new crank bearings

Discussion in 'Technical' started by minivan, Jul 25, 2006.

  1. minivan

    minivan Guinea Pig Test Monkey

    theyre not.. what it is.. is size plus grade (which varies 1-2 thou between jounals)

    this can only really apply as far as i can see to the crank off the factory floor.. its worn now.. i just got ACL standard size bearings.. as the machine shop said i need standard size bearing.. pretty sure he said this to you too.. and i double checked clearances with acl flexiguage.. and its all within spec (no not withing 10th of a thou.. but im not anal about such things..)

    engine is back together method.. but im in the middle of painting my car now.. engine would have been running by the end of this week if i didnt haveta drop the engine work and paint the bloody thing

    if all he does is build race/drag engines.. why would he build yours.. he can no longer say that??

     
  2. Claymen

    Claymen Active Member

    So what did you have done?

    Did you get all the crank and where the bearings altered to be all the same size and also go up a grade for the bearings?
     
  3. tom@pzp

    tom@pzp www.pzp.com.au

    crank was just measured and journals polished just to make sure all was good.... so no machining (still standard size bearings required).

    I checked the ACL website and am going for the Race Series Bearings in Standard size... this should be fine.... (i hope)

    I'm sick of f'ing around... just need a car :)

     
  4. Claymen

    Claymen Active Member

    Are the race series stronger?

    Got a quick link, im at work so dont have time to browse the ACL site looking

     
  5. tom@pzp

    tom@pzp www.pzp.com.au

    apparently yes they are....

    link: http://www.aclperformance.com.au/NissanVG30DETTBearings.htm

    just got off the phone to my mate... $158 for rod and mains! booyah!

     
  6. Claymen

    Claymen Active Member

    Nice

    Im seriously contemplating pulling my engine and having a tinker hey.

    My only real issue is that I would need help pulling the engine and putting it back in. Im happy to go buy an engine stand but being this would be the first engine pull ive done i'd love help. Maybe have to give you boys a ring sometime with the offer of beer.... ;)

     
  7. method

    method Active Member

    mine isn't a race engine, obviously. It is more of a one off referral job :) He also isn't 'building' my engine, he is doing all of my machine work and may do some assembly, again which is the obvious thing to do if you do the machine work on certain parts. Machining is machining, whether it be for a race engine or not he isn't 'building' my entire engine.

     
  8. ZWEETT

    ZWEETT Active Member

    ha har maybe

    Ill just come and do more burn outs eveyr night of the week at like 2am out side your house to help modivate you to get your car rolling so you can come do the same to me :) HAHAHAHA woooosh !
     
  9. tom@pzp

    tom@pzp www.pzp.com.au

    hahahahha yeah no probs mate....

    i like the drag strips out the front!


     
  10. Baron

    Baron Active Member

    I really don't think people understand the rational behind Nissans use of different grade bearings during the build of one of the finest tolerance mass produced engines around.
    The crankshafts ARE mass produced. Electronically measured and matched to different "grade" bearings to maintain the finest tolerance.
    Rebuilders don't have that option.
    When we decided mine needed grinding, we purchased the new bearings, fitted them to the rods, measured with micrometer and dial indicator and ground each journal to suit each bearing. Incredibly fine tolerances . The same was done for each individual bore and piston. Expensive but accurate. Nothing but praise for Coorparoo Engineering & Performance.
    I cringe and squirm in my seat when i read some of these threads:eek:
     
  11. tom@pzp

    tom@pzp www.pzp.com.au

    being a perfect suited bearing for the stock coded '3' bearing and only 0.01mm between the stock '2' bearing; i really don't think it's going to make sweet fa of a difference...

    go cringe buddy :D

     
  12. method

    method Active Member

    If they did such a good job, then why the bolt on counterweight? lmao.
    Other engines can have the same or better matched tolerences without having different grades etc, I am not going to be biased towards the Z just because I own one and enjoy it so much. Each to their own.

     
  13. minivan

    minivan Guinea Pig Test Monkey

    hahaha.. yeah well within a few thousand ks those tolerances are out the bloody window..

    cringe blah.. hahaha spend good money for nothing
     
  14. Baron

    Baron Active Member

    By definition (Oil) Pressure is restriction to flow. Reduce the restriction at the bearings and all the other places that need the oil (top end/piston coolers etc) are also dis-effected. Still think it's critical to get it right.:)
     
  15. Mr G

    Mr G Active Member

    We often mock Nissan

    which is fair enough sometimes (ie. the cost of going to them for replacement parts for the Z is a frikkin joke), but they used different grade bearings for a good reason...
     
  16. tom@pzp

    tom@pzp www.pzp.com.au

    Thanks for that lovely insight Mr G with no reason behind it :)

     
  17. Mr G

    Mr G Active Member

    ?

    Oooh, SNAP! :)

    Better matching --> finer tolerance --> less restriction --> better flow --> more efficient engine!

    Each to their own though!
     
  18. tom@pzp

    tom@pzp www.pzp.com.au

    LMFAO :D

    Gotta love that saying

     
  19. scump

    scump John Dorian

    wow man ur work never stops, mechanic in a previous life?

    lol p.s. thats possibly best quote ive head in a long time...

    "and dont forget to lube up your shaft very well else the friction will destroy the fun?
     
  20. method

    method Active Member

    I'm sure other manufacturers have achieved the same, if not better results without using graded bearings. Saying the the tolerances would be out after a few thousand k's is pretty lame, unless you plan on using olive oil in your engine. If that was the case, all of our engines would wear out by 100,000k's. They will 'bed in' but it wont alter the tolerances that much. I think ash pulled down a Z after a few thousand K's and everything was exactly the same as how he assembled it. And people on tt.net go on and on about getting the tolerances as close to perfect as you can because 'Nissan went to all that trouble to match to 0.001mm' so if you are going to be anal about bearing grades, at least do it right although I still believe an engine freshly built with close to perfect tolerances and clearances will last, but who knows how long as there are heaps of other factors involved when considering it.

     

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