R33 Pistons

[StevenCJR31]

hi, hope it hasnt been covered before (cowers) simple question, can r33 rb25detpistons be used with a r34 neo head? ive noticed that the r34 pistons have valve reliefs so im bit concerned about piston to valve clearence and an increase in compression? thoughts? comments ? (no nasty ones please)

[GTSBoy]

No, they cannot. Neo head has 10cc less volume in it. R33 pistons + Neo head = BIG COMPRESSION.

[StevenCJR31]

thanks for the reply gtsboy. is it just the compression thats an issue ? or piston to valve clearence as well?

[Simon-S14]

theres no difference on the top of the piston in terms of valve clearance in comparison to a neo piston

[GTSBoy]

I'll take Simon's word with respect to the actual clearances.

The piston height (above the gudgeon) is also different. Neos use RB26 rods, which are a different length to older 25 rods (I'm pretty sure....).

[StevenCJR31]

thanks guys, youve given me a bit to think about

. . picked up a 34det neo dirt cheap and (also havea 33 bottom end) it has a damaged #3 cylinder and just working out my options for using what i got

it had swallowed a small bolt which made it run on 5 and the guy who owned the car drove it for three months like that. .

[GTSBoy]

Use the Neo bottom end. Buy pistons. Sell R33 stuff to someone else. Profit.

[jet_r31]

No, they cannot. Neo head has 10cc less volume in it. R33 pistons + Neo head = BIG COMPRESSION.

out of interest, how much roughly?

cheers

darren

[StevenCJR31]

Use the Neo bottom end. Buy pistons. Sell R33 stuff to someone else. Profit.

wildo that , originally was told number 3 was dead and was (possible detonation damage) cos the owner was running it on 91 ulp

owner needs shooting as this motor still has factory hone marks on the bores

if anyone here has some low k (stock size) 34 pistons in good condition please pm me as the internals of this motor are in otherwise mint condition and wouldnt take much to get it going again

[kitto]

Neos use RB26 rods, which are a different length to older 25 rods (I'm pretty sure....).

Nope.

RB25 non NEO and NEO and RB26 share the same con rod length.

NEO uses the same 'stronger' rod as the 26 though.

OP - I have a full set of 34 NEO pistons and rods in excellent nic for sale, unless Simon still wants them?

[StevenCJR31]

nah simon doesnt want them :-p

kitto can you pm me a price for them please?

[Simon-S14]

kitto beat me to it.

neo rods same length as non neo. As is the pin height on the pistons. in fact the neo piston and non neo piston share all the same dimensions but the neo piston has more cooling passages under it where oil is squirted. its probably lighter also but need to weigh some to confirm.

the difference in compression is all in the head.

[GTSBoy]

You know I've probably been told that before (about the rods and piston heights) but some stuff just doesn't sink in. sigh.

[brad 110]

I have several neo sets of rods and pistons if you still require some

[StevenCJR31]

^^ thankyou for that brad but im getting a set off Kitto

[StevenCJR31]

You know I've probably been told that before (about the rods and piston heights) but some stuff just doesn't sink in. sigh.

its all good gtsboy

we still luvs ya!