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offrdbus70 Samba Member
Joined: August 23, 2006 Posts: 512 Location: Pine Valley-SD
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Posted: Sat Dec 07, 2013 4:51 pm Post subject: It started blowing blue smoke |
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Ok so I have been chasing an oil pressure loss issue for like 5 years in my bus engine. If you tread really hard on it it loses pressure not to return for 4-6 seconds.
So I hit up another VW nut to help. He comes over yesterday and we take a look. First thing we find is it is down a quart of oil. WTH I say i just topped it off yesterday.
So he says "lets go for a ride" So we roll down to the store and buy a quart of oil. We put it in and I proceed to romp on it hard. No pressure loss. Of course it will not do it when I need it to. We get back to the shop and I check the oil level. Now it is a quart over. "Wait I say what is going on?'
'It should be dead on not a quart over?'
So we start it up and shut it down and check it real fast. Now it is dead on. Ok i am confused.
So I go home yesterday and notice blue smoke pouring out. Mostly right after decel when getting back on the gas. Is this because it is overfilled somehow? Or am I in engine trouble mode?
Thanks!
MG |
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SRP1 Samba Member
Joined: January 06, 2007 Posts: 4340
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Posted: Sat Dec 07, 2013 5:06 pm Post subject: |
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Split the difference, 1/2 qt and see what happens.
Sounds like you overfilled it, but also have a pickup and return issue at the same time.
Also how is the engine vented? Is excessive crankcase pressure holding the oil in the valve covers?
Sounds like a leak down test is in order.... |
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offrdbus70 Samba Member
Joined: August 23, 2006 Posts: 512 Location: Pine Valley-SD
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Posted: Sat Dec 07, 2013 5:10 pm Post subject: |
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It is vented from both covers and the center of the case. I know it is leakdown time. Uhg.
Would overfilling it cause it to smoke? (grasping at straws here).
Thanks
MG |
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SRP1 Samba Member
Joined: January 06, 2007 Posts: 4340
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Posted: Sat Dec 07, 2013 5:15 pm Post subject: |
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Yes overfilling can cause it to smoke as oil is drawn past the rings and into the combustion chamber on decel. Same goes for loose or worn intake guides also. |
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SRP1 Samba Member
Joined: January 06, 2007 Posts: 4340
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Posted: Sat Dec 07, 2013 5:16 pm Post subject: |
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Try blocking off the #3 valve cover vent also, see if that changes your oil pick up issue. |
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modok Samba Member
Joined: October 30, 2009 Posts: 26790 Location: Colorado Springs
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Posted: Sat Dec 07, 2013 5:17 pm Post subject: |
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If the engine is able to drain the volume of oil in the cooler then the oil level will appear high sometimes. Hard to guess what the cause is.
now, the losing oil pressure and taking several seconds to come back is easier to guess, that problem is probably somewhere between the pickup tube and oil pump. The pump has excessive clearance or there is a leak/restriction on the pickup side of it.
Does this thing have an oil filter? single relief case? |
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mark tucker Samba Member
Joined: April 08, 2009 Posts: 23937 Location: SHALIMAR ,FLORIDA
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Posted: Sat Dec 07, 2013 5:34 pm Post subject: |
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after 5 years I would pull it & rebuild it befor something takes it appart by it's self. |
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SRP1 Samba Member
Joined: January 06, 2007 Posts: 4340
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Posted: Sat Dec 07, 2013 5:53 pm Post subject: |
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Years ago we had problems with oil pressure doing the same thing, dropping under high RPM use, and at times at idle depending on the oils level.
Problem was the engine case and the oil pump! So it was a parts combo issue.
Oil pump was a 30mm Melling (No not the problem you all are thinking about now. ) and the Brazilian AS41 cases.
What happens when married up is the oil pump mating surface on the case was in a different spot than the German and Mexican cases. The mounting surface on the case for the pump pushed the pump slightly further away from the intake port which left the port just slightly (and I mean slightly) exposed. In other words the pump would not drop down in the case far enough. Other issue was the Melling pump had a little to much material on it's case mounting side, again not letting the pump drop in far enough.
Between the two problems it made for one big problem, this would only become an issue during high RPM use as the oil level in the sump would drop and expose the port thus causing a loss of prime to the pump. The symptom was a 4-5 second recovery time to regain oil pressure.
Sound familiar? |
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devbear12 Samba Member
Joined: November 24, 2013 Posts: 123 Location: Tuscaloosa AL
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Posted: Sat Dec 07, 2013 7:10 pm Post subject: |
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This may sound stupid but if you have an oil filter adapter the oil filter shouldn't drain back and maybe it is! Try a different brand oil filter????? I know it sounds dumb but I have personally seen oil filters cause low oil pressure, and it could explain the level changes. |
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SRP1 Samba Member
Joined: January 06, 2007 Posts: 4340
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Posted: Sat Dec 07, 2013 7:35 pm Post subject: |
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devbear12 wrote: |
This may sound stupid but if you have an oil filter adapter the oil filter shouldn't drain back and maybe it is! Try a different brand oil filter????? I know it sounds dumb but I have personally seen oil filters cause low oil pressure, and it could explain the level changes. |
True! just had an issue with this on a personal vehicle last week (non VW) filter had a small foreign piece of rubber debris jam between the anti drain back flap and the filter housing that caused the flap to stick open and let the filter drain back when the engine was shut down. The tip off was I noticed it took the oil pressure gauge twice as long to show pressure as normal because it had the fill the filter every time the engine was started.
Took the filter off, saw the problem, changed the filter, problem solved. |
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offrdbus70 Samba Member
Joined: August 23, 2006 Posts: 512 Location: Pine Valley-SD
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Posted: Sat Dec 07, 2013 9:56 pm Post subject: |
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Thanks guys. I run a Mahle rabbit diesel filter. I do not know what the deal is with the pressure.
Aluminum case. Auto Linea.
1.5 sump
Pretty sure it just sucks up a big glob of air instead of oil.
Game plan is to tear it down. Again. Take the case to Adrian for his pressure mod.
Move the cooler closer to the rear of the van.
Add a huge sump 3.5-4 qts
Put Total Seal rings in it
Lose my fake swivel feet and get Porsche ones
If that does not fix it I am going to burn it.
What do you think of the plan? |
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modok Samba Member
Joined: October 30, 2009 Posts: 26790 Location: Colorado Springs
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Posted: Sat Dec 07, 2013 10:01 pm Post subject: |
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You don't need to do all that.
Check the cylinders with a dial-bore gauge, if they are too far from round no rings will seal.
Inspect the oil pickup and oil pump and the fit of the oil pump closely, the problem is there.
A bus will be on two wheels before you have enough g-forces to need a deep sump, I did it plenty myself |
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offrdbus70 Samba Member
Joined: August 23, 2006 Posts: 512 Location: Pine Valley-SD
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Posted: Sat Dec 07, 2013 10:12 pm Post subject: |
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Good evening Modok.
I have replaced the oil pump with a 28mm Shadek. Was a 30
Tig welded the pickup tube extension on.
Pulled the case in half and glued in the pickup tube then checked vacuum to make sure there was no leak.
Plugged the stock oiling hole to prevent leakage.
Cut off most of the hat of the pickup tube to allow for a faster return.
Drilled larger return hole from front of case cam gear area.
Went to a Rabbit Diesel filter with a one way valve to prevent false oil level.
And I am still losing pressure at high rpm. 4500 UP
This engine has come apart 4 times so far. Cost a grand it seems like every time.
I will dry sump it if the above does not work. |
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modok Samba Member
Joined: October 30, 2009 Posts: 26790 Location: Colorado Springs
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Posted: Sat Dec 07, 2013 10:19 pm Post subject: |
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ah yes, I remember now. baffling
Did you pull the plugs out of the case and look for junk in all the passages including the pickup? How is the pressure sender and oil cooler plumbed? |
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SRP1 Samba Member
Joined: January 06, 2007 Posts: 4340
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Posted: Sat Dec 07, 2013 10:58 pm Post subject: |
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I agree with MODOK, spec it all out and don't bother with a giant sump, waist of time and it's not the answer. Also if the cylinders are not honed perfectly, don't expect them to be the all mighty answer to this either. Total seal rings are nice, but require the cylinder to be honed at the machine shop to work correctly. Their not as forgiving as say a set of Mahle or Grant rings, but they are nice once done correctly.
You have covered allot of bases to try and fix the problem, and I think while some of what has been done is good, other things may have hindered the problem even further.
The one that concerns me the most is the fact that you cut the "hat" off of the pick up tube. The hat has many reasons to be there and without going into detail I recommend that you put a complete German pickup tube in that engine. I would also run a windage tray to help control the oil. Many don't like them, but I know for a fact that those people just don't understand how to set them up. It's not easy to do, but they work!!!!
Another very possible problem is that the oil return behind the cam gear is not open. The aluminum case have a problem with this as sloppy casings have closed off that return. If closed you could be holding up a couple quarts of oil in that cavity that would have a very slow return. |
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offrdbus70 Samba Member
Joined: August 23, 2006 Posts: 512 Location: Pine Valley-SD
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Posted: Sun Dec 08, 2013 1:34 pm Post subject: |
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SRP1 thanks for the reply.
Yes the hat on the pickup tube serves a purpose. But that goes away when you install a sump and put an extension on the pickup tube. Now it blocks oil from returning to the 1.5 sump. So I cut it off. Pressure issue was previous to this mod.
The Total Seals are because my rings gave up two weeks after the last assembly.
I used the old rings and did not hone. (dumb ass move i realize)
It only had like 200 mi on it.
So it ran all snappy and went soft after a couple weeks. So now I need a proper hone and new rings. Gonna take them to Major's
Yes the cam return hole was partially blocked on this case but I fixed that. It is a big return hole now.
Windage tray? Yes worth a shot for sure. I will add it to the list. Who makes the best one?
After looking at prices last night I think I am going dry sump. I do not like the sump I have as it leaks and has no drain plug. Another sump is like $200 and will maybe not fix my issue. Dry sump will for sure.
Now what kind of dry sump pump?
And is anybody using the external Jaycee pressure control?
Thanks!
MG |
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