Can someone explain why using the 2 ports at the back of the block on a boosted b18c5 results in excessive catch can filling, as opposed to venting the top of the valve cover?

Catch tank filling in 20mins hard driving plumbed back of the block, compression and leakdown results- comp 11bar across all 4, leakdown within 10%.

I've read numerous places that using the back of the block will require a return drain, i'd like to understand why.

Thanks

 

it might be that the lines your using are to small in diameter,cause a sucking effect.i have a alll motor,13.1 comp and it fills perrty good.what i did is just used the same breather lines for the drain.never fills up now.you be surprised how much pressure a 10% leakdown block can blow.

 

So use one of the 3 ports at the back of the block as a drain return?

We'll use the original PCV return hole in the back of the block for the return line and see how it goes. Looking at a bare block we have here, the main oil drains from the head run directly past these 2 ports on the back of the block, so yes it does make sense that too small a diameter pipe would increase gas velocity and draw more oil through.

 

also something to keep in mind is that with colder weather, (not sure if your area is)
you will have quite a bit more fluid in the can as campared to a warmer place where condensation will not occur as easy.

 

ORLY? Ugh, no thats not evcen remotely the issue

 

well i have only one line in the back,and one on the valve cover.the rear serves as a drain as well.i would drill your original fitting to the biggest an fitting and weld it and i belive that will solve your issue.one vendor does sell these 10an fitting in the market place.good luck

 

try -12 AN fittings. I'm doing two from the front of the valve cover to the box and a drain from the bottom of the box back into the block. Z10 engineering has the -12 fitting that threads into the back of the block. That should be more than enough to help your situation

 

I have never tried to tap the back of the block myself, but I know people that have. They have the same problem with the endyne kit, and they used the return line as well. Theoretically the reason why is because of the oil galleys from the head to the block are in the back, and with spirited driving the g's push the oil to the back, thus sending oil up and into your lines. People have mounted their cans higher and ran -12 lines which solved a little bit of the problem. The can will still fill up, but not nearly as fast as smaller ID lines. Best is to tap 2 at the front of the valve cover since the head and the bottom end share the same amount of crankcase pressure. This will allow the motor to breathe without filling up the catch can.

 

i know when i lived up north i was always having to empty mine.. now in arizona its all ways empty with just a little bit of oil. it was just a thought thanks..i always have used -10an lines no problem

how high is the can mounted?

 

My 02:

My setup:

2 - 10s of the top of the rear of the VC (Under the baffling on a H22 its in the back)... Endyn (Moroso) can (1 QT), -8 recirc to the FRONT of the pan. Part of the reason the rear of the block breather setups (even setup to drain in the rear) "back up" is due to oil "slosh". Like when people say they had no issues on the dyno but on the street their can pukes all over the place.... well I decided to put my drain to the FRONT of the top of the pan... Reasons:

1.Under Accel, rear PCV setups (especially the ones with the fittings on the back of the block) get ALOT of slosh up the rar of the block impeding drainage.

2 Under hard acceleration with the return in the front the "drain" acts as another breather as well.

3. The can is baffled well, I have NEVER, EVER had even a hint of oil on my firewall where it is mounted. Just make sure wherever the bottom of the drain on the can is is the highest point of the return.

Hopethat makes sense because it WORKS... I havent even ad to change my breather filter for 2 years, but I might this winter jus to make it all purttty





I had a couple B series friends having issues with exactly what youre talking about with the ENDYN "kit". we put their drains to the front of the motor and not 1 issue in any of the 3-4 or so Im talking about... All 5-600 WHP + cars

:O)