My Tractor Forum banner

1 - 8 of 8 Posts

·
Three of my friends
Joined
·
9,154 Posts
Discussion Starter · #1 ·
With the wealth of information compilied here,does anyone know the the difference in the 2 cranks?I have a B43 with a bad crank and a P218 with a good one and I know the stroke is different but don't know if it is in the crank or the rods.I think DDOGG or P318 will know this one.Thanks :fing20:
 

·
Premium Member
Joined
·
492 Posts
With the wealth of information compilied here,does anyone know the the difference in the 2 cranks?I have a B43 with a bad crank and a P218 with a good one and I know the stroke is different but don't know if it is in the crank or the rods.I think DDOGG or P318 will know this one.Thanks :fing20:
16HP rods are slightly longer than the 18 or 20HP rods. 16HP cranks have a stroke of 2.625 and the 18-20HP cranks are 2.875. Start mixing these up and your piston will either come up short, 16HP crank with 18-20HP rods and have VERY low compression or stick out the top of the block and hit the head, 18-20HP crank with 16HP rods.

Note: The B43G is rated at 18HP but it has the 16HP crank and rods. It has a raised compression ratio to get the 18HP rating.
 

·
Registered
Joined
·
67 Posts
Note: The B43G is rated at 18HP but it has the 16HP crank and rods. It has a raised compression ratio to get the 18HP rating.
Does that mean the heads are different to raise the compression or is the block shorter? Is there any difference in the valve size or cam height or duration differences?
 

·
Three of my friends
Joined
·
9,154 Posts
Discussion Starter · #6 ·
OnanParts ,thanks for the information,I guess I will put the P218 together and put it in my 318 or buy new undersize rods and have the crank turned for my B43,( I prefer the points motor)I just put new valve guides and new rings in it last year but I knew the rod to crank clearance was out of tolerance but put it back toigether any way but it rattles a lot.
 

·
Super Moderator
Joined
·
35,770 Posts
Biker, saw this the other day and you already had onanparts on it so I didn't want to jump in! He is way ahead of me on these matters! I don't go inside the motor too much!
 

·
Three of my friends
Joined
·
9,154 Posts
Discussion Starter · #8 ·
PA 318,thanks,I think I will stay with the B43,the 218 is apart in a box,it's all there,it broke a rod and I have one for it but it came out of a Sears tractor and I think the PTO side of the crank is smaller and I know the condition of my b43.Good Day
 
1 - 8 of 8 Posts
Top