Warp 11 End Cap Bolts Upgrade

Tom, a fellow EVer in Pennsylvania who is now converting an 05/1996 BMW 328ti, reported that he observed that his Warp 11, after sitting outside in the driveway this past winter, showed beginning signs of rust on the shaft and the four cap head bolts that secure the Aluminum accessories end cap to the body of the Warp 11.  Although it was anticipated that any shaft that is not oiled or protected will gradually show signs of rust, it was not anticipated that the black oxide coated cap head screws would rapidly rust as well. 

Picture TK09142014-1 showing the shaft and nascent rust on the cap head bolt (center at 12:00).

Cosmetics being important, it was elected to preempt the rust and replace the four black oxide steel bolts that are readily accessed at the accessories end of the motor, with equivalent stainless steel cap head bolts.  The bolts were sourced at McMaster Carr (part number 92196A636, $1.04 each, 3/8-16 x 3 inch, partially threaded).  These bolts are Stainless Steel 18-8 (18% Nickel and 8% Chromium) and they are roughly equivalent to a Stainless Steel 303.  They should work very well, and they are not as expensive as the 316 Stainless Steel equivalents (10-14% Nickel and 16-18% Chromium, McMaster Carr part  92185A636) which are priced at $2.79 each!

The bolts were tightened with a 5/16 hex key wrench.

The four equivalently located bolts at the opposite end (transmission side) will not be changed until the adapter plate and transmission are disassembled at some future point.

Picture DSC01708  of the OEM black oxide 38-16 x 3 inch cap head bolts next to the replacement stainless steel cap head bolts.

DSC01711-B showing the Stainless Steel 18-8 cap head bolts installed in the end cap of the Warp 11.