Rothsport Racing Oil Inlet Check Valve Result

[RSBob]

As you may have seen on the What did you do to your.... I installed the oil check valve to reduce the smokescreen on startup. Background, 82 SC with 165K on original engine. Have SSIs mated to a Dansk Sport, so no cat, but have 02 sensor.

Install took about 1.5 hours including oil change since you have to drain the sump and the tank.




You need to bisect the S hose and remove 1.5" from the center for the valve. The only penalty for installing the valve incorrectly is catastrophic engine failure due to oil starvation. But that is just a nit and a great excuse for that engine upgrade you always wanted but could not justify to your wife/sig-o, dungeon master or whatever.

So without further ado the result. After running the car to work and back after the install and letting it sit for 4 days I fired it up and experienced a catastrophic reduction in smoke. Actually it was about a 50+% reduction in smoke. However, when cold, the car does run rich at about 1300 RPM.

So without a cat, a medium high mileage car, with a high-ish idling cold start I did see a reduction which is just is a bit more rich than when the car is fully warm. So it does work to an extent, but the extent is contingent on what you are running and what shape it is in. Would I buy it again at that price? Undecided. ( which is better than, not). Let's just say it is not a cure-all for a high mileage motor, but on the plus side the Mrs. didn't cover her nose for once.

[jumpinjimmy]

Perfect timing on your post as I just posted about this valve myself on this forum. I'm contemplating buying one to address an oil leak that is a result of the car sitting for weeks without running. It would seem that the oil is slowing filling the crankcase and finding it's way out. Thanks for the post and photos. Very helpful to me.

[RSBob]

Originally Posted by jumpinjimmy

Perfect timing on your post as I just posted about this valve myself on this forum. I'm contemplating buying one to address an oil leak that is a result of the car sitting for weeks without running. It would seem that the oil is slowing filling the crankcase and finding it's way out. Thanks for the post and photos. Very helpful to me.

Happy to help. In your case I would think it would be extremely helpful. All the best.

[jumpinjimmy]

Installed, and it did indeed help out my issues of oil migration.

[chris_seven]

Scary device.

I am not sure that I like the idea of any valve that can stick on the inlet side of the pump.

It is only the suction pressure on the inlet side of the pump that opens the valve and it must have enough resistance to deal with the static head generated by the tank when the engine isn't running so its setting must be finely balanced.

I guess it is more likely to stick open rather than closed but I am still not keen on the concept.

[metalracer]

From what I read about it, the valve stays open if/when failure occurs. Jeff Gamroth is no neophyte to the engine business and I can't imagine him producing a product that could have such great/broad-scale liability (for him) if the thing wasn't absolutely...100%...not going to cause oil starvation.

[chris_seven]

It must be 'normally' closed as otherwise it wouldn't keep the oil in the tank so how does it fail and stay open?

The static head does clearly try to open the valve in the same direction as the suction pressure from the pump which is either a good thing or limits the capability of holding up the oil when the engine is not running.

I agree that sticking closed is unlikely but I am not sure it is 100% and if it does stick the results would be catastrophic.

I guess whether you like this device or not it is a matter of faith and I just don't like the idea of restricting flow into the inlet of the pump with anything that can close.

[zippy_gg]

I can dig the concept, I just don't like the price!

[47silver]

My 75 smokes on startup at times (especially on the side of the hill at the pittsburgh grand prix) so i looked into installing one of these, however:
I believe that this device uses a hinged gate disk to isolate the oil when the motor is off. To me I see 5 problems with this valve.
1. every time you start the motor the flapper is going to crash open under the high cold oil pressure and the velocity of the oil.
2. Since it relies on oil pressure to stay open and not a spring or actuator, when the oil is moving through this valve the disk will be subjected to high velocities. the high velocities will create a vortex which will cause the disk to be vibrate and and eventually the hinge pin or disk will wear out and break.

3. If the car sits for a long time the disk may become glued to the valve body and not open.

4. When it falls apart (which it eventually will from the open and close cycles and vortex shedding, where does the hinge pin and flapper go after they become detached? will it go into the pump?
5. The valve opening is slightly smaller than the hose it is connected to, you will get a differential pressure across this devices which will act to restrict the oil flow somewhat.
After i thought of all the problems that can occur i decided to live with the smoke and if it is installed
I would consider this a wear item to be replaced at x oil changes and not a devices that is installed and left to operate.

[rsscotty]

With all due respect, the description of how you think the valve is designed is totally incorrect.

This valve is patterned after the OEM factory valve that came on all 996/997 Turbos. All we did is repackage it to work with the various early model Porsche cars as the Rothsport website describes.

Any questions or concerns can be directed to Jeff @ Rothsport.

Jeff Gamroth

[47silver]

we use check valves in the hydronic business and they are flapper type and they are subject to the problems i stated above, I thought that this was the same type.

[Nick Triesch]

I'm OK with a little smoke at start up. After minutes it is all gone!!!!

[tirwin]

I'm glad to see this discussion. I get how it works under normal circumstances and I was wondering how it would fail operate if it failed.

[chris_seven]

I am sure that the replacement part is a better design than the original but I would probably still worry.

996 Turbos which took a time to put out their oil lights were fairly common.

[ralphnct]

How do you get the oil to flow through to the engine when you are changing the oil? I bought one and intend to install it but am wondering how this works.

[john walker's workshop]

Originally Posted by ralphnct

How do you get the oil to flow through to the engine when you are changing the oil? I bought one and intend to install it but am wondering how this works.

Do you know about the oil tank drain plug?

[boyt911sc]

Originally Posted by ralphnct

How do you get the oil to flow through to the engine when you are changing the oil? I bought one and intend to install it but am wondering how this works.

Ralphnct,

Same thought occurred to me about this device. A simple test could demonstrate our concern about the oil flow after an oil change. I would install the device at the other end of the S-hose open to atmosphere and pour oil into the empty oil tank. Observe how the oil flows out from the device and collect the oil in a suitable container.

Anyone who has installed this device done this test already? Why would this device helps or reduces smoking during cold start ups? Thanks.

Tony

[Wingman911]

Just installed the check valve in my 1986 Targa Carrara.

The car smoked for about 10 minutes and then was fine.

It still smokes after start up after a few days but less.

I read somewhere in the forum if I let it idle foe a couple of minutes that would move some leftover oil in the engine sump back to the tank. I have not tried that yet.

[RSBob]

Just purchased a second one to install in the 914-6 No issues with first one in the SC

[Jeff Higgins]

Hmm... different strokes, I guess. Myself, I will gladly put up with a bit of smoke on startup (don't let the damn thing sit so long!) rather than risk having a mechanical device in the oil line fail and cut off the oil supply to the motor.