355 build crank in and specs good rods in and plasta gauged at .002 but after assembly turning engine over by hand back and fourth seems to be a lot of play in rods at crank any ideas?
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355 build crank in and specs good rods in and plasta gauged at .002 but after assembly turning engine over by hand back and fourth seems to be a lot of play in rods at crank any ideas?
Welcome.
.002 is usually the max recommended rod/crank clearance on a street SBC. Even at that clearance, with the bearing and crank coated with assembly lube or even oil, there should be very little or no noticeable looseness in the assembly.
Plastigauge is a cheap, fairly quick way to check assembly clearances but it is not as accurate as a good set of micrometers. One thing I learned long ago when building engines is that if there is any question during any part of the assembly process……stop right there and figure out what is going on. At this point I would pull at least a couple of the loosest piston/rod assembly and actually measure the rod/bearing and crank and verify what the clearances are. What you find will dictate what your next move is.
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ok thanks for info that will be my next step plasta gauge said .0002 but it just seems to loose for my liking.
Watch your decimal points! 2 ten thousandths would be way too tight,2 thousandths nice. That is dry,no lube. If after checking again they still feel loose,mike the crank,you may have egg shaped journals. Hank
Or over sized bearings
Might want to check your rods if they have not been sized.
most bearing books say any weres from as low to .0009 to .003 and rods for oil clearance thats about were.003 i like them for races engines . they now make a over size shell bearing I .D for the ls engines some rebuilders used then to make in older rods good if they have bin hurt . i just re built set of chevy rods on housing bore i like them at small end of spec holds bearing better in housing bore . helps with bearings size for oil clearance if the rod moves side to side that side clearrance and that just how thick the rod is more to a point is better here that can be anywere from .018 to 025 so the middle is were you want to be this size can over time get bigger from crank grinding and rods getting rebuilt as i allways clean the side of the rods when i rebuild them . is i stop useing plasic gauge many years ago . as i fit and spilt many times a set of bearing to get the size i want its far better with a bore gauge the reads in .0001. plasic gauge is still used just not some thing as good as knowing the real size. name brand of bearings play in to size as to oil clearances you may or not want