Building A Forged Rb25

[jangles]

but then we wouldnt get any awesome threads

[GTScotT]

race ready 500hp small block, yep ill take the one in blue

Do these come in men's?

[XxNinjaxX]

sounds to me like you just want to be able to tell people you have a forged engine and that you built it yourself.....

as far as im concerned a standard rb25 thats been serviced and tuned well should hit 200000ks no worries, i'd also trust an unopened used engine more than a first time forged item some guy built in his shed.

your basically spending 5k+ for bragging rights?

lol. im not building this motor for "bragging rights" im doing it because i feel im some what capable of handling the task and the learning experience. fyi my current engine is on 187,800km's, not too far off 200,000 probally been thrashed 90% of its life cause the syncro's are pretty much gone and its got mild piston slap when cold. also my "shed" happens to be a nissan workshop.

[Rolls]

I get exactly where you are coming from but you are pretty much guaranteed to fail which would be a pitty considering you would just be throwing your money down the drain.

I would highly recommend just getting a replacement donk, Nissan have built 1000's of these motors and I could pretty much put my hand on my heart and say they are the best at doing it. They may not be as strong as a forged motor but with the turbo and power you are after they will take any punishment you can throw at them! Building a motor yourself no matter what parts you use won't be a improvement it WILL be a step backwards.

I'm in Perth as well and have access to a very cheap NEO motor with low kms and not abused that would be perfect for what you need.

PM me if you are interested.

Cheers

Simon

yeah and you will still have to pay someone to torque the block with a torque plate and do the homing for you, then you'll have to measure everything VERY precisely to get the clearances right, checking weights etc, this isn't something you will get right with backyard tools especially the first time, my mate tried rebuilding gemini motors to get some practice (same idea as you) and they all either smoked from poor clearances or they rattled loose in a few weeks doing big ends etc, ok when you only spent $300 on a gemini motor, not ok when you spent $5k on brand name RB parts.

it sounds bad but I can almost guarantee you will butcher your first motor due to a simple mistake or poor tools

[zebra]

Do these come in men's?

Lol Well you could always buy a 815cube 1800hp John Kaase crate big block.

Cheaper than the Tomei RB28 Crate motor too lol

[marksuxass]

lol. im not building this motor for "bragging rights" im doing it because i feel im some what capable of handling the task and the learning experience. fyi my current engine is on 187,800km's, not too far off 200,000 probally been thrashed 90% of its life cause the syncro's are pretty much gone and its got mild piston slap when cold. also my "shed" happens to be a nissan workshop.

a 6 million dollar workshop recognised all over the country, with a floor scrubber that costs more then most peoples cars do!!!

[XxNinjaxX]

yeah and you will still have to pay someone to torque the block with a torque plate and do the homing for you, then you'll have to measure everything VERY precisely to get the clearances right, checking weights etc, this isn't something you will get right with backyard tools especially the first time, my mate tried rebuilding gemini motors to get some practice (same idea as you) and they all either smoked from poor clearances or they rattled loose in a few weeks doing big ends etc, ok when you only spent $300 on a gemini motor, not ok when you spent $5k on brand name RB parts.

it sounds bad but I can almost guarantee you will butcher your first motor due to a simple mistake or poor tools

we'l see, im not taking this build lightly. im well aware that everything must be precise and i plan on taking my time on this motor insuring everything is 100% and every bolt is torqued to specification. keep in mind i dont require the motor just yet as my current engine seems happy enough at the moment despite the knock when cold, im sure it will last until the new motor is complete.

Measuring will be pretty minimal as i have all specifications and the main bearing grades are stamped on the bottom of the block, big end's on the rods and piston grades stamped on the top of the block. shouldnt be too much of a problem

Edited November 11, 2010 by XxNinjaxX

[Rolls]

you do realise to do honing etc you need a special machine?

[r33_racer]

lol!

[FineLine]

lol!

What more can you say.

[zebra]

you do realise to do honing etc you need a special machine?

Really????, I thought just a honing tool and a drill is all that is needed

Seems to work for most builds

[Rolls]

er I meant boring lol

assuming the block needs it to match your pistons and get clearances right.

Edited November 11, 2010 by Rolls

[r33_racer]

You require alot of experience inorder to hand hone with a drill. Its very easy to create tapers and incorrect cross hatch angles. For a quick roughen up after a glazed bore its okay. But it was a real art back in the day before automated machines.

I believe the latest machines are virtually totally computer controlled based off load sensors built into the head, it can build a graphic drawing of the bores shape and will automatically take out, out of round and tapered sections. You end up with a perfect bore, the exact cross hatch angle and almost no human involvement in the process. When its done you just check it for roudness and piston to bore clearance. I guess the less human interference there is, the less risk of stuff ups.

I think the first process was with some diamond cutting stones that machine the bore close to size, then finer stones for final finish then some nylon pads that give the plateau finish. Quite amazing but no doubt expensive.

[zebra]

You require alot of experience inorder to hand hone with a drill. Its very easy to create tapers and incorrect cross hatch angles. For a quick roughen up after a glazed bore its okay. But it was a real art back in the day before automated machines.

I believe the latest machines are virtually totally computer controlled based off load sensors built into the head, it can build a graphic drawing of the bores shape and will automatically take out, out of round and tapered sections. You end up with a perfect bore, the exact cross hatch angle and almost no human involvement in the process. When its done you just check it for roudness and piston to bore clearance. I guess the less human interference there is, the less risk of stuff ups.

I think the first process was with some diamond cutting stones that machine the bore close to size, then finer stones for final finish then some nylon pads that give the plateau finish. Quite amazing but no doubt expensive.

Ive seen a couple of those machines in action, impressive stuff, but yes very expensive.

But yeah, I wouldnt be trusting myself on a freshly bored bore with a hand help hone, unless it was just for a factory style freshen up. its very easy to take too much meat out of the bores and have crap clearances

[Rolls]

I would just pay the money for someone who can use a CNC style boring/honing machine along with torquing up the block correctly, too much guess work with a human I mean you want it to be better than stock don't you?

[zebra]

yeah for 300ish bucks its not really worth doing it yourself.

Everything else I do though (deburring oil galleries/returns, cleaning the casting dags out of the ports etc)

real port work I would leave to professionals as its very easy to go backwards.

[r33_racer]

I would just pay the money for someone who can use a CNC style boring/honing machine along with torquing up the block correctly, too much guess work with a human I mean you want it to be better than stock don't you?

Yeh exactly. That is the best way.

Its amazing just how advanced some machinery is these days.

Soon enough it will be one machine that bores, hones and decks the block. Along with almost anything else you would need to do...The only process I couldnt see it doing would be tunnel boring.

[Rolls]

They can CNC an entire engine block out of billet these days with those new 10 axis CNC machines so I am sure that is possible, not that you would do it because its so expensive but it can be done.

Edited November 12, 2010 by Rolls

[d1_drifter]

Build a 25/30.

[XxNinjaxX]

block is standard bore measured roughly between 86.00>86.05 and all the honing has been done same with the head recon.