I don't know how strong the crank's are, or how far they can be bored out
but how about stroking it by off center grinding the crank and also boring it
out a bit.....
Errol Smith wrote:
> Luke,
> The main problem with the NA (naturally aspirated) FJ20 is the lack of
> abilty to get a high CR (compression rato). The NA FJ20E cannot get a CR
> over 9.8 approx, due to the head design. Valve angles in the head are wrong
> and pistons get in the way of valves etc. So if you shave the head you must
> put reliefs in the pistons, that further lowers the CR. The best you can
> expect from a NA FJ 2.0 is approximarely 185 - 190 hp, and that is a good
> one. In NA form the engines are good for an easy 160 - 170 hp, but over
> this it will cost you a large amount to get those last few hp. In stock
> form the NA head flows sufficiently to acheive approximately 240hp so head
> mods will not improve the HP capacity much if at all. It may even cause you
> to lose some driveability at mid range speeds. Rather than looking for more
> power from the engine, maybe look at ways to lose less of the available
> energy to things like cooling fans, alternators, flywheels, body weight,
> overall gear ratios etc. You can still get really good performance from
> the NA engine at 170 hp as it is a high torque engine design.
>
> The FJ engine was originally designed as the FJ24 NA. In this form the
> swept volume of the cylinder is sufficient to achieve CR's of 11:1 and then
> you can get some real power (260hp is realistic). To the best of my
> limited knowledge the Z24 crank is not compatible with the FJ24 block.
> (cylinder spacing is different I am told?). To make an FJ 24, you need the
> FJ24 crank, rods and pistons.
>
> The FJ's weight is a real downer in NA form in terms of hp/lb or Kw/Kg
> engine mass. In spite of this I think the FJ is still Nissans best Turbo
> engine in terms of reliability for power output. SR's do have a habit of
> breaking exhaust rocker arms when used at reasonably high engine speeds.
> Check the comments on the SSS automotive site on their engine designs etc
> for more info on Datsun/Nissan engine designs and especially the FJ series.
> Cheers
> Feral Errol
>
> ----------
> From: Leadex <[EMAIL PROTECTED]>
> To: ozdat <[EMAIL PROTECTED]>
> Subject: FJ mods
> Date: Friday, April 21, 2000 6:54
>
> I am desperate for some cheap ways to get some power from my FJ running on
> webbers. The engine is in good nick as it is, so will a bit of simple head
> work and bigger valves get much more power? Also, will Z24 parts fit to
> build a 2.4L engine?
> What is a cheap four cylinder place that can supply the parts and do some
> of the work?
>
> Thanks
> Luke
>
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