CaliConquestAlex Posted July 14, 2012 Report Share Posted July 14, 2012 I got my car running recently and I'm noticing a loud sucking noise when the car is running which persists after the car is shut off for a couple seconds. I'm thinking this is being caused by my krank vents. When I put the car back together, I swapped the PCV valve out for a straight through fitting and therefore it's getting more flow. It worked fine when I had the PCV in the valve cover. I read that it may be necessary to run a restrictor. I'm struggling to figure out what to use as a restrictor. Any ideas? Link to comment Share on other sites More sharing options...
Metric-man Posted July 14, 2012 Report Share Posted July 14, 2012 (edited) http://www.et-perfor...kv_install.html Oil cap seal leaking air ? Edited July 14, 2012 by Metric-man Link to comment Share on other sites More sharing options...
Caliber308 Posted July 14, 2012 Report Share Posted July 14, 2012 (edited) 1/8" hole for the restriction inline (After the Small KrankVent) I used a .30 caliber shell casing cut down in length with the primer removed. You need a reading of 5 to 7" of vacuum at the dipstick on Idle. Don't have that? Change your restriction size up or down to get the vacuum reading I mentioned. Bill Edited July 14, 2012 by Caliber308 Link to comment Share on other sites More sharing options...
CaliConquestAlex Posted July 14, 2012 Author Report Share Posted July 14, 2012 (edited) Thanks for the replies. I'm going to get a vacuum gauge from autozone this weekend and figure out what it's pulling. It seems to be pulling a lot more vacuum with the PCV swapped for a normal BSPT hose barb fitting. I'll have to get creative with the restrictor....I'm thiking about trying to drill a hole in a bolt or something...I do need to check if the oil cap seal is leak too. I didn't think about that. Edited July 14, 2012 by CaliConquestAlex Link to comment Share on other sites More sharing options...
CaliConquestAlex Posted July 16, 2012 Author Report Share Posted July 16, 2012 Ok, I put in a restrcitor and checked the vacuum with a guage in the dip stick with the engine running. It's dead on at 7". I still hear the sucking noise....I think it's coming from my valve cover gasket as I put it on without any rtv because I knew I'd be retorquing the ARP's after a couple heat cyles. I plan to pull the vavle cover and torque the ARP's and put some RTV on the valve cover mating surface. Hopefully this fixes it. Link to comment Share on other sites More sharing options...
CaliConquestAlex Posted July 16, 2012 Author Report Share Posted July 16, 2012 I fixed it. I torqued the head studs down and rtv'd the valve cover and that seems to have made the sucking sound go away. Link to comment Share on other sites More sharing options...
Caliber308 Posted July 17, 2012 Report Share Posted July 17, 2012 I fixed it. I torqued the head studs down and rtv'd the valve cover and that seems to have made the sucking sound go away. You need the engine to be completely sealed to run KrankVents. If you want to....Try to get your Vacuum reading at the Dipstick to read 6" by altering the inline restriction. Bill Link to comment Share on other sites More sharing options...
mstieg Posted July 17, 2012 Report Share Posted July 17, 2012 (edited) I used a hardware store 1/4" valve in line that works perfectly to adjust the vacc. pull from the intake. PM me a reminder to post a pic later if you really want. (it may be 1/8", I forget - get the smallest one avail in the fittings section w/ the barbs, compression fittings such) Edited July 17, 2012 by mstieg Link to comment Share on other sites More sharing options...
CaliConquestAlex Posted July 17, 2012 Author Report Share Posted July 17, 2012 I used a hardware store 1/4" valve in line that works perfectly to adjust the vacc. pull from the intake. PM me a reminder to post a pic later if you really want. (it may be 1/8", I forget - get the smallest one avail in the fittings section w/ the barbs, compression fittings such) You aren't concerned that over time the valve with open or close from the vibration of the engine? I thought about this too but I figured it wouldn't keep a constant setting. Please do post a pic of what you used. That would be very helpful. Link to comment Share on other sites More sharing options...
mstieg Posted July 18, 2012 Report Share Posted July 18, 2012 The ones at Ace were pretty stiff and def. will not be turning on their own regardless of vibration, most of which isn't transferred through the thick silicone hose anyhow. http://www.26liter.us/gallery/albums/userpics/14392/KV_valve___cam_gear.JPG Disregard the output block. I tried hooking up to an old gauge to check for pressure/vacc in the pan, but it wasn't sensitive enough to work. Link to comment Share on other sites More sharing options...
Indiana Posted July 18, 2012 Report Share Posted July 18, 2012 Why are you using those? Link to comment Share on other sites More sharing options...
Caliber308 Posted July 18, 2012 Report Share Posted July 18, 2012 (edited) Why are you using those? Why have I used them for 7 years now, With no negative results on a expensive Engine Rebuild? I'm just waiting for someone to tell me that the K.V. set up is junk If you have never installed them on your car, you can't give a viable comment on the performance of them. Bill Edited July 18, 2012 by Caliber308 Link to comment Share on other sites More sharing options...
RonnieJ Posted July 18, 2012 Report Share Posted July 18, 2012 Why is nobody running catch cans? Link to comment Share on other sites More sharing options...
mstieg Posted July 18, 2012 Report Share Posted July 18, 2012 Let's agree to disagree on using KVs guys. I'm still somewhere in-between, but it's been debated & argued at length with no real positive outcome otherwise. The OP can run a search on those threads without re-heating that topic. Glad he found the issue & resolved the gurgle. Link to comment Share on other sites More sharing options...
CaliConquestAlex Posted July 18, 2012 Author Report Share Posted July 18, 2012 (edited) I feel like the crank vents do a very good job of keeping the engine under vacuum, which would seem to reduce oil consumption because the pressure would help seal the rings better. I haven't read any negative Krank Vent effects and I've had them on my car since the rebuild without any real issue. I'm going to go to Home Depot and see if I can find a similar valve like the one posted and see if I can adjust the vacuum down to 4-5" as it's right around 7-8" currently. Edited July 18, 2012 by CaliConquestAlex Link to comment Share on other sites More sharing options...
Caliber308 Posted July 18, 2012 Report Share Posted July 18, 2012 Why is nobody running catch cans? Because on a Stock Starquest set up you don't need a oil catch can. On a KrankVent set up some use them off of the large K.V. at the Rear Valve cover. I tried one when I first installed the K.V.s What did it catch? Nothing. That is why I now run a small oil breather off of the Large K.V. Works for me. Bill 1 Link to comment Share on other sites More sharing options...
RonnieJ Posted July 18, 2012 Report Share Posted July 18, 2012 Gotcha Link to comment Share on other sites More sharing options...
Indiana Posted July 19, 2012 Report Share Posted July 19, 2012 I feel like the crank vents do a very good job of keeping the engine under vacuum No they don't. Its the opposite. Link to comment Share on other sites More sharing options...
DieHARDmitsu. Posted July 23, 2012 Report Share Posted July 23, 2012 Just wondering, what sucks the pressure out of the crankcase under boost using a KV system? Link to comment Share on other sites More sharing options...
lionbull Posted July 23, 2012 Report Share Posted July 23, 2012 i think the pressure wants to get out however it can, and the vent provides that way.good question. I just guessed on that.Can the experts chime in? Link to comment Share on other sites More sharing options...
CaliConquestAlex Posted July 23, 2012 Author Report Share Posted July 23, 2012 (edited) Here's a good explanation taken from another site. Source: http://www.3si.org/f...ch-cans-412236/ 1) Low load, the crankcase vapors are pulled into the plenum thru the PCV valve. This valve meters the flow so there is not so much flow that it affects engine operation. 2) As the load increases, blow-by also increases, possibly overrunning the PCV valve, . . . the excess blow-by vents into the intake 3) Once the load increases to the point that the plenum pressure is greater than the crankcase (atmosphere), then the PCV closes. . . . At that point ALL of the blow-by exits out the vent tube to the intake. 4) If the PCV is bad, and leaks, it could allow boost pressure to leak into the crankcase, causing even more flow out the other side into the intake. Could the crankcase become pressurized? That would only seem possible if the blow-by and boost leak is so great that it overpowers the vent tube. 5) The addition of a catch can in the vent tube could clean up the vapors, keeping the intake, turbo, and intercooler line cleaner. 6) If the catch can is vented to atmosphere, then that would eliminate all the contamination from the intake, but would be going directly into the air we breath. 7) The installation of Krant vents creates a vacuum in the crankcase during low loads (because the vent tube is now closed).There is a claim that this could possibly increase power by placing a vacuum on the underside of the piston. That would make sense when considering the power stroke and intake stroke, because the vacuum would pull the piston down. It seems though that advantage would be eliminated during the compression and exhaust stroke when the piston is moving back up.One sure benefit of a vacuum in the crankcase would be that it would be nearly impossible for oil to leak out of seals from crankcase to atmosphere under these conditions. 8) Under boost, the Krank vent equipped engine would act similar to condition 3 above, except that the upper Krank vent is certain not to leak like the stock PCV might. 9) & 10) no diagrams . . . Catch cans could be installed with Krank vents, similar to 5) and 6) above Edited July 23, 2012 by CaliConquestAlex Link to comment Share on other sites More sharing options...
Indiana Posted July 24, 2012 Report Share Posted July 24, 2012 They are useless on a turbo motor. Link to comment Share on other sites More sharing options...
Technology Posted July 24, 2012 Report Share Posted July 24, 2012 Large bore breathers on a catch can (multiple if possible) will give you the most "performance." Link to comment Share on other sites More sharing options...
mstieg Posted July 24, 2012 Report Share Posted July 24, 2012 I highly suggest those of you asking questions do a search on Krankvents before posting here, as it's a very touchy subject that has sparked debates several times between some members - plus the info is already out there to be read so that you can come to your own conclusion. Personally I found them neccesary and helpful after I got my forged engine built (7.5:1 compression if that matters). Each engine isn't exactly the same and condition of the stock oil separator system also likely plays a part, as does the cfm your turbo is pushing, condition of seals, bearings, etc. etc. Proponents of KV's have to admit that there is not a way for them to continue creating vacc under boost (arguably when it's needed most!). The stock setup does this however by sucking vacc from the turbo intake with the separator in line preventing oil from going into the turbo intake. KVs do vent pressure out the rear valve however, so pressure "shouldn't be a problem", although that's also up for debate. To each their own, but without question the KVs acting simply as a one-way valve are MUCH more heavy duty than an OEM (or WORSE, Autozone brand) PVC valve. Word around here is the dealer PVC valves are the only way to go, if using them with the stock system. I'm still figuring out a few ideas, but will be adding a stock separator back in. Link to comment Share on other sites More sharing options...
DieHARDmitsu. Posted July 24, 2012 Report Share Posted July 24, 2012 (edited) Glad you chimed in, we had a talk about this catchcan/KV thing a while ago.http://www.starquest...1 I run a Bigger than stock catch can with a slightly bigger bung coming out the back of the valve cover. Yes, its necessary to have the suction of the turbo aid in venting the crankcase rather than leaving it to vent when pressure becomes excessive.Indi has been preaching this for the longest... Edited July 24, 2012 by DieHARDmitsu. Link to comment Share on other sites More sharing options...
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