Lubrication - Experts Please Chime In

[Amskeptic]

I have a few Headflow Master engine customers recently having issues with their lubrication. Upon researching the Pressure Relief Ball Modification further, I have some questions about the claims of this modification.

Please read Lubrication Notes (link below) and note how VW utilizes "waste circulation" to pass more oil through the cooler than the engine actually uses. This is a factory blessed "leak" that occurs with grooved relief pistons in the closed position. The oil pump has known about this "leak" since the day it was designed and engineered.

For an engine without waste circulation, if the all the bearing surfaces heat up 4 gallons of oil each minute, the oil cooler only cools 4 gallons per minute.

With waste circulation, the bearings are still heating up 4 gallons per minute, but that relief piston groove has allowed the cooler to flow 5 gallons per minute, 4 to the bearings to get all hot, and one gallon dumped right back into the sump unused, cooled and ready to help drop oil temperatures.

http://www.itinerant-air-cooled.com/viewtopic.php?f=46&t=12422#p212557


The advertised "advantage" of the Adrian Ball Modification is that it improves oil pressure. Well, getting rid of the waste circulation indeed will increase oil pressure and defeat the purpose of the grooved relief piston.

Factory on Left * * * * * * * * * * Adrian Ball on Right.

More troubling, the sleeve (red) blocks the thermostatic purpose of the relief valve piston. No longer do we have the choice for cold oil to pass through to the main bearings and/or the cooler. The oil either passes through the cooler or it is dumped directly into the sump past the ball. A ball is merely an on-off switch. It does not allow gradual switch over of the pump's output from the main gallery to the cooler as the oil warms up.

I have visited two customers within the past eight weeks with this modification installed in their engines. I have seen a gallery plug blow-out at the engine's first start for break-in, and I have seen a new engine with barely six hours total run time showing 20# at 2,500 rpm at 155* using 5-50W oil.

I cannot recommend this modification. If you have oil pressure problems, YES, you can increase pressure by plugging off the waste circulation, but the actual problem with your engine is more likely to be that:
a) bearing clearances have left factory parameters
b) your pump has been mangled by debris
c) you are using modern low viscosity oil
THAN
d) this notion that your relief piston is "leaking" out oil pressure . . .
Colin
_________________
www.itinerant-air-cooled.com

[SGKent]

I know there has been a lot of discussion over the years of how the pressure valves work on VW engines. I was amazed by how much thought the engineers put into it because in my youth it never occurred to me how sophisticated it is. Richard Ratwell - Ratwell.com has a good graphic of T1 -> T4 engine pressure systems on his website. Here are two of Richard's images showing the main two T4 variants - an early solid lifter and late hydraulic lifter. There are additional variants not shown -> in 1976 when the GD case was introduced, it was used with a single relief for both solid and hydraulic lifters. In addition, the oil bypass was re-routed in some of the late GD (and I 'd guess all GE) cases back to the oil pump inlet instead of the sump. On these rerouted cases, the oil pickup tube is a different length as well. One can see in the photos that the valve nearest the pump is slotted, so it allows the oil cooler to cool more oil than is flowing through the bearings and lifters. On the later cases where the oil is rerouted back to the pump inlet, it is already cooled oil that is being rerouted so the oil pump is getting cooler oil than if it only drew from the sump.

Beneath the two images of Richard's is a image of the late 1977 supplement 17 showing how the case was reworked. Colin - like you I am concerned anytime someone re-engineers oil systems. I know that the pre-doghouse T1 buses needed additional cooling for several reasons, and an external cooler was often used. I went to an extended sump on my T1, a solution that worked exceptionally well as the oil would remain stable for multi-hour long desert runs to Havasu in summer. My T4 bus oil sump heats up too quickly on mountain climbs when it is 100F outside but my oil pressure is extremely stable. The general rule for engines is that 10 PSI of oil pressure is needed per 1000 RPM.

_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[71whitewesty]

I'm very curious about this as well. I have an engine coming with this modification. I'm not sure if it's too late to have him change it back to stock. (Can you change it back once it's modified?)
I'm starting with a brand new case as well....
_________________
71 Westy 1600 DP, all stock Bus 1
1970's Snow Trac 1600 SP (sold 12/2016)
1968 Tucker sno cat, sold 2021
1969 Tucker Sno cat 542
2017 VW Alltrac
71 tin top stock 1600 DP (project but runs)
Twin 71 White Westy, Bus 2, that I pulled from a 15 year slumber in a dry eastern WA field in 2015.
1966 Sundial Camper "Boomer"

[raygreenwood]

I deal and have dealt with a lot of industrial oiling systems that have some of the same attributes of the ball system....in that that use ball and orifices as the pressure regulating choke points. The ball valve in the type 4 oil filter head uses the same concept.
The fuel injection fuel pressure regulator uses "somewhat"...some of the same physics (I come back to that).

I have not yet studied the diagram enough to comment on the changes to actual oil routing....this is just pertaining to the ball as a valve.

The problem I see with the ball regulator system that I see....from my experience.....is that it is strictly a pressure relief system. Because the affected hydraulic area....the area that the oil is capable of multiplying force against. ...is so low....in most cases a fluid like motor oil or only moderate density....can only really move the ball far enough from its seat.....to relive pressure. ....but that gap will be so small as to not pass much volume. If that same ball design were being used with a lubricant of much higher density...say with a paste grease.....it would work more similarly to the standard piston relief valve.....which works as it does because it has so much surface area in the face of the flow.

The fuel pressure regulator is somewhere in between ball and piston.....as I think the ball hypass valve should be if it were to be redesigned.

The fuel pressure regulator pintle usually uses a fairly wide conical point. Fuel leverage is shunted to the outer edges evenly with very low pressure build up at the actual sealing edges. Its designed to pass more volume at a constant rate while relieving pressure......so i5 does not dump and snap shut....causing oscillation....which is one of the risks of ball type valves with limited surface area....in the face of high volume flow and moderate fluid density.
just pure speculation.....but I think the ball mod would be more uniform performance....if the valve shape were somehwere between piston and ball.....a conical shape. Ray

[Amskeptic]

[Amskeptic]

[TomWesty]

I'm far from an expert, but if your diagrams are correct, I certainly see the value in the stock system cooling the oil better.
_________________
If you haven't bled on them, you haven't worked on them.
Visit: www.tomcoryell.com and check out my music!

[raygreenwood]

[Wildthings]

I guess I lucked out when I got into VW's by already having experienced that high oil pressure and thick oils don't necessary provide the best in lubrication. I think people worry way too much about the oil pressure in their VW, not realizing that the engine is designed to use oil pressure to regulate cooling. You don't want or need very high oil pressure in one of these engines, I would say that 30 psi at highways speeds is sufficient.

In their early engines VW specced straight 20wt oil up to 68°F and only 30wt above that as these thinner oils caused less oil pressure and thus higher cooler oil flows. I am not a fan of oils like 0w20 or 5w-20 nor am I a fan of 20w50 or heavy straight weights like 40wt or 50wt. There are oils in the middle range with more normal viscosities that work just fine, 10w30 was long the best selling oil in the world for a reason.

I think Colin is right in that the VW grooved piston provides an important cooling function that is lost when a ball style relief valve is used. You want the relief valve shut for the best cooler flow and the ball relief isn't going to provide that.

[oscarsnapkin]

Oy vay. Any idea how long this mod has been added? I had my GD engine rebuilt by Adrian last spring/early summer and installed it/started it a few days before Thanksgiving. I don't know anything about the lubrication system, but could this explain why my engine leaks oil for a few minutes after a cold start? It appears to be coming from above the oil filter bracket. I figured there was a relief valve there and the pressure was too high because of the tight clearances in the new engine. It leaks a smaller amount of oil now than it did when I first installed the engine. I have less than 50 miles on it, running Brad Penn Break-In oil, changed it around 20 miles and filled it with the break-in oil again which I figure I'll keep until 1000 miles. So, what does all this mean in layman terms? Should I run a specific weight of oil? Figured I was safe going with Adrian because of his rep. Can never win.
_________________
- 1977 CEI Sunroof Bus 2.0L F.I. Hydraulic Lifters
- 1973 Thing

"It’s so easy to laugh, it’s so easy to hate, it takes strength to be gentle and kind."

[Amskeptic]

[Wildthings]

[Amskeptic]

[Ian]

I'm sorry, but I don't see a problem with VW's original design and I have never ever ever put an engine together with any thing other than factory oil relief pistons and springs. They spent a lot of time with testing and developing the Type 4, why modify it? The only thing I do that is "other than factory" is open the exhaust guides on the AMC heads so they don't seize to the valve stem when they get hot.

Stick with stock. It's not rocket science.
_________________
All your Buses are belong to us.
Love and good roads!
IN LOVING MEMORY OF ROB CRESS 1968-2012
**ACHTUNG DO NOT USE AA BRAND PRODUCTS OR BUY ANYTHING FROM PACIFIC PARTS INTERNATIONAL IN CALIFORNIA**

[Wildthings]

[kreemoweet]

[Abscate]

Maybe my Easter project will be to pull a couple of springs and measure the spring constants....
_________________
.ssS!

[raygreenwood]

Its not really the spring "constant" That will be the issue when comparing between the stock flat faced piston and the ball relief valve. It will be the initial unzeating pressure required for the spring at any given preload....combined with the fact that a ball valve and seat assembly installed in an otherwise same size bore as the flat piston....with have a much reduced surface area for the oil flow/pressure to act against. They will have totally different unseating pressure characteristics. Ray

[Amskeptic]

[Bleyseng]