How to Polish a Crankshaft at Home
HTML-код
- Опубликовано: 8 фев 2025
- Here I give some very basic and easy to follow advice on how to polish a crankshaft at home. If you are going to do a rebuild or a refresh on your engine, and your crank is still within spec, then this is a great way to save some money and time on your project. This tutorial is pulled out of our 350 engine revival series.
#sbc #crankshaft #revival #diy #autorepair #chevy #enginerebuild #rebuild #willitrun #smallblockchevy #trending #classiccar #350chevy
Got a hold of a 350 engine out of a 1970's Passenger car. The catch is that this engine is carless. Meaning I don't currently have a vehicle planned for this engine. I'm going to go through it then put it on a stand and make it run. Once that's done I'll figure out a car to put it in (with the viewers help).
Great video! The only thing I wanted to add was to make sure whatever string you use covers the entire journal. If it’s only covering half of the journal, all of the pressure you’re applying is not being evenly distributed and can cause uneven polishing.
It can be tricky maybe its all about the person doing the job to make sure to not apply too much pulling force on both ends of the shoe laze at the same time, only on one side to make it spin that way and let the sandpaper do the work. With the polish rag just move it deliberately just like when honing a cylinder to make sure to cover the whole area.
That looks amazing, thank you. When you do clean the crank, don't forget the oil passages.
I did this with a compressor crank that locked up - still works fine several years later.
I've done this before on several cranks, but honestly, the local shop charges $60 to check and polish cranks. Worth it to me.
Yeah the price at the shop really isn't that bad. But for those who are cheap or where longevity isn't a concern this is a great option. The materials to do this at home are around 10$. Thanks for the comment!
What local shop? I haven't seen this kind of shop within 100 miles radius. I am in boston.
Also, have to consider turnaround time
@@xushenxin i can do it for you, i am in boston. Specailize in EURO (Audi, BMW, and Porsche)
At this level, you are right. If it’s the right garage with the right machine, it’s great. But if they are just doing it this way, what’s the point. But the main reason I am watching it is, it’s not that easy to remove the crankshaft. I am going to do it from under the car.
I pretty much do same, except i put ear plugs in oil holes.
I’m about to do this on a small block ford. I was feeling pretty bummed when I pulled the caps (trying to avoid machine work) but I feel better now having watched you do it with good results 👍
Thanks bloke, this is going to help out no end.
Yup...been there done that several times. Good job
I used to have a race kart, as a kid. I used the shoe lace and valve grind compound. The last time, I used small lea😢belt.
Proper method is to mic it before to make sure the journals are on size, but he didn't have to do the extreme! A fine grit scotch bright pad (only enough to take the varnish off the middle of the journal and close to the radius but before you do that clean the oil passages and then polish..
Not sure about getting metal polish into the lube oil orifices. I would definitely flush those oil passages when you are done
very nice, thanks; will be trying this out today
Very cool Matt ! Thanks for sharing buddy :) ATB - David
Thanks 👍
Thanks the video, good simple metode.
Glad it helped. Thanks!
Hence : your bearing clearances may vary , being done by hand !
I always polish my crankshaft at home. What kinda monster does it in public!?!
Good One! LOL!
Your stupid comment explains why you have to polish your own crank.
Haha 😅
🤣
😂😂😂
Do not use red shop rags for cleaning engine internals, they fall apart easily and the fibers will get stuck to parts even after washing then will start to collect on the oil pick up screen after running.
Nice job, thanks
Couldn't you just skip the final polish step? I mean after all 1000 grit is polishing in the machine world. And what is Brasso really going to do, I doubt it does anything to that hardened surface, maybe a shimmer, but that will be gone as soon as that crank takes the first couple of revolutions.
Nice video brother.
Man that’s cool I’ve learned something today
Derek is the best.
Will this work on the journals on a camshaft? What 800 grit wet or dry sandpaper?
Yes and use oil or something
at what point should the necks of the cams be polished? if you can't see the marks with your eyes and fingers, does it go away?
thank you very much! very helpfull. i will try it this week end! i subscribe then.
Thanck youvery much
If you wanted too, could you polish a bad main journal down ten thou? Or is that something only a crank grind could accomplish? Asking for a really cheap friend...
I would not recomend that. with the sandpaper in that grit he may take his crank down .0001" or maybe slightly more and you see him only do one journal. You are talking about taking of .010" or 100 times as much material so you can do the math on the time involved. The other reason is your journal will never be flat enough when removing material by hand to lubricate properly as well as the radius in the corner of the journal is ground on purpose and are a huge contributing factor to the strength of your crank. If you sand it and put a sharp corner there you wil break a crank much easier.
That's a job for a machine shop. It would take forever and be inaccurate as a diy project. Former crank grinder here.
If you use shoe lace you need to move it side to side and not stay in one spot.
Good job
Thanks
Nice. I have a v6 3.3L VG33E Nissan motor with a worn crank and it started causing knock about 160,000 miles. Bearing material confirmed in oil. I have had the motor removed and a used one put in. I want to remove the crank from the motor that's sitting in a tire, with the crank exposed and facing upward. I want to hand sand the crank and reinstall. Do you have or know of any basic guidance to do this? I've never done this before. Thanks.
That will probably need measuring and checking be lucky if u get away with just polishing the crank also the rod housing will need checking for ovality as its been knocking
You will need a machine shop to repair that damage. Former crank grinder here.
@robertnewton4825 I had the motor pulled and installed a used $650 junkyard ebay motor. Sold the old long block for 300.
@robertnewton4825 I had the motor pulled and installed a used $650 junkyard ebay motor. Sold the old long block for 300.
Hwsit can I polish crankshaft at home and then use standard bearing
wouldve liked to see how you cleaned the inside of the crankshaft after all your nice polishing work.
Probably some acetone, a blow gun with compressed air.
That's what I was wondering
I am a DIYer🙈 and I was so curious what to do with my crankshaft on my BMW N54 engine.
I'm definitely gonna try you technique. Thank you for gr8 clip👌👍
did you end up doing it and did it work? i have an n54 as well and need to put it back on the road.
The polishing is good, but after polishing will it still meet spec? Did you measure the diameter?
I think if your crank ok. Just clean & polish. No need for sanding. I will try that on my engine soon
He did say if your crank checks out...and with the grit he's using ( used to final wet sand paint) , he would have to stroke it for a loooong while
well, that certainly makes it LOOK good, but it basically ruins the journal to bearing contact areas.
If I am going std. Bearings I always polish my own crankshafts with a old soft dress belt and some emory cloth.
That's what I was thinking. This method would probably remove too much material.
Oil pump failed on my car and its melted big end bearing onto the crank. Is it possible to polish it with this method? Thanks
You will need a machine shop.
Did you have any sign of bearings marking up the journals
Thank you! I would say slow and steady. And why is everyone afraid of brake cleaner and compressed air to clean oil passages after the fact? Practice on a bad crank first. Proper mics before and after.
Question I gotten a new crankshaft for my SBC 350. An it turns good but when I tighten my rods . I can't turn it wtf am I doing wrong
Check the clearances might be out of spec
use plastiguage and check your clearances
I believe VGG used 400 and 800
I think the surface is uneven with this method unles using heavy enery paper for even pressure . Sorry mate.
How much did you take it down? My jornal is worn out about .013 under standard so down to .020 would do me right. I bet taking down .007 would be a long time.
You CANNOT resize your crank using this method ... it only shines the journal and achiever virtually nothing !!!
No egg shapes?
Ok
BLOW AIR THRU OIL PORTS.
I don't see why the direction you sand in matters your crankshaft should never touch anything but oil.if the crank eats the bearings you've got bigger problems than the way you polished it.
Why don't you just buy a Polish-made crankshaft ?
Why dont you just go lay down somewhere😅
Yeah lay down on his mom
Um I would not do this as you are going to force polish and debris into oil feed hole with no way of getting it out then first time you run the engine for the first few seconds it will be polish and debris right on you engine shells not good
I've seen engines that have utilized this budget cut go 150-200k. As long as the tolerances are within spec, you are putting the correct amount of assembly lube on all your crank bearings, and are blowing/cleaning the debris inside the crank out then any leftovers would be mitigated. Of course anyone should clean the crank thoroughly before reassembly. It also depends on the purpose of your build. If it's a little beater get around thing then it would be perfectly fine. I would never suggest anyone try this with an engine they intend to race or otherwise compete with. Cheers and thanks for the comment!
@@JunkMissions To be fair mate I love a tryer especially in your own workshop best of luck in the future
No worries :) Same to you as well
Do you not think he would not use a pipe cleaner brush & hot engine oil to flush out the polish before installation????????????? You just a Hater.
Don't do this by hand. It may look pretty, but you're just making the crank out of round. Why do you think shops pay all that money for the equipment?
Thanks for the comment! This method is NOT meant to be a replacement for precise machine work. It is really just an alternative for those who are either 1)Cheap/Broke or 2)Not overly concerned with longevity. As a previous commenter mentioned a crank polish at the shop is not very expensive. It is better to get it done professionally if the money allows. I have seen this done on cranks that went 100k+ miles with no oil consumption and good pressure. Mine was mic'd after I did it and it was still in spec.
Everyone is a white knight in the RUclips comments, but in reality everyone takes their own shortcuts when no one is looking
A crankshaft grinding machine is worth about $45,000 Australian dollars
Guys have been using this exact method since before you were a twinkle in your old man’s eye.
You must be a educated tech I've got 2 race engines with hundreds more like thousands of laps at 5500 rpm constant that still run great I did same thing to both cranks in those engines
I let the little woman do all the polishing around the house.