How to: DIY Crankshaft mirror polishing

[@ablueeyedmale]

i got in a lot of trouble when my mom caught me polishing my crank shaft.

[@georgekolotouros230]

Henry Koller haha !!!

[@marklowe7431]

Stroking usually results in more inches

[@hassanm2357]

Looooooooooooooooooooooooooool

[@demetriusrivers5203]

Lol nice one

[@Moparmaga-1]

Don't do it in the kitchen !!! Go to the bathroom ya know

[@richardloehn8466]

Really good way to get rid of stains . A good uniform surface

[@caveone-365]

Shoe laces work great for this purpose. What I've always used on my cranks.

[@bryangraves9608]

Great method, worked great on my Yamaha outboard crank. Thanks

[@keithb4007]

"Today I'm gonna show you how to...polish your crank." Made me laugh and kept my interest. Overall, I love the idea and I'm gonna play with it tomorrow.

[@VitaliyKhomich]

Do you like to play with crankshaft?

[@EliTheDriftPanda]

I think I read somewhere that you're meant to polish against the direction of rotation until it looks good, then go in the direction of rotation for a bit longer (but it may be the other way around... research required). It's hard to explain without a diagram, but imagine it like shaving, and by going in one direction, these microscopic eccentricities are all pointing one way. Then, by reversing direction, the polishing action knocks them right down.

[@reaganwright8209]

This. Though you have it backwards, depending on how you interpret the meaning of what you are saying. The final polish should fight against the direction of crank rotation, because the microscopically fine "fuzz" will be pushed down so that it does not dig into the bearings. If it is laid down pointing toward the direction of rotation, it will cause faster wear. Google Clevite bearing catalog. There is a good description and diagram in the front few pages about crank grinding and polishing. Or just go here and download one of the pdf catalogs from the manufacturer to see it: www.mahle-aftermarket.com/na/en/catalogs-and-literature/catalog-pdfs/

[@adifferentwaytodoit]

There are engine builders and engine assemblers... Great job every bit counts when rebuilding a engine..

[@jppatterson8565]

If you make that rag a circle you can use it on your drill chuck.

[@luckyPiston]

Scotch-Brite Style Super Micro Finish crankshaft polishing belts are ideal for high performance engine work where crankshaft surface finish is critical. Our Super Finish belts are perfect for final finishing and will create a mirror-like finish. Manufactured from high strength, premium aluminum oxide resin bond material, these crankshaft polishing belts create a non-directional finish and will not remove material. The sides of the Micro Surfco crankshaft polishing belt will conform to the journal radii. One belt is included per box.

[@DELTRANIO99]

Great info vid ,,BTW how much metal you taking off using ti method ?

[@kuyamakel]

Very relaxing to watch. Thanks

[@martinez1701a]

I usually just polish with 600 grit and some oil never did a mirror finish, built many engines this way.

[@dawson40010]

That was my thought, I am not a machinist, but I figured a mirror polish would reduce the ability of the oil to remain in place and would basically wash out increasing friction

[@martinez1701a]

dawson40010 Yup exactly! The way it was explained to me was that the reason we dont do a mirror finish is because the journal wont grab the oil as well spining and making that barrier between the journal and the bearing makes alot of sense. I was also told that would cause bearing failure its kinda like a tire with good tread and one thats bald obviously the bald tire wont grab its the same with the journal.

[@Chriselectricfingers]

Lol quick bedroom fix

[@hassanm2357]

Everyone has his own way .. I never used grits below 1000 and taking all time to perfectly finish the polishing .. But technically speaking it depends on the crank webs condition , i totally agree ..

[@NISMOIZKING]

Douglas Ward wouldn't this remove too much surface of the journal?

[@JohnAnderson4242]

This was most helpful - I got those same oil stains on 1 of my journals. Not going to do and sandpaper WD40 - learning I don't need to. Thanks !

[@25227168]

Brilliant Vid Arron

[@feral4mr2]

I do this with Purple metal polish and flat shoe strings.

[@makethman007]

the problem in the journal is that its overheated due to lack of oil so the oil way needs to be de gunked

[@chief1972]

Interesting.I've never seen anyone use metal polish on a crank,just sandpaper.I think this did a better job.

[@Robery82]

What do you do about the surface rust on the balancing plates?

[@SophiaAphrodite]

sand it off then wipe with an oily rage to protect it. You are not going to affect the balancing with light sanding.

[@rifatselimoglu7908]

Deep detail well done but doesn’t need i think!! If i need to do I do with 2000 sandpaper and use wd40 to make it wet

[@kornbred8934]

Wicked cool trick mate

[@AaronUnknownPerformance]

Korn Bred thanks hope it helped

[@gregh7457]

Does oil stick better to polished cranks?

[@thomassmith4925]

greg h they shouldn't be completely smooth, just like cylinder walls shouldn't be. The crosshatching holds oil.

[@jordanwiley4582]

Oil doesn't stick to the crank, it just fills the space inbetween the crank and the bearings. It gets bled out, goes back into the pan, and gets picked up by the pickup tube again.

[@s.v.gadder1443]

Wtf cross hatched journals? Where the Fuck do y'all get this shit the another thebetter reduces friction which robs power smdh go educate your self

[@seanb9436]

im so adding "crosshatched journals" to my joke repertoire

[@thomassmith4925]

I guess I was wrong lol. I always thought they held at least SOME oil but upon research you guys are right. The bearing is also eccentric a bit

[@Soggz7785]

Auto solve is your friend.👍🏾🇬🇧

[@grahamjohnson2764]

Hi dos the z20 fit in the corsa vxr

[@josephmorro5744]

How polished should the rear main journal where the main seal sits be ?

[@thetruthwithin1]

Armchair racers be like it can remove 5 thou...do you even know what 5 thou looks like? There is no way he’s even close to a thou

[@johnbrakingground]

Xxjr89xx exactly.

[@Moparmaga-1]

Maybe .00005 after an hour

[@tecguru100]

What's the benefits to doing this

[@SophiaAphrodite]

saves you money.

[@bareegogingenandre]

I prefer my journals to be circular

[@timbenham516]

Lol

[@SophiaAphrodite]

@mcb sprint yeah the same people that made his journals out of round also told him vaccinations are bad.

[@mcplutt]

Plug your oil holes before polishing.

[@adamadamhoney]

Svein Hanssen earplug foam, then blow the our with air, masking tape up the holes to get em all out. Works a treat 👍

[@JalopyTechnology]

Four or five thousands clearance? By that time you have a rod knock! Rule of thumb clearance... .001 per inch of journal diameter.

[@kanejoseph37]

Rick Schlabowske yes sir, we all do things differently but I agree. This method has served me well.

[@scottstemple8105]

mirror polishing doesn't let the oil lubricate as good I would finish with 600 you need those fine marks for oil flow

[@SophiaAphrodite]

Not on a crank you don't. The bearing handles the oil flow. The crank " floats" on that oil. The smoother the finsih the less friction.

[@robbyberry8911]

Make Shure you plasti Gage those bearing to get the real tolerances of the clearances if more than four to five thousands you will need bigger bearings for that rod or crank jernals .....

[@AaronUnknownPerformance]

+Robby Berry yes I agree always plastigage!

[@bigstinky5128]

I doubt a polishing compound would even remove .00025" lol

[@Pocketbassist]

Plastigauge don't even give you super accurate measurements lol

[@DeaFBRED]

McGyver said Just make It till The Credits Roll

[@mikeschneider634]

Plastic gauge is a poor mans way of doing it. Will get you “close” but use a bore gauge on expensive parts

[@goosegregson8132]

good man

[@Lennoo_K]

Simple, but works.

[@AaronUnknownPerformance]

Arman Kh exactly :)

[@tzajaczajac]

Cranks should never be mirror polished!, causes oil skating on the mains and accelerates wear, the specific grits in the papers machine shops use are there for a reason, it gives the oil something to hold onto(keeps it on the bearing and crank journal face)

[@pbysome]

There is the voice of knowledge.

[@JohnDoe-hx1wx]

How would they accelerate wear? Can you elaborate? Because as far as I know what causes the wear in the first place is friction...which many times is caused by low/no/bad oil which damages it and once damaged they just go in a rapid deterioration which damages the internals and scores the crankshaft.....sooo even if it did cause this "oil skating" so long as there's no friction the same oil pressure the car uses to push oil into the crank should keep everything well lubricated?

[@pbysome]

@@JohnDoe-hx1wx the surfaces don't touch they are reliant upon the oil separating them if the surfaces are microscopically polished the oil will not be retained long enough to do its job, rather like the crosshatch on a bore a certain amount of surface hatch (not visible to the naked eye) is required to retain the oil Polish really isn't the best thing, fine "polish" grind rather than "polished" is the way forward.

[@JohnDoe-hx1wx]

@@pbysome interesting, funny that you say they are naked to the eye because on a qr25de engine I'm working on right now it has HUGE crosshatching on the journals, it actually looks like cylinder crosshatching but in one direction. And I honestly thought it was a spun bearing but now that you say that I have to reconsider everything. Thanks for the knowledge! I've been looking for the past 2 days and the information is really hard to come by online. Sadly most of the internet is being deleted without our knowledge.

[@pbysome]

@@JohnDoe-hx1wx a good engine shop/machinist would guide you as to what is optimum, there shouldn't be visible scratches, remember they are ground not turned so the grit that they are ground with dictates the courseness. In my experience you would only polish grind if the surface is iffy but within spec or maybe if you tuftride a crank it may need a light polish grind. The main thing with a crank is that it is straight and the bearing housing are the same, this is the way to reduce friction, every thousandth it's out of straight reduces or increases your running clearance in one place or another.

[@laqutis1119]

It is actually not the best to have a mirror finish, the oil needs something to cling onto when going through the bearings, and mirror finish can cause damage

[@SophiaAphrodite]

the oil is only supposed to cling to the bearing, that is what a bearing is for.

[@BruceLee-xn3nn]

Idk engine builders have started doing micro polishing to cranks.

[@Moparmaga-1]

Nice

[@vwivancc]

Good trick!

[@AaronUnknownPerformance]

+vwivancc thankyou

[@0lddragracer426]

The sound is terrible. I wasn't able to understand much of what you were saying.

[@deweysturgill6220]

Why eets bluddy Anglish Mate we speak Ed all over de wurld whie even hear in Ten uh see

[@ziaseyedi8686]

interesting

[@georgekolotouros230]

I guess it's OK to do this providing that the journals aren't egg shaped. Me, I would rather take it to a machine shop and pay the money.

[@SophiaAphrodite]

Why would anyone use a crank from a damaged engine in the first place? They are only going to be egg shaped if you threw a rod.

[@MrTaylorTexas]

@@SophiaAphrodite That's a dumb question.

[@BruceLee-xn3nn]

@@SophiaAphrodite or a spun rod bearing.

[@ralphhobday8764]

What speak uppppppp

[@andreh8590]

Liked the video then unliked it. 688, is the class of submarine i was on. I'll re-like after someone else defiles that.

[@howardcamp1291]

I'm with you on that. I was on the 714 and that damned number follows me.

[@Chriselectricfingers]

Nice but make sure it dont have scarfing in the journals

[@logandj2399]

whats scarfing mate ?

[@armindogomes47]

Keep in that cranks are polished from the factory, and cleaning them up isn’t going to remove material from a heat treated part. As far as the surface, you want it near mirror so it doesn’t create friction against the oil being pressurized in between the bearing and journal. Micro polish all My races, and crank in my engine and transmission. Upon tear down not once did my Polished bits look scared. I also run 5w40 amsoil and GL4

[@luciankristov6436]

Why are bits so soft spoken and quiet 🤫. Speak up!

[@boh348]

I have run many lose engines for 1000s of miles by polishing the cranks and then use a high volume NOT HIGH PRESSURE oil pump. The first thing you do to a race engine is polish everything a couple thousands loser anyway.

[@banjominer9682]

So wrong...soooo wrong...if the clearances can be loose..why do Indy cars have to preheat before cranking..the clearances are tight and the engines produce more power when built correctly....not with slop in the bearings....

[@bernardwarr4187]

@@banjominer9682 that because of piston to cylinder clearness. They will not turn over at room temperature

[@bry40l]

@@banjominer9682 performance engines are built generally with looser bearing clearances to allow more oil between the journal and bearing.

[@MrTaylorTexas]

@@bernardwarr4187 That's the dumbest thing I've heard in a long time. How do they start the engine if it won't turn over when it's cold?

[@pbysome]

@@banjominer9682 I think he is mistaking bearing surfaces with bores, modern machining and materials even make that unnecessary.

[@CORRIGEEN71]

Who cares about the oil staining

[@Franks_Garage]

dang brotha speak up

[@emanuelnamseth1469]

Always polish a cast crank in the direction it rotates. Or you can ruin your engine.

[@deweysturgill6220]

That's an old dead Peter bench tale, right along with the one of never laying a crank flat on its side it will warp and the myrid of other hot rodding superstitions

[@mikeschneider634]

Wrong.

[@rescuedabyss]

Yeah...and don't leave your battery on concrete either lmao

[@CORRIGEEN71]

Pointless the crank is fine

[@kd5yut]

If you would speak clearly and stop mumbling

[@wilsonmaingrette715]

James skippinhopper lmfao he's still a child

[@banjominer9682]

Mirror finishes DO NOT hold oil an will wear out faster .. truth

[@beardedg500]

Yep. Its true....that's why you have to hone piston cylinder for oil control

[@lizwilliams6120]

You need mirror finish on a crankshaft journal mating surfaces never make contact as long as you have good oil pressure it will ride on a film of oil if you had cross hatches/rough surface It would eat up a bronze bearing in no time because it causes load to distribute unevenly on combustion stroke

[@majorkin19]

You don't need it to hold oil, you want the oil to pass on the surface of the crank journal and bearing as smooth as possible, a mirror finish is required. I don't know who the hell told you otherwise

[@majorkin19]

@@beardedg500 piston cylinder hone is for seating the piston rings properly to create a proper seal, not oil control, that's why the pistons have a gap for oil rings, and one to scrape the oil back down,(in other words lubricate the cylinder walls to reduce friction between the piston and cylinder)

[@100Chicky]

im an aeronautical engineer. trust me, you are wrong. in this scenario a journal bearing benefits from being polished. there is a clearance gap between the sacrificial main and big ends where a cushion of oil under pressure keeps the crank afloat under normal use. the oil comes from the pump and is supplied to the bottom end first, it then makes its way to the heads. the bearing clearances determine the oil pressure to some extent, which is what the crank floats on. smoothing out that passage will improve flow and possibly help with cooling etc. also, when you switch off, the oil pressure drops and the crank beds down onto the lower half of the mains until next start up. considering the bearing linings are very soft white metal/tin/lead alloys, a cross hatched journal will only wear away at them until oil pressure is restored - admittidly that happens very quickly. however, over the course of many shut downs and start up this will have an effect on bearing longevity. hope that makes sense? when running it doesnt make much difference though.

[@JohnMiller-tr1vm]

Smoother the better for oil etc. Get a little life in your voice before you put us all asleep!!

[@dumbotater2158]

Lots of mumbling here!

[@charlescurtis7715]

Nice idea man,but for God's sake learn how to speak English

[@johnnyjohn8073]

Small minded Charles Curtis, you're in the wrong place to to hear people speak proper English, buddy. I didn't like the video but I'm not going to give the guy a hard time. I won't even give him a thumb down. You want English lessons? Go to college you idiot. Even at the university I heard plenty of professors make mistakes in speaking English. People make mistakes in writing comments here also. Big deal. You write your comment quickly & that's it. You don't really check to see if the cell phone or computer's auto correction software changed the words you entered. It's KZbin videos not some university lecture. Besides what's a pretentious supposed highly intelligent person like yourself doing watching videos on doing manual dirty labor? Isn't this dirty work beneath you? Dick head.

[@t4k3chfre]

Charles, that's just narrow minded. But I rest my case since you believe in God. I bet he actually can speak your language better than you could ever speak his language. Go high five your invisible guy of wisdom, he probably concur with your illicit behaviour since he forgives people who can't help being stupid.