garyo Posted April 22, 2003 Share Posted April 22, 2003 Could someone explain the layout of the crankcase vents on a car running VHPD KV6 bodies? Am I right in thinking that there are just two vents on the rocker cover, and these should be vented to catchtank and then the atmosphere? I think the standard exiges (non 190 upgrade cars) vent back into the inlet system somewhere - is this before or after the throttle butterflys? Cheers, Gary. Link to comment Share on other sites More sharing options...
Steve-B Posted April 22, 2003 Share Posted April 22, 2003 look up V7 SLR (nigel) and compare notes. His VHPD has / is haven't mods like this. there's a lengthy discussion on the se7ens list a few weeks ago... Steve 210Bhp Sinister Version-VHPD here Link to comment Share on other sites More sharing options...
Griff Posted April 22, 2003 Share Posted April 22, 2003 Gary, If you're running a dry sump system this apparently creates a vacuum in the crankcase so the engine will be sucking not blowing. Both breathers on my rocker cover were blanked off. I've also been warned this can create excessive vacuum that can suck in the crankshaft oil seal, perhaps why mines developed a leak from the rear seal?! It's been suggested I unblock one of the breathers and put a small filter to allow air in which I've not tried yet. Not a whole heap of help to you, but it'll be interesting to see what other advice you get on this thread. Mike Link to comment Share on other sites More sharing options...
Griff Posted April 22, 2003 Share Posted April 22, 2003 Gary, If you're running a dry sump system this apparently creates a vacuum in the crankcase so the engine will be sucking not blowing. Both breathers on my rocker cover were blanked off. I've also been warned this can create excessive vacuum that can suck in the crankshaft oil seal, perhaps why mines developed a leak from the rear seal?! It's been suggested I unblock one of the breathers and put a small filter to allow air in which I've not tried yet. Not a whole heap of help to you, but it'll be interesting to see what other advice you get on this thread. Mike Link to comment Share on other sites More sharing options...
garyo Posted April 22, 2003 Author Share Posted April 22, 2003 I'm not runnning a dry sump system, so I think I have the opposite problem and need to attach one of my pipes to either atmosphere or maybe a vacuum take off on the engine side of the throttle butterfly. I'll have a dig around in the se7ens list archive. Gary. Link to comment Share on other sites More sharing options...
Bob Corb Posted April 22, 2003 Share Posted April 22, 2003 Gary If you look down the two connections on the cam cover you'll see that one is underdrilled and has opening a v small flow area, this is the part load breather and on the Exige is connected to a series of small tappings on the runner between the head and the throttles. The Exige/340R has special tappings for this which you dont have on a Caterham VHPD. The other connection in the cam cover is fully open, this is the full load breather and on the Exige connects onto the back of the airbox/plenum. Again, on a Caterham you dont have this connection. Caterham supply a 1 litre washer bottle which you fix somewhere in the nose, they recommend that you connect two hoses to the breather vents and make holes in the top of the tank for them to poke through. You then drill several hole in the cap for the gas to escape. The problem with venting the gas back to the inlet system is that small droplets of oil can cause detonation which is more serious as the engine is more highly tuned. I'm trying to plumb mine in as we speak, I'll let you know when I've worked out where the bottle fits best!! BC Link to comment Share on other sites More sharing options...
garyo Posted April 22, 2003 Author Share Posted April 22, 2003 cheers Bob. I do have a vacuum rail that I guess used to be connected to the MEMS ecu, so I could use this but I think the diameter is too small to be really useful for this sounds as though I need to buy catch tank! The car is actually a GTM libra but I think I'll be able to find the space to fit one. Gary. Link to comment Share on other sites More sharing options...
Leadership Team SLR No.77 Posted April 23, 2003 Leadership Team Share Posted April 23, 2003 Hi Gary, my catch tank is now a fancy blue anodised "Sigg" bottle (check out outdoor shops) mounted to a fabricated ali bracket. Use velcro and tie wraps to enable removal to empty. I used a length of 1/2" (internal) heater hose - enough space around the hose to allow breathing at the neck of the bottle. The vacuum pipe is not enough - believe me Stu. Link to comment Share on other sites More sharing options...
timbo Posted April 23, 2003 Share Posted April 23, 2003 Run a rubber hose from each cam cover vent to a catch tank. Mine are vented to the atmosphere beneath the belhousing. They are simply breathers. Link to comment Share on other sites More sharing options...
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