Dual relief oiling system. How it works.

[Jimmy111]

Yes, miniman is correct.
You need to look at the control valve as a waste gate or overflow valve. It is not really a pressue regulator. VW installed them to make the motor seem to last longer. When they used a 21mm pump in a single relief case there was no extra oil. So as the bearings wore you steadly saw the oil pressure drop slowly over time. They added the Control valve and a larger pump so there was more oil and more pressure. the extra oil from the larger pump just went out the control valve. As the motor wore and the bearings required more oil the control valve would slowly close untill it stopped flowing oil all together. From then on you would notice your oil pressure start to drop but it would drop in 15,000 miles instead of 60,000 miles. But for VW it was a simple and inexpencive change to make the motor seem to last longer.

[mailman]

Thanks, guys! This is actually starting to make sense...

This type of info is exactly what we here on the Samba need more of. This is a great start!

I can see where we could use a similar thread for the cooling system.....

And another one for the starting circuit of the electrical system.....

I see questions posted here on a daily basis by guys that just don't understand how the VW was intended to work in the first place (me included, sometimes).
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'64 Bahama Blue Beetle / steel sunroof
'64 Bahama Blue Beetle Sedan (future ragtop)

[millerje78]

nice contribution, jimmy! oil system for dummies!!! I love it.
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always seeking a better way
my 73 standard project

do your research, consult with experts, and buy quality parts. you won't be sorry

[Jake Raby]

Excellent information on a topic that is misunderstood by most. The data parallels what I have seen at various pressures as well, but I haven't ever done a study on the topic.

Jimmy, if you don't mind me asking why were you doing this research work and why were so many engines tested??
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Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell"

[Jimmy111]

Hi Jake. It was in 1979. I was working for a Engineering company that was doing a project for a company that wanted to mass produce small budget 2 seat helicopters. At first we did 10 motors but the results were inconclusive. The readings were all over the place. The owner of the Engineering company went to a salvage yard in Tustin and bought another 90 motors and so we tested them all. Dont really know why. The project was to turn the Motor so the flywheel side was up and attach a bell housing and use belts to drive the transmission. It worked ok except it was difficult to keep the oil seal at the pulley from leaking. I dont really know what happened to the company that hired us but I think that they still exist. Not positive. it was 29 years ago.

[Jake Raby]

Cool.... The Helo looked something like an OH58 if it's what I am thinking of... Thats cool!

I have often wanted to do something similar to this, but change bearing clearances and oil weights to see the differences of the pressures and volumes across the engine... I don't have time for all of it, thats for damn sure!
_________________
Jake Raby
Raby Engine Development
www.rabyenginedevelopment.com
"I've never given anyone Hell, I just told them the truth and they thought it was Hell"

[74 Thing]

This is a great post and I love the technical discussion.

If you are using a 30mm pump what modifications do you need to make at the control valve. I noticed on one of your photos it indicated to re-cut the bevel if you resurface the mating surface for the control valve and also increase the size of the hole (is this the hole that runs to the bearings and do you increase the size the whole length of the case?

Thanks for the info!

[pupjoint]

jake, you mentioned ometime that you also use the 30mm oil pump in your engines...do you do any mods to these engines? did you face the same prob as jimmy?

[Jimmy111]

There is nothing wrong with using a 30mm oil pump in a dual relief motor as long as you are using a remote cooler and the motor is full flowed. The problem occures with the relief valve that sends oil to the oil cooler on the motor. When the oil pressure is too high the relief valve thinks that the oil is still cool and continues to bypass the stock cooler. This is cause of a lot of overheating new motors. I have the drawings that explain this but I dont have time to scan them right now. I will do it on the weekend.

A 30mm oil pump in a single relief case is a really bad Idea.

[Jimmy111]

The one that you want to increase is the cross drill hole. You will need to remove the plug behind the flywheel and drill straight thru the valve into the case. So effectivly you are drilling 2 holes. On the outside of the case you will need to tap for a plug too and install a tapered pipe plug.
Ill make it more clear in the drawing.

I added a photo of the location to drill.

[Lionhart94010]

Jimmy111,

Wow Extremely helpful, I was searching for the information your tests show, I have a Berg full flow pressure relief oil pump cover plate that limits max oil pressure to 95psi, but was looking for clear information on what effect the 30mm pump w/95psi max would have on the oil control & relief valves.

If I understand your data correctly it would seem that the 30mm pump has a result of prolonging the time it takes before the oil reaches its optimal operating temperature, by routing oil through the oil cooler before it reaches 180F and once the oil has reached 180+ the oil control valve does not shut as it should and allows some of the hot oil to bypass the oil cooler and go strait to the bearings, causing an accelerated upward spiral in oil temp? And that the best way of relieving the problem is by increasing the size of the oil control(flywheel side) relief channel from 5mm to 7 or 8mm and using a 4-7psi relief valve spring (on new engines) to relive the excess flow induced over pressure cased by the relief channel bottleneck.

Please let me know if I have got it wright :0) I have a T1 2007cc Motor in the works, that has a 30mm pump, I is full flowed and has the Berg 95lbmax oil pump cover and will also have an external oil filter and external oil cooler with thermostat that will run in conjunction with a stock oil cooler setup. I do not want the external cooler kicking in before the stock system has been overwhelmed due to climbing a steep graded or due to high external temp...

I look forward to seeing your additional information, your posting will probably save many of us a lot of grief!

Thanks again :0)

Andre

[redhot]

[Jimmy111]

They did not exist when these tests were done. But You got to be careful about the pump that comes with the filter adapter. You need the Mexican pump for the filter to work. Many sets that I have seen dont come with the mexician pump. They come with a standard 30mm pump. This pump does not have the passage for the return from the filter and oil will just fill up the filter and the oil never leaves it.

[redhot]

Haven`t got the pump where I live now, but will check it out.

Is this correct?

Inlet on right side of gear, outlet to filter on left sides of gears, and outlet from filter into the pump body in the solid to the left of the gears?

Do you have a illustration of some sort?

[hd74cid]

So for us technically challenged people sitting in the back of the class, would a softer spring in the oil relief valve allow more oil to enter the cooler? I've built a really nice, stone stock dual port but the temps keep rising. Cools down quick in stop and go traffic, even in the high 90's both temp and humidity.

I'm now thinking about going spring shopping at the hardware store. Am I on the right track?

BTW - YOU Samba gawds are who got me back into vdubs and I thank you every day when I crank up "Timex"
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My other bug is a 2 wheeled vert

[Jimmy111]

A softer spring will bypass the cooler and less oil will go to the cooler. You need a stiffer spring. Many of the springs we tested were off a lot mainly weaker. You might want to just try a new stock spring. But first you should put a oil pressure gage on and see what pressures you have.

Redhot. i will post a photo of the pump later.

[Jimmy111]

This is a standard pump.

This is the pump that works with the filter plates or the In/Out Plates

If you notice the hole on the pump, that is for the return to the case thru the pump.

[redhot]

Thak you again for taking the time to answer these questions.
It was as I thought, and I`ll make sure to check.

[Tvättbjörn]

I have seen engine cases where somebody installed a bushing (pressed in) in combination with a steel ball and spring (on the pulley side). Not like the regular piston and spring. I like the idea , because the ball will never bind compared to the piston design.

any thoughts on that??

[Jimmy111]

I have heard of them but never seen one. The only one that I know of that is recent is this one in this post.

http://www.thesamba.com/vw/forum/viewtopic.php?t=290867

But the reciept says it is for a type 4 and it does not seem to have a seat.

I cant see how a press in seat will work because there is not much room between the valve seat and the hole for the oil gallery. The seat whoud need to be very thin and machining would need to be done to the valve seat to provide more room.

Also a ball has more surface area available to the pressure of the oil so it would close at a much lower pressure...