Where to get custom pistons???

[stuartgallafant]

without going in to too much detail, I want some!!

so, if anyone knows the best place to get them, can you let me know. also, if you have custom pistons yourself, let me know your experiences

cheers guys

[oakey]

heres JE Pistons website:
http://www.jepistons.com/scpdrawings.asp

[e21Jason]

Hi

Top end performance in the states do the JE stuff for BMW's lots of designs of the shelf.


Jason

[yamoda]

Best pistons we have used are from Mahle, not the cheapest but unbelievably strong. We usually order them direct from Mahle in germany.

[stuartgallafant]

what would be the best way to go about using custom pistons?

getting my crank and rods sorted, then getting camshafts for the head, and then asking them to design pistons around these specifications?

[yamoda]

The cam and type of induction you use has to be suitable for the compression ratio you are running, so the CR is usually first or very high up on the list of decisions you have to make, that will dictate your piston choice.

[stuartgallafant]

im still undecided whether to run my supercharger or not?!

i was thinking to just get the pistons based around an NA setup, then if i want the s'charger on, i'll buy new custom pistons

if im going NA, will getting the cams/crank specs help with the piston design? if i ask for a specific size, say, 86mm, i can get the bores machined to match after

i just wanna make sure the piston is not gonna crash into my valves coz of fitting a lairy camshaft!!

[yamoda]

im still undecided whether to run my supercharger or not?!

i was thinking to just get the pistons based around an NA setup, then if i want the s'charger on, i'll buy new custom pistons

if im going NA, will getting the cams/crank specs help with the piston design? if i ask for a specific size, say, 86mm, i can get the bores machined to match after

i just wanna make sure the piston is not gonna crash into my valves coz of fitting a lairy camshaft!!

You dont really want to go much over 8.5 to 1 with a blower (Less if you are using a turbo)
You would be better off trying to decide what way you are going before you order the pistons cos they aint cheap (A set of 4 for a little Starlet turbo cost us £650, but its still embarrasing scoobies with 10k miles done at 1.8bar)!!
I would go 8 to 1 with a blower or 10/10.5 to 1 N/A.
As for valve clearances talk to the guys at Mahle about your cam and they will know how much to allow for higher lift.

[stuartgallafant]

im looking at a set of cams already from a different company. therefore, i was gonna get them to go high lift, and just get the pistons built to suit

i do really wanna put the charger on though, but im just deciding if its gonna be grief or not

[yamoda]

The other thing to think about if you are going to use a blower is that a cam thats good for a n/a engine wont be so good with forced induction (The stock cam would give noticably better results than, for example a 288 cam) the longer duration and overlap will let some of the mixture escape through the exhaust valve whereas if the engine was n/a it uses the greater duration and lift to keep mixture speeds high. I would personally stick the blower on a stock engine to iron out all the crinkles and buy another lump (They are cheap enough) to build that would get the best out of the blower i.e lower comp forged pistons, better rods, a proper bottom end balance and a cam suited to a blower, it'll be much more fun that way and will give you loads more bhp/£.

[stuartgallafant]

might just go N/A for now then, and whip it all out next yuear and change it again for S/C!!

its only money eh!!

[appletree]

its only money eh!!

if youve got lots of it al take some off your hands!!

might have got bored of my set up by then stu so that might be up for grabs!

[stuartgallafant]

got a charger already matt, just unsure whether to bolt it all up!! are you changing your cam?

[jpboost]

Stuart,

work out why you want custom pistons, rather than deciding you want custom pistons and the trying to work out what you want them to be like.

i.e. normally you'll decide what cams & compression ratio you want, then get pistons made with sufficient clearance for the cam profile you've chosen.

what's wrong with the std pistons?

you way be able to get them machined if it's just a valve clearance issue.

your engine build should be significantly different if you are going the supercharged route. build it once, and build it right. It's less agrro, and cheaper in the long run.

If you're at the point where you need custom pistons, then you'll also be in a position to know what spec you need them to be.

give me a shout if you need any advice.

FWIW, there are quite a few suppliers, Mahle, Omega, JE, etc etc.

as for full custom spec, it's not cheap. (but you know that already). It may be an advantage to find someone who's done a similar build and see what they used, and who made it. Cheaper and less design work.

btw 2nd m3 coming on well (albeit a little slowly), white one for sale soon...

John

[Jhonno]

some good points here..

decide what your doin before deciding what you want

an f/i engine is built to very different specs to an n/a one..

[stuartgallafant]

i know that F/I is completely different, which is why im trying to get my head around it!!

i have a feeling though, that i want to stay N/A

i got let down on a crank that i wanted, and without the crank, i cant spec the rest of my engine. i have an idea of what i want, but im just not totally sure

thanks to you guys, im learning the best way to go about it all

[e21Jason]

HI

For a budget FI set up you could use m40 pistions to lower the CR

Jason

[stuartgallafant]

nope, this has to be custom im afraid?!

may be able to use some S50 B32 pistons, but i think theres some things i just wont be able to get my head around!!

[yamoda]

Give us a couple of pointers as to what you want the engine to do.

[stuartgallafant]

going for torque really

getting some cams made up. i just think custom pistons will allow me to achieve greater advantages. so when the cams open, i obviously dont want the pistons to hit the valves

[yamoda]

For more low down torque a blower is the way to go, if you are staying n/a then upping the compression is about all you can do for decent money, all the other n/a mods (Cam, exhaust and port work) will push the torque curve higher up the rev range and in real world terms will feel like less torque untill you get to the new cams power band. The classic way to get more torque without going down the f/i route is to increase the stroke, maybe a 2.7 conversion?

[maxfield]

he's using M42 so 2.1 is about the limit IIRC?

[yamoda]

he's using M42 so 2.1 is about the limit IIRC?

Ah, my mistake. Got to be a blower then

[stuartgallafant]

i cant be arsed with F/I

thanks for your help anyway lads. i got something on my mind now

[m-dtech]

omega pistons ;)