Dry sump venting open or closed.

[Ant]

I am now running a 4 stage pump which includes an air/oil separator, this setup requires a vacuum regulator, as the manufacturer mentioned it may make upwards to 19in/hg and I anticipate running about 12in/hg of vacuum.

I have read where I will need a pop off valve incase of a pressure situation, so what I thought was as the vacuum regulator can fit into an O ring thread on my valley cover behind carb, and leave the valve covers clean without any plumbing.

Plumbing the pop off valve from where the mechanical fuel pump used to be on SBF, and if I wanted to use a normal breather for road use just remove the pop off valve, the question maybe is the fuel pump area on the block a good place to take a breather from....

any thoughts.

[PLDRIVE]

Ant

I put my vacuum relief (moroso) in the valley plate and my pressure relief in the passenger valve cover.

Hope this helps,

Mark

[Ant]

As you have similar to me with Reg installation, I would prefer to have the pop off valve coming from the fuel pump cover plate rather than the valve cover, but I don't want to run vacuum all the time so will probably weld a fitting on valve cover to take a -10an line to the puke tank, the problem maybe with the Dailey pump is it spins at 75% engine rpm so -10 may not be large enough for a breather as it may still have a few in/hg of vacuum...

Reason I want to run a breather on the road is the car may do some minimal slower running and I don't want a lubrication issue, and with final break in using no vacuum...

[PLDRIVE]

Do what makes u happy. I ran vacuum during break in, and had no ring setting issues (regulate to low vacuum during break in).

Why does Dailey want the pump turned so fast? Is it to try to achieve your vacuum level goals?

Why do think u will have a lubrication issues at low engine speeds?

[Ant]

I am not sure on the 75% speed, he stated that some run his pumps at 100%, I assume its to achieve a good vacuum, I never intended on running a sealed engine, the 75% is where he starts off.

Oiling an engine, I have read where running a higher vacuum figure there maybe less oil around camshaft and other parts, and cranking a few rpms may promote better oiling....

[vector1]

I've settled on running my Dailey pump at 90+% which is the next step up from 75%, the 75% was a tad low at the idle for some reason (engine builder I would guess), and I was under the impression for the air/oil separator to work it needed so much rpm, which the 90+% ratio would provide at the lower running rpm's, so let'er spin. It's a neat pump, you can also change the size of the internal pressure gear, and the tolerances are very close on the inside and what he uses for bearings is interesting. Nice stuff and a great guy to work with.

[PLDRIVE]

Ant anything under 12" of vacuum is not going to cause any problems, but
go with what your builder says.

Vector1 I guess Dailey ops for a smaller pressure section. He is does make nice stuff.
Mine runs at 65% and idles at 35psi hot, with 1.25 pressure section.

[Ant]

Originally Posted by PLDRIVE

Ant anything under 12" of vacuum is not going to cause any problems, but
go with what your builder says.

Vector1 I guess Dailey ops for a smaller pressure section. He is does make nice stuff.
Mine runs at 65% and idles at 35psi hot, with 1.25 pressure section.

This pump has a 1.45 pressure section, if its too much I can fit the 1.25 gears with spacer...

[Z-linkCobra]

Interesting read guys.

[Z-linkCobra]

Let me throw something out there for thought. Im running an all aluminum 302 with a weaver brothers 5 stage pump. Closed valve covers, tank is vented to puke tank with an air cleaner. I was thinking of running a line from the bottom of my puke tank back over to the motor and allow the vacuum to pull any oil out of the puke tank back into the motor.

I realize that what comes out of the puke tank sometimes doesn't look to good. It did however come out of the motor and nothing but a little moisture in the oil. I run a belt drive distributer and crank trigger. I was thinking of tapping into the distributor hole plug and running in right there.

Thoughts?

[PLDRIVE]

Ant
I would try what Dailey says first. Heres some food for thought. An engine only needs a so many GPM of flow (every engine is different), So if u have excessive pressure at idle and or upper Rpm then the pump is bypassing (wasted HP) If u can get it to idle at 15 to 20 psi at idle HOT and make 60 or so PSI at WOT (very little bypass) then u are sized correctly on the pressure section. In an ideal world a 1.0 pressure section and say 1.75 to 2.0 scavenge sections would be a good combination if your goal is to achieve a lot of vacuum.
Ant I will be highly surprised if your pump will pull any where near 19". Thats no poke at Dailey he makes one of the best pumps available. I believe i achieved a max of 8" with regulator set at 10" before the engine got hot(i have a 5 stage with 1.5 and 1.75 scavenge sections). I would be much more concerned with positive pressure when the RPMs or low on your sealed system (from full throttle to heavy braking to back on gas). Engine needs to pull vacuum at idle on a hot engine otherwise u could over pressure the engine. The peterson pop off is design for engine failure not a continuous pressure burps. I would change the spring (softer) so that it just barely seals. Remember you are dealing with surface area in the engine and it has A LOT of surface area compared to the peterson 1" pop off. It could blow a seal without the pop off every opening.

My recommendation is to try what u have, and see what the results are (pump). Replace spring as soon as u get the pop off.
Make sure it will pull a vacuum at idle while engine is warm, prior to doing you dyno pulls (if u run it sealed).

Hope this helps

Mark


Zlink
Why are u not running sealed with the 5 stage pump?? Scavenge sections too small to pull a vacuum??
I need to think about what u proposed for a while. Maybe one of the pros will comment.

[Z-linkCobra]

Well pldrive you ask a good question. My valve covers are sealed and my tank is sealed other than a line running from the top of the tank to an overflow/catch can. Im not running any type of vacuum regulator or any of that. I am learning a little on this thread. Going to have to do some more reading.

[PLDRIVE]

Ok now we are getting somewhere. Z Link from what u described u are running a sealed system. Have u checked to see what the vacuum is?? If not u need to .

[Z-linkCobra]

Have not checked vacuum. Have been wanting to just have not got around to it. Car has not gotten on the road for any length of miles. Just up and down the street and to the gas station. Fighting trying to get this thing titled.

I have done some reading and what not on several sights including Petersons. I plumbed my system based off of what the majority said. You guys are talking about pressure release valves and vacuum release valves. My car is strictly street...no desire to race it.

I was just curious about using the vacuum generated by the pump to pull any oil out of the catch can back into the motor so I dont have to worry about the catch can over flowing should i forget to check it.

One way I saw to plumb a system was to vent the tank back to the valve cover and run a pressure release valve on the opposite end of the same valve cover. No tank vent at all.

[vector1]

I've read a guy refer to the Weaver pumps at not real efficient, or in other words not pulling a lot of vacuum or trying to pull vacuum and not being able to.

[GBowman]

I wouldn't want what I see in my breather can (mounted right off of the reservoir) to re-enter my engine, Iv'e never seen any oil only water. I am working through some growing pains on a dry sump system so I don't have much experience, however this has been my limited observation thus far. My breather has a valve and stem to drain it and only water so far.

[Ant]

My recommendation is to try what u have, and see what the results are (pump). Replace spring as soon as u get the pop off.
Make sure it will pull a vacuum at idle while engine is warm, prior to doing you dyno pulls (if u run it sealed).

Hope this helps

Mark

Mark what you are saying is the pop off doesn't react quick enough for pressure spikes?
I am intending on running a Peterson inline Pop off from my fuel pump plate, I assume Peterson have gone a little heavy in the return spring so the valve seals in most situations so its a matter of me finding a light spring to hold the valve in place.
My Nascar Ford valve covers have a pop off valve welded on approx 3/8" ID I was going to weld a -12 boss fitting there and use a breather for road, and cap it for race use.

[PLDRIVE]

If the engine goes from pulling a vacuum to positive pressure it could blow out a seal in the engine. The Peterson pop off spring pressure is more for catastrophic failure then repeated positive pressure cycles. My knowledge is not from personal experience, its from my engine builder (He builds dry sump engines on a weekly basis).

I would consider cost of a spring cheap insurance.

MP

[Ant]

Originally Posted by PLDRIVE

If the engine goes from pulling a vacuum to positive pressure it could blow out a seal in the engine. The Peterson pop off spring pressure is more for catastrophic failure then repeated positive pressure cycles. My knowledge is not from personal experience, its from my engine builder (He builds dry sump engines on a weekly basis).

I would consider cost of a spring cheap insurance.

MP

I gotcha and that makes sense. The valve cover pop off has a very light spring hardly enough to seat it so I guess that won't take much pressure to work..I might consider leaving that there, and if I want minimal vacuum I can adjust regulator down to 2"

[PLDRIVE]

Sounds like a plan