Jump to content

Crank o-ring and case matching


Recommended Posts

hey guys trying to get everything ready to build my 421 serval and i want some input on 2 things. The first is this spot on my crank were it looks like an oring should be but its not. i orderd it from m&m and i didnt do anything but take it out of the box and put it the case cause i used the box they shipped it to me in to send my old crank out. if i do need one whats it called and where can i get one? heres the pic. PART_1320367530306.jpg

 

 

The next thing is case matching. this is my first time doing anything like this so i didnt want to go crazy and hog out the case and end up fucking something up. i put the cyls on and there is just a little bit of an over hang (nothing close to what it was when i started) its very nice and smooth not a "ledge" like feeling like it was before i started. heres the pic of my first try at case matching, let me know what you think. PART_1320370986929.jpg

Link to comment
Share on other sites

JJ is correct. The groove farthest out is for the lip on your seals. The groove around the bearing seat is there for the c-clip.....basically it is there to act as a thrust washer ( i believe) and keep the crank from walking side to side in the cases. I know that when i split my cases last winter and test fit my crank and everything......there WERE a few times that clip would get hung up on the bearing and go with the crank when i would pull it out. Look at your old crank and see if its on there.....if not you can order them.....pretty sure Jeff from FAST carries them in stock. im sure kevin at HJR carries them too...

Link to comment
Share on other sites

It looks like you've removed some material from between the cylinders..... :whoa:

 

If you have the tooling, I think I'd try to blend the junction better by removing more material below the mating point so it was more vertical there. I think you'll have swirling due to the low pressure point you've cut in since you're forcing air from a piston at moving at 56 feet per second average. The velocity at 90 degrees crank angle in conjunction with the small transfers will have a significantly increased flow rate than merely piston speed so IMHO it's all about the blending.....

 

I usually port my pistons a little bit and may match the case as well next time I have it apart.

Edited by jayzx750
Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

Loading...
×
×
  • Create New...