Over Sized Pistons in l28

[Tommo560]

the car has been down on compression and i've just got it at the mechanics now and he said that the bore is worn a bit and it'll need to be bored. this means oversized pistons, but i have no idea what i need.

i'ts currently an l28 F54 block, 2 mm shaved p90 head, some rods (prob standard, dont know), and flat top pistons. i race the car (read: spends most its time at 5000-6500 rpm) so i need some pistons that are going to be able to take this abuse, but i and my mechanic are not sure what to get. anyone got any good ideas? i am sure someone has done this before but a search proved fairly useless.

I am in autralia so if i can get some stuff locally that would be good, but if it has to come from the us, thats cool too. price isnt tooooo much of an issue, they just need to be good lasting pistons, but i dont want to be spending thousands either.

Thanks,

Tom.

[e_racer1999]

i wonder if the KA24DE 89mm (?) pistons are reliable for your application....

[Tommo560]

I've seen a few articles that say 89mm is too big to go reliably? but like i said i have done a bit of searching but just cant find anything conclusive.

Tom.

[venom42]

I believe that motorsport has forged pistons now. If your car is N/A then those should stand up to anything you can throw at them.

[NZeder]

If you F54 is still the stock 86mm then get some L24 rods and pickup some of those Forged Pistons from Dave at Arizonazcar.com 87mm bore and right compression height for L24 rod on L28 crank. see http://arizonazcar.com/piston.html

[Tommo560]

Just gone and had a look at the car and the engineering shop where the pistons where x-rayed says that they are worn and need to be replaced anyways, and they've scored the bore so i'll be boring the motor anyways.

now comes the hard part, how big to bore it and what pistons to use. ofcourse i want to go as big as possible (why the hell not) so i was thinking 88mm is safe from what i have read (i believe that would raise displacement to 2.95 litres?), but then what pistons can i put in that will still keep the high compression ratio? chatted to a few z savvy people around here and they have all said that stock pistons will be fine so what have people used that has worked well for them?

i believe the rods are from an l24 but i dont know for sure, will have to do a bit more investigating but for now work on the assumption that they are l24 rods.

does anyone know how hard it would be to track down an l28DE crank in Aus or is it not really worth all the extra effort and cost and should i just stick with the crank thats in there already?

Thanks,

Tom.

[Mr Camouflage]

An LD28 crank is not really an option for you Tom. It would mean you would have to get different rods and different pistons. Also they are hard to get, and anyone in Aus that is selling one, wants an arm and a leg for it.

If you have friends or rellies in NZ, then they are pretty easy to find and relatively cheap too.

If you go the LD28 crank route, I think you would be building a 3.1 litre stroker engine, and should have a read of these before deciding to:

http://www.geocities.com/inlinestroker/

http://zhome.com/rnt/3.1Cobb/3.1engine.htm

http://zhome.com/rnt/3.1HanveyProject.htm

If you go the standard route, and go one size overbore with appropriate pistons, if you still have the option to go the next size later, if you need to. If you go the max overbore straight away, and ever need a re-bore, you would be looking for a new block.

[Tommo560]

Thats some good advice Mr Camouflage, thankyou.

its turns out the motor is already .04" oversized so i think we will probably go to .06" (87.5mm?). now we just need to find some pistons.

Tom.

[wishihadaz]

If you F54 is still the stock 86mm then get some L24 rods and pickup some of those Forged Pistons from Dave at Arizonazcar.com 87mm bore and right compression height for L24 rod on L28 crank. see http://arizonazcar.com/piston.html

Anybody actually running L24 rods with these pistons in a 2.8L?

I will possibly need to get new pistons and I am contemplating my options.

Thanks

[Robin]

Arizona Z is out of the pistons to match up with the L24 rod. I called him a couple of weeks ago and the re-stock of these is on the back burner for now. Good luck.

[xray]

quick google search...."280zx forged pistons"

http://www.importperformanceparts.net/imports/pek-nissan.html

Scroll down to #16...a bit pricey, but it's a full kit. No 87.5mm bore, but they do have an 88mm bore in a variety of CR. I assume they are for stock rod length and crankshaft stroke

Steve