Larry Driskill

On another thread Rick asked,

"Larry, Do you have a picture of the VA piston and rod that you could post. Also what would be the best material to use for the piston and retainer with a cox cylinder. This is something I could find time to do on a weekend."


Here is the piston, carrier, shims and sleeve from a VA .049. The shims can be used between the screw-in carrier and the top of the piston to change the timing. I had the engines made with pretty much the correct timing for CL Combat without shims. For milder timing one could add .002" or .004" shims.

Other photos are VA parts including a batch of pistons from the junk box. Some are stock and some are pretty mutilated (ah . . . lightened). Also a few sleeves - stock on the left and progressively opened up a bit as you move right.

Piston material is beyond me and critical. ABCs and AACs are apparently using a high silicon content aluminum alloy and the folks making the engine are often pretty quiet about the specifics.

D Bronk

..I see, Larry has no fear, of, the Dremmel tool either..LOL.

..I worked in a Foundry, back in the 80`s( machinist )...Occasionally,I would be called off my 20ft planer,and would have to help pour a Large Heat useing an Extremly large Laddle,weighing TONS, transported, through the plant, with a manned Crane.Dangerous buisness.Where I`m going with this is, If I was going to make pistons..I would get a hold of a few Worn out Pistons,probably, look For Wiesco forged pistons (real tough).Take those to a Technical school.Thats where ,I had my first experience, with sand mold making and metal casting.Have them make you, a sand mold ,useing ,a wooden Dowel,that`s ,a little larger, in Diameter,than the size of pistons, you intend to make..That will be your pattern,for the mold..Most Tech Schools, will have equipment, to ,melt down those pistons..Get them ,to do, a pour for you.You`ll end up ,with them, making you,Poured Aluminum Rods, with a Quality(good Silicon Content) material, that will work just fine ,for turning your own model engine Pistons .Plus they will last ,and ,not wear out ,very Quick.

..Thinking of this ,made me , dig up my Ashtray.Here`s a project ,I had to do, for ,my Machine Shop Class, in High School.It`s Sand Casted, with the School Logo, in the Bottom of it.Once it cooled and,came out of the Mold,.It went on the Engine Lathe,and was turned.For Grades, we had to set up the lathe, to do tapers on the Ashtrays ,inside ,and ,outside.All the Turning,on all the Faces ,were done ,with a 4 jaw Chuck..The only thing, that didn`t get machined on the project, was the Cigarette Grooves .They were just cleaned up useing a Rat Tail file..Anyways ,the Raw Material,for my pour, were old ,Stock 302 Ford pistons, from the Automotive Mechanics Class ,down the Hall..SO IF I was to make pistons,That would be How I would go about it.Once you have the Rod you just slice the pistons off ,like you were Slicing Baloney..Most Tech Schools, and Colleges, are looking for ODD,and UNIQUE jobs like this, for the Students, and Charge very little.It`s Win,Win Situation.

Japanman

Hey dave,
I`m glad your school so activly discouraged smoking amongst its pupils!

I`ve been looking into this side of things here a bit and have found the best high silicon pistons so far from two stroke motorbike engines.
I need to get a bit of borax (i think) to help de-gas the aluminium but the aim is for the fora to have a nice hard pistin like the V.A.
After casting heat treating is quite critical for the final hardness and strength but luckily it can be done in the oven

S

D Bronk

Lots of Good Options, for used pistons around.. Find someone Who races ,They`ll most likely have a Box ,of Good, Junked ,Quality pistons..I can`t Rememder what the powder was, that we used in the Foundry,but, a pre-packaged bag of it was tossed ,on to, every Riser ,on each poured mold.It May, very well have been a mixture, with some Borax in it,I`m just not sure..My Ashtray wasn`t heat treated ,It`s pretty hard to Scratch it though..We mainly, poured Steels, at the foundry.When we did heat treating, of Certain Parts.There would be large Wagons, on Rails, that would go into the Ovens,they would sit in there for up to 24 hours to normalize .When it was time, to Take them out of the oven, the Rack, that the parts were set up on, on the wagon ,would get hooked to the Overhead Crane ..4 men, would hook up the Chains,all were dressed in heat reflective suits from Head to toe..This had to Happen very Quick.The whole "Heat" coming out of the oven,had to be "Water Quenched"immediately..That ,is an Unreal sight ,to see.The Whole "Heat" ,Get`s dropped, in to a very large in ground water tank.When that Rack ,hits the Water,there`s a tremendous "BOOM",and then, a Blow -up of water, that Shoots out of the tank ,going about 35 feet in the Air.Basically it`s an explosion..

..A person, should read up ,on some Metallurgy. to do the job right.That`s the Nice thing about the Tech.School ,the pouring job ,will be done, By the BOOK..and, the necessary products will be on hand there..Dave

Rick W

My Feedback: (20)

Hello guys,

Larry, thanks for the pictures they were helpful. Now for piston material. It is my understanding that using high silicon aluminum can only be used with a plated liner usually made of brass where the cox liner is steel. In my early days of playing with aluminum pistons we melted a Chevy Vega block and used the aluminum from it. Very high silicon content.

I'll do some research and look into different materials.

Was the VA an ABC-ABN engine.

Tim any chance you know what cox used to make their pistons.

Thanks,

Rick

Tim Wiltse-RCU

Rick,


The Cox pistons are made from the same ledloy steel as the cylinders are.

LAter,
Tim

Larry Driskill

[quote]ORIGINAL: Rick W



Was the VA an ABC-ABN engine.



ABC

ptulmer

My Feedback: (5)

But the pistons are supposed to be hardened. The recent rash of crappy pistons makes me wonder if that process wasn't skipped on the newest surestarts.

D Bronk

...Rick ,It`s good ,that you have some experience ,finding Aluminum Donor parts ,to melt Down,and pour,to make something totaly different..[sm=thumbs_up.gif]..But ,I think ,you`re back, in that Box again.[sm=50_50.gif][sm=teeth_smile.gif].A Suggestion for you..Pour the piston material,and make a 12" rod for machining on the lathe.At the same time Pour ,and make another rod ,to machine into your new cylinder from.Since your doing this, Why not make a mold, and Cores ,for pouring your own engine Block,too..For your Cylinder Coating ,instead of Nickle, or Chrome.Your forgeting about a technology..Why not ,a ceramic coating ,like the Norvel Revlite engines..Maybe just coating the Piston would do the trick..I Don`t know much, about that ceramics stuff.But The Norvel engines are Aluminum ,Ceramic ,Aluminum.Something for you to look into..I`m only teaseing, about, the Box thing

..Who knows, all about the Ceramic Revlite Technology..Can you ,give us some Fiction,and Non-"FRICTIONS",[&:]about that topic??

Rick W

My Feedback: (20)

Hello All,

Well I dug through my stash of metal and found some 12L14 for the piston. Got my brother involved and we started the CAD drawings and should have them completed today I hope.

Probably during the next week we'll make about 10 pistons and get them out for heat treating and grinding. We're using a method simular to the VA engine. The rod is being built out of 6061 T-6 aluminum and bushed with oil-lite bushings. (expensive rod.) We'll probably make a couple of rods without the bushings to see how they hold up.

Anyhow will keep ya posted...

Rick

Larry Driskill

Rick, Good Morning,

A bushed rod is a good idea.

The VAs sometimes suffered from rod (little end) and carrier wear. The VA wristpin is a smaller dia. than the AME pin and I replaced the VA pin with the AME pin a time or two.

Were I making rods I would consider using a larger pin. VAs were 2mm. I might use 2.5mm.

And also make provisions for adequate oiling.

Rick W

My Feedback: (20)

Hello Larry.

Pin size has has beeb addressed and I agree, a larger pin is the way to go. More than likely I'll go with the upper and lower bushed rod drilled on both ends for oil.

Looking at a new CNC lathe, a little smaller that what we, my brother and I already have. This lathe will be used for small runs which will free up a machine for tinkering. So the first piston and rod will cost somewhere in the neighbor hood of $60,000.00. Anyone intrested, it will be for sale.

Will keep ya all infromed on the progress.

Rick