You should consider tilting your energy exposure in the direction of green companies such as Donaldson (NYSE: DCI), which makes environmentally friendly filtration systems for diesel engines.

But before diving into more about Donaldson, just how much of your portfolio should be allocated to energy these days? In answering this critical question, we'll see that right now, all else isn't equal when it comes to this turbulent sector.

makes the best filters in the world, and everyone needs filters!

From a recent Mad Money show:

"This is one where the stock is good but the market is bad. I want to buy this one."

From a recent Mad Money show:

"This is one where the stock is good but the market is bad. I want to buy this one."

10%

recent surge good free cash flow

90
mkt cap - 2.93B
roa - 11.48
roe - 24.77
trailing p/e - 21.19
fwd p/e - 18.61
PEG - 1.54
# qtrs missed in last 4: None

Sep 35 - 2.35

BUY

stock was splitting, pays dividends

Upgraded by Bear Stearns from Peer Perform to Outperform