| Author | Message | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Ok, here's a story with a BIG question at the end... a story about oil lines... I just installed a brand new Garret turbo on my bus, as an altitude compensator device, set to not go over about 10psi on the intake manifold. In doing the turbo, I decided to take it's oil feed line to a little manifold block that feeds my oil idiot light sender, the engine oil gauge, and the feed to my dash gagues hooked to it, because it is right where it needs to be and extremely convenient. Here's a drawing: http://www.heartmagic.com/engineoilTurbo.jpg I did so, and upon finishing the turbo installation, I started the engine and watched the oil pressure just to see what it would be. Now this little manifold is at the end of about 10 feet of 1/4" line... where it hooks into the engine is far away and not easy to get to. So I anticipated that the normal readings on my gauges would be a little lower, because the turbo is now at the end of the line along with the gauges, and using oil. Makes sense that the pressure drop due to the 1/4" line would be noticable. So job done, time for a test. I fired up the engine, and sure enough, the pressure at all my gauges now read 40 psi instead of the normal 50 I usually see. Ok, time for a drive. I take her out, drive about 5 miles, and notice that the oil pressure is fine, staying right at 40 psi just like it oughta. So I get on the freeway. After about a mile, all of the sudden, my oil light comes on, and I see that the gauge dropped to about 3 psi!! OOPS... pull over quick and shut her down, and figure out what happened!!! I look around, no leaks, no popped hoses, oil level in motor is fine, nothing wrong that I can see. So I sit there and make a theory. Theory #1 is that perhaps the turbo was packed with some grease or something from the factory which suddenly went away after a few miles, and now it's free-flowing instead of making a restriction, so being at the end of such a long line, the pressure gauges and the actual pressure at the turbo are actually at 3psi even though there is plenty of oil flow and the actual engine pressure is probably at 50psi where it should be. Either that or theory #2, the turbo blew an internal seal and will soon explode... So a quick test... I pulled the feed line off of the turbo and plugged it (I carry everything including the kitchen sink)... sure enough upon starting the engine, 50psi of pressure at my gauges! Deciding that what's happening is according to theory #1 and that the turbo changed from being restrictive to non-restrictive, I hooked it back up and took off, thinking I'm ok even though it freaks me out to drive with a red oil light on in my face, I proceed 35 miles to my destination. The engine doesn't blow up, the turbo works perfectly, no sounds change, etc. but the gauge remains at 3psi. Hours later I start the bus again to come home, get on the freeway, oil gauge still reading 3, and I drive all the way home very sucessfully. In my mind I'm tending to go with the theory that not many people actually stick a gauge right at the turbo and that the thing is probably designed to freeflow it's oil, so there shouldn't be much pressure there at all.ÊÊI also decide that I should replumb the turbo's oil feed directly to an engine oil gallery and no longer involve the lines to my gauges, so I can have a true indication of what's going on with oil in my motor. NOW for the real mystery: 60 miles later,Three blocks from my home, there is a big hill, a 9% grade one block long...basically a canyon I have to go down and back up. I do it in 2nd gear 'cause it's so steep (9 speed) Down the hill I go.... up the hill I go... at the top of the hill, WHAT THE HELL... the oil light goes out and my dash oil gauge comes back up to 40 psi !!! To make it even more mysterious, now that I'm back on flat ground, the oil light comes back on for a full ten seconds (oil gauge is still reading 40) then goes back off again and now it sits at 40 no matter what I do. So I'm totally miffed.Ê My theory of the turbo loosing a seal or grease pack is totally out the window.... and had I actually been driving at 3psi for 60 miles on the freeway I probably wouldn't have an engine OR a turbo by now... bubbles in the line wouldn't account for it because they would just compress and not make any difference to the gauges... I'm totally at a loss as to what's going on... Any takers?? Different subject... Now that the turbo is there, my old "smokin monster" burns extremely clean. While driving there's never less than 3psi turbo boost, and contrary to how the motor used to run, there's virtually Nothing I can do to make it smoke. Is there anything wrong with running it this way... ie any problems running "lean" ?? I can't think of any reason it should be a problm but you guys know more than I do... Cheers Gary | ||
| Gary Stadler (Boogiethecat) (68.7.217.217)
Rating: N/A |
Well, the mystery remains, however I took the rest of the day, went to the hot rod shop and bought a new stainless steel braided teflon turbo oil feed line 6 feet long, took the old system apart and hooked the turbo to a new oil hole all to itself. Turns out that the Cummins 220 does have a long oil gallery running the length of the engine, underneath where it's nice and grubby (I have so much oil all over me now that you wouldn't believe....ugh...). Anyway, the senders are now all hooked in at the rear of the engine, just like they used to be, and the gallery has four unused 1/8" npt plugs left for my pleasure, so I plugged the turbo into the front hole all by itself, routed the new hose nicely, and fired it up. This time the turbo gets tons of oil, and all the gauges read 50-55 just like they did before. I might stick a gauge at the turbo for curiousities' sake, but I might just stick my head in the sand and go on a trip, because it is definitely getting all the oil it needs. I'm not sure if the pressure at the turbo itself means anything useful other than for paranoia factor... So I have no idea what that was all about, but hopefully I'll never see that read oil light come on again!!! In all of this, I find that I have (and have always had) a cracked valve cover... finally I think I might have nailed the last oil leak on that side of the engine!! Tig welder here I come!!! Still mystified... but onwards... Gary | ||
| Henry R. Bergman, Jr. (Henryofcj) (209.210.116.27)
Rating: N/A |
Gary, I think you already determined the cause of the oil light and pressure gage acting weird. Perhaps you had too much stuff running off of the one oil line maniford causing not enough oil to go around to everything. Yeah, like you already know, perhaps having a dedicated single source for your turbo alone may be the best way to go. Lots of oil quickly. As far as the 9% grade by your house goes... ...maybe the oil pump pickup sucked air for just a second or soossss causing the oil light to light up. We know the upright Cummins does not have this problem....but... ...maybe the pancake oil pan is a little lacking in extreme short grades guaranting oil to the oil pump pickup. Sorry about your cracked rocker box cover. If you would just stop doing burnouts, this would not happen.  Did you use a turbo oil return line about three times bigger diameter than the pressure line? I read somewheres that it is important as the return oil may be foamed up a bit and VERY hot. You see now how clean and neat your 220 now 300 Cummins now runs with the turbo? He he he, you are now burning all that leftover fuel you did not before. CROWNS FOREVER!!! Henry of CJ |