Low Oil Pressure at Idle

[the-unibonger]

I've mentioned my oil pressure problems before but I'll summarize.

Had low oil pressure before the rebuild. Did a complete rebuild but still have low oil pressure once warm. I've used 2 different used Type 4 pumps and still have the same exact pressure. Two days ago I pulled the Relief Valve, Plug & Spring from a spare case. The Valve was a slightly different shape, the spring was shorter and the plug was deeper on the spare. My plug has a bevel on the lower ledge of the groove (the spare has no bevel. just a groove). The spare plug is just slightly deeper and has a VW logo (mine has a wierd design). The pare spring is about 1 inch shorter than mine. My spring is very difficult to compress and get screwed in (sticks out about 1 inch before compressed into the hole). It shoots out when you remove the plug. The spare fits perfectly.

With the new valve & plug (old longer spring) my oil pressure increased just slightly. But still barely comes on once warm and goes out with the slightest tap of the pedal.

Should I try the smaller spring from the spare? Or is there something else I can do.

Before anyone asks. Bearings are new and clearance is perfect. No leak at the sender. Slight oil leak between 3/4 head & cylinders.

I tried to put in 30mm Schadek but the lower shaft boss just barely hits the cam bolts. They were clearanced for the Type 4 Pump but apparently this is not enough for ther Schadek. Is there a way to clearance the pump and not the cam bolts? I'd hate to split the case just to grind down a couple of bolts. Especially if this might not even fix the problem.

[Piledriver]

Tuna, this or some version of this needs to be a sticky or on your site. Permission granted to snarf it.

Unibonger---
Food for thought:

The longer relief spring and/or piston will have absolutely zero DIRECT effect on hot idle oil pressure, but they will have an effect on oil temperature, which does.

Ideally, at low pressure, the piston is sealed up against the top of the bore, and ALL the oil goes through the cooler.

The compression force of that spring determines when the oil cooler starts seeing oil flow.
The STRONGER it is, the sooner the cooler gets flow.

Thick oil or a big pump, esp BOTH, WILL likely try to roast a motor w/o a HD spring kit, since the stock "thermostat" sees high oil pressure as the oil being cold, and bypasses the cooler.
By design.
Not a bug.
No, Really.

Works VERY well with a stock clearances, pump, and factory recomended oil viscosity.

...visualize tooling down the road with 60 PSI oil pressure at 4000 RPM... (20/50 and a 30mm pump)
I guarantee the oil cooler is seeing zero flow with a stock bypass spring/piston, as that is FAR over stock pressure, and the stock "thermostat" is pressure operated...

This is where a true full flow setup and real oil thermostat come into play. IMHO ALL engines should have this.

A full fow setup will also largely avoid "loose pump" issues with some cases.

question:
How "low" is "low pressure", and what are you measuring it with? VDO gauges are not known to be correct. Ever. Just self consistent.

If the idiot light is coming on at hot idle, (~7 PSI), I'd replace the idiot light sender _first_. They fail. Frequently.
Flaky as a 15 year old date.

As I have memory loss...
2: Full flow or no?
(bit harder to do on a Bus, but not impossible)

The pump/bolts can be ground on some, but ideally the cam gear gets couterbored. A little of all three is usually required.

[the-unibonger]

The longer relief spring and/or piston will have absolutely zero DIRECT effect on hot idle oil pressure, but they will have an effect on oil temperature, which does.

Ideally, at low pressure, the piston is sealed up against the top of the bore, and ALL the oil goes through the cooler.

The compression force of that spring determines when the oil cooler starts seeing oil flow.
The STRONGER it is, the sooner the cooler gets flow.

So The shorter spring is the correct stock spring (doesn't shoot out when the plug is removed) and the longer one (takes tremendous force to install it, shoots out when removed and is about 3/4 of an inch longer) I'm using is the after market?

Thick oil or a big pump, esp BOTH, WILL likely try to roast a motor w/o a HD spring kit, since the stock "thermostat" sees high oil pressure as the oil being cold, and bypasses the cooler.
By design.
Not a bug.
No, Really.

Works VERY well with a stock clearances, pump, and factory recomended oil viscosity.

...visualize tooling down the road with 60 PSI oil pressure at 4000 RPM... (20/50 and a 30mm pump)
I guarantee the oil cooler is seeing zero flow with a stock bypass spring/piston, as that is FAR over stock pressure, and the stock "thermostat" is pressure operated...

What is a good temp? I hover around 180 and see 210 on the highway. I have the stock type 4 pump. With the heavy spring. I'm currently running 15-40 Shell Rotella (your recomendation). Could that mean it's not enough pressure to push the valve & big spring down and bypass the cooler?

This is where a true full flow setup and real oil thermostat come into play. IMHO ALL engines should have this.

A full fow setup will also largely avoid "loose pump" issues with some cases.

Can you suggest a Full FLow kit I could check out.

question:
How "low" is "low pressure", and what are you measuring it with? VDO gauges are not known to be correct. Ever. Just self consistent.

VDO Gauge and My new Mechanical Gauge. Both read about 5 PSI at idle. 20 PSI at 3000 RPM.

If the idiot light is coming on at hot idle, (~7 PSI), I'd replace the idiot light sender _first_. They fail. Frequently.
Flaky as a 15 year old date.

I've tried 2 stock senders and a VDO Dual Post Sender. all have the same readings.

As I have memory loss...
2: Full flow or no?
(bit harder to do on a Bus, but not impossible)

Stock Type 4 setup.

The pump/bolts can be ground on some, but ideally the cam gear gets couterbored. A little of all three is usually required.

I read a post from Jake that said not to grind the lower shaft boss because it might make the shaft come out and tear up the cam gear. I only need about 1 mm to clear the bolts with a Schadek 30mm pump..

[Piledriver]

So The shorter spring is the correct stock spring (doesn't shoot out when the plug is removed) and the longer one (takes tremendous force to install it, shoots out when removed and is about 3/4 of an inch longer) I'm using is the after market?

Probably. Use the long spring AND the long piston.

What is a good temp? I hover around 180 and see 210 on the highway. I have the stock type 4 pump. With the heavy spring. I'm currently running 15-40 Shell Rotella (your recomendation). Could that mean it's not enough pressure to push the valve & big spring down and bypass the cooler?

Sounds excellent.
Some people would kill for that.
Should get even better after break in, and even moreso when you swicth to the 5W40 Synthetic.

Can you suggest a Full FLow kit I could check out.

Note---Motor has to come apart for this, unless you are insane.

If you have ALREADY done all the plugs, "just" full flowing it could probably be done safely, you'd have to pull the filter housing and flush everything out good, but full dissassembly probably not required for THAT.

Jake sells a nice setup.
Cam gear, bolts, plugs/fittings, pump, cover.
Fits Without Guesswork.

His pump is only clearanced on the drive snout, and the input shaft is pressed up into the pump gear a few mm IIRC.

Didn't have instructions, probably figured I didn't need them. (I don't, but for anyone else it could be an oversight)

I think he even sells a "version" that includes the drill, tap, and a video
Seriously.

I have done it myself before.
Pays to just buy his.

I did for my new motor, but am currently modifying a CB dry sump setup, and will use the 30mm pump from Jake on _another_ motor. The dry sump IS getting his beautiful billet full flow cover

VDO Gauge and My new Mechanical Gauge. Both read about 5 PSI at idle. 20 PSI at 3000 RPM.
I've tried 2 stock senders and a VDO Dual Post Sender. all have the same readings.

Ouch, but just a tad low. 7-10PSI hot is good.
You do know Shadeck sells 26mm pumps, too?
Your stock pump could just be worn out.
(Even the Schadecks have been known to need a little lovin out of the box, 1200 grit and plate glass... Lap that sucka) The stock pumps are essentially un-blueprintable.
(can't take out the end play)

The pump/bolts can be ground on some, but ideally the cam gear gets couterbored. A little of all three is usually required.

I read a post from Jake that said not to grind the lower shaft boss because it might make the shaft come out and tear up the cam gear. I only need about 1 mm to clear the bolts with a Schadek 30mm pump..

Pin it and grind to your hearts content.
1/16" cobalt drill bits are a buck, and a roll pin is 5 cents.

I have pressed out the shaft, and reintalled it with red locktite at a different level after sanding the boss for fit
...I never noticed a taper in the fit, but I'll take Jakes word for it. (The taper he described would probably be noticable when hand fitting)
IIRC I also peened the crap out of it.

You want an extra mm+ for clearance btw, to allow for cam thrust bearing wear.

[the-unibonger]

I just found a site that says if you have a Type 4 Bus case with the fuel pump boss drilled out, you shouldn't tap the gallery plug by the fuel pump. You'll eliminate the brass push rod guide and it will drop your pressure.

http://www.danallum.com/aircooled/case_prep.htm

I didn't do this, but someone did. Because I have that gallery tapped and plugged. Someone had mentioned that I should install the pushrod even though I didn't use the pump. But it felt so sloppy in there. Now I know why. So I guess I need the brass push rod sleeve. Now I need to figure out where to find one.

[Piledriver]

That would do it.
That's the end of the lifter oil gallery IIRC.

There's a fix for that...

Can't remember what it is at the moment, perhaps Jake could chime in?

Depending on whow it's torn up, JB welding in a shortened fuel pump pushrod might be an option.

Better: put a large, long setscrew THROUGH the plug (tap plug) and have it seal the hole, I can't remember if it's coaxial though, probably is. (red) locktite setscrew to seal

Regardless, time to drop le motor.
Good time to install a fuel pump

[the-unibonger]

Just pulled the Fuel Pump Block Off Plate from my engine. Slid a pushrod in there and confirmed that there is no bushing. Checked a spare case I have and there is a bushing. The bushing is a pretty tight fit around the pushrod. The bushing covers the end of the lifter gallery (I think). And without it, oil pours out of the gallery to the case. Basically an internal oil leak.

Placed a shortened Fuel Pump Pushrod in there and sealed it up. Pressure did increase slightly. But still not what it should be.

Hopefully I can find a fix for this that doesn't involve splitting the case.

[Piledriver]

Previously suggested:

Put a large, long setscrew THROUGH the plug (tap plug) and have it seal the hole, I can't remember if it's coaxial though, probably is. (red) locktite setscrew to seal.

Would require engine pull, flywheel come off, pull/drill/tap plug (and make sure things will line up) NO need to split case.

[the-unibonger]

Previously suggested:

Put a large, long setscrew THROUGH the plug (tap plug) and have it seal the hole, I can't remember if it's coaxial though, probably is. (red) locktite setscrew to seal.

Would require engine pull, flywheel come off, pull/drill/tap plug (and make sure things will line up) NO need to split case.

What is coaxial? I know what this means in reference to wiring. How does it apply to screws? I'll give it a try when I drop the engine to fix the cylinder oil leak.

[the-unibonger]

I just got this suggestion over at my mine & Colin's forum.

what about getting a bigger rod that fills up that hole better...

Orrr what about jb welding your hole and then leaving a pin hole for a little bit of drainage...

I like the first idea. Anyone see any danger in trying this out?

[Piledriver]

"What is coaxial?"

on the same axis.

IOW. is the drilling for the oil passages in the middle of the hole for the plug?

If it is, the screw-in-plug thing will work well, and might be safest.

[bottomend]

Bong, becarefull of using JB Weld when it's going to be exposed to direct oil contact. I've tried using it that way and it disintergrated after a few weeks. I think the stuff like to stay dry.

(Man, you've been busy since I've been gone!)

[the-unibonger]

"What is coaxial?"

on the same axis.

IOW. is the drilling for the oil passages in the middle of the hole for the plug?

If it is, the screw-in-plug thing will work well, and might be safest.

Duh! Tes it is coaxial

Bong, becarefull of using JB Weld when it's going to be exposed to direct oil contact. I've tried using it that way and it disintergrated after a few weeks. I think the stuff likes to stay dry.

(Man, you've been busy since I've been gone!)

Very busy. I don't plan on trying the JB Weld thing.

I went & checked that engine you (Bottomend) have split in my basement. I measured the bore for the Fuel Pump Pushrod Bushing and got a rod the same size. When I went to fit it in, it didn't fit. Got a look in there as best I could (with the engine still in) and it looks like they drilled through the bushing then tried to remove it by drilling it out. They didn't drill it out all the way. They just made the ID bigger. So I found a rod that fits. My oil pressure has boosted a lot. Not perfect, but the light doesn't come on. I'll be trying Piledrivers idea when we drop the engine to fix that cylinder leak.

Speaking of, now that my oil pressure has boosted, that leak is bigger and the flywheel seal leak returned.

[dr. no]

Bong, becarefull of using JB Weld when it's going to be exposed to direct oil contact. I've tried using it that way and it disintergrated after a few weeks. I think the stuff like to stay dry.

I used JB Weld to close off the cut-0ff oil filler/dipstick I use (you know, the normal T4/bus one). It lives in oil (now for 18mos) and is not soft.

[the-unibonger]

Bong, becarefull of using JB Weld when it's going to be exposed to direct oil contact. I've tried using it that way and it disintergrated after a few weeks. I think the stuff like to stay dry.

I used JB Weld to close off the cut-0ff oil filler/dipstick I use (you know, the normal T4/bus one). It lives in oil (now for 18mos) and is not soft.

I did the same thing. Kept the fill but plugged the dipstick and relocated it. I don't like it for this application though.