Why low oil pressure

[jmstu76]

Here are the stats:
Clean early type iv case. 72 or 73 case.
Stock 2.0 crank, not reground, stock main bearings.
Stock 2.0 rods, resized, new bushings installed, stock rod bearings
New cam bearings, CB performance torque special cam, hydraulic lifters
Oil pump: type iv pump blueprinted by Phil. 0 miles on this pump.
94 mm Mahle Pistons and cylinders.

Twin 40 Idf's .55 idles, 120 mains.

Once the oil warms up the oil light is on at idle.

I swapped oil pressure sensors,
I swapped relief valve springs and pistons
Now running VR1 20W-50.

Cam was broken in correctly

This case has the triple square relief valve just under the number 1 cylinder in the side of the case.

Could it be that I am running hydraulic lifters in a case that was designed for solid lifters?

Could the lifter bores be so worn out that I am losing oil pressure?

Fuel pump boss has been sealed off with a plate and is not leaking. I did nothing but installed a plate over the hole.

Galley plugs were installed on all galley passages.

What have I missed??
_________________
James

'76 Deluxe Sage Green Westy
2258 cc GD case 78mm CW crank, 2.0 H-beam rods 5,325” 22mm pin, JE forged pistons with 15cc dish, JE rings, type 11 clearanced oil pump, CB Eagle 2205 Type-2 “Torque Special” hydraulic cam with matched lifters fed by CB Dual Weber 40 IDF MX with 6” foam air filters, currently 55 idle, 130 main, 200 air correction, 32 mm venturis. 27in General Grabber AT2 All Terrains, Berg Shifter, stock '76 exhaust HPC Ceramic Coated. 11/18/2020

[Wildthings]

What is the condition of your oil pump? Assuming its a Type 1 pump, did you check the endplay? Sometimes you need a thin gasket under the cover and sometimes you don't.

If your case was machined for a mechanical fuel pump and you are not running one, you need to get a fuel pump rod and slip it down into the guide bushing. If you use a Type 4 rod it needs to be shortened.

[timvw7476]

Toss a fuel pump pushrod in there. (the bore where the old pump bolts to)
You also should cut it down so it does not crash your block-off.
I ran with no pushrod, my adjusters on the 1/2 side got flattened/smashed quite a bit over 75k-ish miles without that rod blocking the oil flow up on that side.
No damage was done to the camshaft brgs. or rods/mains though. Hammered that 1800 real hard too.

[aeromech]

I went through this issue on a 1973 stock newly rebuilt engine. Once warm (20 minutes) on my run stand the oil pressure fell on its face. I fought the battle to solve the problem but never did. Even sent the longblock back to the rebuilder and once again, no luck. Ultimately the owner decided to accept the bus with the hot idle low pressure issue. I tried like seven different things and ultimately lost the battle with this problem. If I had to guess, the shop that rebuilt it fucked up with the bearings.

_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[W1K1]

[jmstu76]

[jmstu76]

[W1K1]

[Wildthings]

Did you plastigage the split bearings and have the one piece ones miced?

[Manfred58sc]

For sure throw a real gauge on it. I've had lots of problems with sending units leaking and triggering at incorrect values right out of the box, freaking me right out.
_________________
Fat chick owner/operator

[richparker]

James, I’m running into the same problem with the freshly build 2175 in my ‘65. Beetle. I’m using a dual pole VDO sender with a VDO pressure gauge, both bought from CIP. It reads 55 - 60 PSI on start up, 5-8 PSI at idle when hot and the light is on. These which numbers are totally fine, but definitely makes me concerned that the light is on. These VDO senders trip the light at anywhere from 7 - 12 PSI. A stock sender trips at ~4 PSI. We are not the only ones with this issue, lots of threads on it in the performance forum.

I’m running the same sender/gauge set up on the 2275 in my bus. There are no issues with that sender. So, I’m guessing it’s just the luck of the draw on what you get.

Please let us know if you find/get a good sender that works. I’m contemplating buying another sender myself, in hopes I get one that works better .

Rich P
_________________
__________
’71 Westy build
Adventure thread
’65 Deluxe Build
’71 Double Cab

[aeromech]

To the OP

Swapping relief springs and pistons doesn’t cut it. There’s a special tool that grabs the plunger. Then slide it up the hole and try rocking the plunger. This is to check wear on the bore. The bore is softer than the plunger. After 45 years in a T4 case the plunger to bore tolerance gets excessive. So check it.

The fix is to ream the bore. A two step process using two different sized reams. Once reamed install your new custom made plunger. This has worked well for me.
_________________
Lead Mechanic: San Diego Air and Space Museum
Licensed Airframe and Powerplant Mechanic
Licensed Pilot (Single engine Land)
Boeing 727,737-200-300-400,757,767
Airbus A319,320,321
DC9/MD80
BAe146
Fokker F28/F100
VW type 1 1962,63,65,69,72
VW Type 2 1971 (3 ea.) 1978, 1969
VW Jetta
VW Passat
Capable of leaping tall buildings in a single bound

[orwell84]

I think you really need to know what the oil pressure is at speed and across varied conditions. When I went through this, I had an oil pressure and temp gauge on the dash and a mechanical pressure gauge in the engine compartment.

The most important measurement to me was oil pressure at highway speeds when the engine was completely heat soaked and oil temp at its hottest. There is always a pressure drop once the oil hits around 200*…not unusual at all on a bus. The whole 10 psi/ 1000 rpm goes out the window a bit on a bus. It is necessary and expected that oil will get hotter and thinner than on a water cooled car where oil temps fluctuate much less. Hot idle oil pressure is a less useful measure of engine health, especially if you are using the stock idiot light as your only guide. Oil pressure is quite low at hot idle. It is a matter of a few psi either way that trigger the light and the sensors themselves are not very accurate.

With my engine, changing the main relief piston and spring made a huge difference. Not only was the oil pressure higher, but more consistent and it would not fall off as quickly with decreased rpm. Switching to one of Phil‘s pumps, blocking the fuel rod drilling and building a tight engine all boosted my oil pressure. I also ran an engine for a long time at highway speeds (3800 rpm) with oil pressure in the mid to high 20‘s. Upon teardown, I didn’t find any evidence of insufficient lubrication.

[richparker]

Hwy speeds is what I’m looking at as well. I seeing 40 psi at 70 mph, which is ~3800 rpms with my Beetle set up.
_________________
__________
’71 Westy build
Adventure thread
’65 Deluxe Build
’71 Double Cab

[jmstu76]

[Wildthings]

[timvw7476]

[jmstu76]

[jmstu76]

[richparker]

Bump. Where are you at with this?

What oil filter are you using. Some filters take more pressure than others to move the oil through the element. Wondering if a high pressure one was used, if that would lower oil pressure at idle. Just a thought, no Scientific data to back this up.
_________________
__________
’71 Westy build
Adventure thread
’65 Deluxe Build
’71 Double Cab