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Removing main bearing caps - 18V engine

Last post 07-27-2009, 7:03 AM by moonsail. 3 replies.
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  •  07-24-2009, 4:37 PM 20394

    Removing main bearing caps - 18V engine

    I am rebuilding a 78 18V engine.  In the teardown, I can't get the middle or rear main bearing caps to budge.  I see they have a tapped hole in them, and I found a reference to adapting a slide hammer to them to remove.  Any other tips out there?  (Since I don't have a slide hammer - yet.)
  •  07-25-2009, 11:19 AM 20399 in reply to 20394

    Re: Removing main bearing caps - 18V engine

    moonsail,

    If you have a pretty strong grip you can get the center one out easily. Take two main cap bolts and insert them in the holes of the cap, but only down to about where the threads begin on the shank. Now grasp them with your stronger hand and squeeze them together while rocking the cap fore and aft and hauling upward. Just a little at first, and then as the cap starts to move, more rocking. BE CAREFUL! Now is when it'll come loose suddenly. Before I had a decent lightweight slidehammer, I did it this way for years. The rear is more difficult.

    The rear cap has a lot more contact with the block, and therefore a lot more friction. Rocking this cap is almost out of the question. We have actually built a little puller for this job here in the shop, but once again, I remember doing this before that puller. You need three hands, but it works.

    Insert a bolt in the central hole in the cap. The longer this bolt is, the better. Now, insert screws in the oil sump screw holes near the edges of the cap. Place a couple of small stout wooden blocks outboard of the cap and use a pair of large screwdrivers under the heads of the sump screws to pry the cap upward evenly. Use the big bolt to keep the cap moving vertically, as it will want to wander off kilter and strike the crankshaft. This may all sound quite eloborate, but it is vitally important not to distort the caps or use anything to pry against their working surfaces, including those surfaces which bear against the block in any position or manner. Enjoy the process.


    Motorbill
    From Lola to Land Rover, If it's British and has wheels, it's likely I've bloodied me knuckles thereupon
  •  07-25-2009, 2:30 PM 20400 in reply to 20394

    Re: Removing main bearing caps - 18V engine

    I use a method similar to Motor Bill.  I have some threaded rod to match the threads in the bearing cap.  I run this through the hole in the center of a 2 X 2 which spans the crankcase and rests on spacers to allow room for the bearing cap to come up under it.  A big washer and a nut on the threaded rod - the nut is just run down to pull the bearing cap up.  If I run out of room under the 2 X 2, I just add more spacers at each end and keep working the cap up until I can pull it the rest of the way by hand.  I got a slide hammer off center once and broke out part of the threads on the top of a bearing cap, so I the more conservative approach described above now.

     


    Cheers,
    Dave
    http://homepages.donobi.net/sufuelpumps/
  •  07-27-2009, 7:03 AM 20423 in reply to 20400

    Re: Removing main bearing caps - 18V engine

    Dave and Motorbill,

    Thank you both for the replies.  After posting I remembered that AutoZone lends tools, including a slide hammer.  With just a few taps both caps popped out with no trouble.  Amazing how easy things are with the correct tools.

    This is not my first rebuild, but my first MG, so I may be back.  Thanks again.