Oil pressure jumping around at higher RPM's - add a windage tray?

[Jetmugg]

After watching my Ohio Mile runs a little closer, I have noticed a scary sight.

My oil pressure gauge shows that I'm having some momentary drops in oil pressure at higher rpm's.  I wonder if I'm foaming the oil?

While I'm driving it, I'm too busy looking out the front window, but the video shows some loss of pressure (first gauge to the right of the steering wheel).  Scary.

https://www.youtube.com/watch?v=PBGNUAL5nzw&feature=youtu.be


Steve.

[vanbcguy]

Wow - yeah that doesn't look good...

Fortunately a ready made easy to install windage tray solution exists (if that is indeed what the problem is)

https://www.greaseworks.com/store/index.php?route=product/product&product_id=341

I used one on my AHU build...

I assume your timing belt is tight enough - if it is loose or if there are any oil leaks around it the belt can slip on the IM shaft pulley fairly easily.  Seems like it is only happening at the top of your RPM range.  Really though the belt is being pulled hard against that pulley by the engine so it SHOULDN'T be a problem...

Are you allowed to use a custom oil pan?  Something with a couple quarts more capacity definitely wouldn't hurt and would help mitigate foaming - just some side chambers welded to a stock pan would be dandy.

[Jetmugg]

I will check the belt tension for sure.  My mind is racing, trying to figure out how I can have a loss of OP at higher rpm's.

The video shows a "bobble" of oil pressure in 3rd gear as well, but it comes right back.

I can use any pan I want, but there's not a lot of ground clearance underneath this thing.

I'm hoping to see some skid marks on the belt that may indicate some slippage.

Oil foaming at higher rpm's is the only other thing that comes to mind right away.

Steve.

[theman53]

Those are the exact gauges I have IIRC the autometer sport comp 2". If you are running an electric like mine and not a manual gauge then I bet you have a ground issue or a loose wire. 4th looked scary, but for you to lose pressure like you did in 3rd the truck should have blown up if it was for real. Usually you don't lose it all at once like you did in 3rd. 4th looked more gradual and believable. Check the wiring or wiggle it and see if you get any results.
You did use the little plastic thing that clips onto the pickup tube didn't you? I honestly think that is all you would need. I use the windage tray, but I don't think it helps with the oil pressure as much as wind up.

[damac]

The first 1.6td jetta I got had low oil pressure down low at idle and it was dipping just a bit below spec at speed.  That annoying buzzer system I thought was freaking out was warning me I guess.

That engine was tired with blowby and flaked im bearings but I let family run that sucker for years until the head gasket blew after a blown coolant hose.

There is this 18 mile  stretch of twisty up/down mountain that we had to try and drive like a race car to get around people and get to work in a reasonable amount of time and that car would get pissed with the buzzer on the sudden turns and long sweepers.

I have had other use engines since that were borderline oil pressure spec with flaked im bearings but they didn't do what that first engine did.


I have since freshened up 3 daily drivers and used the cam cover, windage try with 36mm oil pump and the plastic deflector and I have never seen this crazy drop in oil pressure since.  I use auber gages now.

[air-cooled or diesel]

in 4th I could see a steady loss of pressure, I wouldn't rev the rpms up until you get this solved; nice run though,, belt could be slipping, could be a bad im shaft, bearings, or vac pump/oil pump drive could be adding drag to shaft/belt.

[Jetmugg]

I''m planning to move forward on at least 2 fronts....

First, my mind won't be able to stop thinking about possible causes.  Windage/oil frothing seems to be the first thing that I'm thinking about.  However, I can't explain everything I see in the video based only on that.  In 3rd gear, the OP jumping around, losing it and then getting it back while accelerating, I can't quite figure that part out.

In 4th, the OP goes away at higher rpms (probably around 5K), but then comes right back as soon as I lift out of the throttle.  There's another one I can't quite explain.

Over the next few days, I'll be carefully draining and inspecting the oil, along with cutting the filter apart and looking for any debris.

I was using Mobil 1 Turbodiesel Truck oil (5w30), and a Bosch oil filter.

I will most likely pull the oil pan as well, at which time I can pull a main cap and a rod cap for bearing inspection.

This engine is very fresh (probably less than 20 miles on it), and was broken in on a chassis dyno, using Joe Gibbs break-in oil.

The IM shaft bearings were replaced at the rebuild.

The belt might be a tiny bit loose, but I don't think it can explain what is seen in the video.  I will snug it up.

There are no leaks.

When I put the bottom end back together, it will get a windage tray.

I'll also have a look at modifying an extra oil pan to give additional capacity, and a more protected area for the turbo drainback line to discharge.

I'll be moving the GoPro camera more forward and centered up, to give a better view of the gauges for future runs.

Keeping my fingers crossed.

Steve.

[CRSMP5]

Well i have few ideas....

Oil too thin... Gets too hot by that point.... Whats oil temp?

Oil pressure releife valves do goofy things....

Aaz head has hydro valves.... Starting to float giving issue...

But first to me... Wrong oil for application.... If its got hydro valves, had to use oil pump for hydro... The vac pump could also be seizing up... Belt slips... No op...

For your egt, for mile... Turbo red hot.... At min 15w40... Id do 20w 50 for salt flats... Turns to piss water thru turbo, dummps head op where gaugemounted

[Jetmugg]

The vac pump is gutted, so I don't think there's an issue there, but I will pull the cap just to be sure.

I'm definitely considering heavier oil - didn't realize there was a different spec for hydraulic engines.

I'm using the 36mm oil pump.

The guage sending unit is mounted in the back of the head (over the transaxle).

I'm planning to add a great big red Oil Pressure warning light right next to the tach!

Keep the suggestions flowing, please.  I need to regain piece of mind before Bonneville.

The engine didn't sound any different or stop pulling when the OP dropped.  Thinking back, I might have expected some lifter problems.

Steve.

[air-cooled or diesel]

I personally don't think the oil is a problem, mobil 1 syn is good for most applications. I d think of checking end of im shaft, the end-play that collar is rather thin, but you have to remove timing belt to get at it. 1 thing I was thinking over prolonged high rpm, there may not be enough oil in pan, shouldn't be a problem, but the oil level may at these high rpms be going lower than the pump intake. oil foaming with this oil may be a problem, its pretty good oil, but with these high prolonged rpms its possible. ?try a stronger oil?

[Jetmugg]

I used to mess around with Oldsmobile powered jet boats (455's).  They were known for their propensity to pump all the oil out of the bottom of the pan.  They couldn't drain the oil back to the pan fast enough to ensure proper oiling.  I was wondering if there were any issues with VW hydraulic diesels in this respect.  I'll check my "puke can" to see how much oil is in it, but I don't see how it's possible for the upper part of the engine to hold the entire 4 or 5 quarts of oil.

My gut says that windage problems are causing this, but I don't have a good way to check, other than adding a windage tray and making some more high speed runs.

I am running a Summit Racing oil filter/cooler adapter, and a pretty good sized oil cooler in front of the radiator.  Oil temp doesn't look like a problem, but I will check the video and the gauge readings to verify.

My turbo oil drain-back is a braided -10 A/N line (5/8" inside diameter) that discharges directly into the oil pan through a bulkhead fitting.  The fitting is located on the back side of the pan (towards the firewall), a couple of inches back from the crank pulley.

My sense is that if I had an IM bearing problem, the oil pressure would be low throughout the RPM range, and not manifest itself as a problem only in the upper RPMS.

As far as picking the right oil, I have 100% confidence in Mobil 1, and it's provided free of charge from one of my sponsors.  That being said, there are enough different grades of Mobil 1 that it might be beneficial to spend some time checking other weights of oil.

Thanks for all the brainstorming, guys!

Steve.

[theman53]

I really think you have a gauge issue, maybe not if you have the smaller 3 quart oil pan instead of the 4 quart like most have. I have a 4 quart I would send you for shipping if you need it. I have those exact gauges and they did similar to me a few times. FREAKED out and then went over connections and it hasn't happened again. I don't have hydro lifters but I do have a hydro head and 36mm oil pump.
The only other thought I have is maybe your oil cooler/lines could be suspect. I really have a hard time believing that it is foaming. If you have say 3/8" lines on your oil cooler at 5k rpm it may not flow enough to sustain pressure to the head like you want. The head loses pressure first since it is last to get the oil. Then when you let off you see it jump right up as the oil is there, just not enough to flow the pressure you want. If this is the case a thicker oil may yield worse results as it could find it harder to get through. IIRC I used 1/2" lines on my oil cooler, but if you have to change it I would research what is best.

[theman53]

as far as I know and have seen there are no oil return issues with the vw engines. Same head design as the gassers that run even higher RPM with no issues. The hydro head has 4 very large oil return holes, so I doubt it is an issue.

[theman53]

For racing here is the oil I would use if you get it free anyway. I like scheaffers oil myself, but free is free and Mobile makes ok stuff.
http://www.theoilhub.com/Mobil_1_15W50?src=Google&gclid=COD2kqO6774CFdSMMgodkXkAaQ

also, I know it is hard to do with your cooler full of ice, but I usually don't boost hard until the oil temp is 150f or higher. It doesn't flow correctly until then...stuff you are probably already doing, but figured I would share.

[Jetmugg]

15W-50 sounds good.  I'm sure Mr. Bauman at Bauman Oil will be willing to provide a jug of the good stuff.

I will be changing my icewater cooler operation a bit.  I'll warm the engine up without running the circulation pump, then will turn on the intercooler icewater pump just before the competition run.

Steve.