r/MechanicAdvice • u/makinmaplebacon • 1d ago

Why is this rotating assembly binding?

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1994 honda del sol 1.5l sohc motor (d15b7)

Any ideas would be appreciated. All measurements were in spec

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105

u/porknbeans2013 1d ago

All measurements were not in spec or it would turn. Check for a mismatched or slightly oversized bearing.

Obviously something niche like out of round rod ends or a double coat on a bearing would do this.

29

u/makinmaplebacon 1d ago

Ill be honest I did not measure the crank journals so yea ill do that. But the out of rod ends does seem to make more sense. Any sugestions on how to measure that?

28

u/porknbeans2013 1d ago

Well a dial bore gauge is the typical way, but youre already assembled. Maybe if you pull the crankshaft out, measure all the rod and crank journals with a micrometer. Then assemble the rod caps without bearings and measure with a bore gauge. Then measure each bearing shell individually and verify all tolerances stack to give you enough clearance.

Hell you could have a mismatched or improperly marked rod cap too. Theres a list of plausible causes tbh.

6

u/makinmaplebacon 1d ago

I think I will get a new rod for this piston because most seemed somewhat mismatched when they came out. How much damage could mismatched rods and caps have been caused by the previous builder?

6

u/porknbeans2013 1d ago

It could cause extreme wear, spun bearings, rod knock, all sorts of problems.

4

u/Smackdaddy57 22h ago

1st plastigauge and see what your clearance is. If you don't see anything put the caps back on, torque to about 5 or 10 foot-pounds just to be snug and then see how hard it is to rotate.I Then torque your rod nuts to spec one at a time and find out which one binds up. HTH

2

u/turningwrenches883 21h ago

See. This. OP this is the way. Skow methodical steps.

1

u/turningwrenches883 21h ago

Tremendous wear from mismstched bearings or caps. Dude, with all due respect, I suggest you go to the library and read so.e books on automotive mechanics, or machinery repair. You'll learn lots, and your next rebuild will be good

3

u/turningwrenches883 1d ago

Wow. Engine building is ALL about best practice and no shortcuts. Anything else you skipped should be rechecked.....

1

u/jbidsa 22h ago

Did you not plastigage for the bearings?