DIY Crankshaft Polishing
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- Опубликовано: 15 авг 2017
- In this video I am polishing the crankshaft to my 1978 Ford Bronco. I am using a basic method that anyone can do at home.
Just an FYI, I am not a mechanic so forgive my terminology. I'm just a do it yourselfer finding a cheap and effective way to do things while sharing it with the world. This video is for demonstration purposes and anything you do is at your own risk.
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So many commenters saying “take it to the machine shop and do it the right way!” A machine shop isn’t some magical place in a magical forest where parts magically get renewed, in fact so many things come back from “machine shops” all jacked up these days, you might be better off doing it yourself until you find a shop you can trust and even then it cost an arm and a dick because people just replace parts and a machinist is so specialized now.
This video was made 6yrs ago, price the machine shop today and you’ll really be ready to see what can be done at home!
This is good info for when you don’t have a choice because your in a remote area or in a place where machinists are far and few.
Anyhow, the only thing i would add is maybe a step to wipe the burrs in the direction of spin and yes, if you have the ability, then mic the journals before and after or at least plastigage it and check clearances. Nothing wrong with this if you take your time and use your head 👍
Kevin, thank you so much for taking the time to make and post this video. Just what I needed since my old bus has just run a bearing. Really wasn't looking forward to removing the engine and this method definitely looks like it can be done with the crank in situ.
Peace and long life.
Paul
Thanks for your video. I am in deepest Africa, with little money and a truck I need to get going. Thumbs up
Thanks for taking the time to share this helpful video.
As you know, the professional machine shops use a type of belt sander to smooth and polish the bearing surfaces on the crank shaft. Thinking about how I might duplicate the same procedure, I modified the above method shown by this RUclips author by using a sanding belt (1 x 20 inches, or so in length) and a rubber adapter used for a round or barrel (cone?) sanding paper. I inverted the sanding belt and placed it around the journal to be polished (with the fine emery cloth already in place, as in this video tutorial). I chucked the rubber adapter into my power drill and inserted the rubber end inside the sanding belt and started the polishing in this manner. Why did I invert the sanding belt? The sanding surface of the belt allowed the rubber adapter to "grab" the belt more firmly, as well as to hold onto the emery polishing cloth firmly as well, especially when you have sprayed everything with WD40. I mounted the crank shaft on supports under either end allowing me to rotate the crankshaft as I polished the journals. It worked, but it took a little effort and concentration to maintain that belt in the center of the rubber adapter and the journal. The belts cost about 4 and rubber adapter which came in a kit for about 7 dollars, both at Harbor Freight.
Thanks for the vid. It saved me a lot of money
@ Ollie Mcintosh- Glad it helped you out. Thanks for watching.
Tried this on a motor that I didn’t care too much about in similar condition. Got the journals about 1/3 way to where they needed to be and quit. Machine shop quoted me $125 for a four banger. I already have it in the trunk of my car and will drop it off Wednesday. It needs to be pretty smooth for this to work. I do have one that I will probably touch up with 1000 grit and polish though.
Will be trying this method with crank stíll in place from underneath sump
Great job Kevin
@ Blair Guinea- Thank you and thanks for watching!
very good video. thanks
Did you plastic gauge it after? Have you put any miles on it? We did this with a inline tractor motor but just the main bearings.been together for 5 years nice oil pressure no noise.
Thanks for the tip. didn't know one can start on a 220 if its bad. I'm not so clued up with engineering but the buffing compound and fine metal will it not stay in the engine cuz we know a hair is bad for journals?
🙏👌👍
Maybe u saved my BMW
I try That in a few days and i Côme back to tell u guys of its ok !
BUt i m sûre it will be better than now!!!
Thank u for this video
This is what I did and my 20 year old crank has no problems and majority of the time it will require oversized bearings not undersized when taking a lot of metal off when doing this. This tends to make the stock bearings not fit, even when tightening them down to torque specs if your connecting rods still have play that's where the knocking sound comes from
You are wrong with your description of the replacement bearings. You have it backwards. You are making the journal smaller, so you need undersized bearings. Think about it like this, you get oversize rings for oversize/ larger diameter pistons. Oversize bearings are for use in a block that has been line bored after a main bearing has spun in the block. They make oversize/standard I.D. main bearings and oversize/ undersized bearings for a block that has been line bored and had the crank turned. I know what I'm talking about, I sold engine parts for 41 years in both the automotive and truck industry in a dealership. I just wanted to make sure people understand the difference when they go to get replacement bearings. The video maker used the correct word for use on a turned or polished journal that is smaller than standard dimension, undersized bearings.
hello I write to you from venezuela the work looks good at a good time what is the polishing capacity of the crankshaft friend
I’m curious to know how this worked? Were you able to start this motor? Did it makes good oil pressure? Was there any knocking from the crank?
@joedell71- I apologize for the incredibly late response. I dont alway get notifications for new comments. Yes, the motor did start and maintain oil pressure. As far as I can tell so far, there is no random knocking or vibration.
I like your idea, however did you mic your journals 1st to get a reference point.. U would need to mic all mains & rod journals 1st, then sand & polish, then re mic all journals so you know what size bearings to put on which journals.. It is possible to run into a spun bearing down the road if measurements are not taken before and after...Just a thought..Keep up the good work..
Did you use or consider .001 undersize main bearings?
Good video. I am also trying to rebuild my 03 4v modular in my garage. Something I been wondering about is how to finish hone the modular engine’s hard cylinder sleeves that are installed in aluminum blocks?
Same here, I'm doing an 04 navi and am ready to put some cross hatch on the cylinder walls
you can use a flex hone, "Dingle berry hone", you'll just need to get the one for your size bore. also the 3 leg hone from harbor freight works good too
My only concern with your method is you may have removed too much material, causing too large of a gap in the bearings.
U trained me..Retired Larry
Wonder if the film that the polishing cream leaves behind will affect anything? Just curious, because I have the same polish and was thinking about polishing my crank journals.
@Empire Kruse - before I put it back in I cleaned it off with some degreaser and brake cleaner for safe measure. I also cleaned the ports with small wire brush.
@@kevindiy8169 right on! I was thinking brake cleaner, but wasn't sure if it would remove the polish residue all the way. Thanks for the info Kevin!
what size main beaing did you use afterwards?Standard,undersized,oversized?
Good question. I was thinking .001 undersize might mic out to spec.
hello i am just curious how the engine turned out after doing this? have you put some miles on it? does it hold good oil pressure with no noises? i have never rebuilt an engine myself but wonder can this work for someone trying to save money. thanks
@ Jim Jones- I have yet to started the motor. I ran into a slew of electrical issues with my wiring harness, distributor, and finding out that I also need a new battery. Damaged/ rodent chewed wires was quite a problem that I've been slowly working through. Especially since a new wiring harness is about 600$ if i recall correctly. I think I have sorted all of that out and I will be attempting to get it started this or next weekend. This was also my first attempt at rebuilding a motor, on my own. All I can say if you're trying to rebuild on your own for the first time, is to take a lot of pictures before and while you tear everything down. It will help you a bunch in the end when you're reassembling everything.
Still awaiting. Thanks
that explains it......your first attempt at rebuilding an ENGINE. i was wondering why you would spend the time on the crank instead of using a GOOD MACHINE SHOP..........
How about now???
Running yet?
Why did you wipe it down with a paper towel when you were done instead of using a clean microfiber?
@ Bart Goins- I just did that while filming, I just used what was closest to me. I did a full clean up with brake cleaner and air hose when I was done and yes, I did use clean microfiber cloths during that process.
I always use a white paper towel, reason being you can see if you have ANY residue/metal particles left on the mating surface before assembly/polish.
paper towels don't hurt. Only people that are superstitious go that far. I have wiped down many cranks with paper towels with zero problem. I just stay away from red shop towels since they lose lots of fiber and get stuck on everything. Haven't had a problem yet.
paper towel hairs are soluble in oil, so it is ok to use on journals
After doing this will I need a different size bearing
How about .001 undersize?
I want to know how much material did it take off?
It takes off less than. 001 on average, personally never used 400 grit but I've polished many a crank with 800 and 1000. I was taught not to get a mirror finish as oil clings to the metal. I've got a motor 80,000 ks in Australia still going strong after doing this as s first year apprentice. Older engines are more tolerant of clearances, i wouldn't do this to a modern Toyota with. 0001 clearances.
Truth is that your barely taking any material off of the journals to affect the tolerances. Your mostly taking off the surface gunk that has built up over time and putting a shine back on. Most you'll take off is less than a .001.
The Great White Goat The journal steel is hardened so, yes, you won’t affect tolerance too much. You’d have to really go at it with some coarse grit paper to remove enough material to use an oversized bearing. That would likely affect roundness though. I think you’re better off just polishing as he does in the video and living with the oil clearance you get with a standard bearing.
Just take it to a machine shop and do it properly.
how much material did you manage to take off
To be honest, I didn't measure the crank before getting started. I just know that the center main bearing on the crank was the most worn due to some idiot putting the bearing on backwards and I was .0013 inside of minimum tolerance when I was done.
Well damn..... I've worked on cars my whole life. Backyard budget style. But this is my first set of rod bearings. So sorry if this sounds pile a noob question but How can you put them in backwards. Mine look like they only go in one way because of the notch on them?
@@jakelong82 your not helping g yourself or others with.this video. Nothing even nothing going be true .going be.a cheap 10000 mile at the most fix.wont carry oil pressure and rattle
@@monty-tq6iy I understand. Unfortunately sometimes that's worth a weekend day worth of work and 4$ for ther bearing. And believe me I know how that sound. I didn't have ther money to do it the correct way so this was my only option. I have a few hundred miles on it and it has a slight tap from the one time I had to punch the gas. Other than that I'm extremely light on the pedal just hoping for the best. I feel like there's a lot of people out there that are in the same position.
@@monty-tq6iy i read a comment on here u saying you did this to somthing like a john deer tractor 5 years ago and it was running fine and holding oil pressure to this day im just wondering what made you go from that comment to saying this will never work
You broke it roundness!
Never last waste of money
Done this many times, older classic cars going strong after polishing cranks with wet and dry. I was taught this as an apprentice years ago and never had oil pressure issues or a knock from any.
this is a good method , but next time plug up your oil holes .
@ Ross Hoek- I was thinking of doing that the next go around. What would you use to plug up the holes? Cloth, paper towel, wax?
foam ear plugs?
They are fairly easy to clean out, you can see with some light all the way through them to tell when they are clean
Brake cleaner with a tube on the nozzle. Do all of the journals, spray every oil passage out with brake clean, blast it with air... done. I've done it that way on quite a few smallblock cranks.
Candle wax. It will seal an oil holr. Use a small pick to clean it out. If some is left it, will melt away.
Dude u taking off too much material, and u will make the surface uneven because u are doing it with hand it won't be consistent all around some parts will be heavier sanded than others
fakeeee
How so? Machine shops will put the crank on a lathe and use an electric belt sander to polish up the crank. This is just the poor mans method. Don't knock it till you try it.
i don't get it,,,,,,,,,,,,you're gonna rebuild this engine and skimp on one of the most important phases......why wouldn't you spend a few bucks and have it done the right way........by a machine shop..........this makes me wonder what else you skimp on.
@ yard limit- Allow me to help you understand. This is a DIY Channel. Not a send it out to a machine shop because I have money laying around everywhere channel. This video is to help those find an effective way to remove wear marks and polish a crankshaft without having to spend the extra coin that "WE" do not have. With this method, you can achieve comparable results to a machine shop. The only difference is, that this is significantly more tedious, time consuming and way cheaper on the wallet. But overall, you get the same and or similar results. It all depends on the time you're willing to put into it. For all we know, this is how people used to polish the crankshaft back in the day on the farm when they could not afford to send it out to a machinist. Or when the auto shop didn't have a lathe and the special belt sanders for the crank. I originally heard of this method from and older gentleman that used to work with. This is probably a lost art of sorts. Nonetheless, if you can't afford to send it in to the machine shop like most of us, give this a whirl. (if you're looking at options such as this on youtube, you probably can't afford it). If you can afford a machine shop, send it in. But don't come on here with the intent of trolling myself and others for trying the DIY method. Move on.
@@kevindiy8169 Agreed!!! I'm glad you made this video
@ James J. McCloud- You're absolutely welcome!
@@kevindiy8169 I subscribed just for the effort u made in this video!!! Gonna check out your others later on!!!
@@kevindiy8169 hey kevin, i wasn't TROLLING ANYBODY, you made a u tube video knowing people make comments......you read my comment.......if that's what you want to do it's no skin off my back ,,,,,,,,,go for it....but..........when you rebuild your own engine you already are saving money,,,,,,,,,,,spend some on the machine shop..........now we can both move on.