Hey all, hope everyone is well and healthy. As I’m digging deeper into my motor (1976 R90/6) I noticed the nose of the crank is a bit deformed. Maybe where a puller had slipped off center. After I pulled the connecting rods I also noticed the big end rod bearings are oversized by .5mm. I’ve spoken with multiple friends on what I’ve found and I received two answers. First being that a cut airhead crank significantly loses its integrity and could fail. Or, that it is totally ok and there is no worry of it failing despite what has been done. I’d like to reach out to y’all and get some advise on the matter. Since the nose is boogered up a little I’m inclined to purchase a used crank (one in better condition) but I’m just not sure if it’s necessary and worth the extra money. Any opinion is greatly appreciated. Trying to get a feel on what an experienced owner would do if it were theirs. Thanks ya’ll.
-
Welcome, Guest! We hope you enjoy the excellent technical knowledge, event information and discussions that the BMW MOA forum provides. Some forum content will be hidden from you if you remain logged out. If you want to view all content, please click the 'Log in' button above and enter your BMW MOA username and password. If you are not an MOA member, why not take the time to join the club, so you can enjoy posting on the forum, the BMW Owners News magazine, and all of the discounts and benefits the BMW MOA offers?
-
Beginning April 1st, and running through April 30th, there is a new 2024 BMW MOA Election discussion area within The Club section of the forum. Within this forum area is also a sticky post that provides the ground rules for participating in the Election forum area. Also, the candidates statements are provided. Please read before joining the conversation, because the rules are very specific to maintain civility.
The Election forum is here: Election Forum
Cut crank integrity
- Thread starter achart17
- Start date
-
- Tags
- cut crank turned crank
Darryl Cainey
Sir Darby
A few pictures of the nose damage would help to make an assessment.
If done right oversize bearings should not be a problem.
If done right oversize bearings should not be a problem.
Thanks Darryl, I’ll get a picture loaded up today and I appreciate the opinion. Ted from the Beemer Shop told me he has seen under sized crank journals in the past but they are rare and a tell if the crank was turned would be to look at the counterweights because they need to be removed to properly turn the crank. Does anyone know of any other things to look for?
