<VV> oil filter and alternator mount bolts...

[JVHRoberts at aol.com]

You will, in fact, break the bolt long before you pull the threads from the  
aluminum. This isn't determined by the material strength, but by the thread  
engagement. Rule of thumb for aluminum using steel bolts is to make the 
threaded  portion at least twice as long as the major diameter of the threads. On 
Corvair  engines, the threaded holes have even more thread engagement than this. 
And if  the holes are in good shape and the bolts are the right length, the 
bolts WILL  yield before the threads do. 
 
 
In a message dated 7/31/2005 11:46:32 AM Eastern Standard Time,  
kirbyasmith at gwi.net writes:

Aren't  these bolts threaded into aluminum?  (Sorry, but its been a while  
shice I built my motor.)  I'd be surprised if the aluminum is higher  
tensile strength than any reputable 18-8 stainless bolt, even grade  2.

kirby


JVHRoberts at aol.com wrote:
>  
> I  would agree, except get Grade 5, and nothing less. SS bolts tend to be   
> Grade 4 at best. 
> Grade 5 have three lines on the head.  Typical hardware  store stuff is 
Grade 
> 2, and may stretch at the  required torque.