Warning: preg_replace(): The /e modifier is deprecated, use preg_replace_callback instead in ..../includes/class_bootstrap.php(430) : eval()'d code on line 106

Warning: preg_replace(): The /e modifier is deprecated, use preg_replace_callback instead in ..../includes/class_bbcode.php on line 2958

Warning: preg_replace(): The /e modifier is deprecated, use preg_replace_callback instead in ..../includes/class_bbcode.php on line 2958
Fitting a Datsun crank
Results 1 to 8 of 8

Thread: Fitting a Datsun crank

  1. #1
    Join Date
    Mar 2007
    Location
    Ballarat, Victoria, Australia
    Posts
    4,797

    Fitting a Datsun crank

    While this is a modification for the more horsepower hungry enthusiast that

    wants the best and most reliable engine package they can. This conversion

    these days will not be for the person with a limited budget thats for sure.

    machining and fabrication costs will make sure of that. You can even buy a

    brand new crankshaft made on the dastun specs but ready to fit into your old

    cortina block again not cheap around $ 2000 to $3000 aud depending on

    specs. You would find the circuit racer or historic racer using this mod as

    'good old crankshafts' are now non existent.

    This article was used with permission from the New Zealand author

    Marty L.

    thank you marty


    .
    Last edited by jewels; 2nd January 2009 at 10:08 AM.

  2. #2
    Join Date
    Mar 2007
    Location
    Ballarat, Victoria, Australia
    Posts
    4,797

    Post

    Fitting of Datsun cranks into Ford Kent pushrod based engines has been very popular here in New Zealand for a number of years. It has also been done in Australia and South Africa. Bob Homewood told me about this alternative when the crank in my Escort Twin Cam was cracked, and all susbequent Ford/Lotus cranks subsquently found were cracked too !!. Since then I have modified Datsun cranks to suit Lotus Twin Cams, Ford/Cosworth BDAs, and 1600 Ford Crossflows.

    All L16 and L18 Datsun cranks are made from a factory steel forging. It is but it is certainly a tough steel as it gives the carbide cutting tools a very hard time when being machined. These cranks are an inexpensive alternative to UK sourced steel cranks, not as strong ultimately but certainly far stronger than the OE Ford cast iron cranks.

    First step is to find a suitable crank. For Ford 1500cc precrossflow blocked engines using standadrd 72.75mm stroke then a crank from a Datsun 1600 (L16) is required (73.3mm stroke). For Ford 1600 crossflow engines using a standard stroke of 77.62mm then a crank from a Datsun 180B (L1eight) is required (78.0mm stroke). A Datsun 200B 2lt (L20B) can also be made to fit into a Ford 1600 crossflow blocked DOHC engine, such as the Twin Cam or BDA. The longer stroke crank (86mm) requires a lot more machining. Also the block requires some machining to allow clearance for the rods. I've gotten it to work on a dummy build using a 'Cosworth' type rod . However Isuzu Gemini rods have been suggested as an alternative. Rod to stroke ratio is important, so the longer the rod the better.

    Why do it? - Is it economical for you?, or worth the bother?. The Datsun crank provides an affordable steel crank compared to the more expensive purpose made UK cranks. Access to the necessary machinery to modify the crank keeps costs down. I only pay for grinding and balancing Datsun cranks do have different counterbalancing compared to the Ford and Lotus items. Miles Wilkin's quotes BRM as having modified standard cranks by adding more counter balance weight. This is a topic in itself.

    Personally I think the OE Ford and Lotus cast iron cranks are built too light with a flywheel that is far too heavy (standard Ford 1600 Xflow flywheel weighs 10kg). I believe the heavy flywheel on the light crank causes them to crack. Having said this it could be argued that the Datsun crank has overweight counter weights. For this reason I feel happy to machine down the counter weights to reduce the Datsun cranks' mass.

    What has to be done to make it fit? If you lay the Datsun crank next to the Ford it will be self evident. The front snout has to be machined down, cut back, and drilled and tapped. The overall web diameter has to be reduced to aid clearance in the block. The rear flywheel mounting flange is shortened and the spigot bearing hole bored out to suit the Ford bearing. The webs and counter-ballances will need to be slimmed down, and some chamfered. As the Main and Big Ends are larger these can be ground down to suit standard Ford bearing sizes and strokes.

    Don't forget to preserve the all important fillet radii when the crank is ground. The keyway for the front pulley can be milled in. The Datsun crank is a 5 bolt not 6 like a Ford. You can make a flywheel to adapt the Ford clutch plate and starter ring gear to fit the Datsun crank. A medium tensile steel (EN eigth) or a high tensile steel (EN25) can be used. Or try modifying the Datsun flywheel.

    I have always made a flywheel as I prefer this solution. Also it is safer to make a light weight flywheel with a steel blank.




    The photo above shows five different types of crank shaft.

    Far Left:
    Standard OE Lotus Twin Cam cast iron crank (72.7mm stroke)
    Second from Left: Datsun L18 fully counterbalanced crank modified to suit 1600 Crossflow.
    Centre: Datsun L18 fully counterbalanced crank modified to Suit Ford/Cosworth BDA.
    Second from Right: Datsun L18 fully counterbalanced crank prior to machining.
    Far Right: Datsun L18 partly counter counterbalanced crank prior to machining.





    The photo above shows a more detailed view of the differences between the partly and the fully counter balanced Datsun L18 crankshafts.



    The photo above shows roughly where the crank will need to be machined. The pens are pointing to areas that will need to be machined.



    This photo above shows the modifying of a Datsun crankshaft - in this case a L16.


    The photo above shows the modifying of a Datsun crankshaft - in this case a L16.



    The photo above shows the modifying of a Datsun crankshaft - in this case a L16.
    The rear of the crank is machined as per the Ford crankshaft.




    The photo above shows the modifying of a Datsun crankshaft - in this case a L16.
    The webs are machined to clear the webs in the Ford cylinder block.









    The photo above shows a flywheel made to suit both the 5 bolt Datsun crank, and the Ford Lotus Twin Cam 8.5" clutch. In order to reduce weight five 20mm holes were drilled near the centre, and segments were milled at the periphery of the flywheel. Total weight is around 5.75Kg. EN8 medium tensile steel was used.



    Last edited by jewels; 2nd January 2009 at 09:14 AM.

  3. #3
    Join Date
    Mar 2007
    Location
    Ballarat, Victoria, Australia
    Posts
    4,797


    The photo above shows a L18 fully counter weighted crank set up for a Lotus Twin Cam. The flywheel has been made from EN25, and mates to a Tilton single plate competition clutch. The front of the crank has been machined to suit the Twin Cam sprocket and pulley.




    The photo above shows a L18 fully counter weighted crank set up for a Lotus Twin Cam. The flywheel has been made from EN25, and mates to a Tilton single plate competition clutch.








    thank Marty L.


    .

  4. #4
    Join Date
    Mar 2007
    Location
    Ballarat, Victoria, Australia
    Posts
    4,797
    for those who want this in PDF form

    here tis.
    Attached Files Attached Files

  5. #5
    Hi Jewel, how are you?
    I am from canada and was wondering if I can get the contact info for Marty as I would like to have a datsun crank modified.
    Thanks Curtis

  6. #6

    Pdf

    hello the pdf link does not work. it would seem the link is pointing to a gif file. called clear.giff. i have noticed the wedsite has many errors this ould be why no picturs or pdf are working.
    Could you please email me pdf if you still have it thanks.

  7. #7
    Not working on my end either. Probably had an error for being uploaded for about 7 years.

  8. #8
    Join Date
    Mar 2007
    Location
    middle northern Melbourne
    Posts
    2,549
    Seems like I can't attach files either - so a forum update goes on my very long list of web related stuff to do. Oh yay...

    However, if anyone wants to PM me their e-mail address, I'm happy to send the Datto crank PDF directly to them.

    Cheers, Al
    www.cortina-mk1.com
    Contact me for parts.

Similar Threads

  1. My Datsun-powered Mk.1
    By benny in forum Your Cortina(s)
    Replies: 17
    Last Post: 4th November 2009, 09:28 AM
  2. Boot Seal Fitting??
    By kaisersolsay in forum How to's & tech documents
    Replies: 8
    Last Post: 19th October 2009, 07:10 AM
  3. fitting a essex v6 engine into a mk1
    By garson in forum Engine conversions or swaps
    Replies: 7
    Last Post: 2nd September 2009, 07:48 AM
  4. Fitting accelerator cable
    By Kieran in forum Original engine, transmission & diff
    Replies: 2
    Last Post: 29th July 2009, 08:41 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •