The Stovebolt Site Forums The Shop Area Engine Shop main caps loose?

Been doing some work lately on the 235 in my depts 1945 fire truck. I dropped the oil pan to replace the rear main and oil pan gaskets. After dropping the pan, I found that I can "wiggle" every main cap north and south(going front of truck to trans). The caps are tight left and right(east and west) but every single one has some play north and south. This truck was parked in a barn in the late 70s, and we don't know how it ran at that time, and it has not ran since we got it. The head is off right now getting new seats, valves, and springs. I haven't had a chance to check the torque specs for the main caps to see if they're correct.
any ideas? I've never seen something like this on any other engine I've rebuilt/worked on.
any ideas? What would cause this? I plan on pulling a main cap or 2 this weekend to inspect the crank and bearings, but did not have time last weekend.
thanks!

Somebody must have been in there before you. It would probably self destruct if started.

Might be why is was parked in a barn in the late 70's?

What do you mean "wiggle"? Are you talking about end play of the crankshaft? If you are dropping the pan,did the pan look like it was taken off before? There is suppose to be end play in the crank maybe about .006-.012 from front to back. How are you checking for this "wiggle"?

Are you sure you are not finding the "wiggle" in the rod cap as you feel the side clearance of the bearing on the journal?
This would be normal but the main bearing support can not live with weakness.
One loose cap/bolts might survive for a while but looseness in all would fail quickly.

I'm bettin' he's moving the rods around. I don't think you could move the main caps around with the bolts even finger tight.

Kurt

Based on what we have been told by the family that donated the truck to us it was running fine when parked in 1977. The owner died and it never moved again. We'll go back and take a look and make sure what we think is moving really is.

First thing to do is count how many of the parts there are that are moving. There's six rod caps, and only four mains. I suspect that you're moving the connecting rods around, which is normal. There should be no up/down or side-to-side movement, but a little front-to-back movement of the rods is OK. The main bearings hold the crankshaft to the engine block, and have bolts with a 3/4" head on them. Rod bolts have nuts with a 9/16" size. The front three main caps have 2 bolts each, and the rear main, where the rope seal is located, has 4 bolts attaching it to the block. You'll need to loosen all the main bearing caps a little, allowing the crankshaft to drop a few thousandths of an inch, and remove the rear main cap completely, to change the rear oil seal.
Jerry