Polishing A Chainsaw Piston With Apprentice Dave

Polishing A Chainsaw Piston With Apprentice Dave
In this video Donyboy73 shows Dave a quick way to clean and polish a chainsaw piston and make it look shiny and new again!
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Watch Dave's video here after cylinder is installed;
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Easy to follow and thorough step by step tutorials do it yourself (DIY) to help you with your broken lawn and garden equipment including snowblowers.
I do my best to teach you how to easily diagnose problems the fastest, quickest and most efficient way with real repairs beyond just replacing a spark plug. These tips are for both the homeowner and shop owner.
Whether it be a handheld, two stroke, two cycle engine like a chainsaw, weed eater, weed wacker, string trimmer, grass trimmer, line trimmer, hedge trimmer, strimmer, brush cutter, leaf blower, or four stroke, four cycle units like a lawnmower, wood splitter, lawn tractor, snowblower, pressure washer, generator or a ride on mower that needs parts installed or replaced, I’m your go-to guy.
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[@scottfirman]

The most important thing is porting and polishing a cylinder more than the piston. I have rebuilt many snowmobile engines and we replaced the pistons on 98% of what we rebuilt due to the fact the piston is not that expensive anyways. The main thing is making sure the ports in the cylinder is smooth so rings do not get caught on the edge of the ports. The shape of the port also affected the performance of the engine. If you take off too much material, it changes the way the fuel air mix is drawn into the cylinder. I learned how to port and polish from an expert.

[@TheReal1953]

I take the the brown ScotchBrite pads and do this by hand. No danger there of going too far. Doesn't take "hours", but minutes.

[@IronMan-ml5yi]

Don and Dave, the two most famous small engine mechanics on the internet.

[@Bungi81]

Great tool 👍👍 Thanks for sharing 👍😉

[@saltymarine]

The videos are so much better with two people !! Thanks for posting !!

[@fredclark4033]

The pads do a great job with careful application.

[@Swabian_sawman]

I personally use a Dremel with brush. It takes for sure a few minutes longer but I can be very precise.. Best wishes from Germany

[@jimgroulx3956]

Hey Don and Dave I must say I have become a keener watching your vids. I have become a diy small engine hacker in my old age and have found your videos both interesting and helpful. I am currently making an attempt to rebuild a husky rancher 455, something I have never done but the biggest issue I’m running into is finding a good site to pick up parts and the odd tool from. I know you have mentioned where to get this from on previous vids but honestly I don’t have time to go back through all 1200 of them to get that info. Would you mind mentioning these sites again please? Thanks much

[@Jake-jw3sk]

Awesome video, every time I see that die grinder I can justify another reason to buy one. I noticed in the video description you changed your Patreon to buy me a coffee instead of a beer, lol. Great video!

[@waynestefinashen239]

Absolutely correct Don, the 3M are the best quality and Milwaukee carries a great line of tools. Rigid just started doing new ads LIFETIME WARRANTY ON ALL INCLUDES BATTERIES. Bought my Rigid impact driver and drill on the 50th anniversary (1985/86) and batteries were upgraded to 18V on warranty. Re registered the new batteries online and basically never need to buy another impact driver or drill again but did get the new brushless M12 Milwaukee driver.

[@robertsimard735]

Great tutorial for novices like me.

[@lesfogerson1092]

A better way to buff out a piston is to use a scotchbright wheel on your bench Grinder. Light pressure of course and constantly rotating the piston.This will eliminate focused spots for a more cylindrical buffing action. Have you heard of anyone using an aluminum weld process to fill in the scratches? A little hand work would bring the piston back to factory specs pretty quickly. I'm a Machinist so I know this can be done. Just curious. Thanks for all your hard work bringing good videos to us all.

[@johnclarke6647]

I found out something interesting, yesterday, when I was looking up the specs on my Stihl 024 AV WB. It has a chrome plated bore. I thought it was Nikasil but the specs say chrome plated, like the old MAC’s and Homelites. It also said it was made in Germany in 1993. I thought the 1980’s but it was the early 90’s. I just buy a new cylinder and piston instead of trying to restore a smoked piston and cylinder. If I ever have to polish anything, I use very fine grit “wet or dry” sandpaper and a saucer full of soapy water. I restored a Stihl bar bor my 024 the other day with 120 grit and soapy water. I got all the rust and resin off of it with the 110 grit and then switched over to 440 grit to polish it out. The, I painted it Flat White to match Stihl bar colors. 24 hours between coats. It looks nice on the 024.

[@carlmiller1034]

Good to know this quick and easy tip. I havn't had the need for this, but good to know it works. Thanks Don!

[@adnacraigo6590]

You two guys are easy to understand and very informative.

[@DavesSmallEngines]

That's what we aim for!

[@deanwhitaker7374]

That's amassing I have always used sandpaper to do my things!!! Not any more👍👍👍 thanks for the information on the die grinder I have always been afraid to use anything like that before just for the same reason you exsplained taking to much of the metal off. Thanks again God Bless keep up the great work

[@kygtx]

You guys hit a home run with your video! thanks

[@donyboy73]

thanks!

[@DavesSmallEngines]

Thanks so much!

[@Sensei948]

@@donyboy73 apparently there are cases of jamming rings at 33: 1?

[@rpavlik1]

Scotch brite wheels make everybody look like a hero, especially on machining KZbin. I used a bigger version of this (on my angle grinder) once on the head of my snowblower. Found out later it's probably too aggressive? But man, that, plus Hylomar blue on a brand new head gasket, it's amazing. I can idle it down to a couple hundred rpm, no surging, and it's been one-pull starts for over 5 years. (And it's from 1995, it's not a young blower)

[@mscir]

Great video, great shop. Thank you. I've definitely scored metal removing stuck gaskets with a razor blade, this looks less destructive. Great tips.

[@PShay78]

Brake cleaner and a shop rag works just great at removing all the gunk off of the piston. It'll be nice and shiny when done and the numbers will be clearly visible.

[@stoolie10]

Too many projects too little time! Love watching the videos guys 😃. I worked with my 82 yr old mentor yesterday freeing a stuck intake valve on my 3hp Mclane Edger 👍

[@donyboy73]

Awesome! Thank you!

[@robgrossen3905]

Great video fella's! I use scotch bright alot to clean up! But that was slick!

[@williamwhite9321]

Ty that’s awesome information 👍

[@Hydrogenblonde]

Those vertical gouges in the piston look bad but could be cleaned up with a second cut file, filing at 90° to the gouges. As long as the ring grooves are not damaged, filing off the high spots on the piston skirt will be ok. It will look bad but the file marks will actually hold a bit of oil. That is why many pistons do not have super smooth skirts, they leave the machining marks there to hold some oil.

[@kellyeakin18]

Just a little FYI for you on that 3m product you're using on your die grinder. The Technical name for it is Roloc pronounced (ro-lock) just thought I'd pass that along not very important but it's easier to find different pads for the attachment. They are used in auto body repair those little boogers are awesome.

[@joelarcher7940]

Thank you. I was having a hard time finding the pads.

[@robfahey1349]

Dave if you really want and or have the money checkout a tubing sander it's made for sanding round stock. It's basically a belt sander but it allows slack on the belt to contour to the curves so it wraps around. Just use a really fine belt or the highest grit you can get I believe they use it to sand and polish stainless steel tubing.

[@KensSmallEngineRepair]

I’ve knurled hard to find pistons before to get the right diametral fit to the cylinder so I don’t get slap. Sometimes it works sometimes it doesn’t. Parts aren’t that expensive so I usually replace with OEM or a quality aftermarket top end. Depends on the Saw, customer, and budget. On a Poulan Wild Thing I wouldn’t spend the same as a Husky 372 for obvious reasons. Good vid guys!

[@Gordon_L]

I was going to mention knurling piston skirts , we used to do it years ago on 2 stroke dirt bikes , the knurling not only gives a tighter fit ( emery cloth on piston while still in the lathe , try fit , sand more etc. to get it right ) but the knurling retains oil for cylinder lubrication .

[@rogervonschleusingen4603]

HEY !!...SOMEBODY TELL DAVE HE AINT ALLOWED TA SMILE WHEN ON CAMERA , BE HAPPAY AND SAFE EVERYONE !!

[@BrucesShop]

Now I want to try this on a piston i have used these on a gasket surfaces.

[@tc3603]

Wow those pads are amazing

[@jmaclaren4147]

Another trick ye can use when ye done, is buff graphite powder intae the skirt. This wi give good wear resistance from piston slap if the tolerances are exceeded. I did this on a "Weed Eater" product, 18 cc. The machine lasted me 11 years since the work.

[@KINGOFOUTWEST]

I use light sandpaper on my Goped breakdown. Will have to try this.

[@rogervonschleusingen4603]

THANKS FOR THE TIPS GENTS , GREAT INFO !!

[@marcelcanicchio8877]

I but one after your last video showing this grinder 👍😁

[@bobanddebbiec6929]

Don love your videos

[@markkupaltola3341]

I have fixed few two stroke outboard engines cylinders with tiny amount of hydroclorid acid if there isn´t too deep scratches. I´ll take a wooden stick with cotton on the top and dip it in to the acid. The acid will cook that aluminium away which is stuck in the cylinder walls, but you have to be very carefull and have wet rag to wash that acid before it damages the engine. Cook all piston remains away, hone cylinders and new pistons with rings, engine is almost good as new and you may use it several years after that.

[@michaelfarris2556]

You been dieing to get that new grinder out and running. May have get one. They seem very handy. All purposes tool right there.

[@fillslawncare]

Спасибо Don за информацию 😄

[@dinkumannely3963]

i would like to know for example present piston is 42.5mm instead of polishing the piston, would i be able to put 43 mm piston instead and polish only the score bits of the clyinder.

[@Firby1988]

What saws have Nikosil coated cylinders? It says that the ms661 is Crome and what is best ?

[@Boost_Addict]

Innovating tuning is from buffalo ny , or was they have closed but yea iv been there 2 times. Just recognized the shirt !

[@bohydrus7108]

what do you recomend for removing the aluminum from the cylinder wall? hone? you mentioned it sticking but didnt say what to do. on a crank you can use acid . not surr if the hone will work on aluminum without clogging up. thanks in advance

[@heavysnow8616]

Muriatic acid on a q-tip.

[@kjell-richardlvdal373]

IT look you two Have fun time together, and at the same time shear of your knowledge

[@donyboy73]

absolutely!

[@nathanwindle9816]

Do you need to put back some horizontal scores on the piston so it retaines some oil/ petrol ? Ive been told a smooth piston isn't a good thing for holding compression as the oil just runs off ! Just curious as ive got a few cylinders and pistons with mild scores which appear obsolete unless i buy a Chinese fake .

[@donyboy73]

no you don't

[@paulmorrey733]

Thanks Don & Dave

[@DavesSmallEngines]

Hey Paul! Thanks for watching!

[@wilkey40]

Soda blasting works much better. Rings touch the wall not the piston so marks do not matter on the piston. Slight sand to take off high point but not much more that that!

[@queenstownkid]

thanks guys

[@michaelstebar3823]

If the rings seal the cylinder why would scores on the piston but not the cylinder affect performance

[@swordfish1120]

Does polishing a piston top give any performance advantage over a piston that does not have any skirt grooves or cylinder scoring, but does have carbon build-up on the piston top?

[@charlesgunzelman3323]

If you get pinging, removing the carbon can help. It will bring your squish gap back to normal. Disregard the rest of this video. In short, it's never worth the effort to polish the sides of a piston, only the top. Polishing the sides of pistons removes more material on a surface that already has material taken off by normal operation. Pistons that are too small start to rock in the bore, you can tell just by ear how much play there is at the skirts. You need some play but too much and the rocking will shatter one or both piston skirts. Then tear down the engine enough to pull the crankshaft out and double check there's no shards of piston in the bearings.

[@jeffferguson899]

you are a great mentor

[@DavesSmallEngines]

He's doing okay... ha!

[@Sensei948]

OIL MIX 1:33 OK ? HUSQVARNA LS +

[@cassandrafaber40]

What if your piston is a small crack on top.

[@RussellBooth1977]

I wouldn't use a Roloc disc even though it's blue the soft metals such as aluminium because I wouldn't want to take ANY material off the piston skirt. I have cleaned a piston up which be seized up inside of a Ryobi line trimmer but only with some finer wet & dry sandpaper,I wouldn't reuse that piston either !

[@JeffinTD]

I was going to say I would not consider that piston a candidate to clean. 3M pads come in silicone carbide or aluminum oxide. In angle grinder size they are excellent for removing mill scale without gouging or clogging.

[@kidsx249]

I use jig a loo or some type of lubricant along with those pads! its a little softer on the material!

[@DavesSmallEngines]

I love that stuff!

[@seenithere]

You can polish Alum to a chrome like finish if you use DoAll Tool Saver & Scotchbright pads.

[@tomnorton8218]

A question ! I'm a carpenter so this is abit foreign to me! Why buff the sides of the piston, isn't it the rings that contact the cylinder?

[@Ron0963]

Great Tip! ..Been using these for a long time (Princes Auto)

[@anthonygostling]

scotch brite, wet & dry with paraffin (lamp oil)

[@dodidodiflorian4050]

So porfekt

[@jensenwilliam5434]

Thank you!!

[@mariogelinas3076]

Hi Don, I bought a chainsaw (broken recoil) without chain. What can tell me the kind of chain I can put on? On the bar there is so much number, and if it is not the original bar, may I trust those numbers? How can I know that a MS170 will take a 67 links chain, instead may I put a 72 links chain? I would like to learn more about this world. Thanks!

[@IntegraDIY]

If you knock off all the high spots of the scoring from that piston, would you be able to get a little extra use out of it? Even if the scoring is deep?

[@donyboy73]

probably could but it may not work well

[@davidkirkland4364]

I have used these pads with some oil based lube in an effort to cut down on the marks and to keep the area cooler. I think it does help. What do you think?

[@donyboy73]

probably does

[@j31355a]

A question for Don and Dave: Is there a barrel or bullet-shaped pad that can be used to smooth out small imperfections on the inside of a cylinder or similar concave surface. It seems to me that they should make such a pad for these applications where a flat pad won’t work.

[@DavesSmallEngines]

They make cylinder hones for just this purpose!!!

[@cherylkygirl7181]

I always find your videos so informative. I need help with a B&S 7.25 PLATINUM assembly after pulling off sump cover. A couple of things fell out & I'm not sure where they go back. I'm a mature, independent woman and this was first time I've attempted a repair on small engine. I replaced crankshaft & now stuck on how to proceed. Can I send pics & get direction from you? Thank you!

[@DavesSmallEngines]

Cheryl - I saw your comment on my channel. I have very limited experience on the 4 stroke mower motors - Don would know best. Cheers!

[@donyboy73]

hi cheryl, send pics to [e-mail]

[@ianbutler1983]

Does it matter if there are scratches on the piston below the rings? Why?

[@donyboy73]

yes it does, it could affect the compression a bit and it will cause friction

[@ianbutler1983]

@@donyboy73 Thanks Dony.

[@seanmcgillicuddy956]

Would using a fluid like WD-40 help ? Thanks for the great video's

[@donyboy73]

Great suggestion! yes it might

[@brianbanks3044]

we called the discs....cookies..........they WILL take off material quickly so be careful with anything you put it against

[@rocktremblay8318]

Bonjour Donyboy je sait que tu tres bien francais j,ai une question pour toi je possede une chain saw sthill 08 s je suis a la recherche d'un guide chaine et une chaine elle est monté avec un spaket 3/8 7 y a t'il une model de remplacement merci

[@donyboy73]

tu devrais allez visiter le Stihl dealer, la chaine 3/8" est tres populaire

[@ricardasuktveris4225]

you need to clean piston ring socket .I used sandpaper 1000

[@jrhenry24]

What brand is that attachment with the scotchbrite? Are the scotchbrites cut outs you cut yourself?

[@donyboy73]

Roloc brand, you can buy the 3m roloc pads on amazon

[@KensSmallEngineRepair]

Don, was that a little mill-drill set up on the left at the end of your video?

[@donyboy73]

it's a small milling machine

[@Monza62000]

i would use a scotchbrite wheel on a grinder

[@DavesSmallEngines]

I've had good luck with brass wire wheels too - just cant apply too much pressure.

[@johnkosheluk1041]

How are you going to do the cylinder if the piston is that bad replace the piston and cylinder not worth the labor to hopefully think the saw will last

[@donyboy73]

i mention in the video that the piston is not being re-used

[@CWalsh-pj9cp]

Hey don, this is unrelated to a chainsaw piston but I have a poulan pro lawn tractor with a 14.5HP Briggs and Stratton power built engine and I adjusted the valves properly and basically what it is doing is when you start it, it turns over hard once and then after that it turns over fine. What could that be? Thanks

[@Gordon_L]

I have an 18hp V-twin Briggs & Stratton in an MTD Yard Machine that did that , I adjusted the valves as you did , checked all the intake side but from a cold start it would come up on compression and stop , I'd have to release the key and begin again until it would spin and start . The battery was 2 years old and I noticed if I used jumper cables from the car it started easy . I replaced that 280cca battery with one rated at 380cca and it's been starting beautifully ever since . Also make sure you are running a 30 or 10w-30 engine oil and not a heavy grade . Final thought , if your valve guides are worn you might have a little bit of oil in the combustion chamber giving a slight hydrolock effect until the piston can push it out . Does the engine smoke for a few seconds after it starts ?

[@CWalsh-pj9cp]

@@Gordon_L Hey man thank you for commenting . Basically what it does it when you turn the key it does one hard turn and then it turns over fine after that. It doesn’t do it all the time but it does it more than it should. There is no smoke that comes out of the exhaust. After start up.

[@Gordon_L]

@@CWalsh-pj9cp How old / healthy is the battery ? Those 14.5 hp Briggs are usually trouble free , millions of them around , you could also strip the starter if you're keen and clean the commutator , make sure the brushes have good contact as well as the cable ends back to the start solenoid , good earth to the frame and battery itself . Basically that's all about eliminating losses but if the battery is aging or responds well to a booster pack , replacing it could be all you need to do .

[@CWalsh-pj9cp]

@@Gordon_L I just replaced the battery about a month or so ago. It’s got no issues starting it just cranks hard on the first rotation other than that it runs great!

[@donyboy73]

check battery

[@dudewest9847]

How about making one on cleaning out the cylinder itself

[@IronMan-ml5yi]

Yes I second this

[@andrewklein-kfs2362]

Agreed! With discussion on “ how bad can it be before it just needs to be replaced”.

[@zorancesljarac2626]

How much money do you get to advertise a milwaukee because that piston doesn’t work well

[@donyboy73]

nothing

[@johnkosheluk1041]

Or you put a cheep aftermarket

[@johnkosheluk1041]

if the piston is that bad then the cylinder is bad to it will not last

[@johnkosheluk1041]

but the cylinder is bad you can't get that out

[@mikem5475]

Lose this lame dude