stroked ej

[lachlan]

dragin up an old topic but its a good one

if one wanted big bore , short stroke and long rods .

could a ej22 block be used with the pistons made with higher gudgeon pin (for the 2.5 crank 2.35litre combo) but a 2 litre crank and longer than stock rods

so aiming for a 2.2 litre but long rods

or do such rods not exist ?

[hijacka]

 lachlan said:

dragin up an old topic but its a good one

if one wanted big bore , short stroke and long rods .

could a ej22 block be used with the pistons made with higher gudgeon pin (for the 2.5 crank 2.35litre combo) but a 2 litre crank and longer than stock rods

or do such rods not exist ?

Yes you can get the pistons with offset gudgeon pins and different comp ratio. You will have to get custom rods made because they are all the same length,

If you are after a Shorter stroke and bigger bore why not destroke a ej25, EJ257 block/ Ej25 de stroker pistons and ej20 crank . would make more sense if money is a factor.

Heres a de stroked ej257 9k pulls makes you want one aye lol

Some light reading http://forums.nasioc.com/forums/showthread.php?t=1924076&page=13

I remember reading somewhere else on there was a guy on a budget that just used normal pistons with a ej20 crank in a ej25 block with V3 sti heads not cnc\'d or anything was running like 6 or 7 to 1 comp ratio but was making 500 hp at wheels engine only lasted about 15000k i think.. blew a valve right off from memory.

[lachlan]

already have a 2.2 block .

yeah was more after the longer rod to play with rod ratio

[rex-leggy]

id be steering away from using a long rod . from what ive read changing gudgen height is a better option.

if somthing brakes its eaiser to get a eaisly avalible part rather than a 1 off.

stick with 2.2 they can be epic!

[hijacka]

 rex-leggy said:

id be steering away from using a long rod . from what ive read changing gudgen height is a better option.

if somthing brakes its eaiser to get a eaisly avalible part rather than a 1 off.

stick with 2.2 they can be epic!

Why a 2.2 over a 2.5? because you have one lol?

[lachlan]

i was thinking about changeing the gudgeon height so i "could" run a longer rod

not get custom rods to cover up another mis match

so still 2.0 stroke and 2.2 bore . but the longest rod that fits inside that .

just thinking out loud

yeah a de stroked 2.5 is mint but youd need a lot more gear/work to make use of a 9k redline

id take a 22 over a 25 also .

[rex-leggy]

a 2.2 is a 2l stroke with 2.2 bore

and a destoke will be happier to rev

[lachlan]

which conversation are you in ?^^

[hijacka]

So that still doesn\'t explain why a stroked ej22 is better than a de stroked ej257

I know afew reasons why its not better:

Shorter stroke means higher rpm and less load on engine.

Ej257 is semi cosed deck, ej22 is open

Ej257 is rear thrust crank can drop a cross drilled 75mm stroke crank in

Ej22 is centre trust so will need machine to accept rear thrust cranks

Ej257 crank is more exspensive.

Custom rods are exspensive.

You can buy off the shelf manley de stroker pistons for ej257 block

Point im making here is you will find it easier to put a destroked ej257 block together than a stroked ej22 and you will yeild better results with a de stroked ej257 with less money spent.

[lachlan]

oh im not defending it or arguing the point . was merely thinking out loud .

also i never planned on stroking a 22 . rod length has no effect on stroke .

i write a few replies in each message

[hijacka]

 lachlan said:

oh im not defending it or arguing the point . was merely thinking out loud .

also i never planned on stroking a 22 . rod length has no effect on stroke .

i write a few replies in each message

I Know that, they are all the same length, but some do use a longer rod in ej25 block with a 75mm crank instead of off the self pistons(see doms link above i believe he makes them?). Reason being you dont lose the 2mm up top and 2mm down bottom, all of which makes about 2.35 litre, If you use say manley destroker pistons with ej20 crank in a ej25 block then you lose the 2mm up top and down below(79mm stroke vs 75mm stroke) which would actually make it around 2.3 litre.

Im just thinking out loud.. no arguements here at all, just gas bagging lol

[funkytown]

If you go 2mm short at the top with normal pistons it will have hoooorible compression

[rex-leggy]

 lachlan said:

which conversation are you in ?^^

just you alread have a 2.2 block .

what would the effect be of chaging gudgen height and making the rods longer other than having to have custom rods and pistons?

my thinking was a longer rod is going to be weaker.

also the cost of getting a block compared to custom parts which would win.

I gues ive had to many drinks and read somthing wrong

[lachlan]

so the rods for a de stroked 2.5 are 2 mm longer ?

a ej22 with a with a bore of 97 and a stroke of 75 . can we take 2 mm off the piston height ( gudgeon to crown) and use a 2 mm longer rod

nasioc already took all the fun out of this discussion . read most of it untill it got boring

http://forums.nasioc.com/forums/showthread.php?t=1870538&page=2

[lachlan]

 rex-leggy']

[quote name='lachlan said:

which conversation are you in ?^^

/quote]

just you alread have a 2.2 block .

what would the effect be of chaging gudgen height and making the rods longer other than having to have custom rods and pistons?

my thinking was a longer rod is going to be weaker.

also the cost of getting a block compared to custom parts which would win.

I gues ive had to many drinks and read somthing wrong

just to change rod ratio . the pistons can be had off the shelf . and it looks like the rods too

[rex-leggy]

without reading the thread you posted is there gains when it comes to rod ratios?

[Koom]

 rex-leggy']

[quote name='lachlan said:

which conversation are you in ?^^

/quote]

just you alread have a 2.2 block .

what would the effect be of chaging gudgen height and making the rods longer other than having to have custom rods and pistons?

my thinking was a longer rod is going to be weaker.

also the cost of getting a block compared to custom parts which would win.

I gues ive had to many drinks and read somthing wrong

The benefit of a longer rod is that it changes the geometry so that the piston dwells for a longer time near tdc. It also decreases the maximum g-forces that the rod sees so effectively it can be weaker (all else kept equal).

It will shift the power curve to the right as all of the effects of longer rods is beneficial to top end power. So the peak torque may be lower than possibly but it\'ll happily rev more.

Long rods are pretty easy to obtain. Pauter being the main option that I can think of for custom length rods. When I spec\'d my EJ20 stroker, I also made sure I got a gudgeon pin height that allowed longer rods as I was aiming to balance some of the benefits of the longer stroke against the benefits from longer rods. Still yet to determine if it was a good/bad/indifferent conclusion.

But if you want a rev happy motor, stuff the longest rods you can possibly fit in there

[rex-leggy]

nice good info I likely

[lachlan]

yeah theory being that longer rod means piston accelerates slower away from head so you get more push on the piston from each bang .

however one point on naisoc was a shorter rod moves it away faster so you can run moore boost/timing for a bigger bang with less chance of det

also that they rekon the ej25 is a bit of a hash and shouldnt work as well as it does