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Author Topic: Oil Pressure Delay?  (Read 959 times)

September 28, 2017, 03:23:08 pm

Ibuprofen

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Oil Pressure Delay?
« on: September 28, 2017, 03:23:08 pm »
Hello all, long time lurker but first poster here on the site.

I've recently installed a rebuilt mTDI AHU into my vanagon but I've noticed something and I'm wondering if this is typical behavior. When I start up the engine it takes about 5 seconds before I start to see oil pressure on my pressure gauge. During this time the engine sound changes from louder to quieter as the pressure builds. Is this typical?

I tried to post a link to a video of this but I get the message "Sorry, you are not allowed to post external links."

Here is a video showing what I am describing: youtube.com/watch?v=FU-FoxOSbqU

I also drive a Mercedes 300SD turbo diesel and the oil system builds pressure nearly immediately after starting.

Thanks!
« Last Edit: September 28, 2017, 03:27:27 pm by Ibuprofen »



Reply #1September 28, 2017, 07:28:45 pm

libbydiesel

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Re: Oil Pressure Delay?
« Reply #1 on: September 28, 2017, 07:28:45 pm »
That looks normal to me.  Vanagon?  If so, then that is a looong run for a mechanical gauge.  If you have any air in the line it will slow the gauge reaction time.  When the oil is cold it will also seriously slow the reaction time. 
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #2September 28, 2017, 11:30:23 pm

ORCoaster

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Re: Oil Pressure Delay?
« Reply #2 on: September 28, 2017, 11:30:23 pm »
Could you clarify if that gauge is mechanical or electric with a senor on the engine.  But honestly that isn't a big wait.  The injectors take longer than that to warm up and they quiet down much later on my Rabbit.  Maybe I need to rebuild them.  Delay would be explained better if a mech gauge.  You can bleed some of the air out of the line if you want by cracking the nut on the back of the gauge once it it running.  Just remember to have a cloth under it and only crack it ever so slightly to get some oil out.  That might improve the delay. 

How are the pressure numbers?  That is the important part.

Welcome to the Forum by the way.  Good to have the lurkers become registered members. 

Now Own 1981 Caddy as the NEW DISTRACTION to all that is around me.  Project Away!

Reply #3September 29, 2017, 12:28:04 am

Ibuprofen

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Re: Oil Pressure Delay?
« Reply #3 on: September 29, 2017, 12:28:04 am »
Thanks for the responses. That is an electric gauge.

I think my engine has low oil pressure from some of the numbers I've read on the interwebs and was hoping maybe this was unusual and potentially an indication of something. Once the oil is warm I see somewhere around 10psi per 1k rpm. I don't have the tach setup yet so I'm not certain but I haven't seen pressure above 30psi with warm oil.

Because the engine is a rebuild, is there any recommended path forward other than doing a bearing replacement on the crank and intermediate shafts? I suppose I could try just the intermediate shaft but the amount of work it takes to get everything out I may as well just keep going and do all the bearings?

Thanks

Reply #4September 29, 2017, 01:13:13 am

vanbcguy

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Re: Oil Pressure Delay?
« Reply #4 on: September 29, 2017, 01:13:13 am »
Where is your gauge sender located? If it is in the head then your numbers are typical. If it's in the oil filter flange then you may have some issues.

It takes about 5 seconds for pressure to stabilize on my electric gauge mounted to the head on my AHU too.

Sent from my LG-H873 using Tapatalk

Bryn

1994 Jetta - AHU M-TDI - Jezebel Jetta
2004 Jetta Wagon - 1.8T - Blitzen

Reply #5September 29, 2017, 12:28:50 pm

Ibuprofen

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Re: Oil Pressure Delay?
« Reply #5 on: September 29, 2017, 12:28:50 pm »
The sender is on the second port of the oil filter flange next to the stock sender. I left the stock sender in the flange but it is not wired to anything since my electric sender has two connections, one for the gauge and one for the idiot light.

When your engine pressurizes do you notice the engine noise change? I think it must be the lifters filling with oil.

Thanks

Reply #6September 29, 2017, 03:47:17 pm

libbydiesel

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Re: Oil Pressure Delay?
« Reply #6 on: September 29, 2017, 03:47:17 pm »
Hmmm, electric gauge and at the filter flange, that doesn't look right.  You say the engine is rebuilt but you want to change bearings again?  Weren't the clearances checked and brought within spec for new parts during the rebuild? 

Oil pressure is affected by the following:
-oil clearances at main bearings
-oil clearances at rod bearings
-oil clearances at cam bearings
-oil clearances at intermediate shaft bearings
-oil clearances at oil pump shaft bushings
-oil clearances at lifters
-oil clearances at turbo bearings
-opening pressure and proper operation of piston cooling oil jets
-seal in bottom of vac pump gear
-oil pump clearances
-oil pressure control valve located in oil pump pickup
-oil pump screen blockage or blockage in oil gallery
-any leaks (e.g. cracks or missing plugs) in oil passages of block, head, or crank
-leak at pressurized oil channel in head gasket
-incorrect oil filter
- oil viscosity
-oil temperature

That's all I can think of. 
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #7September 30, 2017, 01:33:52 pm

Ibuprofen

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Re: Oil Pressure Delay?
« Reply #7 on: September 30, 2017, 01:33:52 pm »
Wow, thanks for the list Libby.

I bought this engine from craigslist and it was supposedly a new Quality German rebuild. The seller never installed it. I've made a few changes in order to adapt it to the vanagon which could have altered the oil system.

1. I've swapped out the outer/front intermediate shaft bearing for one that I could reclock. The original discussion is here: http://forums.tdiclub.com/showthread.php?p=4562442#post4562442  Images of the bearing I used here: https://imgur.com/a/CcgJa
2. The oil pump was swapped to the 50 degree pump, Febi brand was what I read as being the best replacement. part no 068115105BP
3. The Turbo that was originally installed on the engine was dumping oil into the intake but I swapped in a spare that I have. I have a video of this! https://www.youtube.com/watch?v=FlU_m_ItNVE

I should probably borrow a second oil pressure gauge to make sure my gauge isn't being weird, though it is the same gauge I was using on the wbx engine. Another thing I noticed on this engine is when I went to button everything up and turned the intermediate shaft by hand it was significantly more difficult to spin than what I'd felt before the bearing and oil pump was installed. Maybe the machining process altered the bearing diameter, or maybe the oil pump was installed incorrectly. I don't know how this would factor in with low oil pressure unless the belt were slipping on the intermediate shaft pulley, which I don't think is happening. I need to get another set of eyes to make certain this isn't the case.

I have doubts that Quality German would send out an engine with low oil pressure and am wondering if the bearing swap or the pump may be at fault. I may just replace the pump and put in a new unaltered intermediate shaft bearing and see if things improve. It's a bit of a pain on my install to get into the engine since the transmission, flywheel, and adapter plate both need to be removed to get the oil pan off which is why I mentioned replacing all the bearings for good measure. It would be best to find the problem and fix it instead of throwing money at it, of course!

Thanks!

Reply #8September 30, 2017, 03:27:18 pm

vanbcguy

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Re: Oil Pressure Delay?
« Reply #8 on: September 30, 2017, 03:27:18 pm »
Definitely verify the pressure with another gauge. No sense going in for major surgery without knowing for sure.

Sent from my LG-H873 using Tapatalk

Bryn

1994 Jetta - AHU M-TDI - Jezebel Jetta
2004 Jetta Wagon - 1.8T - Blitzen

Reply #9September 30, 2017, 07:13:04 pm

libbydiesel

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Re: Oil Pressure Delay?
« Reply #9 on: September 30, 2017, 07:13:04 pm »
Indeed.  I've done a considerable amount of work on a couple different engines because of gauges not reading correctly.  I now have a nice quality 'test gauge' for checking oil pressure. 

Why adapter plate vs. diesel vanagon bell housing?

Did you do a 15 or a 50 install?  If 50, then I would recommend getting the diesel vanagon bell housing instead of the adapter plate.  You might also consider the TDI splined vanagon input shaft (~$100) in order to have a nice array of clutch option.  If using the SMF, you can get a channel machined in it and have it balanced and then easily remove the oil pan without removing anything else.

It is normal with new intermediate shaft bearings for the shaft to be harder to turn.  As long as it is spinning properly, I doubt the bearing modification is the issue.     

Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #10October 02, 2017, 01:26:29 am

Ibuprofen

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Re: Oil Pressure Delay?
« Reply #10 on: October 02, 2017, 01:26:29 am »
Thanks for the replies, I'll definitely get a second pressure gauge connected for a sanity check.

The install I have is 50 degrees but I'm using a Porsche 915 transmission which is the reason for the adapter plate. I purchased my buddy's diesel setup after his AHU threw a rod (different engine than mine) and he decided to re-power with something else.

Any preferred gauges?


Thanks!

Reply #11October 02, 2017, 08:04:39 pm

ORCoaster

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Re: Oil Pressure Delay?
« Reply #11 on: October 02, 2017, 08:04:39 pm »
Mechanical is my preferred.  Stewart Warner or VDO  Black face, White numbers.  Just like to keep it stock.
Now Own 1981 Caddy as the NEW DISTRACTION to all that is around me.  Project Away!

Reply #12October 03, 2017, 11:57:35 am

libbydiesel

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Re: Oil Pressure Delay?
« Reply #12 on: October 03, 2017, 11:57:35 am »
Nice trans choice.  You're excused for using an adapter plate.  :)

As far as testing/confirmation use a test gauge.

Mechanical oil pressure gauges don't work very well in Vanagons.  The ~12-15' run from engine to dash makes for very delayed reactions in cold weather. 

It is my experience that the electrical oil pressure senders fail very quickly when mounted solidly to the engine.  I believe the diesel vibrations shake them apart.  I would recommend remote mounting with flex hose between engine and sender.  If you add an oil to air cooler (very good idea) then adding the electric sender in the line to or from cooler is one way to accomplish it. 
Use, abuse or ignorance of any information is at your own risk, confirmation or refutation is your own responsibility, no further 'proof' will be given, take it or leave it, YMMV,terms subject to change without notice, avoid contact with eyes or skin, contents known to cause cancer in California

Reply #13November 07, 2017, 01:20:35 am

Ibuprofen

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Re: Oil Pressure Delay?
« Reply #13 on: November 07, 2017, 01:20:35 am »
My buddy let me use one of his large mechanical gauges to sanity check with my electric oil pressure gauge. He was adventurous enough to ride in the back of the van with the lid removed reading the gauge while we drove around town. It was interesting seeing differences between the two gauges. In general, they were pretty similar but the mechanical gauge was very quick to respond to changes in pressure.



Having verified that the oil pressure was still no bueno, I set into the task of pulling the engine to remove the oil pan to inspect and eventually swap in a new oil pump. I had already purchased a new oil pump from FCP Euro (Febi 068115105BP) to have on hand and what we found was that the pump I'd originally installed had smaller gears than the new Febi pump. The installed pump was ordered from Bus Depot, same part number, but what I received was Topran brand. After sitting at the computer and reading some more online it would appear the Topran is likely a 30mm pump, Febi 36mm.

I haven't yet installed the Febi pump as I'm waiting on connecting rod bolts since I plasticgag'd while I was in there (con rod bearings appear within wear spec) and I also want to reduce the Febi oil pump's vertical lash, which seems to be a bit too high as I can pull on the shaft and I get a decent click sound from it. I'll update this thread with what I hope is good news after the Febi pump vertical/end lash is reduced and checked with plasticgage and installed. The internet hive mind suggests top lash somewhere around 0.001-0.002" so I'll aim for that.

In hindsight I could have compared the Topran brand pump with the stock TDI oil pump and I'd probably have noticed the gear size difference. At any rate, I haven't actually fixed the oil pressure issue!

Stay tuned...

Reply #14June 08, 2018, 04:00:32 pm

Ibuprofen

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Re: Oil Pressure Delay?
« Reply #14 on: June 08, 2018, 04:00:32 pm »
It's been a while, but I ended up swapping in the correct pump. The oil pressure response is improved and the warm oil numbers are a bit better. I'm seeing 30-ish PSI on the interstate when up to temp, still no tachometer so I can't say for sure at what RPM but it's probably in in the 3k area. I've been driving and keeping an eye on things, if I notice the pressure is dropping I'll stop driving it but thus far the numbers are at least consistent and not dropping.

Changing the topic a bit but I'm wondering if anyone has the part number for the ALH injection pump sprocket hub? I am in the process of swapping on a land rover pump.

EDIT: sprocket hub appears to be part number "2 466 434 005"

Thanks!
« Last Edit: June 11, 2018, 12:01:28 am by Ibuprofen »

 

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