See pic: Can the rear oil (galley) plug be used for oil return from a turbo?

[johnny23toronto]

I've seen and read about the rear oil galley plug on the rear of my 4.0 sohc. Is this an area of pressurized oil? Even if it is pressurized, is it a good idea to connect the return side of the turbos oil line to it? The turbo would then be higher than the return line... I've looked at other peoples setups:

-"justin146", he returned into the oil filler neck
-"l8psiexplorer", "...used a push lock-line and ran it back to the passanger side V-cover just like the vortech system does..."

So far, no one else has done this... no one that i've found.

I'm asking this because the turbo may be mounted slightly lower than the rocker covers, so the return line can't go upward to the rockers, and the oil pan on the 4.0 sohc has no real space on the pan (it doesn't really have any sides, its almost flat like the transmission pan) to weld/tap in a return bung.

Any suggestions?

 

[gijoecam]

That's going to be a pressurized part of the engine... I wouldn't use that myself... it'll be at or near the same pressure as the source resulting in little oil flow through the turbo.

There is a lower 'skirt' on the SOHC block that the oil pan bolts to. I would think it would be quite easy to drill and install a fitting to dump the return right into the pan. I might even consider running it through a small cooler on the way, depending on the location of all the pieces...

Drop the pan and take a gander... I'm sure you'll be inspired.

 

[johnny23toronto]

Thanks gijoe for the response.

Please see the below excerpt about these engines (upside down view)... Do you think that there is enough meat to cut and tap a drain plug? To even get this tapped, I think I will have to drop it from the truck. I was looking under the truck the other day (hiding quietly from my girlfriend) the surface is filled with thickened girders/webs to reduce vibration and increase its stiffness/strength... not a flat surface in sight...

Has anyone dropped this skirted aluminum oil pan, this pan-above-the-pan.

It looks to me like I would have to remove the flywheel cover... and I guess that means I have to remove the starter?... maybe even an engine mount to slide it out...

Has anyone ever removed this part here?

 

[gijoecam]

From what I recall from a previous discussion, that's best done with the engine out... But I could be thinking of another vehicle.

 

[Cobraguy]

A turbo can use quite a bit of oil flow. It also cools the turbo and returns to the engine hot. You don't want it draining back to a rocker cover and flood your valves and valve seals. Return it to the pan. Also, I would make sure I had an engine oil cooler if I had a turbo.

Sounds like a great project!

 

[johnny23toronto]

Cobraguy, as shown in the picture below, there isn't enough space to put the return bung anywhere, eespecially such that there is at least 1" clearance above the top of the oil level.

I will be spending the day tomorrow just on this objective, so any advice/help from others on this forum would be greatly appreciated. I've looked at the other 4.0 setups and none have done this - to my knowledge. I think Amac told me he drained it through his own tapping on the timing cover near the drivers side front (I see a flat spot there)... but that seems to involve removing the fan and rad for access.

I will post pics of myself crying if I can't figure this out!

I really did give it a good look last time, and couldn't figure out where the best spot would be.

Maybe, i can find a place to tap and bolt through a threaded/barbed hose fitting in the ALUMINUM skirted area above the pan, that is, after I verify that the oil level is at least below this point (hopefully i will see the dipstick here and can work backwards from that.) I wonder how much the oil level changes when the truck is running compared to when its off.

This is all part of another remote turbo setup... I've been keeping it quiet since I don't want to post my progress until I have more done... by my photobucket (http://s396.photobucket.com/albums/pp47/johnnybee23/) can show you some of my piping (and ideas/pics I took from others) and wideband stuff... I will eventually prepare a nicer writeup for anyone of interest (plus to ask questions when I get stuck)... I don't want to fill the forum up with my useless gibberish... at least until I've got more done.

 

[Cobraguy]

That is a valid concern I hadn't thought of. And you wouldn't want to just drill a hole in the block somewhere and plumb it there because you might be dumping oil directly on the rotating assembly. Not good at all. But I'll bet if you get the pan off so you can see what's going on there, you can find a spot. And if you have the lower pan removed, it may give you access that will allow you to install a bulkhead fitting instead of a pipe fitting if you so choose.

You know, doesn't James (the SCT tuner) have a turbo on a SOHC motor? Worth finding out and asking him what he did. But I would still try and keep the oil return out of the rocker covers if you can.

 

[gijoecam]

There is plenty of flat (or flat-enough) area on the lower pan itself to weld a bung uf you wanted to. The disadvantage is that it would be hanging off the bottom of the motor, and IMHO, too vulnerable to getting whacked by any debris on the road. I wouldn't try it myself.

There's plenty of room on the upper portion of the oil pan for drilling and threading a bung. It might require a stubby drill and a right angle adapter, but you should be able to get in tehre without too much trouble. You could even drill the hole from the inside out, and just tap it for a pipe thread from the outside where there's clearance. If you use a tapered pipe thread, it doesn't have to be a perfectly flat surface since the threads deform to make the seal. Just don't run them in too tight and you won't have to worry about cracking it.

Another thought: Why not run it back into the drain plug hole? Admittedly it's probably not large enough, but that could be remedied quite easily. You could drill out the existing bung, weld a larger one if necessary, and just install a T-fitting to drain it when necessary. It wouldn't be pretty, but it, too, would be functional. I'd probably look for an earlier design one with the fitting pointing to the side to avoid low-hanging parts (if you can find one in good shape).

-Joe

 

[Cobraguy]

Joe, he is trying to keep his drain fitting above the oil level in the pan/crankcase if at all possible. When you shut the engine off, the oil in the turbo will gravity feed back to the engine. This is a very important consideration because any oil remaining in the turbo will "coke" with the extreme heat of the turbo. This causes deposits, sludge, all kinds of nasties in the turbo...not to mention what it does to the oil. In fact, I have seen some very elaborate systems with pumps or accumulators that pumped oil through the turbo or centrifugal supercharger after engine shut down.

 

[gijoecam]

Understandable... But putting it into the upper part of the engine as some suggested isn't going to help either...

The total system capacity from the OEM is 5 quarts. Half a quart (or more) will sit in the filter, and another half quart will be in the galleries. That leaves four quarts in the pan on a good day. Even iff he doubled the oil in the system with the turbocharger, it might bring the oil level in the pan up another inch, maybe an inch and a half, and that's with ALL the oil in the pan. The upper half of the 'oil pan' is 3 or 4 inches tall IIRC... Seems like it wouldn't be terribly difficult to get above the oil level.

And even so, why does it need to be above the level? So long as it's running downhill, won't it drain out of the turbocharger? I'd be more worried about it leaving a thin film to cook in the turbo. At least a large volume can dissipate more heat.

Also, in order for it to drain, it needs to relieve the vacuum at the top of the system... what's going to feed it in the first place? (Don't know what most people use...)

-Joe

 

[gijoecam]

One more thought... From the engine tear-down instructions in the service manual, they call it the 'lower block'. When you get to those steps, it says to remove the pan, remove the oil pickup, then the 8 bolts inside there, then remove the two 'frame bolts' (they appear to run front to back, possibly into the front timing cover?) then remove the lower block. The 8 main bearing caps are a much later step in the process, so it's safe to say the mains aren't bolted through that upper portion of the oil pan. It may be removable without yanking the motor, although I don't know anyone that's tried it.

 

[Cobraguy]

There won't be a vacuum because the inlet is plumbed to the oil system and it's not sealed. It's open to atmospheric pressure.

Since it's gravity feed with the engine off, the drain needs to be above the oil level or it won't drain. Pressure (weight) of the crankcase full of oil won't allow the little bit of oil in the turbo to drain.

Your thin film argument sure makes sense to me. But Kenny Duttweiler told me that he has seen Grand National turbos actually cook the oil to a lump in the turbo because it didn't drain. That's another reason to run synthetics on turbo cars...and if you really want to do it right, build a system with an accumulator to pump oil through the turbo after shut down. And of course, allowing the engine to idle for a couple of minutes before shut down is a very good idea to cool the turbo. And in my opinion, Ken Duttweiler knows more about turbo systems than anyone else in the world. He has never given me one bad piece of advice. So if it makes sense to him...

 

[gijoecam]

I can certainly understand the need for it to drain, but it's all going to see its own level... If you put a piece of clear hose in a bucket, the fluid will seek its own level provided it doesn't hold vacuum at the other end. If it's plumbed from the oil gallery, it could potentially hold a vacuum and not drain through the turbocharger. Some sort of vacuum breaker at the highest point going into the turbo might help alleviate any issues, but I wouldn't count on it. I would consider an accumulator on the system, and/or an independent oiling system for the turbo run off an electric oil pump and a cool-down timer just to be safe if cooling the turbo is a concern... But I also like to over-build stuff too.

 

[turbo cat]

when the oil leave the turbocharged it leaves in a frothing mess. If the line has any low spots or the drain is below the sump line it will cause the oil to back up. This will allow oil to eventually overpower the seals and oil can escape into either the compressor housing or turbine housing. Once into the compressor housing it will coat the coldside plumbimg, intercooler, intake and so on with oil. Not to mention oil hitting at MAF can cause devestation to a motor (if its a blow thru MAF). WHen oil enters the turbine housing your exhaust will smoke like a extremely rich diesel. It needs to be above sump line. On my turbo 4.0 i tapped and threaded in a fitting into the timing cover it works great. I let my truck idle for a few minutes before I shut it down and ive had no issues in a year of daily service

 

[johnny23toronto]

still no luck

TurboCat, I would be grateful if you could post a pic of that oil return. I searched your old posts and noticed that you hadn't gotten around to posting that particular pic yet. I have searched the timing cover, and the only place that I could envision the tapping or bulkhead fitting going into would be the area on the very front of the engine, drivers side, right close to the crankpully, where the date is stamped on the cover. In this case, the fitting would be facing forwards.

If our engines are similar (which they aren't), is my guess you had to remove the rad, the fan and maybe the front pulley to install this. Is this the case?

I think Amac tapped the drivers side timing cover too, if i recall.

I'm sooo disappointed today. The bottom black steel pan took only 5 mins to remove. The upper pan (aka ladder frame) won't come out... Researching this, ... sources online confirm that at least the front axle has to drop and engine must be detached from mounts and lifted 1.5"/or drivers side header removed.

So, I've literally spent 5 hours looking up the skirt of my truck (perverted?), scratching my head trying to find a place that has both clearance for tapping/drilling and is 1" above the high oil level indicator on the nearby dipstick end. Its torture since there are a few good spots, but they are blocked by - the oil filter, or the transmission lines, the starter... etc and even with my two different angle drills, clearance isn't sufficient.

When I get around to pulling the motor, (I never ever wanted or dreamed of doing that), (to send out for the timing chains/cassettes/tensioners rattle fix) I can pull the upper oil pan out and hug it and tap into it then.

The side on the starter has the biggest free area, but for my setup, I really want the return line at the passenger side, in the small space between the oil filter and the oil pan, on a 45 deg angle. I'll use a 45 deg bulkhead fitting with rubber or copper gaskets on inside/outside. See my image:

Honestly, at this point, I am probably going to get a sump tank and shur-flo pump. This little hitch is costing so much time. Damn it, I was really hoping to avoid a pump setup.

There must be another way to tackle this. I don't entirely believe that the front cam timing cover is not an area of pressurized oil (and therefore a good place for a turbo's oil return). Can anyone help me with this concept?

I hope others can learn something from my "oil return" struggle and find other better options for themselves. I'll keep searching this and other forums, someone else must have encountered this already.

 

[turbo cat]

Yes the 4.0 ohv and sohc are different but Im just giving you ideas of where to look.

 

[Cobraguy]

Did you talk to James? He has a SOHC turbo and may have a solution for you.

jah81592

Talk to him. You are going to need him (or someone like him) anyway for your tune. You certainly aren't planning on driving that with a turbo without tuning it first are you?

 

[johnny23toronto]

More progress made.

Yes, I should really talk to James, he has done some amazing things with his truck. So far, I have not decided on what to do with tuning.

My truck is in pieces, and I really should make the call on tuning now, so that I can put my 42#'s in and get this over with in one shot.

I was planning on running very very low/no boost but still use the stock injectors and all the piping through the turbo, until I could get it to a tuner - then throw in the injectors, a tune, and an 8 psi spring on wastegate.

For now, you can see two days of nasty work - to get the upper oil pan off and drill and bolt through a bulkhead fitting. Oh my god, this was hard. I had to remove/loosen left side exh header, starter, left side catalytic, front diff., etc. Then, by myself I jacked up the engine with prybars and pieces of wood on small jackstands (not fun). I still have all ten fingers, and half a brain.

The hose is silicone multi-ply and rated for 250 psi, high heat, and suction.

here is the place I drilled through the oil pan. It was precisely guesstimated and worked out perfectly. It is just below the crank on the pass side.

 

[CDW6212R]

Very good Johnny, you did it and avoided having to add an external oil pump. I'm going to tap the steel pan for a return for an extra oil filter. The pictures here helped me to select the flat bottom next to the drain plug.

I'm about to drill two holes in my V8 pan of my new engine. It's not in yet, and adding the holes and fitting now is easy compared to later.