Main Bearing caps

[Skip & Lynne]

I am rebuilding the engine in my BT-7 and the main bearing caps have nylon inserted locknuts. Do you guys reuse them or get new ones. Skip

 

[Dave Russell]

Skip,
There is likely to be some disagreement on this, but I think that it is one of those belt plus suspenders things. I don't think lock nuts on main bearing studs are needed in the first place. When you consider how little the joint can flex & the amount of tension used, the locking nut isn't really doing anything. You don't see lockwashers on head bolts which is a similar type of joint.

As far as replacing the Nylocks, what ever you are comfortable with. A better lock would be green Loctite.
D

 

[Skip & Lynne]

Thanks Dave I tend to agree with you. I have seen 427 Chevrolet engines with smaller bearing caps and smaller nuts. The thing looks sort of like a tractor engine inside. thanks Skip

 

[piman]

Hello Skip,
I would doubt that Nylocs work too well in that sort of hot environment. If you must use an anti vibration nut then the all metal type is the one to use (I forget the generic term for them).
Personally I would be happy with the standard deep nut torqued down.

Alec

 

[Bruce Bowker]

<blockquote><font size="1" face="Verdana, Arial">quote:</font><hr>Originally posted by Skip & Lynne:
I am rebuilding the engine in my BT-7 and the main bearing caps have nylon inserted locknuts. Do you guys reuse them or get new ones. Skip<hr></blockquote>

Sometimes they are called aircraft nuts and by aviation rules, they NEVER get re-used. I have some on my boats and re-use them frequently simply because I can't get new ones quickly. But they are not in critical places.

I am surprised they are on main bearing caps. Was this stock I wonder?

[ 05-02-2004: Message edited by: Bruce Bowker ]</p>