ok i am building a 355 and i am going to put in the pistons and i got the #1 and #3 pistons in.... went to put in the number 2 and 4 and the crank will not move..... ALL NEW PARTS..... whats the deal what am i doing wrong? please help.......

 

did the crank spin free without the 1 and 3 pistons in? if it did maybe u put the rod caps on backwards, bearings are not the right size,or u could have torqued them to tight. did u check ur bearing clearnce with plastigauge? check to see if the caps are on the right way. i seen a kid build a motor and put the caps on wrong and we couldnt spin that thing at all we broke a flywheel turner trying to turn it. goodluck hope u fix it

 

Did you use assembly lube? That makes a big difference also.

The rods also have a dedicated side of the big end. If you look at both sides you'll see one is beveled. It goes towards the outside of the rod journal (the radii). Or if you will, the crank shaft "arm".

If you don't have those right, then the edges of the rods will dig into the radii, which is not good. Better to find out now then after start up.

 

1 and 3 aren't on the same pin, the crank should spin even if the caps were backwards, i think. make sure the cranks spins without any rods. if it does i'd start measureing clearances. did you have the crank ground by any chance? if so you might have to make a chamfer on the bearings to clear the fillets on the crank.

 

when putting in the rods i kinda nicked the crank jurnal..... and there are little marks on it...... how can i get these marks out?

 

emrey cloth

 

pokes is wanting to give you a poke i believe with his emory idea. try crocus cloth, sort of hard to find but it works. if you can't find any spend 20 or 30 dollars and let a shop polish it for you ,and remove the marks.

 

hey guys thanks i am taking the crank to a guy that does motor work and he is gonna hook me up.........

 

whats wrong with emory cloth?? u can get really fine stuff. we always used it before

 

emory scratches the journals and isn't fine enough. what's the finest emory you can get xfine? if anything wet or dry would be better, actually i've used 1500 wet or dry when i couldn't get crocus cloth.

 

ok then i learned something new thanks