losi shock pistons

[turbotim]

Hi,

Can someone explain to me how you get to a drilled piston ie. 555 or 666. how are these numbers made up? and what size drills you use to get there.

thanks

[DA_cookie_monstA]

starters, if you drill then 0.666", you need mighty size pistons for over half inch holes, it should read 0.0666" which is roughly, nearly, nats nadgers close to 1.70mm.

But, I do believe Losi used to make a drill kit, for this precise task, maybe Doom could shed some light on whether they do, I remember someone doing it.

[Doughty]

a very good question.

Losi pistons are in 'numbers' as well as colours they are as follows

#60 (Natural)
#57 (Black)
#56 (Red)
#55 (Orange)
#54 (Blue)

now I believe this number also relates to a drill size.

whever people talk about a standard piston in number they would just use the 2 digits or the colour.

if they talk about a drilled piston they will use a 3 digit number, something like 556 or 566.

what it is the last number of the 'standard' piston numbers, notice they are all 5something so that does not matter

so a 556 piston would have 2 holes in #55 and one hole in #56

a 566 piston would have 1 hole in #55 and 2 holes in #56

hope that makes sense, I am not 100% certain of these facts but thats how I unserstand it.

though I dont bother will drilled pistons, my car is normally too far off being perfect for small changes like this ::)

[DA_cookie_monstA]

In other words, it allows you to have too other pistons between a #55 and a #56, and to be honest, like Chris has said, are there THAT many people who would actually have a vast improvement by opening one or two of the holes up???

I know I wouldn't, and, it would just give me WAY too many variables to try, instead of the basics and learning the track.

[richard_cree]

It can make a difference, honest.

The number as chris says relates to an imperial drill size, bear in mind the bigger the drill number, the smaller the hole.

Another thing to consider is a drilled 555 piston will have a slightly different size to a moulded 555 piston, for this reason I always used drilled pistons, even if they are standard versions available.

This really is very fine tuning, but once you get the hang of it you will find the jump between std pistons to be immense.

[Doughty]

I dont understand what you mean with a drilled 555 being different to the standard #55 piston, do you mean moulding tolerances?

[gingapaint]

i believe he does...plus surely due to the moulding techniques, a moulded piston hole edges will be more rounded than a drilled one.. not sure if this makes a difference, just in uni and bored....

[richard_cree]

tolerances will make a moulded 55 hole different from a drilled 55 hole.

If you always drill all the holes in your pistons with the same drill set, then you can be sure the holes are all the same size. Going even further than this I always try and use 60 pistons as my base piston because there might be some variation in piston diameters throughout the range.

[Doughty]

it makes sense when I read it. I could not see where you were coming from when you were telling me! ::)

so how do you get the writing to stay on your pistons then?

[DA_cookie_monstA]

if you are interested Chris, the drill sizes are as follow

#60 - 1.02mm
#59 - 1.05
#58 - 1.07
#57 - 1.10
#56 - 3/64"
#55 - 1.30mm

According to my Zeus book, for toolrooms and workshops, if that helps.

[turbotim]

thanks for that. its just something else to play with. so i could get the drill bits from a tool shop?

it all kinda makes sense, its just just about any set up found on the web kinda has drilled pistons.

[learnerdriver]

if you are interested Chris, the drill sizes are as follow

#60 - 1.02mm
#59 - 1.05
#58 - 1.07
#57 - 1.10
#56 - 3/64"
#55 - 1.30mm


According to my Zeus book, for toolrooms and workshops, if that helps.


can you check to see what #54 drill size is also to complete the set ;)

[DA_cookie_monstA]

#54 = 1.40mm

[richard_cree]

it makes sense when I read it. I could not see where you were coming from when you were telling me! ::)

so how do you get the writing to stay on your pistons then?


Marker pen does the job fine actually!

[MattW]

I've got a racers edge set of piston drills, each drill bit has it's own knurled twist handle. they seem nice and easy to use.

Rich is quite correct in that i don't think moulded parts are ever exactly the same. If there is ever enough of a difference i don't know. AE pistons always LOOK the same, but i must admit i have some losi pistons that have visably more flashing on them than other ones.

[richard_cree]

Thats very true Matt, my dad even used to go to the extent of mounting the lot up on a shaft and skimming them all to make sure they were identical diameter.

[elvo]

I use that trick on all my pistons, wouldn't use one without the flashing removed.
It's really easy as well:
* Mount 8 of them on an old shock shaft
* Spin shaft
* Skim with some #1000 sandpaper


BTW: moulded holes are ever so slightly _smaller_ than drilled holes. And moulded holes are slightly tapered. (Easier to mould)