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Ronstar
10-05-2012, 11:02 PM
How do you guys with big bore LT-5's vent your crankcase.
Still running back to intake? Thru catch can? Right to open breather
Catch can?
XfireZ51
10-05-2012, 11:22 PM
How do you guys with big bore LT-5's vent your crankcase.
Still running back to intake? Thru catch can? Right to open breather
Catch can?

Don't use open breather. LT-5 needs vacuum for PCV. Ask Pete how he knows.
I use a C6Z catch can.
tpepmeie
10-06-2012, 08:13 AM
Haven't measured it, but I get some pressure in the crankcase at WOT on the 427. Pushes the dipstick up, and I'm sure isn't great for ring seal. Was going to run the crankcase breathers open on the next trip to the dyno to see if it makes a difference.

Wish there was enough clearance on the front of the crank to get a pulley to drive a vaccum pump. I have low tension rings, and wish I could pull a vacuum on the crankcase.

Pete, lets hear your story.

Todd
LGAFF
10-06-2012, 09:15 AM
I believe you can run a vac off the exhaust system and achieve something similiar
XfireZ51
10-06-2012, 09:17 AM
Todd,

I forget who, but they are adapting the AIR pump for the vacuum on the crankcase. May want to try that.
LGAFF
10-06-2012, 09:20 AM
http://www.vtcoa.com/forums/f7/crankcase-vent-into-exhaust-40927/
Ronstar
10-06-2012, 08:08 PM
I was using the AIR pump. Was pulling to much oil and destroyed
Pump. Still getting a lot of oil. Low tension rings. Cam cover holes blocked and all ventilation ran thru injector housing to catch can. Don't want oil
running back to plenum but think I need more ventilation.
may try different air pump if I can slow oil a little or run thru
Seperator first.
Pete
10-06-2012, 10:20 PM
I have a question why run low tension rings in a motor that already has crankcase issues in stock form? especially a street car.

Anyway if you look in the FSM check PCV valves working properly you will see it says to put a vacuum gage at the dipstick tube rev to 1500rpm you should have vacuum if no vaccum you have a leak it gives you examples oil pan gasket,valve cover etc.

I had a breather/filter in my cam cover fill cap and was getting nothing but oil.

All the big bore engines here have no issues they don't have low tension rings.
They run a catch can from PCV's and vaccum to catch can.

RonStar what engine/mods do you have?

Todd, how many miles on your motor? enough for ring seal/break in.

Pete