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  1. #1
    casual poster andrew_v's Avatar
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    Default Neoprene and Rope rear main seals on holden v8's

    Its always been my understanding that only really old holden v8's used the neoprene type rear main seals, and every other later type uses a 2 piece rope rear main seal.

    Firstly, is this correct and secondly, what is the difference? Is the neoprene type a 1 piece seal? Can you convert from rope to neoprene and vice versa? Cheers in advance to anyone who can answer this for me.
    Jack of all trades, master of none!!!

  2. #2
    HDTCQ mechanic #2 skidmarx's Avatar
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    im not 100%, but a good mate of mine recons u can get a neo seal for the rope seal cranks, he recons hes done 100's of them..... and hes never led me astray before
    100% pimp factor, long live the VK
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  3. #3
    been here .......too long Smitty2's Avatar
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    Quote Originally Posted by andrew_v View Post
    Its always been my understanding that only really old holden v8's used the neoprene type rear main seals, and every other later type uses a 2 piece rope rear main seal.
    ...correct

    Quote Originally Posted by andrew_v View Post

    and secondly, what is the difference? Is the neoprene type a 1 piece seal?
    ...no, 2 piece, top and bottom
    and they have to be glued/sealed together

    Quote Originally Posted by andrew_v View Post
    Can you convert from rope to neoprene and vice versa?
    rope to neoprene is possible bit involves a bit of work and machining at the rear of the crank

    neoprene to rope..means a new crank as its just about impossible to get the knurled surface for a
    'rope' seal onto the machined area of a 'neoprene' crank
    but
    Having said that I am aware ppl have done by welding/building up the crank
    ..which buggers it and it needs machining/balancing etc etc

    hth

    Smitty

  4. #4
    HDTCQ mechanic #2 skidmarx's Avatar
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    why on earth would anyone convert from neo to rope?
    100% pimp factor, long live the VK
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  5. #5
    been here .......too long Smitty2's Avatar
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    Quote Originally Posted by skidmarx View Post
    why on earth would anyone convert from neo to rope?
    unfortunately...
    ppl mix and match cranks and blocks
    and a rope crank in a neo block will leak
    and
    viccy versa..I believe

  6. #6
    HDTCQ mechanic #2 skidmarx's Avatar
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    ahhh
    100% pimp factor, long live the VK
    www.palmyradragway.com.au

  7. #7
    casual poster andrew_v's Avatar
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    So, Why do I ask?
    I have a vn 5L block than im building into a fairly wild 355.
    My engine builder ordered me a scat 355 nodular cast crank. When I dummy fitted the crank to clearance the block, I noticed it hasn't got the knurled spot where the original crank does for the rope seal.
    Does this mean my engine builder is a knob and has ordered a neoprene seal crank instead of a rope type?

    If the answer is yes, what exactly is involved to use the crank that I have and convert the engine to a neoprene type seal? I have not yet had the rotating assembly balanced and the crank needs linnishing because there is a tiny nick on one of the mains. If there is any machining to be done to the crank or block, now is the time for me to get it done.

    Cheers again...
    Jack of all trades, master of none!!!

  8. #8
    casual poster andrew_v's Avatar
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    Quote Originally Posted by skidmarx View Post
    why on earth would anyone convert from neo to rope?
    I take it that the neo type seals are better then and thats what I should use???

    Is this because they last longer?

    The engine in my VR atm is a stock 250,000ks old 5l with the rope seal, and it leaks pretty bad. It wouldnt bother me so much if it was auto, but it is not I dont like the idea of having oil leaking onto my clutch.
    Jack of all trades, master of none!!!

  9. #9
    HDTCQ mechanic #2 skidmarx's Avatar
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    well, personal preference i spose, but iv never seen a rope rear main that doesnt leak.... and iv seen alot of 253/308/304's
    100% pimp factor, long live the VK
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  10. #10
    casual poster andrew_v's Avatar
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    Hmmm, I had a feeling that was the case. There is definately not a knurl on my crank.

    So anyone know what I have to do to my block to convert it to neo type seal? I imagine I wouldn't have to modify the crank would I?
    Jack of all trades, master of none!!!

  11. #11
    casual poster andrew_v's Avatar
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    Or do I exchange this crank for a rope type? Im confused now.
    Jack of all trades, master of none!!!

  12. #12
    casual poster andrew_v's Avatar
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    Quote Originally Posted by 400HPONLPG View Post
    Yeah,speak nicely to the man you bought it from, at first !!!
    Yeah I will. Ill be paying him a visit on Friday, and ill be interested to see what he has to say.
    I wont be suprised if he tries to tell me that I can just use a rope seal with the neoprene crank or something equally dodgey.
    Jack of all trades, master of none!!!

  13. #13
    Do you ever leave? stroker355's Avatar
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    Yeh, he will probly want to dodge every which way, to try and avoid freight costs etc. The sad part is, somehow he will get those costs back from you if he's doing more work for ya. What do ya do tho ?

  14. #14
    Old Cars have soul. COOPHT's Avatar
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    Quote Originally Posted by allports View Post
    1st: Order a HN022R which is a rubber conversion to change from a rope. (no machining involved) A rope crank is .100" larger than a genuine neo crank at the seal area.
    2nd is the buick v6 rear seal which is avail from ACL for the V6 engine. Drops straight in.
    Like this.


  15. #15
    casual poster andrew_v's Avatar
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    Quote Originally Posted by allports View Post
    1st: Order a HN022R which is a rubber conversion to change from a rope. (no machining involved) A rope crank is .100" larger than a genuine neo crank at the seal area.
    2nd is the buick v6 rear seal which is avail from ACL for the V6 engine. Drops straight in.
    Will these options work with my crank which I believe is a genuine neoprene seal type?

    I spoke to the guy who sold it to me who is unfortunately the guy who is also doing all my machining. He assures me it is intended for a rope type seal. I dont believe him, because this contradicts what 400HPONLPG says. His scat crank has the knurled spot for the rope seal, and mine definately does not. Stroker355, I agree in that he is simply trying to avoid freight costs and hassles. He probable doesn't give a toss if I end up with a rear main leak after a few thousand kays. The crank should have been sent back from day one, because it had a knick on one of the mains right out of the box, before anyone touched it!

    I think I will pick my whole engine up on Friday and take it elsewhere. I got a bad feeling about this guy. He keeps mucking me around and I get the feeling he is taking me for a ride...
    Jack of all trades, master of none!!!

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