Friction Reducing Engine Assembly



Friction Reducing Engine Assembly

Postby rsicard » April 15th, 2012, 11:26 am

Grumpy:

I got involved in a discussion about friction reduction during assembly of an engine. The other person was saying that the crankshaft can be easily spun after torquing the main caps prior to assembling of piston/rod combination. Just wondering what your experience is in checking the alignment of main caps, with and without bearing inserts, crankshaft main journal alignment or concentricity to make certain both the block and crankshaft are as near perfect in alignment.

It would seem that if the alignment and clearances were where they should be and applying oil pressure to the mains ALONE, the crankshaft SHOULD spin freely. As in spin it by hand easily.

Looking forward to your comments on this situation. Thanks.
rsicard

 
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Re: Friction Reducing Engine Assembly

Postby grumpyvette » April 15th, 2012, 12:25 pm

READ THIS
viewtopic.php?f=53&t=852

viewtopic.php?f=53&t=6352

viewtopic.php?f=53&t=3449&p=10012&hilit=assembly+lube+moly#p10012

viewtopic.php?f=54&t=3519&hilit=assembly+lube+moly


IM not 100% sure of your question, but a crank by it self ,sitting in a properly machined block with the bearings in place, having been coated with a decent assembly lube, and the main caps torqued in place should require no more that 10 ft lbs to spin (MAXIMUM) and in most cases less to keep it spinning, in-fact most are easily spun with finger pressure alone.
if it takes more than 10 ft lbs somethings either not machined correctly or your clearances or lube are wrong.
I generally use molly assembly lube mixed 50%/50% with marvel mystery oil as a bearing lube during assembly, and that provides a good slick surface on the bearings.
after you add the rods and pistons with the rings its resistance to rotation obviously increases but should still be UNDER 40 ft lbs to spin an assembled short block
http://www.summitracing.com/parts/CRN-99004-1/?rtype=10
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IF YOU CAN,T SMOKE THE TIRES AT WILL,FROM A 60 MPH ROLLING START YOUR ENGINE NEEDS MORE WORK!!"!
IF YOU CAN , YOU NEED BETTER TIRES AND YOUR SUSPENSION NEEDS MORE WORK!!
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