worbs

iTrader: (8)

Hi all just after some advice regarding crank choice for my engine build.

Im using a 2.0 my94 cdb with crower standard size rods and omega 92.5mm pistons.
I was going to use a new oe ej20 crank but am unsure what other options are available, billet is out of my price range but can i use say a 79mm or 81mm crank with the rods and pistons i have to increase capacity with out the need for major block work?, im not fussed about the rear thrust centre thrust conversion as that is not really expensive.

Any advice would be much apriciated.

Ian

merlin24

iTrader: (1)

Seeing as you are using standard length Crower rods and Omega pistons, a Twin Scroll 75mm crank would be a good choice as they are cross drilled and nitrided - just have the block machined to take the rear thrust mains.
If your running the CDB with the bore squirters, check for clearance at BDC between the Omega pistons and bore squirters.

Hope this helps,

Mick

worbs

iTrader: (8)

Thanks for the reply mate.

Will the 75mm crank give me a capacity increase mate? sorry if a dumb question still learning lol, am i correct in thinking bdc= bottom dead centre, as opposed to tdc top= dead centre?.
In regards to the oil squirters if the need arises can they be removed? i would prefer not to though.

merlin24

iTrader: (1)

Very slight increase in capacity due to the 0.50mm oversize pistons (from approx 1994cc to 2016cc) but the 75mm throw on the crank is standard for a 2 litre.
BDC is as you said above, if there is interference at BDC between the pistons and bore squirters then you can:
Spot machine the squirter mounting boss to drop them down.
or
Relieve the contact area on the bottom of the pistons.

You should keep the bore squirters if at all possible.

Mick

worbs

iTrader: (8)

Sorry mate im using cp pistons not omega if it makes any difference to clearance, would any more that the 75mm throw crank reguire different pistons?, would the longer throw cause the pistons to raise to high at tdc?
Thank for the help fella.

merlin24

iTrader: (1)

Still check for clearance at BDC whatever pistons you are using by doing a dry build(no sealant on the crankcase halfs).
If you increase the stroke by 4mm by using a 79mm EJ257 crank,then you will need stroker rods and pistons to bring the piston deck height back to where it should be for whatever Version engine you are running.

Mick

worbs

iTrader: (8)

I though that would be the case mate thanks.
Can i also ask what other works could be carried out on the build to make the engine more reliable i want to run some thing like a gt30 or equvilent bolt on turbo so will be running failry big power, as im funding the build month by month from the over time im slaving away for lol i will be really worried about it every time i put my foot down, was thinking along the lines of a 14mm head stud conversion and the likes.


Ian