Page 1 of 5 123 ... LastLast
Results 1 to 10 of 46

Thread: Variations in 4BD1 motors

  1. #1
    Bearman's Avatar
    Bearman is offline TopicToaster Gold Subscriber
    Join Date
    Jun 2006
    Location
    Hay Point
    Posts
    4,043
    Total Downloaded
    0

    Smile Variations in 4BD1 motors

    I recently replaced my 4BD1 with a late build 1995 model motor and wonder if anyone can tell me whether the later model motor has piston sprayers and the turbo crankshaft (tufftrided). It has the later style injectors (pencil type) but everything else on the outside appears to be the same. I am told that it will have turbo pistons but am unsure about the piston sprayers and crankshaft. I should have dropped the sump before I fitted it and had a look

  2. #2
    Join Date
    Aug 2006
    Location
    WA
    Posts
    13,786
    Total Downloaded
    0
    AFAIK, late model 4BD1s only got the turbo pistons, not the crank or the oil-spray.

    The Turbo engiones didn't ever get the late model ("pencil type") injectors, according to my manual.

  3. #3
    130 ambulance Guest
    Hi Brian

    I just finished tearing down a 1990 4bd1-T that I bought for spairs It had two big holes in the block one on either side? I did notice however it had turbo pistons, and an oil spray on each cylinder, Not sure if this helps. My $0.02 worth.

    Cheers
    Justin

  4. #4
    Join Date
    Aug 2006
    Location
    WA
    Posts
    13,786
    Total Downloaded
    0
    Forgot to add, that late model engines (both NA and T) had a different cam.

    So - with the higher pressure injectors and different cam, how does it drive compared to the old one?

  5. #5
    Join Date
    Feb 2008
    Location
    Northern Windowlickersville WA
    Posts
    3,403
    Total Downloaded
    0
    Assuming you have a LR spec engine, pistons are different for turbo and non turbo applications and these are NOT the same as Isuzu spec.
    Piston height is 98.1mm for both and both have square combustion bowls, however non turbo bowl size is 50.95mm and turbo is 51.05mm.
    Be careful as LR have a different spec head for the non turbo.
    I only list a crank for non turbo spec, plus I think this is an Isuzu spec anyway but i could be wrong. All my listings are based on Isuzu with references to LR use.

  6. #6
    Join Date
    Jun 2006
    Location
    Bundaberg Qld.
    Posts
    632
    Total Downloaded
    0
    I might have got this confused but the LR spec engines had different pistons to standard isuzu. So what were the piston in the standard isuzu engines like?
    84' 120" ute - 3.9 isuzu.

  7. #7
    Bearman's Avatar
    Bearman is offline TopicToaster Gold Subscriber
    Join Date
    Jun 2006
    Location
    Hay Point
    Posts
    4,043
    Total Downloaded
    0
    It drives very good compared to my old motor which was getting a bit low on compression. It was a 1995 truck motor not a LR spec motor. Thanks for the info. Brian

  8. #8
    Join Date
    Sep 2007
    Location
    Kiwiland
    Posts
    7,246
    Total Downloaded
    0
    I have a genuine Isuzu piston here which I suspect is for an early 4BD1 or 6BD1. It is taller than my turbo pistons and doesn't have the steel inserts.

    If anyone wants it, let me know. It's brand new and I have enough paper weights.

  9. #9
    Join Date
    Feb 2008
    Location
    Northern Windowlickersville WA
    Posts
    3,403
    Total Downloaded
    0
    Quote Originally Posted by Dougal View Post
    I have a genuine Isuzu piston here which I suspect is for an early 4BD1 or 6BD1. It is taller than my turbo pistons and doesn't have the steel inserts.

    If anyone wants it, let me know. It's brand new and I have enough paper weights.
    What you have is a NPR/NPS truck spec piston and is not suitable for LR use.

  10. #10
    Join Date
    Feb 2008
    Location
    Northern Windowlickersville WA
    Posts
    3,403
    Total Downloaded
    0
    Quote Originally Posted by Bearman View Post
    It drives very good compared to my old motor which was getting a bit low on compression. It was a 1995 truck motor not a LR spec motor. Thanks for the info. Brian
    The rev range of the truck spec is lower than the LR, but torque curve will also be lower.
    The pistons also weight more in the truck and have an overall skirt to crown height of 104mm.

    As before, there are differences in the two variants. Changing injectors in 99.9% of cases necesitates injector pump change or modification.

    You are by far better off with the LR spec than truck.

Page 1 of 5 123 ... LastLast

Bookmarks

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
  •  
Search AULRO.com ONLY!
Search All the Web!