Does anyone know the maximum amount of stroke or largest crank that can be used with standard P&B.

i heard it was around 76 to 78 but want to make sure what the exact boundary is.

just want to change my crank if i could and keep the P&B size small, i know i can use larger but at this stage i sont wnat to

thanks in advance for professionals input

It would be cheaper to increase the bore to 94mm rather than increase the crank size

Provided you dont mind using barrel spacers,
and clearancing the case, piston and rods for clearance,
then anything is possible.

With VW journal, and VW brand rods, 82mm to 84mm is tight , but possible.

Longer rods, or rods with a design better suited to clearace may fit even more stroke.

76mm is comfortable, and I would say 78 would be fine to.

74 will fit with very little extra work other than checking for clearance
and adjusting deck height with spacers to make sure comp ratio suits your requirements.

What ever you choose, checking of, and making clearance at BDC for the piston will be an important limtation.

Much to think about, i just want to go a bigger crank rather than bigger P&B as i already have them, the clearancing is easy and i want to keep the cc's down as it will be supercharged anyway.

fuel at nearly $2 a litre and it is not my final motor. cranks from the states are so cheap at the mo.

u get what u pay for with alot of those cheaper ones
when blowing a bug bigger displacement isnt all that necessary
those SC12s turn a stock 1600 into a 2200
my tired stock 1600 with the blower pulled as good as my freshly built 1776 with cam and twin 40mm webers on accelaration and pulled 10x better up hills
the torque of a blown motor is incredible

yeah i have a SC12 going on, i need a new crank anyway just looking at the option of getting a forged 4340 balanced and possible cromolley one.

just looking at going a little bigger with stroke using standard rods and P&B, and a turbo grind cam with head mods.

Most of ths China parts that we get here end up scrap

Im going to make sure i get a good one, just want the biggest i can fit with standard 85.5 P&B's,

if i used spacers would that defeat the purpose of going stroker? i do not fully know how this would work.

Spacers are used to keep the barrel top in its correct relationship with the piston.
It is a requirement to prevent the piston poking out the top too far.

"Stroker" piston sets have a shorter height from top to pin
to keep the piston at the correct height,
but because you want to use the stock piston,
you WILL need a spacer.

It will not defeat the purpose of going to a stroker crank.
The purpose of a stroker crank is to increase the distance the piston sweeps through a rotation.
Stock sweeps 69mm, and strokers sweep more.
The additional sweep will be at both the top of the cycle and the bottom.

Because of the extra 'sweep' the engine tends to ingest a larger volume of air.

Imagine it as if you put longer cranks on your push bike.
When the pedal is down it will be closer to the ground than it was with stock cranks,
and when the pedal is up it will be closer to the seat.

Shimming the barrel is like raising the seat on your bike.
In some cases you may need longer legs(con rods).

i have made 200hp atw with the chinese crap,so it can't be that bad.last time i pulled it down i had it tested.
all was good.
my two cents has run out and i'm done.

lets just say that I have seen the odd China part,

the cranks are only slightly better quality than those garden lights we all payed around $25 for a pack of 4.
I guess that the quality will improve sometime.
Yep 200hp is possible but quality is not assured.

But if you want Bunnings Quality use em

good one johny
i don't mean to be rude.but,small minds do have the problem of looking out side the square.
i think you may be surprised .tomei and 5zigen other big jap brands are all coming of china ,when you ask for a product to be of a certain grade,they wll guarantee it.
works for me.
it all comes down to what they are asked for when making a product,if it's price they can beat it,if it's quality they can match it.
were do you think most of the world is buying products from ,not much of anything is made in the US anymore.
everyone is driven buy profit margines.
even if you buy a yanky crank were do you think the material comes from,you quessed it china.
i suppose what i am saying is deal with it.if you think all the good products are coming from race bread stables then you are gravly mistaken,and i hate to shatter your dreams but if it is quality that you want buy the old german stuff it's the best.

sorry about the harsness,i always wake up crumpy.

Thanks for the input on the cranks, makes a lot of sense now. a lot of combinations now spring to mind.

how much are you thinking of putting in to this engine set up.
budget is important ,but sometime hard to stick to.

looking at doing a little bit but keeping the capacity small as there are a few motors out there at or around 1600 with considerable power output and its going in a bus so not looking at racing, just strong and reliable and can get out of its own way, run smooth and rev if it needs to.

Besides the necessary, like bearings and such, the rotating parts will be changed such as crank (74mm at mo), cam (TCS10 or better) with rockers to match, head work (043 or such with port, polish).

Then the bolt on will be trigger wheel ignition ($200), fuel injection (mexican end castings $40 with a central TB $100) Megasquirt as possible ECU, SC12 supercharger (have - cost $200), lightened flywheel.

Something like that would make me happy, economical when not pushed hard but can really pull along when needed. Changing to IRS also.