Engine rebuild woes
#1
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Engine rebuild woes
My rebuild is not going as planned. Everything going smooth until the last rod cap. As soon as its torqued on the engine takes a great deal of force to turn. Loosening the studs allows the crank to turn freely. Loosened 1 2 and 3 rod caps and torqued 4 down and its at the same nearly impossible to turn crank. Caps installed correctly, standard size bearings, piston installed the correct way. Only thing we did to the crank was take some emery cloth and went around it a few times. Even swapped bearings with #1 and still same result. Also put in old bearings for ***** and giggles, no beans. I think its something stupid that might be going on. Any ideas would be much appreciated. Getting plasti gauge tomorrow.
#3
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This happened to mine once, turned out I threw one old bearing in with the new. All the old ones looked ok, all 32 new and old bearings were "STD" size. One out of 8 with the rods is apparently enough to lock it up pretty good.
#8
3 things to check:
- Rod is not pushed to one side of the piston (too far forward or back along the length of the piston pin) so that it no longer lines up square to the Crank rod journal.
- piston is not turned in the bore (causing the rod to not be square to the crank)
- Piston is stuck in the bore (damaged piston ring, not enough end gap on one or more rings, piston has a nick during installation, ...)
Disconnect the rod at the crank and see if you can push the piston up the bore... All 4 pistons should have about the same resistance.
- Rod is not pushed to one side of the piston (too far forward or back along the length of the piston pin) so that it no longer lines up square to the Crank rod journal.
- piston is not turned in the bore (causing the rod to not be square to the crank)
- Piston is stuck in the bore (damaged piston ring, not enough end gap on one or more rings, piston has a nick during installation, ...)
Disconnect the rod at the crank and see if you can push the piston up the bore... All 4 pistons should have about the same resistance.
#9
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3 things to check:
- Rod is not pushed to one side of the piston (too far forward or back along the length of the piston pin) so that it no longer lines up square to the Crank rod journal.
- piston is not turned in the bore (causing the rod to not be square to the crank)
- Piston is stuck in the bore (damaged piston ring, not enough end gap on one or more rings, piston has a nick during installation, ...)
Disconnect the rod at the crank and see if you can push the piston up the bore... All 4 pistons should have about the same resistance.
- Rod is not pushed to one side of the piston (too far forward or back along the length of the piston pin) so that it no longer lines up square to the Crank rod journal.
- piston is not turned in the bore (causing the rod to not be square to the crank)
- Piston is stuck in the bore (damaged piston ring, not enough end gap on one or more rings, piston has a nick during installation, ...)
Disconnect the rod at the crank and see if you can push the piston up the bore... All 4 pistons should have about the same resistance.
#11
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So you are saying even with the old bearings it doesn't spin? Or just with the new ones? Could be new ones are mislabeled oversize bearings. I guess you don't have an inside mic you can use to measure with do you? Also, are you 110% sure you haven't mixed up the rod caps at all?
#15
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I don't really have an option. Going to have to get the crank turned and buy new bearings. Thats what i get =). Would a .0015 clearance be the cause of the inability of the crank to turn?
#20
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All stock including hardware. I do not have a thrust dial indicator. The only thing that was changed in this build was #1 piston and rod (since the piston on #1 was cracked @ the ringlands), main and rod bearings, and piston rings. I really need to invest in some higher quality measuring equipment. Ill have to check rod end play.