Rb25 Stock Bore?

[zac320]

Hey guys I have 100000k stock block. Bent rods(hydrolock) I have found a really good deal on rb26 forged rods and cp pistons. They are stock 86mm size. Whats the possibility of the bore still being good? I've found a cheap rb26 crank to go with the rods and pistons aswell

[Dose Pipe Sutututu]

RB25 and RB26 both utilise a 86mm bore.

Depends, if the conrod only bent slightly and didn't snap (pray it didn't), smashing into bore.

[zac320]

conrods didnt snap. What im asking is can i get away with using the stock block without an overbore as ive found some really cheap stock size(86mm forged rods and pistons)

[JonnoHR31]

Depends how much damage you've done, you have to inspect it and see. No one on a forum is going to be able to tell you without looking at it.

[zac320]

Okay. Well even its mashed, normally would a 100000k rb25 bore be fine to throw new pistons in it? I know its best to ovebore, but im getting the rods and pistons for a steal

[JonnoHR31]

If the bores are fine then yes, normally you can just hone them and put standard sized (86mm) pistons in. You know 26 pistons will usually give you a lower compression ratio than standard 25 right?

It sounds like your best option could be simply sourcing a good complete stocker bottom end and throwing your head on it. Assuming you don't need a built motor?

[zac320]

I thought if I go 26 crank aswell it won't?

Dnt need a built motor but it's either the forged rods and pistons or re ring the pistons that r in it and new bearings. I know it will be cheaper to get a new motor but I'd like to learn how to do all this

Edited September 25, 2012 by zac320

[zac320]

Hey guys the local mechanic has convinced me to just put a new motor in. So I'm chasing a rb25 bottom end. No need for head or any other accessories. Just block to sump. It needs to be in good condition.

Cheaper the better especially if ur out of Vic as I'll have to freight it

[zac320]

I have the bottom end here and I'm struggling to source a bottom end for cheap so. I'm thinking acid dip and hone block and clean up pistons and basic rebuild.

Bearings mains and rod $200

OEM rings $190

Nissan gasket kit $200

Rb26 rods $75 ( second hand from friend)

[LANDSCRIBBLE]

do it dude. dont listen to that little goblin on one of your shoulders telling you its not worth it.. can i buy the rb26 rods if you decide not to?

[zac320]

I am going to do it. Took it to the Best local engine builder around and he doesn't want to do half the things, eg install rings on pistons but I install pistons. As he doesn't want to be liable if anything f**ks up. But he said I can take me engine into his workshop and do it there and ask for his advice which will be a great learning experience for me.

[LANDSCRIBBLE]

thats pretty cool, hes gonna charge you for doing that is he?

[zac320]

Didn't sound like it. Of course for hot dipping block and pistons as its his time and machine

[LANDSCRIBBLE]

im in your exact shoes.

it was option 1: buy 2nd hand unknown condition motor from someone.

or what i chose, option 2: rebuild, refresh and toughen up ("toughen up" being used lightly) my existing motor (ACL bearings, ross tuff harmonic balancer, crank oil drive thingo, ARP headstuds etc etc).

i think i would be kicking myself if i started getting huge blow-by after 12 months of getting a 2nd hand motor.

[zac320]

He much that cost you scribble?