Anybody make their own pistons?

[Monkeyhanger]

Alum?

How do they usually shorten it, I thought Al was the way?

Hi,

Al stands for the element. However what confused me is that there are a group of sulphate compounds known as Alum which I certainly wouldn't expect to find in an engine (those pencil things that stop shaving nicks from bleeding and deo crystals are types of "alum").

Just plain Alu, Aluminium or (heaven forbid) aluminum would have been obvious but "alum" is something else altogether.

Bye

 

[Stihl 041S]

Monkeyhanger;
I've been typing on my phone aqnd I tend to shorten words, though "addy" still sounds strange. Sorry for the strange words.
Rob
Yeah alum was a little confusing,. I should have said green persimmons.
Thanks again

 

[Kansas]

Dumb question 041, and I dont expect a lashing for asking either, but why build a piston which is near impossible to do properly by mortal working men w/o foundrys and labs and cam grinding lathes etc etc when IMO building a jug to fit an existing piston of whatever is soooo much easier I have done it many times building specialty engines, and I have bought custom piston sets and they are EXPENSIVE I guess I just dont get it do you have a marketing plan or just a one off? j/c

FWIW As long as you have obviously been a machinist I see by reading this thread you are quite capable of doing it if it was possible and you obviously know the dynamics yada yada, but turning a round cylinder is easy and pistons are not round and do not act like round objects I wonder what would the gain be to accomplish this feat besides being famous here and a pat on your own back I guess? Especially if this a 5 figure rpm chainsaw engine you have in mind. (I figure it is btw).

 

[Stihl 041S]

Kansas,. Great idea,

That is why I asked if anybody built their own. Almost didn't ask. No pat on back, no fame, just never did it and had an 090
cylinder and seemed like a fun thing to do. Then got to hort rod. I don't have it figured out, but I was looking for things people have done not what they think cannot be done. A 44 mag has more HP
than a 45 colt in a Ruger, no wait we were wrong. More later.

 

[aandabooks]

Machinists seem to think about this type of stuff a little different. When I'm at work and I bring in a side project to work on with the manual stuff, we call it "Government work". I normally run CNC but occasionally still dabble with the manual mills and lathes.

I spent parts of a couple of nights latheing a rod out of aluminum to go in the bottom of my grease gun for the bar sprocket. Pulls down and hooks to fill with grease. Let it go and it has a spring system to maintain pressure.

Why you may ask, because I could and I didn't feel like pushing the plate up with a screwdriver in the field.

I say go for it Stihl 041S. It would be a neat thing to do and if you have the time and energy then more power to you.

BTW, we make our pistons from cast iron and some cast aluminum but I don't think either type would work for you. Our largest piston is 120mm and runs without a drop of oil in the unit.

Matt

 

[redprospector]

I don't have it figured out, but I was looking for things people have done not what they think cannot be done. A 44 mag has more HP
than a 45 colt in a Ruger, no wait we were wrong. More later.

Anything can be done with enough patience, and Money. Somebody had to build the first one.
Good luck,
Andy

 

[RaisedByWolves]

Machinists seem to think about this type of stuff a little different. When I'm at work and I bring in a side project to work on with the manual stuff, we call it "Government work".

LOL, I allways wondered how it got that name.



041, Im not sure what the designation would be on the type of aluminum for pistons, but even with that, it dosent mean that its not that material with Silicon added. Or maybe that grade has silicon in it? All I know is that a piston needs this to control expansion.



A coworker of mine is Romanian and escaped communist Romania in the 80's. He and I fight like cats/dogs, but we respect each other for what we know nad allways help eich other with out "Gumment verx" as he calls it. He told me about the Silicon through a story about fixing an old JAVA (Jawa) motorcycle in a town where people had nothing and had to scrounge for everything, even going so far as to steal from the military for supplies.




He neded a piston and a cylinder liner in a country where a bike would make you KING(when your 19), but there were no spare parts. What he did was sneak around a road building site in the night and find some Iron sewer pipe to use as a cylinder sleeve. when he had this he was able to machine his sleeve and make the cylinder good again. He did have access to a machine shop as they hired him to clean up when they werent buisy in exchamge for using the machines when he was done. Over the years the locals would find stuff and make a note of it for future reference. One of these things they knew about was a crashed soviet plane about 10km away in what was once a farmers field, but had gone sour due to the fuel spilled and was left to go to weeds. Him and some friends took a trip there one night and scoped things out. they found it to be fairly secluded and proceded to go back and retrieve 30-40lbs of aluminum.



Out of his share Coleman was going cast a piston, and he did, it took him months, but he did it. He machined it the way he was told, checked and rechecked his specs. He made his piston rings out of the best Iron at his disposal (sewer pipe). When the day came to fire up the bike, it fired up in 3 kicks and he motored off into the sunset.......




Ok, he got about 300' and it seized up solid.




So he tried again, and it siezed again.



This went on untill one night he was cleaning up and one of the old timers in the shop came up to him and gave him a paper packet with a pearly white poweder in it. The old man said "This is very precious, I have taken it from the party for the future and watching you struggle and not quit made me realize why I needed to take it. Put it in your metal next time you melt it and you will ride your bike next week."




So Coleman did that (He measured first and measured wrong) and this time his piston lasted for 20 mi! After a couple more tries he had it nailed. He ran the bike on the best gas he could steal from a guvernment farm and mix it with engine oil that would be drained from the machine they were stealing the gas from.


He had the bike for two years and traded it for a boat.


A crappy boat, but the bike wasnt much to look at either, plus you cant feed your family with a bike.


All around, an interesting guy to know.



.

 

[Lakeside53]

Hmmmm... precious white power. They sell that on the streets around here :greenchainsaw:

 

[Pioneer]

I made a piston for a small Homelite from 6061 t6 bar stock, it works fine. Was it worth it? Probably not, it's a lot of work and time invested. Much easier to cast one and finish machine it if you have the equipment, or have the old one welded up if it is localized damage. Best to keep looking for an NOS part if you don't need it in a hurry.

 

[Stihl 041S]

The ansrer is NO

RBW
That is why I was going for T651 not T6 to get the stress in the right direction. A guy at work did the engine for the Wright Flier, seems to know his stuff. Went thru what can and cant be done on practicalmachinist about a kid wanting a deisel for an ultra light.

People gave him all kind of crap, deisel in a plane? How stupid. Till Rutan and Yeager flew around the world, the longest unrefeuled sustained flight was by a Packard Deisel.....In 1932! Someone said well not today, then all kinds of posts on deisel planes.

Maybe use a piston and make a cylinder, or make an elipticle piston, crap I hand fit things all the time.

Can you make a Ruger single six into a 357? Yes, my daughter has one I made for her.

What got me was 2 fold. Those that wanted to help, and the ones that are so sure it cant be done, and heard an urban legend why it cant.

My mentor did a lot of things that couldn"t be done, preload in a titanium rivet, he looked for answers, not excuses why not. Did we fail sometines? You bet, he also has a patent with close to half a billion dollars in sales.

Six guns, you blow them up or send them to H.P.White labs, our shop did both.

Can Vascomax 350 be hardened to 61.5 Rc, no Vasco flyer said so, but Joe Hammer at Vasco R&D thought it was great when we did it and wanted to know how, not some crap urban legend.

I shall rant no more, the answer to the original post is NO.

So if billet is wrong, I'll try cast.

RBW, thanks for the post. I'll blow an engine for ya. You don't know how far it will go til ya do.

Rob

 

[Stihl 041S]

I made a piston for a small Homelite from 6061 t6 bar stock, it works fine. Was it worth it? Probably not, it's a lot of work and time invested. Much easier to cast one and finish machine it if you have the equipment, or have the old one welded up if it is localized damage. Best to keep looking for an NOS part if you don't need it in a hurry.

The thing I don't get is, what is so hard to machine in a friggin piston?

 

[motosierra]

Well,if I fail so be it. i am using the best alum I can, I was building 2 stroke con rods 25 years ago from Titanium. Been cranking handles for30 years, part of it aircraft parts.....65000psi work, CRAP I ASKED IF ANYBODYMADE THEIR OWN PISTONS. I got an outside shot maybe?
Or are you going to fail for me too? The 090 piston is a pretty good print, heck I may build one to test to destruction. All the rest, I do thank you for the info.

Can you turn a slightly domed 281 piston on a lathe? I can provide further specifcations. And can you give me a ballpark figure as to cost?..Thanks

 

[joesawer]

Stihl 041S, I meant no disrespect.
The answer is, Yes There is some one out there making their own saw pistons. His name is Vince Loy.
I don't make my own pistons. I am not capable of doing it. But I do know a little about them and have had custom pistons built.
For me it would be much cheaper to buy a good piston than to sling a rod.
There is a lot of little secrets to making a high performance piston that I don't know. But a few things that I do know are-
1- you don't always want the wrist pin centered, a little offset can really reduce piston rock under load and free up a lot of power. I have seen a formula to figure the offset, but have no idea what it is, but there is at least one.
2- High speed pistons have trouble with ring seal, this can be improved with more true ring lands and micro polishing the land and bottom of the ring.
3- Most custom piston makers have a proprietary alloy. They have balance hardness, tensile, and thermal expansion. Thermal expansion is more critical on a two stroke because the piston cannot have as much clearance. Some high end pistons are being cyrogenically treated after being forged.
A piston can be made, but the learning curve is going to cost more than what a good one can be bought for.

 

[Monkeyhanger]

Yeah alum was a little confusing,. I should have said green persimmons.

Hi,

green persimmons? Does that mean my Suzuki bike engine is made out of fruit? Oh dear...

Bye

 

[Stihl 041S]

Hi,

green persimmons? Does that mean my Suzuki bike engine is made out of fruit? Oh dear...

Bye

Refering to alum. There was a guy with me in the Army in Alabama who didn't beleive how sour a green persimmon was when told so by the local boys. Made a bet he could eat one. The picture of him, after taking a few very rapid bites, trying to force his finger past his now clenched lips to claw the "food grade alum" out of his mouth, still makes me chuckle. Believe the Southern boy next time.

It was just a bit of fun poking on my misuse of the word alum, that I shan't make again, thanks again.

Rob

 

[Saw Bones]

Has anyone turned their own pistons, one off, in their shop, garage, basement?

Do you know what goes into making a piston? Bore, stroke, heat expansion (pistons are tapered, smaller at the top than the bottom to allow for expansion) ring groves, the length of the skirt etc. A lot of research and development. You don't just turn one out in your garage. They are precision engineered. Maybe if you are a mechanical engineer you could make one, but then you would know its cheaper to buy one all ready made. Why re invent the wheel.

 

[Stihl 041S]

Stihl 041S, I meant no disrespect.
The answer is, Yes There is some one out there making their own saw pistons. His name is Vince Loy.
I don't make my own pistons. I am not capable of doing it. But I do know a little about them and have had custom pistons built.
For me it would be much cheaper to buy a good piston than to sling a rod.
There is a lot of little secrets to making a high performance piston that I don't know. But a few things that I do know are-
1- you don't always want the wrist pin centered, a little offset can really reduce piston rock under load and free up a lot of power. I have seen a formula to figure the offset, but have no idea what it is, but there is at least one.
2- High speed pistons have trouble with ring seal, this can be improved with more true ring lands and micro polishing the land and bottom of the ring.
3- Most custom piston makers have a proprietary alloy. They have balance hardness, tensile, and thermal expansion. Thermal expansion is more critical on a two stroke because the piston cannot have as much clearance. Some high end pistons are being cyrogenically treated after being forged.
A piston can be made, but the learning curve is going to cost more than what a good one can be bought for.

Thanks for the info.
1. This is one I will have fun with, Mike will laugh that I didn't know that.

2. A 2 micro finish on carbide for squirting a .066 pin to a .750 depth in stainless with an OD of.093 is the only way to go. A 4 finish is enough when you take a 1942 copper penny and make it into a 1943 copper for your kid, same with 2 headed pennys. Though a 2 tailed coin is always better, cause every cookie calls "heads".

3. Our casting guy ay work has cast pistons before and wanted me to cast them, I wanted to start from billet, and maybe I won't. I was hoping the T651 instead of T6 condition would help this.

I looked up custom pistons, 2618 may be the starting point.

No one has stated hard numbers in any of their objections but the folks wanting to help have so I will take that into my dicision making.

I was in R&D and their were a LOT of failures but that was doing things people hadn't done yet, EVER.

So I was fool enough to ask if anyone here had ever made their own pistons.

The nay sayers have used urban legend and valleygirl speak to make their point that it can't be done and how much they know about the subject. The helpers have given real places to look.

It just reminds me of some great hunter whose uncle's rifle is"the greatest deer killer ever, saw him shoot a deer and it was dead when we hit the ground!!"

The truth be known, he hit the poor deer in the leg and he fell and broke his neck.

There is another reason why animals go down at different speeds, that can't be brought into the shooting equation.

This rant is at its end.
Rob

 

[Stihl 041S]

Do you know what goes into making a piston? Bore, stroke, heat expansion (pistons are tapered, smaller at the top than the bottom to allow for expansion) ring groves, the length of the skirt etc. A lot of research and development. You don't just turn one out in your garage. They are precision engineered. Maybe if you are a mechanical engineer you could make one, but then you would know its cheaper to buy one all ready made. Why re invent the wheel.

I could buy a custom pistol but it would cost me a lot more than me making one. And in this case it wouldn't be as good. No brag, just fact.
Rob

 

[Stihl 041S]

Do you know what goes into making a piston? Bore, stroke, heat expansion (pistons are tapered, smaller at the top than the bottom to allow for expansion) ring groves, the length of the skirt etc. A lot of research and development. You don't just turn one out in your garage. They are precision engineered. Maybe if you are a mechanical engineer you could make one, but then you would know its cheaper to buy one all ready made. Why re invent the wheel.

And another person that can't (won"t)read previous posts.
Whats in your garage?

 

[RaisedByWolves]

Hmmmm... precious white power. They sell that on the streets around here :greenchainsaw:

Yeah, but that stuff only makes you think you got things right.

I made a piston for a small Homelite from 6061 t6 bar stock, it works fine. Was it worth it? Probably not, it's a lot of work and time invested. Much easier to cast one and finish machine it if you have the equipment, or have the old one welded up if it is localized damage. Best to keep looking for an NOS part if you don't need it in a hurry.

If someone was going to make a piston, that would be the style to start with. How many hours do you have on that one? Have you checked it for wear?





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