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

[Gizmoman]

Jetmugg, congrats on your no leak engine!
I wish I could say the same and I'm not even running on the salt. May I ask what type/brand/part number of sealant you used and where? Also, were there any "procedures' you did that were part of your success? I know spotlessly clean is required.

[Jetmugg]

Since this was a complete rebuild, all of the surfaces were squeaky clean, which definitely helped.  I made sure all the drilled and tapped holes were clean and that fasteners threaded in smoothly before final assembly.  Any holes that needed to be chased out were chased with a bottom tap.

I used the regular Victor Reinz gasket set and the aerosol type Hylomar on all gaskets.  I would hang each gasket from a short piece of utility wire, and then spray a couple of light coats of Hylomar on each side of the gasket before assembly.

The only place I used any RTV was on the ends of the cam tower caps, and I used it very sparingly.  It's an AAZ head on a 1.6 Turbo block.

My breather setup is also non-stock.  I welded an AN bung fitting in place of the rubber grommet on the valve cover, and it's plumbed directly to a Moroso "puke can" with a filtered and vented lid.

Steve.

[air-cooled or diesel]

I am running a 36 mm "turbo" oil pump, since the block is plumbed with oil squirters.  It's a hydraulic lifter engine as well.  If the OP loss continues to be an issue, I can (and will) swap in one of the smaller oil pumps as a trial (I've forgotten the mm size of the non-turbo oil pumps).

I don't think your 'trial' with a smaller oil pump can give any good results. you want a 36mm pump, and you have hydro lifters too. they require 36mm.

[Jetmugg]

I suppose if it is pumping all of the oil out of the pan, overfilling may be an option.  I certainly wouldn't want to overfill unless I was sure the windage tray was keeping the oil away from the crank, though.

So many possibilities...

Steve.

[libbydiesel]

For the sake of accurate info, it wasn't until midway through the run of hydro 1.6TD engines that VW went from 30mm to 36mm oil pumps.  There were 2 or 3 years of hydro 1.6TD engines that came with 30mm oil pumps.

[Jetmugg]

Thanks, Libby.  I'd be interested to hear any of your thoughts on this situation.  I realize that the GoPro video I posted isn't very High-Def, but the oil pressure changes are visible (OP is the first gauge to the right of the steering wheel).

https://www.youtube.com/watch?v=PBGNUAL5nzw

Steve.

[Jetmugg]

As soon as I lift off the throttle (after passing through the 1 mile timing lights), the oil pressure jumps right back up.

Steve.

[libbydiesel]

First I would confirm gauge operation by installing a mechanical OP gauge.  I have had several electronic gauge senders fail with few miles  on them.  I odn't think they like the diesel vibrations.  On several TD engines in vanagons I have observed that when the oil level is even slightly low, then OP drops as boost rises much like what your video shows.  I have always assumed it was due to aeration.  If that is your issue, the simple solution is to add more oil.  A larger oil pan and a lower oil pickup tube would help as well.   

[air-cooled or diesel]

my idea wasn't adding oil, but lengthening the pick-up tube, as its not even 2 qts that are going to be out and around engine, draining back, etc. the pick-up tube may only go down into the oil pan 1.5qts maybe less. you wont have as much as 3 whole qts out of the oil pan, I don't figure. lengthening the pick-up tube will guarantee your not sucking down your oil level because your runs are at prolonged hi-revs, and you don't have to add extra oil, but the effect is similar.

[Jetmugg]

OK - I can come up with a mechanical gauge for some testing.

Since the pan is off the engine now, I can also do some measuring to determine how much clearance there is between the bottom of the pick-up and the inside of the pan.

I'm trying to give consideration to all possibilities.  I can do all kinds of testing here, in order to ensure the greatest chance of success at Bonneville.


Steve.

[theman53]

The other pumps are 26 and 30mm gears. The pressure is the same for the spring is the same, but it is supposed to move more volume of oil with the larger gears.

[Jetmugg]

Yeah - I have always assumed that the larger gears actually create more oil flow, not necessarily more pressure.  Any increase in pressure comes from a restriction in the flow somewhere "downstream" in the system.

Looking through the Bentley, I also noticed that early engines call for almost 1 quart less oil than later models.  Were there different dipsticks on early vs late diesel engines?

I have no idea what engine the dipstick I'm using came from.

Steve.

[damac]

I didn't notice a change with 36mm in pump on 2 turbo blocks as far as oil pressure.  I just assumed it was "better" to have the bigger ones so I put them on my daily drivers.

[theman53]

Yeah - I have always assumed that the larger gears actually create more oil flow, not necessarily more pressure.  Any increase in pressure comes from a restriction in the flow somewhere "downstream" in the system.

Looking through the Bentley, I also noticed that early engines call for almost 1 quart less oil than later models.  Were there different dipsticks on early vs late diesel engines?

I have no idea what engine the dipstick I'm using came from.

Steve.

IIRC the dipstick should be fine if the dipstick tube and dipstick are correct for each other. The early 1.6 gassers and I think the early 1.5 diesels had a 3 qt pan. That is why I asked you earlier if you needed a 4 qt. pan. The later vw 8v engines all had the 4qt pan...making it a 5 qt oil change with the filter. The early pan you could only do around 4 qt oil change with the filter and that smaller pan.

One interesting thing I found with my 1.6 vs the 1.9 aaz engines I have is that the IM shafts drive pulley is considerably smaller on the aaz vs the 1.6.

[air-cooled or diesel]

One interesting thing I found with my 1.6 vs the 1.9 aaz engines I have is that the IM shafts drive pulley is considerably smaller on the aaz vs the 1.6.

making the im shaft speed greater, possibly to speed up oil pump.