Results 1 to 10 of 10

Thread: Main bearing clearance NA block

  1. #1
    Forum User Feedback Score 0
    Join Date
    Feb 2013
    Owner Since
    2012

    Location
    California
    Posts
    59
    Thanks
    14
    Thanked 0 Times in 0 Posts

    Main bearing clearance NA block

    I'm putting together a NA block with TT pistons, looking to do a stock 9b TT conversion with NA block (yeah, no extra squirters, no cap stays), looking at the Engine Manual, the standard values: 0.0008 - 0.0020 (0.02 - 0.05mm), I'm getting about 0.0015 at the mains, according to plastigauge, I've read multiple times that is better to aim for 0.0025-0.0030, I'm using ACL Main bearings and King Rod Bearings, crank was polished and turned down to 0.010 undersize, this is a good value (0.0015), considering that I will turbo the engine?

    Also, does it matter if I torque the cap down without setting the thrust first? I'm just checking the clearance before fighting with the thrust washers..




  2. #2
    Forum User Not Verified
    Feedback Score 6 (100%)
    Join Date
    Sep 2010
    Owner Since
    2004

    Location
    Cape Girardeau
    Posts
    4,861
    Thanks
    371
    Thanked 298 Times in 216 Posts
    3 thou is old school thinking, your clearance is better.

    Parting 6 speed
    Pampena 3.5 Stroker, GTX 2867 Gen IIs, AEM Series2, oohnoo SMIC, DN Hardpipes, FIC 1650s, Walbro 525, aermotive fpr, Dejon intake pipes, Tial Q, Koyo Rad, Samco Hoses, Stoptech 332mm fronts, HKS GT4 Coilovers, Spec 4+ LW, JDM 6 Speed, Billet shift forks, Pampena brace

  3. The Following User Says Thank You to Chris@Rvengeperformance For This Useful Post:


  4. #3
    Forum User Feedback Score 0
    Join Date
    Feb 2013
    Owner Since
    2012

    Location
    California
    Posts
    59
    Thanks
    14
    Thanked 0 Times in 0 Posts
    Actually, I got confused about the torque specs (saw the 93+ torque, but that was for the 4 bolt), the 2 bolts have 67 ft.lbs, I was doing 54 ft.lbs, checked again, its just about 0.001-0.0015 at the mains, then I got another problem, after cleaning the plastigauge and putting assembly lube, the crank binds, girdle was aligned correctly, thrust setting in spec....

    I followed the service manual sequence and used 3 steps when torquing the mains, the last 2 bolts (front most 7-8) were binding the crank past 50 ft.lb, checked again the clearance in that one, its still good, I tried with a different sequence, leaving the rear most bolts last (5-6 from sequence) and now it turns easily by hand, something wrong here..?

  5. #4
    Forum User Feedback Score 0
    Join Date
    Sep 2010
    Owner Since

    Posts
    622
    Thanks
    10
    Thanked 26 Times in 25 Posts
    Crank's bent?, very unlikely though as you've just had it turned.
    GTO-TT, PTE 1200's, M20, Emanage Ultimate, OS Geiken R3C,
    TD04-16g`s, Maf-t. 13g`s 12.4@115mph / 16g`s 12.5@117mph.

  6. #5
    Forum User Not Verified
    Feedback Score 6 (100%)
    Join Date
    Sep 2010
    Owner Since
    2004

    Location
    Cape Girardeau
    Posts
    4,861
    Thanks
    371
    Thanked 298 Times in 216 Posts
    make sure the thrusts and all the bearings are installed correctly and you don't have one backwards.

  7. #6
    Forum User Feedback Score 0
    Join Date
    Feb 2013
    Owner Since
    2012

    Location
    California
    Posts
    59
    Thanks
    14
    Thanked 0 Times in 0 Posts
    Checked that before, grooved side down, flats on the girdle, same with the thrusts, grooves out (manual illustration got those backwards), I'm sending the crank to another machine shop, also I think that the bearings got trashed from lots of plastigauging and turning..

  8. #7
    Forum User Feedback Score 0
    Join Date
    Feb 2013
    Owner Since
    2012

    Location
    California
    Posts
    59
    Thanks
    14
    Thanked 0 Times in 0 Posts
    Well, it was the main journal, it was about 1 thou on the tight side, shortblock is done, ring gaps checked, crank endplay is good, rod clearance good, now its hard to turn but thats my new rings

  9. #8
    Forum User Feedback Score 0
    Join Date
    Feb 2013
    Owner Since
    2012

    Location
    California
    Posts
    59
    Thanks
    14
    Thanked 0 Times in 0 Posts
    The car in this post is still running good, I got 16-19psi @ hot idle, sometimes after a hard run, it gets down to 12psi, low pressure light never blinkend.

    Thing is..
    Got another car for a rebuild, 93 3000gt with a spun bearing, the crank was turned down to 20/30 and was straight (rods are trashed), mine didn't spun a bearing so I didn't try to drill the oil galley plugs, just a thorough cleaning with solvent and compressed air, now.. I can't find any shop that would touch the crank balls so I can't clean the sludge traps, I've seen the importance to do that on cranks with spun bearings, that means that unless I remove the galleys crank is junk?

  10. #9
    Forum User Not Verified Feedback Score 0
    Join Date
    Feb 2014
    Owner Since
    2015

    Location
    St Louis
    Posts
    325
    Thanks
    29
    Thanked 5 Times in 4 Posts
    Remove them and clean it, then insert set screws.




    Sent from my iPhone 6s+ using Tapatalk

  11. The Following 2 Users Say Thank You to murphys_law For This Useful Post:


  12. #10
    Forum User Feedback Score 0
    Join Date
    Feb 2013
    Owner Since
    2012

    Location
    California
    Posts
    59
    Thanks
    14
    Thanked 0 Times in 0 Posts
    No one wants to touch those galley plugs, actually I got that video on my phone when I asked about the drilling.

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •  
The 3000GT/Stealth/GTO Web History Project
3000gt.com
3000GT / Stealth International WWWboard Archive
Jim's (RED3KGT) Reststop
3000GT/Stealth/GTO Information and Resources
Team 3S
3000GT / Stealth / GTO Information
daveblack.net
3000GT/Stealth/GTO Clubs and Groups
Michigan 3S
MInnesota 3S
Wisconsin 3S
Iowa, Nebraska, Kansas 3S
North California 3000GT/Stealth
United Society of 3S Owners
3000GT/Stealth/GTO Forums
3000GT/Stealth International
3000GT/Stealth/GTO Event Pages
3S National Gathering
East Coast Gathering
Upper Mid-West Gathering
Blue Ridge Gathering