unfortunately its COMMON because the piston pins on pressed pin pistons are normally
EITHER forced into the piston with a hydraulic press and that can distort both the rod and piston,
OR the rods heated, too expand the small rod pin bore in the connecting rod and
if its heated the pin surface is frequently micro damaged , and theres commonly minor surface damage done to the piston pin bores, have him soak the piston/rod assembly in a 5w30 machine oil for 30 minutes ( I just use MARVEL MYSTERY OIL) in a 2 lb plastic coffee container, as I always have a few empty's
TRY spraying the piston pin area with a good penetrating oil, and working the rods back and forth, if it does not correct in a minute or so with penetrating oil,its a problem, take them back and have the machine shop correct their mistake, even pressed pin pistons should flop back and forth just by moving the rod back and forth, somethings binding, pressed pins are locked in the rods but should rotate easily in the piston pin bore
then take each out and work them back and forth and see if they free up.(they should) as the aluminum tends to wear in rapidly, now
this is one reason I almost always suggest using bushed connecting rods and polished quality ,full floating piston pins and retainer rings
Assuming components were correctly assembled ,obviously the stiffness is not a huge issue on a common street transportation engine as millions of engines are assembled like that as its far cheaper to do so than use full floating pins and pin locks in commercially assembled street engines as the pins rapidly loosen enough for engine oil to seep in and lubricate the rocking pin in the piston pin bore.let me say this,
Ive build close to 180 engines or more MINIMUM now over 44 plus years (I lost count) (thats only about 4-5 a year)and
I use the local machine shop to instal pressed in pins or I talk the guys into free float piston designs and I OWN a 12 ton press and several torches, simply because its a P.I.T.A. to fix if you screw it up,and cheap to have done, and
to do the job correctly you NEED A ROD FURNACE DESIGNED FOR THE JOB
now obviously I could buy a rod heater and have the tool,
but just using the far stronger aftermarket connecting rods and free float pistons makes far more sense to me, than screwing around with weaker rods and harder to assemble pistons
viewtopic.php?f=53&t=978
http://www.youtube.com/watch?v=0TEAWO9P95Q
http://www.youtube.com/watch?v=uTpRfREY ... re=related
