Bigger bottom end....

youngprodigys · February 16, 2011, 04:36:17 PM

type "g40 stroked" into the search box. comes up with bore 77, comp height 34.45 (i think) pin 20.

dani1326 · February 16, 2011, 06:31:09 PM

The pistons are special order only, iv got to order 12 pistons to even get a price, what are my other options??

Richg40 · February 16, 2011, 07:09:07 PM

Either find some peeps who are willing to go in on a deal and buy a set or find one of the few sets that's out there and hand over some big bucks. There's gotta be 4 or 5 sets out there, with at least 1 or 2 sets that are sitting in someone's shed doin' sweet FA.

dub-disaster · February 16, 2011, 08:28:34 PM

Dig deep in your pockets and get some quotes from other manufacturers like je for some one off pistons but as I highly doubt you know the exact spec unless somone who has a new set (young prodigys!) would like to let you measure them up and get a custom one of set made
Either way it's going to be big bucks but if your building a new 1.5 g40 motor you better get used to big bucks my 1341 cost plenty and this will cost a bit more

scotsjohn · February 16, 2011, 09:05:01 PM

The pistons are special order only, iv got to order 12 pistons to even get a price, what are my other options?

I'm seeing 77mm Wossner pistons for £550 on ebay

PeteG40 · February 16, 2011, 09:10:41 PM

you need to ensure they are stroker ones for 77mm though or you may get valve clearance issues etc

dani1326 · February 16, 2011, 10:07:58 PM

Quote from: PeteG40 on February 16, 2011, 09:10:41 PM
you need to ensure they are stroker ones for 77mm though or you may get valve clearance issues etc

Yer that's why there special order or is it possible to skim a standard set??

youngprodigys · February 16, 2011, 10:40:20 PM

thats what my plan was with my other engine! skim a standard set to the 34.45mm deck height.
i really need to work it out. if i dont flog my bottom end- i will CAD it up and work out what i need to do to the pistons in order to attain 8.0:1 comp ratio.
when i fo it will be a super cheap way of having a 1398 bottom end. i will measure up the 1W pistons aswell so i can see whats needed for a 77mm set

polo classic · February 17, 2011, 09:43:08 AM

I'll be ordering some custom JE 8,5.1 for my 1W soon

scotsjohn · February 17, 2011, 09:24:39 PM

Quote from: PeteG40 on February 16, 2011, 09:10:41 PM
you need to ensure they are stroker ones for 77mm though or you may get valve clearance issues etc

I haven't got the maths for it but could you downstroke the crank? There must be plenty of meat on the 1W compared to the standard G.

Richg40 · February 17, 2011, 09:27:10 PM

You what?

scotsjohn · February 17, 2011, 09:36:04 PM

You can alter the stroke of a crank by re-sizing the journals.

Richg40 · February 17, 2011, 09:49:50 PM

Don't make me quote myself.

Yoof · February 17, 2011, 10:23:09 PM

Quote from: scotsjohn on February 17, 2011, 09:36:04 PM
You can alter the stroke of a crank by re-sizing the journals.

You really can't...

youngprodigys · February 17, 2011, 10:34:38 PM

the difference in the pistons is in the height. they are like normal 77mm pistons yet are not as tall and have a wider bowl on them to deal with a higher compression ratio then on a stock G