It seems that the GM problem is far worse than the scotchbright problem. I also would note that if 2 different blocks cut way more on one side of a bank, I might check my machine

These guys are easy to locate in a shop because they are the same ones that use 1/2 tube of silicon on a timing cover. Just find the ones who request the most silicon, and you have the perp.

Does my heart good when I see Gerald come out with a new video!❤ always educating! Ronnie East Tennessee

Been using scotch brights for years to brush the surface never had a problem. The biggest key to it is your just cleaning it not digging into it. Most newbies need not do it.

Never underestimate the power of fools with power tools. It keeps guys like Brand racing working through, so it can't be all bad. 🤣

As a GM master tech there is multiple red "notes" in our service information engine repair stating NOT to use anything mechanical or abrasive to clean cylinder heads or the block deck. We use CRC gasket remover and a razor blade or scraper to clean aluminum blocks and heads! THAT IS IT! When im done my heads look almost like factory

Gerald and Ruby, y'all rock! Lo e the channel and content. Peace ❤ Thanks ,Jackie

It only took me 10 minutes to clean it with Scotchbrite and 6 hours for Mr. Gerald to make it right again.

Nice job Gerald. That block was bad. I really do not like the pads. I always clean and prep by hand. No power tools for sanding. Thanks for sharing. 👍

Sometimes I am glad I have a healthy dose of fear of messing something costly up so thread very lightly when I work on my projects because something like this can happen. Great video Gerald👍👍👍👍

seen alot of things destroyed from cleaning with scratchbrite... Keep on Keeping on my friend

I learned this fixing a "polished" bike frame. They took down the casted bumps with scotchbrite, and mad nasty deep swirls. Took forever to correct.

Several years ago at the shop I work at, a customer brought in a Subaru with head gasket issues. The customer said they had the head gaskets done at another shop a year or two ago. After removing the head, we discovered the other shop had done this exact same thing, cleaned up the aluminum block surface with a Scotch-Brite wheel. This was supposedly a "Subaru specialist" too. The customer didn't want to pay us to remove and resurface the block so we ended up just resurfacing the heads, spraying the gaskets with copper spray, and slapping it together with a note that we would not be offering a warranty on that repair. The customer ended up getting rid of the car before the gaskets started to leak again. Why somebody would take a Scotch-Brite wheel to an aluminum block surface is beyond me.

Nice to see that GM still hasn’t changed the mill cutting head that they decked that block with since the 70’s ! Seen that wave ( minus the scotch bright bandit) on many of small blocks chevys .

I get excited every time I see you have a video

Those scotch brites are no joke. I used to use them at the bike shop for removing stubborn gasket leftovers but I'd turn the air down to the right angle grinder and go way slow and easy. Sometimes you can just pass it back and forth by hand/no grinder and get the job done.

Was the second cylinder bank perpendicular to the cutter? It seems that the cutter did not even touch the deck at all towards the outside of the block for several passes of the cutter. (Maybe GM cut the deck at an angle!)

I use the plastic discs for prepping aluminum surfaces. Also a plastic razor blade type tool for srapping off material.

Master at work fixing another shade tree mechanics repair

so satisfying to watch , plus this man knows what a finish is ;) unlike many uploads here on youtube

I worked with a mechanic who would "clean up" flywheels with an angle grinder and 3M pad whenever he did clutch jobs.

Another great video. That explains the disparity in performance between identical vehicles. I had no idea scotch-brite could do that kind of damage. OEM lack of quality is unbelievable.

I am a bodyman by trade and I can watch your videos all day long I really like how you explain everything as you do the work

Enjoy your videos!!!

the liners are hard to cut with scotchbite wheel, but they're inline with block surface. that makes me believe the block surface is out-of-flat due to massive overheating, not the scotchbritig (altough partial damage may take place on peripheral areas).

I used to work in machine shops for 40+ years.Some of the blocks and heads back in the 80s looked like they were threaded . 3.8 ford v-6,2.3and 2.5 Taurus were the worst

⁠I’m sure many of you know already but mentioning for general consumption for those that don’t know. There are different rolocs/scotchbrights for different materials. 3m (parent company for many of these) has a 40+ page catalog for 100’s of applications. Everything from heavy rust removal to bristle brush try cleaners.

Love all the comments telling Gerald hes doing it wrong. Keyboard warriors telling a guy with decades of experience.

Gerald. Good job mate. Your channel is always top shelf. Do you have someone editing? I personally used to watch the techs at the dealership use scotch brite on the surfaces to speed up the cleaning process. Know wonder people go elsewhere once the warranty runs out. Too much pressure because of book time. Independents crush the ever-growing maintenance/rebuilt demand in the automotive market place.

I once had an older mechanic bring in a pair of heads that he used a body grinder on to clean every surface. It had the edges so rounded the heads were scrap.

Nice! I think El Grande Hefe's pick-up motor needs this same treatment after the cam job..

I use to have a machine shop and did work for multiple dealers, I've had to take a cut on a head, then take them back to the dealers to show them what they were doing to the heads with those pads, great tool but they will fuck up both aluminum and iron heads and blocks fast !!

We loved it welding, scotch brite grain in stainless steel elevator doors, and such

What i learnd from this is let the shop clean it up. This insures the minimum of material is removed.

Wow man they really like scotch brite pads lol. Are you going to have a hard time now getting the correct length rods and will it require custom size pistons now or it is not that far gone. Thanks man. And yea ruby was saying I need my toy Dad.

That looked like a perfect 92.5 degree GM V8 block to me... Still 35 degrees better than a Furd one!

About 2004, at a Chrysler dealer, one of the techs cleaned up the decks on a 3.3 with Scotch Brite wheels and the customer sued us when it started knocking. He took it somewhere else and they found the bearings wiped out. In court, the CUSTOMER shows US a Technical Service Bulletin that says "Never use Scotch Brite wheels on internal engine parts"! Turns out, Chrysler sent the TSB out but, the service manager never gave ANY bulletins to the techs! Nice. The previous manager made sure we saw every bit of info possible and we made 5Star. Lost it with the new manager. One question; can you measure a BBC 454 to see if it's ever been decked? I've got an LS6 that was cast in '72 and, is stamped as a '70 Chevelle but, looks like the correct broach milling.

Yep I used to hate that lazy mechanics would used. But then they would smear form a gasket on it with the gasket and the gasket would turn the mush 6 months later.

Great Video. You don't know how much these videos help this rookie machinist. How much are you cutting per pass? I just got my BHJ Blok-Tru all set up and ready to use. Hopefully deck my first block today.

Scotchbrite pads on a die grinder=The WhizzyWheel of Death for precision machinery.

Just wondering, do you match the depth dimension of both banks deck to crank center line? Great video! Thanks for sharing with us.

So would you use thicker head gaskets after this to not mess up the compression as well? Slowly learning about machining video by video.

Great video. What is your recommended method of cleaning the deck surface?

BEAUTIFUUUUUULLLLL!!!

I just found your channel, I love watching machine work! When you see a block this much off on the 1 side of the block, do you ever question your setup being off a little? or is this just from many years experience and knowing that factory machine work is subpar?

Thank you for posting every interesting videos. Although it may be ok for daily use, but now I know the quality of the block isn't good enough for high performance vehicle.

Yeah I'm sure few a spot was caused by scotch bright but a big majority of it was a factory surface angle cut versus your surface angle cut, as yours's could have been more square versus the factory cut, something you forget to factor in was they may have gotten the engine a little too hot so the aluminum did not shrink back into its original position.

I had to take .007-.008 off a set of 706s that someone went over with a cookie on a wizz wheel just to get them flat again... -_- (fyi, those low spots were between cylinders) I cant believe people still do that and expect it to work well.

I have used Scotch Brite pads to grind broken screw drivers. Usually into some special tool.

How many thousandths were removed? Will it change compression much?

Nice Job Sir. Dare you go to deck true next? ;)...........

How off that block was reminded me of an episode of Roadkill Garage. Steve Dulcich had a shop zero deck a 360 - well, it wasn't making the power he expected on the dyno. Pulled it apart and found (If I remember correctly) #2 piston was like .020 downhole - and #8 was .010 down. You can bet he never took another engine to that shop.

Could the scotch brute damage be pre-existing, from a dealer warranty head gasket replacement, butchered, for warranty flat rate? Thinking I’d want to take a close look at the head bolt threads, in case the fix was to overtorque the heads.

I don't waste my time with aluminum blocks , they are to finicky and for the few pounds you save it isn't worth the hassle . Most street builds you will never have to worry about the extra weight .

Scotchbrite and graphite go together like peas and carrots 😊

you should narrate documentaries!

I just slowly shake my head and roll my eyes when I walk into a "professional" shop and see workers cleaning off gasket surfaces with a 20k die grinder with a scotchbrite pad zinging away and knowing they are not going to be resurfacing that area. I see diesel shops doing that all the time.

Yeah buddy! 😁

Good job; but I don't anything destroyed unless it's NOT savagable.

I use a 2 inch wood chisel to remove the stuff off the surface then put em in the washer cabinet before I throw em on the surfacer, I had an old boy bring me a iron duke head to surface, I put a straight edge on it and you could of thrown a cat under it, Had to cut .021 to fix it, he must of worn out out a whole box of wheels

I decked a set of aluminum Jeep 4.7 heads in my garage using some wet sand paper and a travertine marble tile. Got it to within 20 thousandths.

Chisel gasket removal spray . Razor blade scraper , brake clean ,or a buddy with a wash or dunk tank is all you need and yea ls blocks are that bad straight from GM , cash iron or aluminum, anything mass produced can always use refinement, excellent work gentlemen.

That’s a great example of people not knowing what they are doing, and what tool is correct for the job. Over the years I’ve seen many a precision parts ruined by these. I think the worst was a rare flywheel that someone “scotchbrited” completely ruining the part!

GM.....mark of excellence.....righhhhhhht

i use scotchbright to smooth cylinders, get it half a thou off tolerance and wrap a pad around my honing stones makes them super smooth

John doc has actually done a video awhile back where he took a wiz wheel or scotch bright wheel to a block and then had tkm see how bad it Jack's them up its crazy how fast u can blow thousands of dollars with a 40 dollar tool and not even realize your doin it till its too late lol

id be interested in seeing the process of setting up the block in the machine and zeroing it.

I've always felt that power tools were not meant for gasket removal. Scraper or single edge razor blade?

How much did you take off each side????

According to what I've read, GM does not recommend using Scotchbrite products on blocks or any internal engine parts when rebuilding an engine!

What do you suggest we (home budget DIY) use for cleaning up a deck?

Looks like a flap wheel and angle grinder job 😮

That's why I like cast iron.

Interesting to see what scotch brite does to a deck of a block. Just wondering how much did you end cutting off the deck?? Love the content and the information Gerald.

This may be a dumb question, but here goes. Do you have to do the same process on the cylinder heads?

On an LS engine you literally pretty much only ever need brand new razor blades and brake cleaner it’s that easy brake cleaner will lift up the black parts of the gasket and the razor blade was scrape it smooth without digging gouges into the surface, if somebody uses a buffing wheel on any machined surfaces in my shop they get a big talking to!

Is there any disc that’s safer than scotch brite discs that you could recommend using?

I suspect the block was not mounted flat before machining when one corner is untouched and the opposite diagonal corner is machined smooth

I might be wrong but I think put the coolant on the side that has no paint left on it since it is the side that is actually being cut.

2 questions. One what is the depth of cut? Two did you run an indicator down the bores to make sure you are square? Those passes all looked heavy to the back of the machine.

Having learned machining in the ariospace industry I'm always amazed at how badly automotive factory parts are made. Their tolerance are just all over the place, amazing that some of the factory stuff will even hold a gasket at all. In aerospace when you start seeing you are a thousands out you start looking for why, you'd never see deck angles anywhere near that far off.

There is a big difference between using a Scotch brite wheel and a Scotch brite pad by hand.

how do you "touch off" and not even clean up your touch off line on first pass? i think the setup is off or the touch off was hasty

Too many think "oh I know what I'm doing" those are dangerous. I had a Mazda head on a B2200 back in the 90's. He had taken it to all the pro's and they kept tossing headgaskets at it. When I got it the block looked ok but the head looked funny. Took it to my machine shop guy who I learned my tiny bit if machining and his old ass spotted it right away. He told me to use it as a door prop. They had gouged the head then took it to a bad machine shop who ground the head at an angle. Since the headbolts didn't make full contact (yes it was that bad. Full run-out on one side hardly ground on the opposite) they loosened up which I caught and said they didn't torque it fully then saw the wonky head deck job. Lucky he was the parts counter guy so he ordered another head and sent that junk in for core. My machinist had to deck the one he ordered but nobody had to do another headgasket on that pickup lol.

06:38.....might wanna consider replacing that air line brother.😉

I've seen so many techs and mechanics do this scotchbrite shit and comebacks with headgasket failure and they're super butthurt they have to do it again.

Looks like the mill is not perpendicular to the surfaces of your blocks? Both blocks were immediately showing material removed on one side only...

How much did you take off? What about piston in hole dimension?

I have a question. I have an ls2 aluminum block that was stroked out to a 403 forged setup. A meth valve was ingested and created a hairline crack in one of the cylinders. Can i simply have that cylinder resleeved and install another weight matched piston?

How much do you normally remove on each pass normally? How much did you remove from this block and was it equal for both sides(may be a dumb question, but I had to ask.. I would expect it to be equal).

What would you recommend to touch up the surface for a new head gasket?

Some people are pretty stupid when it comes to abrasives and soft metal. People are applying techniques that used to use on cast iron blocks to aluminum and that's a big no-no

I don't see any lube coming out of that nozzle... is it just so clear that it's hard to see?

I really enjoyed that hillbilly music. Lot better than listening to noisy shop machining, or informative dialogue.

I would rather have the scotch brite guy working on my block than you surfacing it

All blocks be they iron or aluminum should be decked on the mill, same with heads, intakes and exaust manifolds, this way everything can be matched tolerance by the machinist to fit perfectly instead of " eyeballing it" . I weigh every internal component to make sure all parts weigh the same, in my eyes this is the most critical measurement and the crank balancing, polishing and chamfering, rifle drilling the blocks oil passages, installing restictors and stands where needed etc. Working in the aerospace industry made me a bastard for details, lives are at stake

People who do crazy stuff like that should stay well away from engine building, but lucky they came to their senses and brung it to you.

I just always used a wire wheel on my grinder for years ..like 30 to clean blocks. I even know machine shops do the same for a cheap reseal. I never had a issue. Its beyond me why people use roloc discs to clean alu. Especially when they make plastic bristle roloc discs

Loving the videos. Could you please turn the machines off when you’re trying to explain stuff. And could you please tell us how much you’re cutting off each pass. The DICOM helps

Da sander lol, not 2” scotch bright! 😂