I am missing something...case question

[speedo]

I just reassembled a 7R case with a 70.4 crank and polished rods and after closing the case up...2 and 5 rod ends are hitting the web in the case? These are the same rods and crank, and as I look into the case, the webs they are hitting are parallel to the crank. I am perplexed. Thoughts? Same case...same rods, but different crank?

Speedo

[JohnJL]

the rods will hit the webs when they are not aligned to point "up" the cylinders. thread some elastic bands through the small-end bushings and to the head studs to keep them aligned and you should have no problem.

[HawgRyder]

As I understand it....the Engine is partially reassembled and the bottom of the piston is hitting the web?
Sounds like wrong crank....this one is a longer stroke....meaning the piston travels upwards more....and also downwards more.
Are you sure you did not get a "stroker" crank..(one with a higher number than 70.5) ?
The only other cause would be a mis-match in pistons which would be the same pistons did not go back in the same holes.
Bob

[304065]

What pistons?

Did you try to use 2,2 pistons in the 2,4 case? Classic skirt clearance scenario.

[speedo]

I mounted the flywheel, turned the case on edge and supported the rods in the center of the spigots. Now when I turned the crank, all is clear. I guess I allowed the rods more vertical movement in the spigots than I should have. The rods,crank and case were all part of the same engine...which is why it didn't seem possible. I've never experienced this with 66mm cranks...must be more clearance. I am amazed how close the rod ends come to the webbing in the case. Thanks for the responses.

[notmytarga]

I had the same 'problem'. The rods like to get caught up in the case if the ends get closer to the spigot than the piston allows. It takes some giggling to get them free. Rubber bands are a good idea I 've seen but not tried.

[gestalt1]

i also noticed the same thing when i built my 3.2ss motor. i tried to figure out what was up for awile - quite a head scratcher. it really seems like it should be enough clearence but there isn't unless the rods are aligned with the piston stroke.