Is This Normal - Crank Bearings?

S

stonycreek

New member
Joined
Sep 4, 2010
Messages
34
Well I pulled the crank today and couldn't help but notice the misalignment if the oil delivery tube holes in the main bearing. I am not sure what you call the tube that squirts oil to the wrist pins and that is what I am calling the oil delivery tube - for a lack of better terminology.

Please see attached pictures to better help explain what I am referring to? Is this normal and why would they not be aligned over the hole a little better?

Thanks for you input and opinions...
 

Attachments

  • IMG_0441.JPG
    IMG_0441.JPG
    30.6 KB · Views: 0
  • IMG_0442.JPG
    IMG_0442.JPG
    30.6 KB · Views: 0
I thought it was normal, but I haven't been inside enough bottom ends to know.
 
Normal. My thinking is that this allows oil to escape to the nozzle without creating a dry area on the bearing.
 
Hi, guys the oil hole is like that so it has alot of pressure for the green plastic piston cooling nozzles to have the pressure to cover the bottom of the piston. New B series has J-Jet pison cooling nozzles to eliminate this. Its fine I work at Cummins Alt in Greensboro NC and I freaked out the 1st time I tore one down and got laughed at lol. Sorry to but in.
 
Wouldn't the nozzle have less pressure? It would create a restriction before the nozzle. Me thinks that would decrease the pressure.
 
cummins01dw said:
Hi, guys the oil hole is like that so it has alot of pressure for the green plastic piston cooling nozzles to have the pressure to cover the bottom of the piston. New B series has J-Jet pison cooling nozzles to eliminate this. Its fine I work at Cummins Alt in Greensboro NC and I freaked out the 1st time I tore one down and got laughed at lol. Sorry to but in.
Click to expand...

Good info. I haven't seen a J-jet torn up, but have seen some of those green ones broken off.

kazairl said:
Wouldn't the nozzle have less pressure? It would create a restriction before the nozzle. Me thinks that would decrease the pressure.
Click to expand...

I think he's saying the reason they overlap as big as they do instead of something smaller is to get the pressure at the nozzle.
 
Thanks guys and Merry Christmas. When I pulled the crank and then noticed the offset I was a little confused, to say the least. I just wanted to post up the pictures to get some feed back. I feel a lot better now knowing this is the "norm".
 
Yeah its crazy but someone alot smarter than me desighned it lol. I know my boss laughed at me. Merry Christmas guys!
 
kazairl said:
Wouldn't the nozzle have less pressure? It would create a restriction before the nozzle. Me thinks that would decrease the pressure.
Click to expand...


Yes it would. But it would restrict volume way more than it have any influence on pressure.

My guess is that it is done to keep the pressure/volume up in the oiling system BEFORE it goes out to the jets. Oil being forced between bearings is always going to keep some back pressure on the system, but an open oiling nozzle would prob. bleed off more pressure/volume than wanted, starving the crank, cam and even the top end.
 
new storm blocks have previsions for "J-Jet" cooling nozzles feed from the oil galley that feeds the crank and flow alot more oil. those are called "saddle jet" i wouldn't worry about oil pressure feeding the crank, the ISB engine is knowed for good oil pressure. new and old engines use the same oil pressure regulator springs and oil pump. if i was in the middle of a tear down and had the previsions to install J-jets i would
 
Last edited:
forces more oil to the crank brg with a smaller orifice. brgs got less clearance so all the oil would go right out the nozzle instead of oiling the main since the nozzle has less restriction
 
You must log in or register to reply here.
Top