I Sherlock'd My Dead Big Block Chevy and Found Out Why It Broke!

[@davelara1603]

Look at the ramp rates of your camshaft. If the camshaft design accelerates your valve train beyond its ability to control the valve train it will beat everything to death. If springs rockers pushrods can’t maintain contact due to acceleration they are toast. Sometimes it’s the camshaft design not the valve train.

[@bryansaull7554]

So when the engine was rebuilt I think he said the cam was changed ?. could it be the lift was too high.....

[@bigswingin6316]

Very true, a modern cam profile could make similar power with better ramp rates and much better reliability

[@davelara1603]

You can have the same lift and duration. It’s not lift or duration it’s how quickly the ramp on the cam gets it there and also how quickly it closes the valve. No matter the spring pressure the lifter can’t physically follow the camshaft if the ramp rate is too quick. A properly designed ramp can even allow you to run less spring pressure with the same lift and duration.

[@mostlymotorized]

I'm betting the lift ratio on those rocker arms isn't designed for as aggressive of a cam profile. Probably why the cup cracked

[@davelara1603]

If all is well in the setup, installed hight, coil bind, rocker position on valve, pushrod length,and valve piston clearance. The rocker ratio should not cause the problem. I believe it is physics. The cam is moving mass at such a high acceleration rate the springs cannot keep control of the valve, and at points in the cycle things are bouncing around without tension. With the pressures involved in a high hp application it’s like slamming your rockers, pushrods, lifters and spring retainers, with a hammer. At 8000 rpm a valve will open and close 66 times in a second! without total control they don’t stand a chance. I COULD BE WRONG about his cam, but it would be the first place I would have an expert in cam design look. He said it was a Isky cam. But often the cams are ground to a customer spec, not by an expert it the design of cam profiles.

[@smckenzie04]

The valves could have created their own clearance from the contact. Only way to know for sure is to check with "undamaged parts". I love how you handled this topic and I'm glad the culprit was found.

[@patrickmcdonald3427]

Excellent point! However, just installing new valves doesn't correct the marks in the head.

[@Splungers]

@@patrickmcdonald3427But it will give a better reading on actual piston to valve clearance. The bent valve will lie as it has been reshaped by contact with the piston.

[@WTF0v3r]

Unless the rings are pinned (like a 2 stroke), the rings are constantly rotating when the engine runs. When you install them you set them at 180 degrees from each other with the gaps parallel to the wrist pin, to prevent them from gouging bore on first start before the rings are broken in.

[@thedude7726]

100%

[@anthonyjones657]

Exactly

[@jasonwhaley3820]

Yeap

[@DSRE535]

Yep supposedly around and or up to 3-5rpm

[@goldenerapfel4087]

@@DSRE535it‘s only 5 rpm 😂

[@dustydon6419]

Finnegan you are a true gentleman. You never criticized, blamed or blasted the engine builder. There’s so many things that can wrong when you’re dealing with anything mechanical. We all have bad days and make mistakes. I’ve always believed it’s how we handle our mistakes after the fact. That’s nobody’s business but yours and the other party. Yeah, I get a lot of enjoyment watching what you do. Thanks!

[@spock59]

I completely agree. You said exactly what I was going to post. I, like Mike, prefer working on my own stuff as well... and learning from ones mistakes is so important.

[@davevangemert9853]

I just wanted to say I've never made a mistake

[@ShawnGilbert1967]

Well how this builder handled it was to immediately blame detonation for it aka the tune up aka not his fault its your tune that did it.....BS

[@cabrini00]

I really like it when you do this level of detailed engine teardown.

[@SteveMelissaMcAdams]

Pete's a magic man he can fix it. He's Real Good at Doin Stuff

[@ericbrennan1833]

Man you are an awsome dude. Humble enough to take the human variable into account. You know that he is one hell of an engine builder. And I am glad that you are not playing the blame game. Keep up the good work.

[@GorhamWorks]

Mike at FSM, world class quality assurance, you build it he breaks it, and you make more power next time. Proven formula!

[@albr6770]

He seems to break everything…?!

[@freedomfox8183]

This engine was hurt before he even got ahold of it.. I'm no ACE racing engines company, but I have been building small blocks and Big blocks, Chevy / Ford/Mopar for 35 years now and it doesn't matter what he was going to do with this bullet because it was hurt unfortunately from the moment it was started up and ran on the dyno... Either it really wasn't enough clearance hard to say without measuring myself or the stands cane loose and all down hill from there... Sure you can tighten them back up but odds are the damage was done already and not easy to spot without a tear down

[@jerrybattisti5454]

You're correct👌. Been building engines professionally for 26 years for circle track, off road trucks, ect. The stands don't come loose for no reason (possibly threads in the head were compromised from previous valvetrain issues) and unless you do some serious diagnostics that problem don't fix itself. Had issues from the get go.

[@mostlymotorized]

You should check the Piston to valve clearance every 5° for the last 60° of crank rotation before top dead center

[@Framlife351]

You got it twisted my guy,Tony's wreck it Rolfe

[@BCaldwell]

Awesome content man! Thanks once again for sticking with us here on KZbin, A bunch of us really appreciate you.....🤟

[@FinnegansGarage]

Thanks for watching!

[@freedomfox8183]

Your theory is pretty spot on... Engine builder overlooked some important details unfortunately and they were just so so close that it wasn't immediately noticeable on the problem or cause but that definitely answers why you kept breaking springs

[@bigrich7026]

Math is immediately noticeable..you have to quantify everything.

[@codyswenson9078]

The engine builder was in the videos when they were racing the boat. If I remember right, The engine builder seemed pretty clueless when it came to parts that were in the motor like valve springs and other things. I would thing a professional engine builder would keep very detailed build sheets on everything. It seemed Mike was getting pretty frustrated with the builder in those videos.

[@1crazypj]

@@codyswenson9078Building engines as a professional you should sometimes have customers who say 'do I need to know this shit?' If you don't know the info, you ain't a pro.

[@54raceman]

Yeah I wouldn’t let whoever did the work or the most recent builder change the spark plugs in my motor after seeing this

[@chennemeyer]

With so much interference, piston to basically all valves, its amazeing that it held together. I think its a testament to the very high quality parts that were used to build it.

[@breakshot7451]

and a testament to much much money was burned;))

[@54raceman]

Yeah cubic dollars is the solo reason it even made those six passes before eating itself as bad as the work was

[@jasonedwards5292]

Really like the technical aspects of some of your videos. Your valve clearance is technically larger than you figured because both the deck and head surface had a sealant on them. My pops always taught us stuff breaks for a reason, figure out why before you try and fix it. This video brought back some old memories w/my dad especially teaching me to read a mic. Thank you

[@JackWilson327]

Thanks for sharing all this, everyone. I learn so much from videos like this.

[@lamarw9901]

It takes more work to build something from a mesed up situation than to build something new. Fixing a mess up in a hurry leads to more screw ups. Yet, we're racers and want it done now to make the race tomorrrow. It happens. Hope everyone can remain friends and we're all back racing. Yes I am speaking from experience. Granted on a lower budget.

[@bayoumike544]

Been there done that. I ran a 100cc 2 stroke with only one piston ring to make the next heat more than once when I was kart racing. 13k rpm on one ring --- sketchy.

[@bayoumike544]

@buildaboiworkshop Back in the mid 1980's when I was racing a set of 2 rings was 35 buck. I was running a Comet K55 engine on a Margay chassis with a 3 disc Hortsman wet clutch. Had problems sticking the second ring for some reason ( probably a bit of detonation). A new engine back then was about 2000 plus a blueprint and a pipe. When it was right it ran like a scalded dog.

[@bayoumike544]

@buildaboiworkshop rings were sticking between the ports if I remember right. Been out for years.

[@ericwhite4373]

We all have bad days and we all make mistakes...Your grace for the builder says a lot about you...

[@numlockkilla]

Mike isn't going to refund his money, but the call outs are good to let people know that he overlooks alot of stuff and will throw it together regardless and let it self clearance.

[@NikMartin-I-am]

​@@numlockkillathat's what you took away from this video? That the engine builder is a POS? That's not what I learned at all.

[@joe-mac]

Not at all. The engine builder is a world class guy. He builds many engines that are running amazing 5 years later. So one bad call isnt bad in my books. Yes it isnt great but it happened and thats how you learn. You cant learn if you dont mess up ever. And these engines arnt youre typical ls blah blah blah. Blah, they are parted out from many companies and machined to work with eachother. We cant all be machines humans mess up its our nature. People like you are the ones that ruin a good mans name over 1 bad job when he has hundruds of good running award winning engines under his belt 😂​@numlockkilla

[@shadvan9494]

@@numlockkilla that not what i came away with from this video. Mike gave the engine builder mad props for getting back together under a time crunch. that piston skirt to crank clearance was probably so minor that you would never feel it and it may not even show up until it was running at a high rpm. also, the piston to valve clearance seems perfectly fine a .135 and .100. I suspect the springs are not controlling the valves and may not be right for this cam profile. sometime aggressive opening and closing ramps will cause the valve to bounce on the seats but not really be a complete valve float situation. that would also explain the damage on the rocker arms and the pedestal mounts coming loose. I have built tons of big block chevys, but nothing like that 632. when you get beyond the do it yourself 496 kits from summit and other, its pretty much custom fabrication and fitment for everything. back in the 80s before you had the 383 kits we have now, you used to have to measure the cam lobe to connecting rod bolt clearance to make sure you would not wipe out the cam with the rod bolt on cylinders 1, 2, 5 and 6. i did all that on a 383 i rebuilt for a friend, he installed a new chrome oil pan on it, instead of the one i put on it. then called me saying the engine was locked up when he was trying to put it in the car and start it. i get it back to my garage, and i pull the oil can and it rotates over fine. not issues. put the chrome pan on it and it locks up. turn out the pan was not designed for a stroker crank and the cap screws on the rods were hitting the pan rail. thankfully i was able to show him what was wrong, and he went back with the pan I put on it. got it in the car and up and running with no further issues. but he was pretty heated thinking i screwed up the build. i would have made it right if I had overlooked something, and i suspect that mike engine builder will make it right too. as an engine builder your reputation matters, if you screw up, people will hear about it, it how you handle making right that matters. if he does, i am sure Finigan will tell us all he did a awesome job of making it right, if he doesn't, well that would kill his rep as a builder.

[@Hambone00007]

Didn’t really need to through Mike under the bus on nation wide forum . Maybe he should have worked challenges out privately . The engine was not right. Was it really necessary to mention Mike when explaining the engine’s clearance problems ? Wasn’t really necessary in my opinion .

[@jerrybattisti5454]

That's a Bryant crankshaft for sure👌. The rocker stands threads in the heads may have been compromised from previous valvetrain issues. Seen it happen. Also on a T&D rocker arm like you have... the six digit number on the side is the date in which they were made. Can give you an idea of how old some of your parts are and the punishment they may have gone thru before you even owned the engine.

[@vettekid3326]

Back in my younger days in the 1980's I got to work around piston engined aircraft. I wasn't a certified A&P mechanic so all I could do is help but I do remember when we would replace engines with factory remanufactured ones we would do the initial startup and run for like 10 min and then drain all the oil and cut open the filters to look for metal. If everything looked good then more ground running and checks before we actually put any air time on the engines. Also thermal expansion could alter the clearances with the engine running over checking it at room temperature.

[@randr10]

I've thought more on this after doing some yard work. That thing having .120" clearance even after the valve train got hammered to death tells us you need more than that on the exhaust valves given the cam timing you're running. The keepers not coming off and the valve not wanting to come out of the guide tells us the top of the valve was mushroomed. So say you had .100" clearance when it was assembled. With the trick parts made of exotic materials, they grew more than your typical engine build upon heating up, therefore more clearance needed than usual. Probably like 0.125-0.130". Valve hits, makes its own clearance, rockers loosen up. Engine runs good enough for the dyno session and a few runs, but it's just a matter of time, with bent valves, that things get interesting. I'm amazed at how long it held together and that with a valve broken clean in half that it didn't puke a rod out the side of the block.

[@gags730]

head gasket thickness. Was the head gasket changed with a different brand or type?

[@donny763222]

Super great video

[@MrT5mustang]

Even the best engine builders make mistakes. Good way of keeping it real and not throwing him under the boat! I hope he does the right thing in the end and you come back with a video telling everyone how stand up he is. If he is!

[@larrychristopher9147]

You really are knowledgeable and very good at analyzing the problem. Glad you and engine builder are still friends. Tough situation. Best of luck Mike

[@JimmyInKona]

dents in the other piston are probably from valve guide chunks, that valve guide was missing lots of material in the exhaust port.....

[@jasonm3109]

That guide more than likely went out the exhaust... They showed witness marks on the crank from the pistons hitting it too.

[@keithkamps77]

Didn't know you had a channel glad I stumbled across it, love watching you on Road Kill and other programs you never seem to stress about stuff not working right. Great informative video.

[@SS454LS6]

I love that even though you are Mike Miller are friends, you are still just telling it as it is. Truth is the truth, and it has no feelings. Mistakes happen. The big thing that is painfully lacking in today's world is accountability. I'm sure Mr Miller has a list of reasons things may have been done the way they were done, or why something failed. I'm hoping you guys come to an understanding and everyone remains friends and can still work together. Thanks for the thorough breakdown of the engine.

[@teknoaija1762]

I asked a seasoned engineer about ring end gaps and rotation and he said they filmed this in Wärtsilä engine lab and it was about 60 revs per minute.End gaps change position all the time so you have no issue there mike.

[@randr10]

That comment you made about trash in the new build is why I always heat cycle the engine and change the oil right away with a new filter after any internal engine work is done, and cut the run-in filter open to make sure no large chunks in it for good measure. Every single engine I've done have a little bit of fresh glitter in the filter, and I've gotten silly with cleaning on some of them. After the first time I tried that I do it on everything, including if I buy a lawnmower engine from Harbor Freight.

[@TurboJohnRacing]

That is a super nice engine! Nice video and explanations on what went wrong. It happens, noone is perfect and crap happens all the time in the race car world. Hope the rebuild is easy.

[@recoilrob324]

At 26:28 talking about ring gaps and how they should be staggered around the piston: Hyundai did some experiments with radioactive tagging rings so they could use high speed X-ray to watch them in a running motor, and they spun around the pistons at varying speeds. I always stagger them when building a motor...but you really don't need to and they won't stay staggered for long like you installed them unless they're pinned in place. OK...made it to the end and see that the piston/valve clearances measure out OK...so that's not on the engine builder. The problem is the cam choice has too aggressive opening and closing rates and the exhaust valves were bouncing along with pulling rocker studs, bending pushrods and breaking valve springs on the intake side for the same reasons. The engine builder reused the cam that the motor came with at Mike's instruction so only the person who speck'ed out the cam initially has some responsibility for what happened IMHO.

[@jeffreydurham5342]

I think it was overreved, prop coming out of the water or something

[@petemcpeterson6205]

Every exhaust valve was hitting pistons. Good witness marks on both . Should've watched the whole video first.. you guys should've noticed the second you pulled the heads off though like I did .

[@54raceman]

Yeah the fact that they didn’t know they were making contact the second they seen the valves is kinda worrying with the type of stuff they do

[@OGRocker1]

Thanks Mike and Joe, very entertaining for an old gearhead, till the next!

[@EnfieldJoe]

Great video with outstanding commentary. Very educational. Well done. .

[@ionstorm66]

I bet the valve clearance is good now that the valve is bent. The fact is it's still pretty close even after the contact means it had to be much closer. Also titanium valves stretch more than steel. So it's possible it had good clearance and either the valves stretched or the seats moved.

[@michaelreynolds1904]

Especially with 400lbs of valve spring. Chalk this up to sometimes, shit happens.

[@JCWren]

I'm no expert, but with 0.125 clearance on the exhaust and 0.100 on the intake, can there be enough stretch or movement for that to occur? I understand those numbers are with the bent valves, so the numbers with straight valves may be smaller. A quick search on Google says recommended minimum for exhaust is 0.100 and 0.080 for intake.

[@ionstorm66]

​@@JCWren Titanium valves are a mixed bag. They love to creep over time, way more than any steel. So even if the clearance was good when it was installed, as they got hot they could easily close that gap. Nitrous gives you crazy cylinder and exhaust temps.

[@JCWren]

@@ionstorm66Thanks!

[@zmanindy]

Thanks Mike love these kinds of videos. Can’t wait to see what is next on the Caddy.

[@warrenkaye2486]

Excellent job mike, great detective work, and easy to follow and very educational. Kudos to you

[@freedomworx]

Mike, You shouldn't worry with the location of the ring gaps upon disassembly. It was likely assembled correctly, but the rings do rotate around the piston during operation. It's a common misconception that they just stay where you put them. There are several SAE Papers on the topic, and even a standard test method to determine how much they rotate in operation. A radionuclide is imbedded in the piston ring, and the rotation can be detected in operation by following the radioactive signature of each piston ring. One study I read said that 3 RPM is a good rule of thumb for the angular velocity of a ring in operation.

[@guidorollard2944]

Good video's from Finnegan, no drama or big Hollywood show. Just the right entertaining.

[@CliffordThompson-kd7os]

I see a few things that could have been better, but I see a lot of concentration on things that is not the cause of the broken valve and the valves hitting. What you're going to find out in the end is the valve springs are the culprit and the wrong retainer was used, the spring is not correct causing harmonics or the combination of them both. No way should you have to pry the retainer off the spring. This is why the motor wouldn't rev and was down on power. There was no valve control. Cranks will flex, number 2,3 and 4 mains will show it more on the bearings. It's common and not of great concern. Soon as it makes its room for flex or the tune up is corrected, as long as the bearing has not lost its crush or been over heated and not really been tore up, it will continue to run just fine. No concerns of blowing up.

[@MichiganQuadTrailsTales]

Always Great to actually see, and Find Out What, and Why Things Happened ! Great Video!

[@carnut2431]

Good stuff Mike. Well worth watching. Hopefully you can get it sorted.

[@mynameis9057]

the crank will wear more on certain bearings because the difference in the weight of the pistons and rods will throw it off. Pete's going to have his hands full with that puppy, and he'll definitely need to be good at doing stuff to sort this baby out. I'm thinking new heads and set of matching pistons. Sure taller mismatched pistons may collide with the valves. Luckily it's not beyond salvage. Valves spinning into pistons, probably ungood. I'm sure that piston rings also rotate, so having the ring gaps close to each other happens naturally through normal functions. Pete's got it,no worries with him on the job! And if you're really lucky,he may even compose you a song about your engine 😅 As long it's not another polishing turd one! 😂 Good luck 🍀 brother! Nice catch with the sketchy ground on the intake injectors too! Yeah,bump that and you got it with you grounding it elsewhere. They're not hitting the crank, they're just self clearancing types 😅 but oddly enough you'll never find that written on the parts box!🤣 Peace!👍🍀

[@rcadd1ct]

You are definitely onto something. Engine builder built everything right in a static environment. Issue is what happened in the dynamic environment. It is almost like the springs were not in control. As someone mentioned ramp rate on the cam. Thanks for the deep dive I appreciate your knowledge and problem solving skills.

[@doug3805]

Awesome job! So glad it didn’t burn down. I think you are one patient genius.

[@stacy6014]

Plenty of clearance on paper when you do the math. Now when the valve is out of control is another story. Do some research on here for spin tron testing. It is eye opening. Joe

[@bryangreenleaf5001]

Dude. You’re a champion. That was handled with grace and class of a true professional and good sportsman. Stuff happens, nobody wins ‘em all but the way a set back is handled is, in my opinion, the true character of the man. Really good stuff! Best of luck with your projects

[@wdixon27]

as a mechanic i'm screaming at the screen the second i see the pistons THE VALVES ARE HITTING THE PISTONS, the valve train rattling itself apart also shouts that its being banged on

[@charlesrives9092]

Me too. First thing I noticed.

[@randr10]

Yeah they should not have let it back in service after those issues on the dyno.

[@markwelliver2566]

same!

[@KCadbyRacing]

Yup, the marks were obvious...

[@robtdougherty]

Yep right at 21:00 you can see the contact circles on the piston tops.

[@rickhenry8760]

Mike Finnigan ... MEI (Mechanical Engine Investigator). Dud... You literally covered every base in determining the cause and effect of the engine failure. Most mechanics would have scrapped it and started all over with a new crate engine. As far as the old builder, He did right by you in helping figure out what could be some of the issues that caused the engine failure. I'm so glad that Pete was there to help you out in assisting in determining the problems and it's always good to have a second set of eyes on your projects. Looking forward to seeing this project come back to life later down the road. All the Best and Keep them between the ditches !

[@Brutalford]

Hey Mike, I think what I would do is I would measure from the center of the rod crank Pan to the center of the piston pin and then measure from the center of the piston pin to the top of the piston. I think what you've got is 2 different clearances. 2 different measurements from the old setup to the new setup. And then I would check the block and the head services. To make sure there's flat and they are straight. Me, personally, I think the heads are the problem. I think that they have been the root of the problem even when the previous owner, not knowing why or what caused the vast Angie catastrophic failure, but that it was repaired and suddenly he didn't want the boat anymore, I would say that says a lot about the condition of that engine. It was probably never the same. And therefore it was gotten rid of

[@jaredshoemaker9196]

Pete can definitely get rid of the valvetrain issues. Pete is the man!!! Best of luck, take care!!!

[@Mark-um7ey]

My guess would be valve guide clearance is tightening up at temp considering the past history of failure

[@robtdougherty]

very true, never thought of that. He might have enough PTV clearance but if the guides are starting to bite then the piston will close the valves

[@54raceman]

That is very possible and a issue we chased on a buddies engine

[@obsidian....]

This is why engine builders don't like working on other people's garbage. . When someone brings them a random long block this 👆 is the result far too often . Because... 1. The customer doesn't have the exact specs (or just makes assumptions) 2. They don't know who the original engine builder was (or they guessed) 3. They believe they know what parts are in it but... turns out that "only God knew" what was actually in it 4. It may or may not have been machined a bunch 5. Assume it's a simple rebuild with a slight compression change (either because they are told it is or they just make a stupid assumption) . Anyway, it's not an excuse for this mess. I don't know the guy. But what I do know is scope creep like this happens all the time. . I bet he thought he was just dropping in beefier rods and pistons and ended up with an interference nightmare (which turned into a rush job)

[@stevecunningham2759]

I started writing something like this and found your comment. Thanks

[@CliffordThompson-kd7os]

This is also why customers get fired or won't do work for them. There is a lot of rubbish in this video and not of great concern. Piston's hitting counterweights not so great but the crank flex from wrong tune up or an unhappy engine could have made the interference worst. He will find out the valve springs and retainers were the real issue on engine troubles with power and broken valve along with others touching.

[@drade1820]

Tony. Great video. Please do a follow up about surge brakes. Alot of rented trailers use them. People need to know how deadly they are.

[@Gregorybridgewater]

😂

[@chrisdunaway2562]

Valves hitting the piston would also be a cause for the rocker stands coming loose!!!

[@granthoward4144]

The marks on the pistons look like you are right imo

[@lancehowlett3910]

Wow,as soon as he pulled the first head I noticed the pattern on the piston tops.

[@kennynelson2269]

I subscribed to your channel about 3 months ago and i really like your style of videos you break things down and go in depth with everything.. keep it up

[@FinnegansGarage]

Thanks for watching!

[@georgedreisch2662]

You’re leaving the cam shaft change out of your analysis, for the probability that it is the source of the deviation from the original piston / valve clearance…

[@thebrelon]

Was about to comment something similar... Just a little more lift and the pistons to valves clearance is gone

[@joedennison2972]

Thank you Mike for one of your most intriguing videos to date for me. In the past, I guess I get disappointed when all of your extremely hard efforts go up in smoke for some reason or another. It reminds me that I don’t have the knowledge, diligence, patience, and bankroll to play with high-performance racing stuff like that. However, I loved how you went through that engine from top to bottom, in a completely fact-based manner using the right tools and no jumping to conclusions, all the while without trashing the builder. I think that’s why I like your show productions the best because you’re so even keeled, well spoken, no cursing (I could put my eight-year-old in front of your shows to learn about engines and not have a fear of hearing an F bomb) and knowledgeable. Please keep up with the solid content. I’m still trying to analyze wifey’s expression though. Definitely not happy, but I feel like she herself has performance/racing blood of her own and understands the situation.

[@FinnegansGarage]

Thanks for watching! Wifey understands and is a saint. :)

[@papajon-1000]

Wonder if the rods are bent slightly. May have clearanced themselves slightly after all of the contact. Add that to the bent valves and we will probably not know what the piston to valve clearance was when it was assembled

[@photodan24]

But they wouldn't have over-clearanced by 100 thou, which is what the real world measured clearance was. Interference contact probably would have been more catastrophic and he wouldn't have gotten the runs he did. I think Mike is on to something with the valve control.

[@c130steve]

Excellent Investigation techniques, and the video provided a great way to tell the story. Thanks

[@Z287899]

That might be the result, but the why is harder to pin down. Did the valves tulip causing interference? Rods stretch or expand with heat? Was the head gasket too thin? Different cam, was it checked? Springs, retainers? Valve float? So many things could have caused this.

[@Z287899]

Watching further, that cam timing very well could have been off also. I didn't really see but are your timing gears adjustable? Just something else to look at.

[@Bob0sModelFabWorx]

From your description of the history of this engine, I'm wondering how it lasted that long. We do all have bad days. Thanks for the detailed tutorial on what you did.

[@jimhmod]

The cam change could be the cause of valve train issue if the clearances weren't checked. It wouldn't take but .010" more lift or a few degrees difference in duration along with some rod expansion due to heat for the valves to just tag the pistons. It's possible that they didn't touch unitl the motor got fully warmed. The recommended .050"-060" additional clearance for valve to piston obviously wasn't there. Of course the long piston skirts hitting and making debris didn't do it any favors. Typing this before the end of this video. edit: well it looks like a valve spring issue----maybe--or the previous cam-or---------valve guide clearance or------too many hands in build.

[@Kstang09]

Finn, youre so calm & chill when going over this stuff.. never throwing anyone under the bus or getting your knickers all knotted. Admirable, amigo 👍

[@michaelatzenhoffer9197]

You want to check piston to vale with the springs you will run because it pulls the value to the seat more you will probably have .020 difference from check spring to you run springs, I worked for Nickens brothers racing engines in houston

[@DJTruth_1970]

I’d be curious to know which valve dropped originally vs which on dropped on y’all. Did the original dropped valve damage the guide and that guide was never checked properly replaced. Went through this on a race HEMI

[@jasoncardoza6375]

Younger days I always wanted big power engine in my camaro. Honestly all the content on KZbin is starting to prove a realization of mine. Big dollar builds are break prone and to this day I’ve never seen a rebuild of any kind ever last 200,000 miles like a factory engine does with regular maintenance. Always internal premature wear and typically a main bearing.

[@DadeMurphy1507]

Come back to Mabank Tx, we met in the groom and sons hardware store. Episode of RK , you and 12volt were rescuing another tri5. I had my daughter with me. I still need to buy you that beer.

[@bradinch1563]

and this is why i started to build my own race motors, thanks for showing all of this.

[@robertbriggs4176]

Don't the rings rotate around the piston when the engine is running? I thought that was common knowledge.

[@numlockkilla]

They do but if it's right they usually keep their distance because there all rotating at the same rate. If their not its either not put at install or a ringland has a pinch or the area is dirty and gummy. A stopped ring is a bad thing.

[@CliffordThompson-kd7os]

The piston rings will never rotate in a circle at the same rate. To many variables. Ring thickness, material, top ring gets more heat just to name a few. It is an old wise tale.

[@RyanTaylor-tb9ws]

I have checked piston to valve clearance that way before but I preferr the clay method. Try the clay method and let us know what you come up with. Thanks for the cool show

[@redhwk44]

Did you use the same thickness MLS head gasket when it was rebuilt? That thickness could be an issue.

[@patrickmcdonald3427]

I learned something from this that I hadn't previously considered-"pistons chasing valves". We all know about PV clearance. It is not the problem. It is the pistons chasing and catching the valves.

[@michaelgideon8944]

The investigation was really interesting. The lesson in this video: Don't send a combo to your builder that they aren't 100% familiar with. Successful shops are probably too busy to play science project with your franken-motor. At this level of HP just buy your preferred builder's engine.

[@AutoXandTrack]

I enjoyed this one Finnegan. It has to feel good to finally find some answers after all the problems at the lake!

[@z06doc86]

I don’t want to be disrespectful, but I would junk that engine and get Steve Morris to build a new one.

[@kerryhickman2235]

Mike have you ever ran an ATM carburetor? Bill Hoskinson from Old Man's Garage absolutely love them. He has said that everyone he has gotten, he's been able to just put it on without having to adjust it. He was able to put one on a LS & make more hp than it did on fuel injection. He made almost 40 hp more with the ATM. He just calls them up & tells them the info on the vehicle & they build the Carburetor they feel would be the best for his setup. He said he'll never run anything but an ATM from now on. Hope you found this useful if you didn't know about them. I love your videos! Thanks for everything!!

[@davidgierke7582]

You're more magnanimous than I would have been over the shoddy workmanship this engine-builder displayed with your big block Chevy. I've been watching all of the trials and tribulations that you went through in trying to run your boat and get some performance out of that engine, and to be honest the results didn't make you look too good...although I realized that you weren't there (on the west coast) to supervise the engine work. Although you were gracious in absolving this guy of most responsibility, I'm certain that you paid good money to have the job done correctly-which it wasn't. The condition of the crank (lack of polish to the journals); the condition of the cam bearings (disintegrating?); the substitution of the original camshaft?; the piston skirt interference problem; the obvious lack of attention to the valve train, all point to incompetence, and the possible continuation of a bias among engine builders toward customers located on the opposite coast. This guy owes you money and an apology, after which, I wouldn't allow him to ever lay his mitts on your stuff again!

[@srharris88]

We have also had a lot of issues with 632s and their valvetrain. We used to run aggressive cams with a lot of valve spring pressure to make as power as possible, but it kept breaking. We now run less spring pressure and a less aggressive cam. Steel rockers, instead of aluminum and have had much better longevity since.

[@pacoperkid13]

If the valve is bent won't the measurement for clearance be wrong?

[@quiettoni913]

I was thinking that too. The engine may well have self clearanced.

[@unclebobsgarage9136]

We are all perfect examples of NOT BEING PERFECT! Keep up the good work.

[@copycat4496]

every exhaust valve is hitting the piston mate

[@woofersd2383]

Pretty cool investigation. Glad you found the answers.

[@MadmanJnr]

Makes the engine in Blasphemi look reliable is a statement and a half😅 Great break down Mike! Goes well with the disclaimer at the end too 👌

[@PolarisOlle]

Grymt! Alltid roligt att se hur de går, uppskattar de längre avsnitten

[@Fathead758]

Not my money I'm spending but no chance those heads go back on that motor nothing but trouble with them new heads are always the answer😂

[@jfunk62]

Finn, great job of problem solving and sharing. The old addage of "if you want it done right, do it yourself" rang true once again. From the beginning i said all them 632 problems/failures were directly related to the engine builder and not on you/tuning. I know the Sonny engine isnt sit up for nitrous but would love to see it on a boat load of spray in the boat. 😅😅

[@edpetrocelli2633]

Those are rookie builder mistakes.

[@rickybuxton8245]

great video, awesome sherlocking. really appreciate the end and the acknowledgement that little mistakes happen especially when people are under pressure.

[@overyonderjustapiece]

Mike, have you given any consideration that the builder MAY have installed the cam either advanced or retarded to move the power band either up or down? I don't recall you mentioning the timing set being advanced or retarded when you disassembled the engine. That by itself could be your culprit. Excellent video and content quality. Great descriptions and explanations as you are going along.

[@genesound]

40:40 - Egads! FOCUS! The builder overlooked the basics! Unfortunate, sorry for your luck! If the valve stem bent, it should do it close to the valve. What you have causing the valves not to come out of the guides is probably flowered out stem head, from the valves hitting the pistons. This causes the top to swedge out, making them hard to get through the guide. If you force it, you can ruin the guide. Just file/grind down the OD of the stem at the tops to get them out without damaging the guides. When I was watching from the beginning, I thought "it was slowly getting weaker from increasing compression loss". Been around the block before.

[@chrisamon5762]

6 passes out of a Chevy block sounds about right!!!! Mopar or Ford all the way!!!!

[@aserta]

"In the 72 seasons the championship has been awarded, only nine different manufacturers have won it. Chevrolet has been the most successful, with 42 titles. The second most successful is Ford, with 17 titles." Just googled "who has more wins, chevrolet or ford". At this point, that engine is less Chevrolet and just a dog chow of people fixing and making stuff on it. A ford in the same shoes would do exactly the same, especially with those kinds of pistons that are approaching F1 style piston and rod technology (still too fat, but closer than regular engines, that's for sure). If you've ever worked engines, you should know that the moment you modify an engine, it's not ford or chevrolet or whathaveyou, it's "you" and you alone. Any other talk is coping with "your" failures. In this case (as stated) this engine has been rawdawged by several people. Hence "dog chow".

[@freedomfox8183]

Then why is the first thing everybody does with a fox body or mustang is put a Chevy in it ? Ford's trash and and the engines that aren't are way too expensive to go fast with long term ... There is no better solution than a Chevy unless you hate money

[@gbshaw107]

“if you hate children, you drive a ford.”

[@richardmikesell1335]

Great video, I learned alot!!! I hear you on the builder too, we all have a bad day ever now and again. Don't let it spoil your friendship!

[@rickykeaton9236]

We had slop in a timing chain when put it under torque would show up, but just on the stand measuring clearances it did not. It looks like your problem was at one particular point of the cam and crank position with two pistons involved

[@vehdynam]

Thanks Mike , great video and very gracious of you in regards to engine builder. As they say " stuff happens".

[@jamesbriscoe17]

Coolest episode yet man, very insightful about motor wear and how to remedy it. Currently rebuilding two 502CI’s in my 32 fountain and love the info

[@nvrenuf_k5933]

Great video, great autopsy! Thanks for posting all that, super informative and interesting stuff!

[@KCadbyRacing]

I'm really surprised you guys didn't see/realize the valves were (obviously) hitting the pistons but at 65+ years old, I'm still learning 'stuff' as well 👍

[@miketaylor7487]

59:13 that is a GREAT shot of the valve chasing the piston.

[@joef7406]

does a refresh = power wash and slap it back together? Great episode, I hope you keep going until you achieve your goal of record setting performance and reliability, and you will have shown us all something. Looking around your garage your achievements so far are remarkable. Thank you for sharing, Joe F.

[@aserta]

6:15 get one of those stand up broom and tray units do you don't have to bend down. So much better for the back and knees.

[@jam46psu]

The springs were resonating. This explains the loose rocker arms, valves etc. perhaps more preload or a different spring is required.

[@lloydratsoy2057]

Very careless assembly. I would also suspect the camshaft. My brother got a pair of cams for his offshore boat and could not keep lifters in the engines. New set of properly spec'd cams and, bingo, no more problems. 1050 HP X 2! Lots of fun.

[@member369240sx]

Thanks brother for one of the most informative videos i have seen in a while on motors.