Cylinder head oil scavenging pump

It's Friday, let's throw some sh%t at the wall and see what sticks.

As many know, some first hand, the 3rd Gen Taco with 2GR-FKS V6 has an oil return problem. Mostly oil drain back from the cylinder heads, especially during hillclimbing and more extreme side to side angular off roading fun time episodes.

For the unfamiliar, the driver's side head, due to the low and rearward placement of the breather in the valve cover, is a real problem. Oil pooling at the rear of the cylinder head is easily drawn up the breather tube and then on to the engine for ingestion. Best case is a little oil smoke, worst cases are a large slug of oil will hydrolock the engine, or even oil starvation down in the main oil sump.

What to do? Well, fortunately for us, the 2GR-FKS is not the only engine to suffer from this problem. There are several performance engines on the market that utilize additional oil pumps to scavenge the heads and return this oil to the sump. One such engine is right in Toyota's product line... the 5.0 2UR-GSE V8. I think we can borrow that scavenge pump and help solve this issue one and for all.

Here is a drawing of the pump and system as installed on the 2UR-GSE. The pump is belt driven just like a water pump, has two rotors (one for each head), and draws oil from the front.


Incorporating this system, as designed, into the 2GR-FKS, would be a nightmare. Additionally, since it pulls oil from the front of the heads, it won't solve our issue. The cars that run this engine do fine with this system as their oil issues come from high G cornering. A little poking around the much maligned V6 does show a possible solution...

So the passenger side cylinder head on the 2GR-FKS has a location on the back of the cylinder head that drives a vacuum pump via the camshaft. The pump is only on some models, but all have the mount and cam drive. My thought is to drive the scavenge pump from this location, and extend tubes to rear of each cylinder head to pull the oil and send it down to sump.

Problems. Can vehicles w/ the vacuum pump eliminate it, and still maintain consistent brake assist? Does the Atkinson cycle necessitate the pump? Some tunes eliminate it. The scavenge pump is over driven as installed on the 2UR-GSE, it will be driven at 1/2 engine speed on the 2GR-FKS as that is what the cams are driven at.... the V6 supplies less oil and our problems lie at lower RPM, so it may work. Testing will be required. Thoughts?

For now, here are the scavenge and vacuum pumps. Some custom work is obviously required to mount the scavenge pump to the head, but nothing outlandish is needed.

 

Rear of the cylinder head showing mounting location and the slotted camshaft for driving the pump.

 

Well, why not a simple electric pump which comes on when a tilt sensor actuates it?

 

That does not seem particularly simple lol

 

My solution is a simple one, don't go off roading.

 

If there wasn't a suitable place to mount and mechanically drive the scavenge pump, that would be an option. For that very reason, I'm looking at an electric pump to circulate oil in the manual trans, no way to easily mount a mechanical pump. The reliability of engine driven can't be beat. Speed and pumping volume rise and fall as needed. Once designed and mounted, far simpler IMO.

 

Just tap the heads and add a direct drain to the sump. Simple. Same concept as this. https://www.platinumracingproducts.com/products/rb-double-head-drain-oil-coolant

 

Microcontrollers with a gyroscope and a relay would be pretty easy to prototype and not particularly complicated, more work to make it a complete product though.

 

A straight drain is an option, and would likely be adequate much of the time. Still, there are situations where the forced oil recovery will be superior, and can save the day by keeping oil at the sump pick up. One save is all it will take to be worth while.

 

Drill the drain holes larger in the head and block?

 

The left head simply lacks any drain hole behind the rearmost cylinder.... there is no hole to enlarge.

 

Is this a 3.5 problem across the board or do you think yours has a manufacturer if defect?

 

Across the board, it's that less than ideal drain location + the super low breather position.

 

For the record I was just kidding.

 

Lol! That one flew over my head... I should've known better!

 

Dont think it would be too hard to drill n tap the head for an externally ran oil drain in the problem location back to the pan.... WAAAAAY simpler.

Pull the valve cover, determine location, drill and tap for the thread of your liking, do the same down on the pan / intermediate pan.

Cost would be minimal and nothing to go wrong except a little leakage if things aren't sealed.

 

Agreed.

 

For the record @Torspd kidds 98% of the time.

 

He's right you know.

 

Ever considered installing an ‘Accusump’ system?
They work really well on motorcycles to prevent oil starvation during wheelies (Short explanation- The system see’s a drop in oil pressure and injects more oil into the engine galleries)

https://www.cantonracingproducts.com/accusump