Oversized Pistons

[handyandy]

Hi guys, i took my rb30e block to a machinest and was told that it would need oversized pistons.

He said that it would be better to get a block which only need

a hone and could still use standard sized pistons.

Saying that when you go oversized the engine will start to use more oil after the first few thousand kms.

"If you want a reliable engine don't go o/s pistons. It's ok on a V8 but not a turbo engine".\

To me this sounds like a load of shit.

I asked my mate who is a mechanic and he said it will be fine, they make o/s pistons for a reason.

The engine will be a 26/30 and put out about 300rwkw.

Being a cabinetmaker i have little idea on these things.

What do you guys think??

[R31Nismoid]

change mechanic if thats the kinda rubbish advice coming out

if you want a 26/30, its Racepace or nothing IMO

but for 300rwkw, its overkill in the $$ stakes

[AD4M]

dude if your mechanic is saying your in need of oversized pistons on a rb30 he is most probably correct... i recently purchased CP 20thou oversized pistons for mine, but the motor had been rebuilt befor so my bore is already to large for these pistons.

if you dont want oversized then get a qoute from nissan on a brand spanker new block, i seem to remember they are about $400

[handyandy]

sweet, thanks guys thats what i was thinking.

R31Nismoid... yeah, it's something a little different. and i have the time:)

Building it myself with help from a mate and cubes pdf file.

IMPUL R32-R...cheers, if this block doesn't work out i'll give them a call.

Just need to find a decent machinest now.

Thanks guys:)

[1400r]

rb26 n1 block 3.5k from nissan aust

1.5k from signal japan

[Duncan]

1.5k from signal japan

what is 1.5k from signal Japan? Brand new RB26 blocks? If so I'll take 5 what are their contact details? Also Nissan does not have any rb26 blocks, standard, n1 or gt.

There is nothing wrong with oversize pistons you just need to get the block bored to suit. Even if it was already 20 thou over there is no problem going to 40 thou. Be careful with any larger than that though.

They can also sleeve individual cylinders if you only have a problem in one or 2 of them.

You really need a machine shop that knows what they are talking about though.

[wrxhoon]

I'll take 5 as well Duncan at that price, you would be very lucky to find any RB26 blocks anywhere .

Of course there is nothing wrong with oversize pistons as long as the bore is machined to suit with the correct piston to bore clearance.

Even Nissan sell +.5mm(86.5mm) and +1 mm(87mm) pistons .

[handyandy]

i've been calling round to find a machinest.

One has quoted $2000 for the block prep.

I've read that some of the guys are getting their blocks acid dipped, crack tested, honed etc for $200.

Boreing my block out cant cost that much, can it?

[wrxhoon]

i've been calling round to find a machinest.

One has quoted $2000 for the block prep.

I've read that some of the guys are getting their blocks acid dipped, crack tested, honed etc for $200.

Boreing my block out cant cost that much, can it?

Cost will depend on what needs to be done and what you want done but $2000 is a little over the top .

I would want it gold plated for that .

For $20 per cyl( $120 for RB26) you can have it bored and honed, if you want it done with a torque plate add another $80-$100 acid dipping will set you back another $40 and crack testing another $40-$50, deck it and it will cost you another $30-40. Don't forget if you put it in acid you must change all the welsh plugs !! As you can see that doesn't add up anywhere near $2k.

[handyandy]

cheers, it's hard to trust people these days.