Air Box Check Valve Part Number

[RJ]

Does anybody have either the OEM Detroit or a NAPA cross-over part number for the air box drain check valves that are correct for a 6V71? 

It's my understanding that they're different between the 6v, 8v, turbos and 92 series.

There's no mention of them in my 5Cs Parts Book, and my Detroit books are buried in storage.

Geoff?  Cliff? 

TIA, guys.

RJ

[luvrbus]

8996207 for the 1 PSI check valve(900 rpm+or-) ,shop they cost 50 bucks each from Detroit  

[chessie4905]

On the boat forums, a poster stated that there are two; one closes at 900 and the other closes at 1200. I can see that pressure rating should be main consideration irregardless of the number of cylinders feeding into air box.

[luvrbus]

The 1.5 psi for 1200 rpm + or - are no longer available from Detroit, the secret to making those work is they have to be installed on a downward tilt fwiw   

[Geoff]

RJ-- if you have oil coming out the air box drains you have a serious problem.  While the DD 92 Series is prone to leak oil out the air box drains when the oil control rings get old, the 71 Series engine does not have that problem.  So you probably have blower seal problems.  It is possible you may have a broken oil control rings but that usually occurs when the oil control rings are overlapped during assembly.  Good luck!!

--Geoff

[RJ]

RJ-- if you have oil coming out the air box drains you have a serious problem. 

Geoff -

Right now there is no check valve in the air box drain lines, only a rubber hose.

Each might leave a dime-size or smaller mark on the pavement, but not always.

Seems to drip a little more if I've just run errands around town (fuel, dump station, etc.) than after a run down the highway.

I do have a small leak off the oil feed line to the alternator (belt-driven) that I'm addressing this next week.

Engine otherwise seems to be in pretty good shape (other than terribly underpowered IMHO), I'm getting a little over 1500 miles to a gallon of Delo 100, which seems to be fair.

Should I actually install the check valves, or, as the saying goes "if it ain't broke, don't fix it?"

RJ

[Geoff]

Okay, I thought you had a serious problem!!  I don't consider a few drops of oil a problem, and the check valves don't stop parked leaks.  You don't need check valves.

--Geoff

[lostagain]

If the back of your bus and the towed get oily while driving, it could be any oil leak, like your leak at the alternator. Check valves will stop oil leaking out of the drains while under way at above idling speeds, so yes, they will help a little in staying clean. It is nice not to have any leaks and have a clean rear end...

JC

[dtcerrato]

Haven't had check valves on our IL671 NA since 79 and no issues here, we don't fix it if it ain't broke, but that's not to say that we do maintain things... and yet it's a tortoise and we love it and always make our destination no matter what. :-)