The Graded Bearing Debate ? Please Help Answer

[The Dan]

Why not? surely there must be a shitload of RB engines out there that are running reground cranks?

Yeah for sure there are a shitload around. I have rebuilt many engines with ground cranks but you NEVER grind a crank unless you have to. You don't just grind them to get the crank to a specific size/clearance. Usually they are ground when the crank is bent after an engine failure but can also be due to journal damage in some cases.

really? how deep is the nitriding, and how much is ground off for oversize bearings?

2 thou deep is usually the case for most nitriding but it can go deeper. For every 2thou deep you go, the journal size grows by approx 0.00005-0.0001. 10 thou is is what is taken off for a grind

[Simon-S14]

could'nt you have it re-nitrided

[StevenCJR31]

could'nt you have it re-nitrided

^ Thats what i was gonna say,im sure on top of re nitriding there is also cryogenic treatment that will strengthen the crank far beyond factory specs,new cranks are fricken expensive and then you have to piss fart around getting bearings for them? . . pass

[Beer Baron]

new cranks are not that expensive <$1500. when doing a build with top $ parts (pistons rods etc) it's often worth buying a new crank for piece of mind. no point having all good gear with a bent crank...

[The Dan]

^ Thats what i was gonna say,im sure on top of re nitriding there is also cryogenic treatment that will strengthen the crank far beyond factory specs,new cranks are fricken expensive and then you have to piss fart around getting bearings for them? . . pass

you're worried about 'piss farting' around with getting bearings (which are available in 5 minutes at most good auto suppliers or your engineer) but you don't seem to think Nitriding and cryo treating a crankshaft isn't just as much of a stuff around?

Can take them up to 2 weeks to nitride and cryo a crankshaft and even then you have to get it checked and rebalanced after the treatment is done as you are changing the structure of the metal and adding meterial.

Keep it simple - old crank/new crank who gives a shit, new ACL race series bearings, build engine.......skids - no piss farting around at all

[Simon-S14]

i like the skids part

[ZimNismoBoy]

Interesting information put there.

But picture this, you live in a third world country where the engineering standards have never been good, they cant even skim a head properly let alone grind/straighten a crank shaft, and then there is still boring the block and honing, which the honing part i can do but boring cannot be done they are useless, and to make matters worse tunnel boring or line boring block crank journals and head cam journals has been tested here and never comes back good enough to build a high performance engine.

So essentially this is ,my build

New block Factory spec N1

New pistons Factory Spec N1 with N1 rings

New rods Tomei cheaper than factory Rb26 Rods

A set of Acl bearings mains and Big ends X size with 0.0001" extra clearance so the crank can flex a bit

New set of oil piston sprayers

And the rest i already have

Ati damper pulley

Tomei Baffle sump

Tomei high flow oil pump

Tomei head restrictor 1.2mm

Ported and polished head

Viton Valve stem seals

Nismo twin plate clutch with flywheel

New head bolts from Nissan

Greddy 264 Degree cams intake and exhaust with vernier pulleys

Magnetic drain plug and magnetic Oil filters to be safe on the new build

i dunno if there is anything else i missed out but never the less im not aiming for Big hp, im just building a good reliable engine.

So if im getting factory spec block and factory spec pistons to suit it should be good to go ?

[The Dan]

Interesting information put there.

But picture this, you live in a third world country where the engineering standards have never been good, they cant even skim a head properly let alone grind/straighten a crank shaft, and then there is still boring the block and honing, which the honing part i can do but boring cannot be done they are useless, and to make matters worse tunnel boring or line boring block crank journals and head cam journals has been tested here and never comes back good enough to build a high performance engine.

So essentially this is ,my build

New block Factory spec N1

New pistons Factory Spec N1 with N1 rings

New rods Tomei cheaper than factory Rb26 Rods

A set of Acl bearings mains and Big ends X size with 0.0001" extra clearance so the crank can flex a bit

New set of oil piston sprayers

And the rest i already have

Ati damper pulley

Tomei Baffle sump

Tomei high flow oil pump

Tomei head restrictor 1.2mm

Ported and polished head

Viton Valve stem seals

Nismo twin plate clutch with flywheel

New head bolts from Nissan

Greddy 264 Degree cams intake and exhaust with vernier pulleys

Magnetic drain plug and magnetic Oil filters to be safe on the new build

i dunno if there is anything else i missed out but never the less im not aiming for Big hp, im just building a good reliable engine.

So if im getting factory spec block and factory spec pistons to suit it should be good to go ?

You email engine builder in a 1st world country and say 'hey, build me this' and wait for an engine to arrive in your letterbox

[wolverine]

You email engine builder in a 1st world country and say 'hey, build me this' and wait for an engine to arrive in your letterbox

Don't make me revive that thread/s.

[The Dan]

Don't make me revive that thread/s.

?

I'm merely pointing out to him that it's often not worth the risk to build it locally if the standard is so poor.

There are plenty of good engine builders in Australia and engineering standards are extremely high as long as you use Chilton Engineering 07 33911672

[wolverine]

I'm sure it was around 12mths ago this same advice was given.

[ZimNismoBoy]

Look i understand that you guys want me to get a engine built by a good builder, but im tight on budget and have two hands half a brain and two eyes.

i also have the ability to learn and have learnt alot since we last spoke .

I have also built two Rb 20 engines and one 4age engine and have done this with some fair amount of investigation and downloading of clearances etc.

I just wondered why i was told to use a standard bearing size on all the builds i have done so far and needed some clarification.

So i dont want to pay some one else to build an engine i want to build.

We have been down this road and i dont want to even start the topic again either.

Lets put it this way ... im excited to check measure and build an engine as nice as a rb26dett.

And it wont be the last engine i build infact its the start of many more to come i want to build my next gtr32 engine as well to a serious spec.

And then if im going to be boring blocks and needing engineering done i will get a company in Australia to build and machine for me then import it back and run a beast of a car.

But at present i want to build this engine for this car .... note build this engine and this car being the most important words.

Its an aspiration, please dont flame me and put me down i think enough of that has happened, i have often walked away from the forum feeling like an idiot.

So to cut out the machine work, a new block, new crank and new rods will be purchased and ring gaps checked, bearing clearances checked and tested etc.

Then the motor will be assembled and run .

I need guidance not insults and being told where to send my sub assembly etc etc.

I even thought if fitting a Nitto crank 73.7mm crank with rods and pistons and even considered a sub assembly built by a company chosen by Nitto performance.

But there is not satisfaction there, especially for the guys who love building engines their pride is in building checking and assembling a complete motor and then saying, i did that i assembled it and i made it run .

Please dont take offence.... no one should take offence.

Im almost ready to order the parts, then assembly takes place.

[The Dan]

No offense taken by anyone I'm sure, but please understand that no matter how many engines I have built, if my engineer did anything short of a perfect job in his department, then I would not still be in business.

With you saying that getting the engineering processes done well locally is extremely hard, I would say you are missing one of the most important parts of the puzzle.

No one here would be able to spare the time to teach you how to engineer and balance your engine, then assemble it (although you seem to already have that part sorted - it's only a small part in the whole process....the assembly)

Good luck with your build though, the saying is true - the poor man pays twice

[The Dan]

As long as your piston to bore clearances are good, pin to little end clearance is good and the clearances for all the bearings are done, I'm sure you will be absolutely fine. Just make sure you check it all and don't cut corners

[Sub Boy32]

Confucius say "Man who cuts corners, ends up with bend scissors"

[Bl4cK32]

Op is in Africa...according to the wiki "RB30E was found in R31 Skylines and VL Commodores in Australia as well as in South African R31 Skylines "

Now lets throw that spanner into his works

[StevenCJR31]

new cranks are not that expensive <$1500. when doing a build with top $ parts (pistons rods etc) it's often worth buying a new crank for piece of mind. no point having all good gear with a bent crank...

$1500 not expensive?please tell me where you work,i want a job on your salary!:thumbsup:Ps even new cranks CAN be slightly bent

[Bl4cK32]

$1500 not expensive, as BB said

when doing a build with top $ parts

[StevenCJR31]

$1500 not expensive, as BB said

[/quote

Def need a job with you guys!

[Bl4cK32]

$1500 not expensive, as BB said

Def need a job with you guys!

Im not saying that $1500 isnt much for me personally, but some out there who spend the big $$ on parts for rebuilds then a new crank is the least of their problems. Go look in the for sale section and theres a few threads with parts in there like $13K for a block or $11K for a head...add each part of that into a whole setup and the $1500 for a crank suddenly seems insignificant.