Plain bearing crank VS roller bearing

[The Buddha]

OK How much can the rod move sideways in a plain bearing crank ... The savage motor I am working on has roller bearings ... and its not moving at all ... and its supposed to be that way ... my eli900 motor has rods that do move sideways ... How much ... and I have manuals 2 of them and neither has the answer ... I am going to look in the GS manual cos I find everyhitng in ther ... including the meaning of life  :lol:  ... but I thought I should ask in case I turn up blank ... but atleast I will be enlightened ... and y'all have to call me the one for I will be Guru ... see its working already ...  :lol:
Cool.
Srinath.

[GeeP]

There will be a certain amount of end play in a plain bearing crankshaft.  This is to allow oil clearance on the thrust flanges.  

A crankshaft with tapered roller bearings should have no end play.  This is required to pre-load the bearings.

A crankshaft with deep-groove ball bearings should exibit very little to no end play.  This is because deep-groove ball bearings do not necessarily require preload.

End play should be listed in the manual.  Somewhere....    :mrgreen:

[Blueknyt]

now if we could only convert the GS over to roller style and not just the cams either. in know the CB shaft can be converted without much issue, just need to set an oil bleed system to  keep them wet

[cernunos]

Most set-ups I've used on small-block and big-block Chevy have had .006 in minimum side play and maximum of .010. A lot of Cup motor builders say that as long as you have SOME sideplay you should be OK but the preferred is .006. Too much play will allow oil to bleed too quickly and drown the cylinders which in turn leads to poor oil control. Too little will not allow oil to escape which causes heat build-up and consequential galling failure. Also ensure the rod bearing has a chamfer on the side(s) facing the fillet of the crank-pin to prevent riding in that area. Love the little GS and this forum.

C.......

[The Buddha]

Thanks guys that's great ... see I knew I could count on The GS dudes ...
The manual for the savage )roller bearing) had small end movement specs ... guess how much ... 3 mm ... yup under 3mm is OK measured at  the small end ... The eli manuals ... 2 of them said to check the gap should be 1.8 thou to 3.3 thou if memory serves but nothing for what it is at the small end ...
Now luckily my savage had none or very very very little ... this has some but till my feeler guages show up I dont know for sure ... the small end I may be able to check with a caliper so I thought I should check ... but feeler hguages are comming tommorow ... so I'd try that ... No point rebuilding a motor if I am not going to get smarter in the process is there.
Cool.
Srinath.