Sunday, July 17, 2011

Seeking Motorvation Part 2

So, last I left off, I was about to remove the pistons from the engine block.

I started with the front cylinders and worked to the back alternately removing one side and then the other.  Each and every piston easily cleared the ridge at the top of the cylinder and then had to be carefully worked over the ridge for the second compression ring and the oil ring.  Unsurprisingly, the top compression ring on each and every cylinder (except #8) was broken.  I questioned the VMF as to how this happened and the consensus was that I likely broke them when I "forced" them over the ridge.  The problem with this is that I didn't force the first ring at all but the 2nd and oil rings (neither of which broke on any cylinder).  So, my current belief is that the PO had the engine "rebuilt" with new rings but didn't bother to ream the ridge from the top of the cylinder.  I think that the top rings, having no chance to conform to the ridges slowly as when the ridges were formed, snapped under the stress of slamming into the ridge upon each cycle while running.  This would also explain why every cylinder was leaking during the leak-down test discussed in Part 1 of Seeking Motorvation.

Well, there's your problem!
The next step was to remove the crank bearing caps.  This involved removing 10 tightly torqued bolts and then tapping them each lightly with a rubber mallet until they come loose.

Loosen the bolts

Note the caps are sequentially numbered.  Don't mix them up!

The crank is ready to be removed.  Tip: Remove the backing plate first.

After removing the caps, the backing plate had to be removed which actually required me to hoist the block off the engine stand, remove the plate, and then replace it back onto the stand.  The crank could then be removed and set aside.  Yeah, I know that EVERYBODY else removes the flex plate and block plate before they start but this worked for me.  It was nice to use the flex plate to rotate the assembly while tearing the motor down.

Feeling... cranky?
The next step was to remove the cam shaft nestled deep within the safety of the block.  This involves removing two bolts from the front retainer plate, removing the plate, and then sliding the cam shaft forward out of the block.

All safely nestled in it's block.

Remove that retainer plate and the cam is yours.

Slide it out.
After I removed the cam shaft,  I knocked the freeze plugs out.  Originally, I started with a pecking body hammer but soon discovered that putting a large flat bladed screw driver against the inside edge of a plug and giving it a whack, would cause the plug to rotate such that it could be pulled out with pliers by one edge.

One way to do it.
Finally, I had a block ready to take to the machine shop for cleanup in a hot tank for a start.  I'm going to break the block prep into phases starting with clean-up, then hone/bore, cam bearing install, and crank machining as a minimum.

Ready for the machine shop.

This last Friday I took the block to a machine shop.  I may also have the block magnafluxed and/or machined based on findings by the machinist.  More to come.


  1. Other than the ring mystery, it looks like a good block for rebuilding.

  2. Thanks James! Yeah, I think it'll be a good engine when it's done.

  3. Did you get the heads checked out? Curious if the bent push rods damaged the guides. I was lucky on my last rebuild to not need it. Still cost me $225 to get a valve job done.

  4. Mr. Mumm,

    Not yet, I won't have the money to finish the engine for a couple more weeks.