Secondary oil relief Options

[malcolm2]

As I mentioned before, I am refreshing a 1.8 that was basically given to me. PO said it ran around the block and he pulled it.

So I split the case and I am cleaning it up and I noticed that it does not have the pressure relief bolt on the side, between the lifters. No bolt. I figured the PO pulled it for another project. But I look deep in the hole and I see no threads.

Where there versions of this engine without this?

Could the PO have stripped the threads? I can't tell if there are passages down deep.

What is up? I will try to take some pix and add them.

[Mark Henry]

It must be a replacement case, when VW went to hydraulic lifters they stopped machining the lifter relief. I think this was '77 or '78 so any replacement case made after this date would likely not be machined.

What engine code is the case? The code will be the the first two letters of the serial number.

[malcolm2]

It is an EC.

Are the rest of the numbers just counting the number of engines?

[malcolm2]

Can see to the bottom. No threads. No galleys.

[malcolm2]

I am positive that I am the 1st to crack this one open. measures out very straight. Solid lifters, etc....

I found a diagram of the oil galleys, but I think it is type 1. is there one for type 4?

[Tbrown4x4]

I went through this with another member through PMs. I checked a 1.8L (EC) case and a 76-77 van case (GD?), and neither case was machined for an oil relief.

However, both of my 1.7L cases have relief valves in them. It would be interesting to know when or why this happened. I suggest not worrying about it.

[ClayPerrine]

(IMG:style_emoticons/default/agree.gif)

The secondary oil relief is not needed. It just drops pressure to the flywheel end main and the #3 rod bearing. I had it stick open, and it ate the #3 rod bearing on the motor.

There is a part out there ( I am at work and cant remember the company name) that replaces the piston and return spring with a solid rod. I would suggest putting that in the case so you never have to worry about oil pressure drop again.

[Tbrown4x4]

He doesn't need it, the case isn't machined for the second oil relief.

[Superhawk996]

(IMG:style_emoticons/default/agree.gif)

The secondary oil relief is not needed. It just drops pressure to the flywheel end main and the #3 rod bearing. I had it stick open, and it ate the #3 rod bearing on the motor.

There is a part out there ( I am at work and cant remember the company name) that replaces the piston and return spring with a solid rod. I would suggest putting that in the case so you never have to worry about oil pressure drop again.

I found one of these rods in my GA004310 engine. I'm not convinced they are the right thing to do. Cold oil and excessive pressure actually pushes the crank against the bearing and can lead to premature wear on cold start. Remember the oil galley is only one side of the case. This results in asymetric pressure.

Pretty much the same situation for lifters.

No right answer for every situation but I cringe when I hear things are not needed. OEM's don't machine cases, and give away parts because they are not needed.

We can debate the merits of a potentially defective design, possible contamination (debris) that might have led to the relief valve sticking in the 1st place on Clay's engine, whether it was needed for solid lifter and not needed for hydraulic lifters, etc.

Once upon a time standard 914 lore was that the thermostat and cooling flaps were not needed. That has subsequently been proven to be false though it took over a decade to undo that myth.

Clay certainly has a lot of experience with 914's so I don't want to undermine his knowlege but rather give pause to why relief might be there in the 1st place.


As someone that has worked in plants that machined engine parts, I can tell you mistakes happen. Parts get mis-machined. Bad parts occasionally get missed. No one is perfect. Porsche (really VW) was no exception to this especially in the 70's. Here is the flywheel end of my early 2.0L case GA000099. Mis-machined.



(IMG:style_emoticons/default/stromberg.gif) Happens!

However, if the case doesn't have it, I don't think I would go to the trouble of machining it to accept a relief plug either given that the aftermarket plug Clay refers do hadn't caused an immediate implosion of GA004310.

[ClayPerrine]

(IMG:style_emoticons/default/agree.gif)

The secondary oil relief is not needed. It just drops pressure to the flywheel end main and the #3 rod bearing. I had it stick open, and it ate the #3 rod bearing on the motor.

There is a part out there ( I am at work and cant remember the company name) that replaces the piston and return spring with a solid rod. I would suggest putting that in the case so you never have to worry about oil pressure drop again.

I found one of these rods in my GA004310 engine. I'm not convinced they are the right thing to do. Cold oil and excessive pressure actually pushes the crank against the bearing and can lead to premature wear on cold start. Remember the oil galley is only one side of the case. This results in asymetric pressure.

Pretty much the same situation for lifters.

No right answer for every situation but I cringe when I hear things are not needed. OEM's don't machine cases, and give away parts because they are not needed.

We can debate the merits of a potentially defective design, possible contamination (debris) that might have led to the relief valve sticking in the 1st place, whether it was needed for solid lifter and not needed for hydraulic lifters, etc.

Once upon a time standard 914 lore was that the thermostat and cooling flaps were not needed. That has subsequently been proven to be false though it took over a decade to undo that myth.

Clay certainly has a lot of experience with 914's so I don't want to undermine his knowlege but rather give pause to why relief might be there in the 1st place.

Honestly, I only recommend it because of my experience with a sticking secondary relief valve dumping all the pressure so that it ruined the crank and rods, and the fact that VW deleted it in later model engines.

We run straight 50 weight oil in all the 914s to boost hot oil pressure. We really don't get enough cold here, and the summer heat makes keeping the oil pressure up imperative.

If I could find a way to install the oil pressure switch for the light down next to the secondary relief valve, I would. That way you could see if the valve stuck open and do something about it before it trashed the motor.

[Superhawk996]

Honestly, I only recommend it because of my experience with a sticking secondary relief valve dumping all the pressure so that it ruined the crank and rods, and the fact that VW deleted it in later model engines.



If I could find a way to install the oil pressure switch for the light down next to the secondary relief valve, I would. That way you could see if the valve stuck open and do something about it before it trashed the motor.

Just be careful with cause and effect. A stuck vavle could have been stuck by debris from an already failing or failed bearing. Very hard to say which happened 1st and was root cause.

The oil galley would be easy enough to drill and tap for 1/8" NPT pipe thread. I often wonder myself why the oil pressure switch isn't at the end of oil circuit in many cars.

I think the logic goes like this:
If X psi is normal at the front end of the circuit, then you know by design that in "theory" the end of circuit pressure is acceptable.
The oil pressure switch is then set for Y% of X
If the oil pressure light turns on - you just bought an engine.

I'm really not a fan of idiot lights. Oil pressure gauge is the way to go.

[Mark Henry]

There is a part out there ( I am at work and cant remember the company name) that replaces the piston and return spring with a solid rod. I would suggest putting that in the case so you never have to worry about oil pressure drop again.

EMW sells this, it's just a piece of rod. Wouldn't be too hard to make, it uses the stock piston and bolt.