waddisme

Thought I had my excess crankcase pressure issue solved, but got black flagged at VIR Friday. I ran two sessions with no issues and then I check my oil after lunch at it was at the full mark. Then I realized I hadn't added the extra quart, so when I did, it started puking oil out my breather cap for the last two sessions. Did I just have too much oil in system? Oil temps were around 250* and oil pressure was between 25 and 30lbs as always. Thoughts?

RX-Ben

I have inadvertently run down to the "low oil" warning w/seemingly no ill effects. Logged oil pressures showed some deeper valleys, IIRC, but everything seemed to hold together fine.

Kubs

With an accusump or accumulator you already have an extra 3 quarts so there is no need to run more.

Don O.

I always runt he extra quart with the Accusump!

Don

CP Thunder

I have been told by a very well known engine builder that you should run a quart low on the stick if you are using an accusump so you don't aerate the oil when it comes in under low oil conditions (assuming a 3 qt sump)

Edit: Quart lower on the stick meaning 'without' the extra quart of oil onboard (full on the stick)

Bill Dearborn

Not sure I understand how the oil is aereated when running a low oil level with an accusump in the circuit.

Without the dry sump the extra quart doesn't aerate the oil so I am not sure how it happens if the oil level is low.

Bill

db2xpert

Been running an accusump for 10 yrs.
No need for the xtra qt with this.

Before accusump, with xtra qt, it did barf a couple of times on long
left sweepers... but only left sweepers.

CP Thunder

See my edited post. Sorry.

If you have the extra quart in under normal conditions with the sump, it shouldn't aereate. Add that quart along with three more from the accusump under heavy side load conditions, there is an above average chance the crank will get submerged and aereate the oil. Apparently he feels the extra quart above the full line is the difference.

sebdavid

I had a similar problem when running the accusump + extra quart. Extra quart not needed IMO, just run it at the full mark, you have that extra oil in the accusump if needed anyway.

waddisme

During down time at track I was trying to figure out when this issue started as it was not a problem when I first built engine 5 yrs ago. I thought it had something to do with the TFS heads I installed 2 years ago. But in looking at my invoice, that is also when I had the Accusump installed - DUH!!! Maybe I just have too much oil in system. I have the 35# switch on my accusump, and when hot, my pressure is at 25 - 30lbs so accusump is dumped. So maybe like the guy in the other thread, I should change to 20# switch and run the extra quart and have the extra 3 qts on reserve. I will give that a try next track day and stop chasing the crankcase pressure trail.

Thanks guys

RX-Ben

careful with going too low on the switch, higher is safer, and running no switch (eg a manual valve) is ideal.

rustyguns

WOW I had no idea those things dumped with pressure that high. i would think that is the problem. i though you set them around 10LBS?? . I thought I read these engines are designed to run on oil pressure as low as 9 lbs at idle

isn't rule of thumb 10 psi per 1000 rpm? or something like that?

RX-Ben

You can idle below 10psi, but you should at least be in the mid 40s around 6k.

waddisme

Seems like when I ordered mine, the consensus was it was better to have it kick in at 35#s vs 20#s. Not so sure now.

RX-Ben

I don't think it makes any sense to use a valve rated for lower than 35psi. But I also don't think it makes sense to run an electronic valve on the track. You are giving up the protection you paid for by running lower psi valve. Also, your block/rotating assembly is going to have a significant amount of oil sticking to it while on the track, and oil is going to be pooling in the heads, so I don't think the concern about crank splash is that relevant. But I could be wrong.

Re puking - are you running dual breathers yet?

sebdavid

Why is the electronic valve bad? And how does the manual one work?

waddisme

I actually switched to the older style valve covers on both sides for this event. I had a Moroso breather cap on the d/s port, two mini breathers on the p/s valve cover and an oil cap breather. I thought I was dealing with excess crankcase pressure. I ran the first 2 sessions with no oil puking. I did not have any issues until I added the extra quart.

As for the manual valve, I am confused about where you are going with that. From my understanding, all the manual valve does is basically turns the system on, same as electric. The pressure switch still automatically dumps oil when pressure gets below setting and refills when pressure retuns, but only when the manual valve or electric switch is engaged. IIRC, the EPC just allows for faster refill when on the track. I may have to refresh my memory exactly on that.

RX-Ben

http://www.accusump.com/accusump_tech.html

Sounds like you have proper venting, so I'd lean towards dropping down a quart.

hungryhippo

Is that a fact that the manual valve is best? Just curious because I'm installing an accusump right now with manual valve (only because it's the easiest way). I would feel better about really pushing my car knowing that it does indeed work the best with a manual valve.

RX-Ben

A manual valve will flow more than any of the electronic valves, I have seen ANECDOTAL test reports indicate that flow with the e-valves may not flow enough for sufficient flow on the track. It may work fine for your setup but at theoretically, the manual should be better.
Click here for a good depiction of the engine oil and Accusump air pressure situation in an engine.

The manual valve will kick in as soon as there is a dip, leading to a smoother oil pressure situation which should lead to shallower oil pressure valleys.