thinking just the opposite and you had a leaky injector and fuel washed the cylinder wall causing piston scuff.
it looks so clean! subbed as a fellow car guy :)
Did u pre fit each ring in every cylinder i have seen at times when u put the ring in the cylinders at times there is no gap i file to there is a tiny gap even found the same problems in motor cycles at times the piston will go in but on a bind
Would installing one or more of the compression rings upside down cause a problem like this? Of course that only applies to compression rings with a chamfered or fully tapered edge.
Measure the piston skirt and cylinder bore for that cylinder. Depending on the type of piston you should have up to .004” of an inch of piston to cylinder bore clearance. I think factory piston to bore clearance is 0.0008” it that is with factory cast pistons. Machine shop should have checked this if you had the bores punched out or cleaned up
I'm glad you shut it down when you did I would check the slop in that wrist pin
Piston skirt damage like that is typically caused from improper bore size
That’s what I’m thinking I want the piston was rocking The bottom of its bore?
@@timbrown9731 It's heat seized. If it was rocking, it wouldn't have seized. Noisy, up, seized, nope.
Most of the problems are the beautiful craftsmanship of parts lately
Looks to me like either the piston or the bore is out of round.
Not enough piston to cylinder wall clearance.
My first reaction is out of round cylinders. An intake leak could cause a lean condition. What you are experiencing is the problem with home building engines. Some good machine shops check everything the home mechanic cannot, ie matching all mating surfaces, precision boring and honing.
Scuffed piston due to loss of piston to bore clearance. They look to be forged pistons so you’ll need more clearance vs cast. Could be due to improper size of piston and bore or, as others stated, overheated cylinder. Hone the bore and replace the piston. Measure piston OD 90deg from pin and check cylinder bore in 3 height locations.
1. When you first started working on the motor, put a cloth in the carb to ensure nothing gets dropped in. Same after the intake manifold was removed. 2. When using a ratchet, always pull, don't push. That's how you break knuckles.
First thing that came to mind was - when the cylinders were bored, was the torque plate properly installed? Other than that, good thing you shut it down when you did.
the dot on top piston goes to the front. the rod should have a chamfer or angle on one side the chamfer or angle goes to the crankshaft. the squared side of the rod goes toward other rod. good luck
Dumb question. I see you have forged Carillo pistons for a .005 over bore. Did you have the bore enlarged by .005 inch? and if so, was the suggested bore clearance within what Carillo specified ?
Clearances need to be measured, checked and corrected during assembly. Had you measured everything as you went, you would've found these mistakes long before you fired the engine and found them through a blown engine. Measure, Check, Record and Correct where needed. You could always look back at the build measurements and rule that out. Looks like the rod was in backwards, the chamfer goes towards the crank, not the other rod. Rods installed backwards usually get bent from that. Check rod side clearance next time, then you'd know if they were installed wrong.
Compare one of the other pistons to that one. Also, check the bore to the diameter of the piston. Check the ring gap and the amount of ring pressure against the cylinder walls. If there's not enough pressure, the piston could flop around. I've built a few engines, and I have never seen that.
It's been a long time & I have no experience with the LS engines. The piston definitely seized. Did you have cooling trouble before the problem started. Did you follow a break in procedure? Are the pistons forged? Forged pistons require a little more clearance compared to cast or hypereutectic as they expand more as they heat up. The chamfer side of the rod goes toward the crank not the other rod - allows for the radius ground on the journal. Like I said this is old experience but the bearing tangs used to go away from the cam side due to oil slots they used to spray the cam but I'm sure this could have changed. Sorry you've run into this problem.
Good attitude! "Nobody puts Gnarly in the corner! "
Clearance... Clarence....😎
Awesome details. What are the dimensions of your shop?
I could be wrong but it just looks like it has more clearance than it should looking at the pistons in the bore. If Im correct i think it's got at least .010-.015 more clearance between piston and cylinder wall than it should have .
If you take a close look right around 16:55 it looks like the top ring ends are shiny .... thats a sure sign that ring end gap was too tight. Inspect it and if it is infact shiny or polished looking .... thats your problem.