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Is the Engine Rebuilt?

Discussion in '40- & 55-Series Tech' started by Pinion, Oct 16, 2003.

  1. Pinion

    Pinion

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    I am in the middle of restoring my 40 and this past weekend I pulled the motor and have it up on a stand now. Like an idiot I didnt check the compression before tearing into it. I figured instead I would just check everything after pulling the motor. So, the other night I pulled the head and peered down into the cylinders. I was pretty happy to see that all of the cylinders still had the cross hatching on the walls. It did smoke a little every once in a while and the tops of the pistons were carbonized. Is the black on the piston heads normal, or would it be due to either the carb running rich (which it does...its not an Aisin, its a Holley) or bad valve guide seals? I pulled the pushrods and they were in good shape and the lifters had just a small amount of laquer built up on them. The intake valves are a powdery white and the exhaust valves are powdery black. Is this normal too?

    I am curious as to how I should check to see if the compression is ok. I gave some thought to pulling the pistons and measuring them vs. the ID of the cyinder. Is there some PM I can do to the head while it is out? The valves look ok, but should I have the head sent out for a regrind, seals and decking?

    The whole truck looks like it had been totally neglected, but the engine internals from what I have seen say otherwise. I have great oil pressure and dont seem to have any other problems with it. I have most of a gasket kit left over from another 2F swap that I did, but now I am wondering if I should even bother with it.

    When I pulled the bellhousing, all of the bolts had anitsieze on them and the pilot bearing looks pretty new. Clutch as well, although I will need to have the flywheel resurfaced.
     
  2. Rice

    Rice SILVER Star

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    If you're getting smoke some of the time (and particularly when cold in the morning) the first guess would be valve seals. While it's apart it can't hurt to replace them and if there's room for a grind some have them seated.
     
  3. ranger

    ranger

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    Your seats wont cause smoke, it either the guides, seals or the rings. Best way to check is with a leak down tester, but the engine needs to be together. Since you have it partially apart, I would measure the cylinder taper, and see if you can get away with a hone and rering.
    I would venter to say if you can still see the cross hatching in the bores, I would suspect the head, namely the guides and seals. Quick way to check the valve guides for wear is take off the valve spring, and see if you can wiggle the valve back and forth in the guide. If you can the guide is worn. If you can's the seal is probably brittle.