Re-route pressure relief to DS tank

[type1.racer]

Hey guys,

Looking for some help on this. After running my motor for the first time with a DS setup (CB pump) I quickly realized my scavenge stage is not keeping up with the pressure stage. I.E. the case is filling quick than its evacuating. Quick as in, 20 or so seconds and I've got oil coming out of every orifice, mainly the dip stick.

Pulled everything apart looking for an issue but I'm not finding anything. I did put a CB pickup tube in it and my initial thoughts are maybe its sucking air. I plan to seal the tube up but I'm not convinced this will solve my problem. I did pull the tube last night and it didn't take much effort to get it out, so this could be at least part of the issue.

That brought me to thinking of the relief valve on the flywheel end. I'm hoping someone out there can help me with routing the excess pressure to my DS tank instead back to the case. I've searched the forum and I've heard mentions of this, just not sure how its been done. I think plugging the return hole in the case should be easy enough; Looks like I can pull the case plug on the flywheel end, then drill/tap/plug the return port. Main question I have is how are people then redirecting that oil to the tank?

Or is this just complicating things? Should I maybe eliminate the stock system all together and run an external relief between the tank and pressure side of the pump? Then dump the pressure from the external relief to the tank.

Case is an AS21. Running -12an lines on both pressure and scavenge side. I've eliminated just about everything "extra" in this system while troubleshooting the issue. No filter, no thermostat, no cooler. Scavenge side is connected directly to inlet of the tank. From a flow perspective, everything is working. Oil circulates where it should. Just doesn't scavenge quick enough.

[jsturtlebuggy]

Why are you using -12 size hose? CB fittings it sells are -8. -8 size hose is all I ever used since I started using DeanoDinoSoars dry sump pumps back in the early 1970s. Never ever had a problem with oil starvation with -8 hose.
-8 and 1/2in is all I ever seen anyone use with a CB dry sump pump in their buggies.

[Ol'fogasaurus]

Why are you using -12 size hose? CB fittings it sells are -8. -8 size hose is all I ever used since I started using DeanoDinoSoars dry sump pumps back in the early 1970s. Never ever had a problem with oil starvation with -8 hose.
-8 and 1/2in is all I ever seen anyone use with a CB dry sump pump in their buggies.

Well put. Remember, inch sized dimensions are in 16th or 32nds of an inch (if the dash number is higher than 16 then the spec is based in 1/32th of an inch). -12 is 3/4-inch dia., -8 is 1/2-inch dia., -10 is 5/8-inch dia. and -14 is 7/8th if an inch. Besides numbers higher than 16, odd dash numbers can also indicate that the base of the spec is in 1/32nds of an inch, but it would be unusual to see specs being used doing this.

If there are threads in the tube or fitting, that is in the coding of the spec defining the object also.

Lee

[Bruce.m]

Got any photos of the install / pump / tank /hose runs?

Are you getting good oil pressure?

[Bruce.m]

This might be relevant:

https://shoptalkforums.com/viewtopic.php?t=146595

[Steve Arndt]

Maybe block the stock reliefs and use this to return the relief blow to the DS tank:

https://jayceevw.com/products/jaycee-oi ... ol-system/

[slayer61]

This might be relevant:

https://shoptalkforums.com/viewtopic.php?t=146595

Kinda makes sense. The scavenge pump HAS to be bigger than the supply side. You have it plumbed right way 'round... right? IN on the right side of the pump and OUT on the left?

[Piledriver]

The CB pump contains a series of tiny passages, all alike.... nononono, wait, wrong Thing ...with 90 degree bends... and the pressure output dives through both layers to go into the stock pressure port on a T1 or T4...(this can all be changed relatively easily, and even enlarged a bit...)
Output of the scavenge stage does the reverse and comes out on the outer left, opposite the pressure stage inlet.

The stock oil bypass setup can ~easily be plugged or modified to seal off the sump return, and tapped to return to the DS tank... (on a T1 or T4, the pressure relief setup is functionally same even if parts are slightly different)

Racer Chris did this on his national championship winning SCCA EProd 914, (on a t4, so used a straight through inner and outer stage) so its probably a Very Good Idea. Plugged and using an external bypass is also a good plan, and likely far easier with an already assembled motor.

On a t4 a straight through modded DS pump can be used easily, and much larger fittings can be installed, I would go ~as large and short as possible on the pressure stage feed line, and keep the restrictions on the pressure side (oil cooler and filter)
A rock filter like an oberg or maaaaybe an HP-1 are probably sufficient on the scavenge side to the tank, perhaps with a smaller cooler on the bypass return line to the tank.

Using a straight through modded CB pump has one other benefit-- the sloppy case to Schadeck pump fit no longer determines your hot oil pressure, although it can hurt your scavenging a bit, esp with high backpressure to tank setups.

[type1.racer]

Before I respond, I want to make an important delimitation. This car is a track car, it's sole purpose is run high RPM for extended periods of time. I plan to beat on it, hard. I am not using this as a street car and have no plans to do so.

Why are you using -12 size hose? CB fittings it sells are -8. -8 size hose is all I ever used since I started using DeanoDinoSoars dry sump pumps back in the early 1970s. Never ever had a problem with oil starvation with -8 hose.
-8 and 1/2in is all I ever seen anyone use with a CB dry sump pump in their buggies.

Not worried about starvation, i'm worried about scavenge. It was easier to to buy all the same size hose and fittings. I could have probably been fine with -10 on the pressure side but for sure I wanted all the volume possible on the scavenge side. Thus the -12.

Using the same setup (cooler, thermostat, filter) on a full flow system with a 26mm pump, I had pressure issues when the oil would heat up. Pressure as in, i watched my pressure go from 50 to 30 (at 5k RPM) when my oil temp rose to about 190. My thermostat opens at like 185. Where did my pressure go? 100% of the oil went to the cooler. I believe this was a volume issue due to the additional lines, any guess on what size line i was using? -8an. Another reason I stepped up, to avoid this issue.

Kinda makes sense. The scavenge pump HAS to be bigger than the supply side. You have it plumbed right way 'round... right? IN on the right side of the pump and OUT on the left?

Yes, it is plumbed the right way.

Maybe block the stock reliefs and use this to return the relief blow to the DS tank:

https://jayceevw.com/products/jaycee-oi ... ol-system/

This is what i'm thinking, although not with a Jaycee filter adapter.

Got any photos of the install / pump / tank /hose runs?

Are you getting good oil pressure?

Oil pressure hits 50psi instantly on startup.

Racer Chris did this on his national championship winning SCCA EProd 914, (on a t4, so used a straight through inner and outer stage) so its probably a Very Good Idea. Plugged and using an external bypass is also a good plan, and likely far easier with an already assembled motor.

On a t4 a straight through modded DS pump can be used easily, and much larger fittings can be installed, I would go ~as large and short as possible on the pressure stage feed line, and keep the restrictions on the pressure side (oil cooler and filter)
A rock filter like an oberg or maaaaybe an HP-1 are probably sufficient on the scavenge side to the tank, perhaps with a smaller cooler on the bypass return line to the tank.

This is the plan i'm going with. Having first hand seen some issues already on the scavenge side, I see why having the restrictions on the pressure side are a good idea. I think I might leave that as a last resort though as I've got everything mounted and all my AN lines made for the filter/cooler on the scavenge side.

I picked up an external relief. I've got to find a spot to mount it and then make new lines for the pressure side along with a return line back to the tank. I have high hopes this will solve the problem.

[Piledriver]

It should be possible to add a pressure stage output to the l side of the pump, but easier and better way being a full flow cover (go iron, even EMPI)
This requires plugging the stock output of the pump to the case ala a std "full flow" setup.

This isolates the pressure stage from case to pump fit issues---frees you from hot oil pressure loss from sucking air and the internal pressure leak due the consistently poor case to pump clearances of a Schadeck pump.

It also gives a better place (right off the pump) for the remote pressure relief and "fine" M1 or K&N oil filter and oil cooler...

Consider simply installing an adjustable swagelock pressure relief valve to a full flow cover output plumbing for external pressure relief.
In naval brass they are only $45 ish. That reduces a lot of plumbing complexity, and is prime quality hardware.
(the simple ones are apparently harder to find than they used to be, will find part# for one I used and post)

[type1.racer]

Im going with a Peterson relief valve. Welded up a bracket and mounted under the trans. Need to order some fittings to finish the plumbing. Also going to add a temp gauge to the pressure side while i'm here. This way I'll be able to monitor the oil temp going into and out of the motor (other side was already in place).

20220130_171002.jpg

[Piledriver]

Nice hardware. What size internal orifice/passages?.

[Max Welton]

The CB pump contains a series of tiny passages, all alike.... nononono, wait, wrong Thing

I just got this. Well played sir!

Max

[type1.racer]

Nice hardware. What size internal orifice/passages?.

The valve is -12 on the in/out with a -10 on the return line. I debated going with the -10 on the feed (with a -8 on the return) side but I already have line and some fittings. The passage itself in the valve is quite large and a straight shot between the in/out.

[Piledriver]

Slick, if you ever get a chance to get it apart for pics (or make internal diagram) would be interesting.
From the external design I suspect how its set up, if so vgood design.
(at least in the amusement park of my mind)