Hey Folks! I made an air box drain collector like the ones I've seen on this board out of pvc, barbed fittings, and a small breather. My problem is, after a 50 mile run the black gunk is now being pushed through the breather on top of the collector.
This is a used engine that was installed about 200 miles ago. Is this a result of the engine not being run enough yet? The breather I used is similar to what you would see on the valve covers of a race car.
Is the any kind of mesh in the breather to collect liquid and let "air" out? Maybe your check valves on then air box drain lines are stuck open? Jack
I'm not sure that I have check valves. Looks like there are just two brass elbows coming out of the air box connected to the drain lines. The breather is a small cone shape with steel mesh.
What kind of check valves do I need? Could I use something like a hydraulic brake booster check valve, like they have on hand in the auto parts store?
Send me your address and I'll give you 2 if I have 2 left you need the 900 rpm check valves they close at 900 rpm and open on idle the 1400 rpm check work the same
good luck
Clifford,
Thanks a bunch! I'll PM you my address.
Brandon
I had detroit mechanic tell me you don't need them. Mine does not have any. Not had any problems. I also have built a drain box tank and put over 1200 miles since and have yet to have anything drain out.
FWIW,
Bryan
With those breathers, I expect you are creating too much back pressure. You want to have an open system (no resistance). I have found that open mesh created too much back pressure on an 8V71.
Ed Roelle
Flint, MI
Bryan, you may not need the check valves but they were added to raise the air box pressure and every one knows a 2 stroke needs all the air it can get YMMD
good luck
does this help
You sure get my curiosity up Cliff. At least I'm learning and try and pay attention. Are the check valves on the inside of the covers or are they outside? Mine just have copper tubes coming out of each side which I ran into catchcans. Thanks
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So what are the ramifications of not having the check valves? Like I said I don't think mine has ever had them.
Bryan
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you will be surprised in the difference with oil on toad and I can tell a difference in performance...the higher the air box pressure at running rpm the better the performance that is why some engines even use a turbo to feed the supercharger.ck valves let excess fluids out at low rpm then close to put all boost to engine when needed.
Ok, anyone have a DD part #
Bryan
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From my own experience, and talking with old knowledgeable DD mechanics, open air box drain holes don't make any measurable or appreciable difference. Mine, and many 2 stroke DDs run just fine without the check valves.
JC
Bryan if they are free try it and find out for yourself...I see you built a catch can so must have had a reason....mine were only dirty and left spots on car...cleaned and curred problem...happy bussing
Dallas,
Are there only two? I would think there would be four (two for each side of the block). But I don't see any puke tubes for the right side of the engine. If there are two on each side the right side must be a bear to get to on my 4905.
Bryan
Bryan, incline engines drain to the low side of the block one on the high side would do no good DD has a kit for incline engines
good luck
So then I only need two then. I only built the catch can because of what dripped in the drive and hoped to cut down on the oil spots on the rear. My Tuarus fan seal is leaking so I stil get spots ::)
Dallas,
Are the ones you have the right ones?
Bryan
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Thanks Dallas
How often should one clean out or do PM on these drain valves? I've heard horror stories if they don't work, causing oil to accumulate in the airboxes and possibly causing runaways. I think my engine doesn't have an emergency air shut-off flapper, so I can't risk anything that could increase the chance of a runaway. I think my valves work OK, because I can't feel any air coming out of the snot tubes when the engine is over 1000 RPM or so; they definitely drip an occasional drop at low idle!
Why are there different versions of these valves - one for 900 RPM and another for 1400 RPM? Is the difference the pressure they close at? Why would one want some intake air bleeding off at any RPM higher than fast idle?
Sorry for all these questions - my Detroit info doesn't talk about this.
Many thanks, John
Speaking of catch cans, has anyone ever added some type of catch can to the crankcase breathers? Or maybe redirected the breathers to the air intake between the air cleaner and the turbo?