Oil inlet check valve -- beware....

[thetorch]

Just finished my rebuild and went to build and test oil pressure before first startup. 10 quarts of oil put into my oil tank.

A few cranking tests without my plugs failed to generate any pressure, so I pulled a couple of chain tensioner lines and they were bone dry. Then I pulled the sump oil drain plug: bone dry.

I inherited a Rothsport oil inlet check valve on my oil tank S-hose. It had to be the culprit: preventing the oil from getting to the sump. Sure enough, pulled the end of the line at the oil cooler: bone dry.

I drained the oil from my oil tank, and then pulled the S-hose and check valve. The check valve seems to rely on suction from the oil pump to open, but of course with a rebuilt motor the oil pump needs to be primed from the tank to create the necessary suction. The weight of 10 quarts of oil did not open it.

No harm done but I will no longer be sporting this check valve. New S-hose is coming tomorrow.

Now I understand why if this thing fails you're screwed. I vaguely recall a debate about this issue. Now I get it.

[Zuffenwerker]

Wow. Good to know - leave them off new engines for sure.

[Peter M]

A good reminder that our oil pumps aren't much chop as air pumps and the circuit needs to be primed with oil before installing a check valve.

[thetorch]

Originally Posted by Peter M

A good reminder that our oil pumps aren't much chop as air pumps and the circuit needs to be primed with oil before installing a check valve.

Agreed. Is there a standard way to prime -- put a couple quarts of oil down the breather or something similar ?

[Neil Harvey]

Yes these can be problematic. I'm talking in this case, the factory ones used in 996 & 997 Turbo and GT3 engines.

Warning, when the exhaust system come close to the part. Happened to one of my customers. The heat soak once the car stopped seized the valve and the engine was start without oil.

[cgarr]

how about an electric valve that opens with the key if its that concerning?

[stownsen914]

Originally Posted by thetorch

Agreed. Is there a standard way to prime -- put a couple quarts of oil down the breather or something similar ?

Putting oil into the sump won't help unfortunately, since the 911 is a dry sumped engine. The only way to feed the pressure side of the system is via the hose where the check valve is.

I have no experience with these valves (and don't plan to), but I'd guess that priming the system probably involves disconnecting the hose from the valve until you get oil flow and then reconnecting. Sounds messy

[Neil Harvey]

Do not want to upset those that make and sell these units. User just be aware of consequences. My advice is not to use. Have away to disable the fuel delivery and crank the engine until you get Oil pressure and the pump has had time to scavenge the sump. If the car has sat for sometime, do the same, but crank longer.

Seems to me, the safer way to do this.

[BoxsterGT]

We have used a Pre-Oiler for a long while when taking used motors out of storage that have not been run in years.....



It consists of a 5 gal Pressurized Paint bucket filled with about 10 qts of oil and pressurized at about 35 psi regulated air. This is connected to the Main Oil Galley at the pressure sender connection.

Perhaps this could be used on a fresh engine so that everything gets a good shot of oil BEFORE starting same.

Just a suggestion.

len.cummings @ verizon.net

[Henry Schmidt]

Originally Posted by Neil Harvey

Do not want to upset those that make and sell these units. User just be aware of consequences. My advice is not to use. Have away to disable the fuel delivery and crank the engine until you get Oil pressure and the pump has had time to scavenge the sump. If the car has sat for sometime, do the same, but crank longer.

Seems to me, the safer way to do this.

+++
If you are convinced of the value, Use a standard S line to prime the engine/break-in and then install the check valve on a fully oiled engine.

[Emo993]

I had the same problem with my 2.2 install on my 914-6 tribute. Did it Henry's way then reinstalled with the check valve. Just FYI, with the 914-6's and using the check valve the oil line is too short to make a good 90 deg angle to the tank. So I make a copper angle to hose to check valve. Works great. Mark

[gled49]

I’ve used the drain back valves on all my engines. When the engine is still on the stand I put some Torco Assembly Lube in to the intake port of the oil pump, and turn the engine over a little. It’s thick enough and sticks to the gears, no priming needed at start up.

[Emo993]

And I am a big fan of the Rothsport check valve. With out it all my oil would be in the bottom of my motor in two to three weeks. And they are great people to work with. Mark

[mepstein]

Originally Posted by Emo993

I had the same problem with my 2.2 install on my 914-6 tribute. Did it Henry's way then reinstalled with the check valve. Just FYI, with the 914-6's and using the check valve the oil line is too short to make a good 90 deg angle to the tank. So I make a copper angle to hose to check valve. Works great. Mark

I would use better clamps.

[Emo993]

Why Mark, what clamps would work any better. This is not pressurized. Mark L.

[Richey]

I have used an air hose to slightly pressurize the oil reservoir tank , you can here the valve open and
the oil flow . an easy way to prime .

[mepstein]

Originally Posted by Emo993

Why Mark, what clamps would work any better. This is not pressurized. Mark L.

I’m probably being picky but I know how nice your car is. There are clamps/metal straps that tighten permanently and then you cut off the excess. Similar to what goes on a cv boot. They use a special tool but the guys at the shop just used pliers to tighten them down. Clean install and won’t loosen. That hose isn’t under pressure but it would still be a bummer for a clamp to loosen.

[Emo993]

Mark, I do get the look portion, they are ugly. But even the Rothsport valve comes with them and I've never had one come loose. I do appreciate your input. Thanks, Mark L.

[ahh911]

Went to the local farmers market, parked far enough away from the stalls.
Stall owners asked, why didn't you park here?

Reply, not sure if its going to puff out a ball of smoke.

Since then, I can't remember a puff unless sitting overnight, once in awhile in the morning I'll back out through a cloud of smoke. Not the proudest moments Smoke out of tail pipe disappears immediately, but the cloud roams the neighborhood a little.
I'll live with it.

[safe]

My crankcase fills up to after a few days, oil seeks equilibrium. But I see absolutely zero issues with that.
Don't over fill with oil.