application:

APS single turbo with APS blow off valve

problem:

at low boost, the APS BOV sounds like it normally does, but at high boost, there is a shrieking noise coming from the BOV. besides the sound, everything appears to be normal.

i took the BOV apart and notice that even with hand pressure, the brass piston is not opening up easily. so i remove the piston and spring and notice when outside the housing, it moves freely. there is a viton o-ring on the inside of the BOV housing.

it seems as though the piston is "sticking" to the o-ring. there appears to have been grease inside the BOV, possibly to lubricate the o-ring/piston interface.

i spoke to others and they say they have not had to re-lube while some say to use WD-40 to give it a spray.

anyone else experience this? I'm thinking to buy some mobil 1 synthetic grease to lubricate.

thoughts???

 

how's the piston look, I've seen ones on evos that expanded and cracked forcing the bov open. but the piston was jacked up look like someone whaled on the top of it with a hammer for a while. personally I would swap it out for something else unless you love the bov and would get a new one then.

 

piston looks fine. it goes in smooth and only hits resistance at the o-ring location.

will try to go get some grease later this week.

 

I first read this as a Semi-Truck BOV.. and I said, 'sweet'