Type 4 engine oil pressure relief valve was never put in.

[malcolm2]

recap: I am freshening up a 1.8 out of a 914 to use in my 72 bus. I am 99% sure that I am the first to open the case. Yesterday I noticed that the secondary oil pressure relief plug and piston is non existent. THe one on the side of the engine between two of the lifters. Is this normal?

One picture shows deep inside and there are no threads and no galley cuts. THis hole is plugged.

What do you think the result is? Why is it not operational?

_________________
My Toys: '75 Porsche 914, '92 Ski Nautique and now a 1972 VW Transporter Deluxe (punch list fixing)

[orwell84]

I know that later type 4 bus cases did not have that oil control valve and a somewhat different arrangement of oil galleries. Someone will chime in with more specifics, I’m sure...

[Oil Phil-M]

I believe when the T4 motor made the switch to hydraulic lifters they deleted the second relief valve. Idea was to maximize oil to the lifters For awhile I think I used an engine tin screw in the spring to disable this valve on the advice of others but I think I went back - I have solid lifters. I'm only using my bus during the warmer 1/2 of the year and with 10w30 oil the second relief valve didnt seem to make any difference to oil pressure whether it was functional or not

[raygreenwood]

All of which means....its doubtful that it was an original 914 1.8L. None of them came factory with hydraulic lifters.

Or....pull that plug...and I bet you find its actually a length of rod with a ball point on the end being used to plug the hole in the galley inside. Not an uncommon mod to slightly increase oil pressure.....but usually the rod is mounted to the threaded plug.....and there still should be threads there.
Ray

[Wildthings]

I am going to guess that this was a VW test of the later oiling system. They may have built up a few dozen blocks to do their tests and only used a third of them and then the others ended up on the production line.

I would be wary of removing this plug as who knows what is actually under it and what one would have to do to make things right again.

[busdaddy]

You think that's a plug?, from here it looks like it was just never machined.
_________________
Rust NEVER sleeps and stock never goes out of style.

Please don't PM technical questions, ask your problem in public so everyone can play along. If you think it's too stupid post it here
Stop dead photo links! Post your photos to The Samba Gallery!

Слава Україні!

[malcolm2]

As I mentioned I believe I am the first one to open this engine. I did not mention that it had solid lifters. But it does I did some research and EC motor code was only used on 914. And lastly I did say that it was plugged. But I think you took that wrong it does not look like it’s plugged it looks like it’s part of the case. So I guess I am understanding if the relief valve it’s not there I may expect a little bit higher oil pressure. Question is higher than what because I do not have a reference for this engine.
_________________
My Toys: '75 Porsche 914, '92 Ski Nautique and now a 1972 VW Transporter Deluxe (punch list fixing)

[malcolm2]

[Wildthings]

The other relief valve is going to control your oil pressure and the flow of oil through the engine. I would presume that the drillings for that relief would be specifically designed to cover all the necessary functions of both valves, but don't really know. VW experimented with the relief valves on both the Type 1 engine and the Type 4 engine many times over the years. As mentioned above I don't think removing the plug (assuming it is a plug) would be a good idea and if it isn't a plug, drilling the bore out would be even a worse idea.

[Abscate]

OP - please change thread title to reflect content for future search
_________________
.ssS!

[raygreenwood]

The valve we are speaking of is an oil "control" valve. It is the thumb over the end of the hose....occupying the same spot in the oil system that the fuel pressure regulayor occupies in the fuel system.

It keeps overall volume of the system as stahle as possible. Tbe oil pressure relief vwlve is just that.....its designed to bypass the cooler.

The problem with the oil control valve was not its designed function.....but its poor design. It ...unlike the fuel pressure regulator....has no ability to actually 100% seal. It only modulates pressure based around a range of pressure/volume.

When volume gets low.....like when the engine is hot and loose bearing tolerances....pr when oil pressure relief valve function is not ideal....it just acts like a leak on the system. Ray

[Wildthings]

I would like to see the German names for the two relief valves and the meaning the German engineers wanted expressed with the names. It seems the "relief" valve near the pump does much more controlling of the two is it controls not only the pressure but the flow through the oil cooler. The "control" valve relieves pressure and does nothing else but relieve pressure.

To make a wild guess, I am going to say that the "control" valve was the sole relief valve used on the earliest Type 1 engines and then when the oil coolers were added the "relief" valve was added with it (or soon after) to control the oil flow through the cooler. Don't have a clue as to whether the original "relief" valve had any intended relief function or not, but eventually it obviously got that function. Likely VW couldn't get good of results as they wanted out of these two valves as they tried many variations/improvements over the years. They certainly were able to improve the Type 1 oiling system with time and seem to have started out well enough on the Type 4. Steve Kent does seem to think the later Type 4 system has some flaws to it, don't know how the oil supply system for the air cooled Vanagon engines compares to the late Type 4 in a Bay, but it doesn't seem to get much discussion on the Vanagon forum.

The oil pressure regulating system on the water cooled Vanagon is much simpler as it does not in corporate any provisions for oil cooling.

[SGKent]

you do not want to drill it out. You'll gain nothing but a heartache in my opinion. A half million motors or more had only one valve and they ran just the same as the ones with two reliefs.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[raygreenwood]

[Wildthings]

[SGKent]

oil relief valve - taking a pee
oil control valve - holding it until you can take a pee

Happy Thanksgiving to all. Our Kent family will be celebrating the 400th year of giving thanks this time of the year in the New World. The first Thankgiving was at Berkeley Plantation, Jamestowne VA upon the arrival of The Margaret in 1619. My English (of Scottish descent) people were on The George, which arrived also in 1619 at Jamestowne. The proclamation that arrived aboard The Margaret for the people of Jamestowne, and those who sailed aboard The Margaret read - "Wee ordaine that the day of our ships arrivall at the place assigned for the plantacon in the land of Viginia shall be yearly and perpetualy keept holy as a day of thanksgiving to Almighty God."

Enjoy the meals and only talk happy things. No discussing motor oil - just feast and watch football.

But if you drink a lot of beer watching the game, and the action is intense, you can think about the difference between that oil relief valve and the oil control valve.
_________________
“Most people don’t know what they’re doing, and a lot of them are really good at it.” - George Carlin

[raygreenwood]

Wildthings.....you know...... .....you could be exactly right! Swapped at birth!.

Really....by design.....the oil control valve (to be an overall pressure regulator/modulator).....IS.... in the correct location. The tail end of the line...as far from the pressure source as possible so as to keep as much head volume between the user points and control point as possible.

But.....you have lots of "user" points in between...bearings....lifter bores etc.....and this one big damn temperature and speed variable leak very close to the pressure source.

It makes me think that a couple of newby engineers designed the control valve thinking...hot damn we are going to have stable oil pressure on this baby!.....great idea!

Then the old guy walks into the room and looks at it and says......"where is the damn oil cooler?.....and the pressure relief valve for it?".....so they slapped all of that back in and left the damn control valve in as well.

Control wise.....the control valve is a good idea. A pressure variable....small, tail end of the system relief valve to keep system head pressure from spiking and causing even bigger hydraulic movements at the oul pressure relief valve.

I just think that:
A. Its orifice is poorly sized and
B. The internal workings of the valve itself....pretty much a flat faced piston trying to seal up transversly across a round bore against a hole in the wall of that bore...meaning no real sealing surface.
........is a poor design.

I keep thinking.....that a better place for a ball check valve like the Tangerine racing oil pressure relief valve.....would have been at the oil control valve. Ray