Hey Tinman, US Chrome of Wisconsin can remove the chrome, Nikasil electroplate and diamond hone to size. I have used them for racing cylinders. They help many racing teams around the world. Highly recommended service. But you will need to send a piston along with the cylinder so they can size it properly. Can you say 'Big Bore'? find a Stihl or Husqvarna piston that is close to size (a bit bigger than stock) and will fit the rod with close to the same deck height (you can chuck it up and cut to correct squish). Just a thought.
Wasn't yours or Buckin's fault. As you said mac's are known for plating issues, usually on the exhaust side😪 so glad Buckin sent her back and you're sharing the autopsy with us👍
That second piston you showed is exactly what my p60 piston looks like! I haven’t run saws enough to recognize the symptoms and stop! Plugged fuel filter leaned the saw out and I blindly kept cutting. Live and learn I guess. Hopefully we can both find parts and get them running again!
Some thoughts. 1. Steel sleeve that jug, there is a fellas on AS that has set up the tooling to do it. 2. Find an 81 jug & piston, much better plating than the later Black & Decker produced/cost cutting chrome of the 850. More than a few ways to convert the 81 to electronic ignition as well. 3. Source a new piston and send to US chrome thru Woody for a re-plate. Cheers Tinman, always enjoy your vids, builds, honestly & thought processes. 🍻
Years ago I worked with a lawn mower and chainsaw businessman and owner for a few years. This guy was a magician on any one lunger. I learned so much from Snyder the mechanic. I was ten years old and worked with him for three years. He told me any saw that does not get enough warmup which he said was three minutes minimum. He said you would have problem. I owned a many old saws and never ever cooked any of them. I can tell you that I have heard that the MACkS are "TENDER" was the word used when someone told me that years ago. Do not remember who told me Tinman. Rest easy fella, you cannot win all the time. Life would be boring for sure. Peace vf
Hi Tinman that Pro mac 850 may have blew up because I have been noticing there is too much ethanol maybe above 10% in the fuel this year. My saws and mowers have not been running too good the past 3 months they seem to run lean and boggy I have been finding water in some of the carbs from the ethanol gas when I switched to ethanol free gas they run fine. Ethanol gas will make the engine run hotter. Maybe that is what happened.
I agree the plating lifted off. Probably was ready to but I’m sure the rpm’s didn’t help lol. It is nobody’s fault, just old parts. I’d wish some companies would start showing up with re pop parts for old saws.
As already mentioned there are some really good replating options within the powersports industry with a product most likely better than the original, Used those services when I raced back in the stupid years. But what is interesting this still resonates around the internet like it's a cataclysmic event. A couple of things come to mind...simultaneously :) You are taking 40 year old machines and bringing them to a entirely different level than their original form.....on used parts. Failures will happen, and probably would have even had you not touched them ( assuming they were in use ). You are breathing life into them, saving them from the scrap heap, not just yours but to all out there who have discovered the fun in this. Showing folks how to enjoy this stuff. Just keep building these, damn the torpedoes and don't worry about the "sample of one" & resultant over analysis. BUT there is one point that gets over looked. Your creations are actually being USED often as true work saws, especially with one famous fellow in sustained operations vs. the GTG cookie cut race saw that might see 50 hours in it's entire service life. Something to ponder :)
Lol yep "a sample of one" for sure. I don't put much thought into why saws like this blow up. Probably 40 year old used parts for sure. And you hit the nail on the head, my mission is building reliable, fast, fun vintage ported work saws that get worked. These things are too much fun to not play with. I'm sure I'll do another 850 soon and maybe turn it up more. Always love your honest real word approach, I've enjoyed watching you for many years.
Tinman dude thanks for the education I got my 372 running awesome thanks to you. your advice worked out perfectly. I just ported my echo cs-800p It's a beast now. I can't thank you enough.
It wouldn't have mattered if it was running alky and a little tip-o- the can, or box stock on super unleaded, when the plating isn't tight, you're doomed. Wish there was a way to tell, but it seems it can happen to a brand new nice thick plate, or on the verge of wearing thru. The latter seems to be the most common, but years ago I did the snow machine thing and we'd get both, mid-life seems to be the safest time to do port work, at least it was with the cylinders from the 70's and 80's . Almost always fails around the exhaust port, probably because it's the hottest and driest. Been watching 2strokestuffing do his own nikasil plating, that fella is the hardest working builder I've seen. Thanks for sharing, hope you find some parts!
Nikasil is tricky. Nickel plating with silicon Carbide suspended in the electrolytic bath. Yup the Two Stroke stuffing guy is great fun to watch. You have to plate slowly for a long time. Then diamond hone to size. Not easy for the home-gamer but I've messed with it some. Hard Chrome is easier but I feel the Silicon Carbide Nickel is the way to go. 'Nikasil' is a trademark of the Mahle company. They have it down and will license the process for a 'small fee'. :)
@@tonyalto1014 Mahle has a few very good processes in their arsenal, the Grafal skirt coating actually holds up in alcohol motors and the insulating dome coating saves the runtime (4 or 5 passes if you're drag racing) to coat the pistons and get the setup to settle down. Before that came along we used to use grey VHT header paint. Mahle automotive stuff is generally quite good, wish they'd do chainsaw stuff, but I'm afraid us chainsaw guys don't spend enough collectively to justify the tool up. They WILL do custom work, but you don't want to know the price.... It's actually easier to get top fuel pistons than chainsaw pistons. Guess we need to do the Burt Monroe thing...
Funny, I thought the same when I saw that mark. I thought the ground electrode came off the plug but the chamber looks good. I didnt see any marks on camera.
Hey Buddy sorry to see that that saw popped, but thats just part of porting vintage saws. Honestly the chrome on these Macs are their demon tweak and its not the first or last one to be taken out by chrome flaking off the cylinder walls. It is interesting that it flaked off at the bottom and not around the exhaust port like most of them do. Sadly rechroming the cylinder is probably not the best option in this case, but the cylinder can still be saved. It’s definitely more work but you can bore and install a thin steel sleeve in these cylinders and it has been done in the past by other saw builders to get rid of the chrome. In the end it makes them a more durable saw since there’s no longer any chrome to flake off but at the expense of adding weight to the cylinder. You can also now get a new pistons for a Pm850/Sp81 from little red barn and try to save the wrist pin bearings since I don’t think anyone is reproducing those yet and an NOS set is hard to find.
You do fine work buddy those old saws are fragile just like people 40 or 50 years old .😂 never give up that saw sounded awesome if you had new parts she would last a lot longer . Keep up the great work and content . Love your mower I’m looking for one now it’s tough and reliable.
One has to be extremely careful as how much these old saws can be pushed. Just spoke to a very reputable porter, and he described exactly what happened in this video when a saw is pushed beyond its boundaries.
If I were still snowmobiling and I saw piston wash like that (you reference scorch marks on top of the piston), I'd say that was plenty lean.. BUT.... I'm out of my wheelhouse on a piston that small - and it does matter. At any rate I believe it's worth your consideration
Win some and loose some. Could have used a nos cylinder and still have the same results, those macs are notorious for this issue. Replate might work but not cost effective for a work saw. Find another one if ya can and try again is all ya can do. Take er easy my friend
Maybe the lower atmosphere in BC had something to do with the plating. Just thinking loud, no expert by any means. To bad it failed. I'd blame Buck'en and a dull chain...😆 just kidding 😂🤣😅. TC Tinman Mahalo 🤙🤙🤙
Maybe not enough oil in fuel mixture! I just today about had this happen to me . Wound it up for abit shut it off ,afew minutes later went to pull it and about slapped myself with it thinking I had a ton of compression and then it came to me as I dumped gas out asking myself just how stupid can I be . And the answer to that is " pretty gadamn stupid" ! Alittle 40 in it broke it loose by hand and we're on the road again!
Wounder if a guy could use that process that Steve Moris has used on a few of his billet race engines he builds? He used a company that coats the pistons, the piston sleeve etc.. with a nano type substance that adheres and fills in all the tiniest gaps so everything is perfect, I forget the process you would have to find the video where he explains the process and the company etc.
I've got a left thumbnail similar to yours, a bit advanced though. I'm hoping it will be grown out & back to normal sometime in July. Injured 12/24/2021.
Well that’s how it goes some times to bad that there is no one who can machine out all that Crome a re plate it with nickel side plating or re cast a slider and same with the pistons now for Mac parts check out a gall in Florida who has s all engine shop and a tube Chanel called chicanick she has some old Mac part her shop is in Florida
As per the charts, this looks like insufficient lubrication, or lubrication quality issues. Not enough oil or poor quality oil relative to exhaust sidewall temp and clearance....as per the charts. Therefore, not a tinman problem.
That's why you buy a new saw with a good warranty, and don't fuck with it. Most people use these as tools, to do a job with. If your going to build a racer, maybe go into stock car racing.
If it were possible to nikasil the cylinder and cast new pistons. It could open up a whole new ball game in the old hot rod saws . More like restomod saws now that would be limitless fun .turn d we m up hard then !!!
Can’t some one machine it out an nickssied it and react a piston or a Clyde’s .? As for Mac parts there is female u tuber who has a mall engine shop in Florida called her Chanel is chic anic she migh have some parts
