Rothsport oil inlet check valve
 

I'm curious if anyone has tried this and did it help prevent oil from draining back to the engine? Also, did you install a new S-tube at the same time?

https://www.pelicanparts.com/techarticles/Porsche_911/03-ENGINE-Oil_Inlet_Check_Valve_Installation/03-ENGINE-Oil_Inlet_Check_Valve_Installation.htm

I have a 79SC with 215k miles. Unfortunately it sometimes sits 8-10 weeks or more between drives. It smokes considerably on start up. Strangely with 215k miles, after I drive it 50 or so miles, the smoke clears up and it doesn't smoke on startup.

This time however, on first startup, I actually saw about 1/2 teaspoon of oil on the floor behind the exhaust when I ran the rpms up. Before I consider a rebuild, I'd like a way to determine how much of this oil is due to it sitting 8-10 weeks at a time.

cannot comment on your "leak." But I have heard reports from a very reputable shop that the Rothsport check valve is very worthwhile for cars that sit.

If you call Rothsport, I am sure that they can share perspective.

In the last two or three years I've seen a few posts from Steve Weiner that said this valve was very well designed and it worked. That's a pretty reliable endorsement.

Mark

Indeed. I respect his opinion. I think I will try it. I really need to eliminate the drainage issue to tell how much is a result of age.

It may be just me, but anything that can stop the flow of oil in an engine can also fail. It may be remote, but it just creeps me out. If it clears up after a few miles maybe it’s not such a big deal.... Just saying

I have it. Works great. It’s been discussed before. It’s the same design as the one the factory uses in the GT3. Fortunately those engines aren’t as valuable as the ones in our old aircooled cars.

Had one before my rebuild, works well, the only concern I had was changing oil and oil not being able to get into the sump. Figured it out. But the valve does work as advertised

Did those of you that did the install buy a new S hose or use the old one?

I have it. Works as advertised. I used the existing S-hose (it was pretty new already).

A guy with a race prepared car installed a ball valve on the -20 oil return hose from his 4-5 gallon oil tank up under the front hood in the smuggler's box. To make sure he didn't forget to open the valve he installed a switch, so with the valve closed the engine wouldn't run. Good idea, but somehow on the track jiggling things around his engine quit because of the switch.

I don't see the Rothsport setup as a must have item, and I am happy enough to live with the occasional start up smoke, but I think the only rap on it here came from someone who had just rebuilt his motor - maybe an issue about the oil pump, perhaps without a heavy coat of assembly lube or something, perhaps not being able to draw oil past the valve? Not an issue once the motor has been run and everything is filled with oil? A search on this site should pull this up.

If I recall reading that thread, the oil pump couldn't draw enough "vacuum" to open the valve. The natural question then is whether the pump is supposed to work in a near fluid free condition, the answer to which appears to be no. A related question is what the effects are, if any, of drawing more air than normal during the initial startup as is probably the case with the valve installed. The GT3 has a similar contraption, as informed by our experts, but it would be great if they can share more details on the oil circuit, how is the valve mounted, where etc in that design.

GT3's had a check valve in the crankcase vent line, not in the oil supply circuit. The oil supply circuit comes straight from a metal tube from the oil tank, which is mounted to the engine. The check valve allowed the scavenge side of the oil pump to build up a vacuum in the crankcase to reduce windage losses.

my expert garage recommended i remove mine...they stated its not part of the design and could be problematic in long run

I find this funny.
Some “experts” advise over Jeff Gamroth and Steve Weiner.


Sent from my iPhone using Tapatalk

Rothsport oil inlet check valve
 

Delete.

I bought a new S hose. Old one was, well... old.

If you still have it, it would be interesting to play with the mechanism, see how it works and measure what its operating parameters e.g. opening, closing pressures etc are.

The original post states:
"after I drive it 50 or so miles, the smoke clears up and it doesn't smoke on startup"

To me that indicates excessive ring/cylinder wall clearance. Smoke on cold start from oil leak back should clear up in 10-15 seconds max. When the car smokes for 50 miles and then clears up you're just experiencing full heat soak which restores proper, but minimal acceptable, cylinder clearances.

Cold leak down test might expose one or more bad cylinders, but maybe not if the issue is cumulative in all six barrels.

I've never done it, but these new, cheap borescopes might reveal cylinder wall issues.

I find it equally funny that some folks believe that the design of these relics (not just the oiling system) can't, or shouldn't be, improved upon, because "Porsche". :)


Such kink, pNutz!!! :eek:

Have to agree with that.
Few if "any" shops have more knowledge about Porsches that Jeff or Steve.
Maybe none....