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Stag with pcv

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vader Part of things Posts: 425 Club RR Member Number: 93	Stag with pcv vader @vader Club Retro Rides Member 93
	Aug 21, 2019 18:48:41 GMT Select Post Deselect Post Link to Post Back to Top
	Right, I’m in need of some advice from you clever people if you don’t mind. my Stag is fitted with a Weber instead of Strombergs and because of this it breather from the cam cover doesn’t go to the intake just under those carbs, the breather just went to the air filter. Problem is this causes oil leaks so, I was advised to fit a catch can and pcv with the pcv having a connection to the intake manifold. i have fitted a take off point below my carb on the adaptor plate, I trial fitted the pcv on its own betweeen the cam cover and intake, unsure of which way around to fit the pcv so made an educated guess! With the engine running there was negative pressure under the oil filler cap (suction under cap) I took the car for a reasonable test drive and it didn’t leak oil but seemed to use quite a bit, so I thought I’d fitted the valve the wrong way around. i have now plumbed in the catch tank and pcv. So, pipe from cam cover to catch tank, catch tank to pcv, pcv to intake, I have turned the valve around. With the engine running there isn’t any negative pressure under the filler cap, result I thought, no. I took the car for a short run, on hard epacceleration I can get a whiff of oil when I got home I have my oil leaks again! Can anyone help out with what I’m doing wrong? Thanks
	Triumph Stag Ducati Supersport Shanks’s Pony

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scimjim Club Retro Rides Member Posts: 1,503 Club RR Member Number: 8	Stag with pcv scimjim @scimjim Club Retro Rides Member 8
	Aug 22, 2019 7:31:42 GMT Select Post Deselect Post Link to Post Back to Top
	The Essex rocker covers have a baffle below the PCV (which is mounted into the rocker cover) to stop oil being sucked into the carb spacer plate - I think you had it the right way round to start with? It should only seal one way when you blow down it (to stop fuel going into the rocker cover if it backfires). This valve - larger dia fits in the rocker cover with a rubber grommet, smaller dia with pipe to carb. I’d plumb it with the catch tank but the PCV the other way round?


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vader Part of things Posts: 425 Club RR Member Number: 93	Stag with pcv vader @vader Club Retro Rides Member 93
	Aug 23, 2019 14:38:29 GMT Select Post Deselect Post Link to Post Back to Top
	Hi thanks for that. I’ve plumbed it in with the catch tank and put it back to how it was, I now don’t have massive suction under the filler cap, I assume this is because of the catch tank? Any way, I’ll run it like this and see what happens. Thanks again
	Triumph Stag Ducati Supersport Shanks’s Pony

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Darkspeed Club Retro Rides Member Posts: 4,885 Club RR Member Number: 39	Stag with pcv Darkspeed @darkspeed Club Retro Rides Member 39
	Aug 23, 2019 14:56:40 GMT Select Post Deselect Post Link to Post Back to Top
	Is the catch tank sealed - just the two conns - cover and PCV or does it also have a vent? Cheers
	'70 Ginetta G15 998cc '76 Autotune Gemini 1660cc & 3900cc '93 Litton Corse I Strato's Replica 2700cc '95 Ginetta G27 4500cc Flowbench Thread

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vader Part of things Posts: 425 Club RR Member Number: 93	Stag with pcv vader @vader Club Retro Rides Member 93
	Aug 23, 2019 18:19:44 GMT Select Post Deselect Post Link to Post Back to Top
	Hi, it has a vent with a filter
	Triumph Stag Ducati Supersport Shanks’s Pony

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Darkspeed Club Retro Rides Member Posts: 4,885 Club RR Member Number: 39	Stag with pcv Darkspeed @darkspeed Club Retro Rides Member 39
	Aug 23, 2019 18:42:09 GMT Select Post Deselect Post Link to Post Back to Top
	Aug 23, 2019 18:19:44 GMT vader said: Hi, it has a vent with a filter I would blank block off the vent of the catch tank vent so you only have a 2mm - 4mm hole to atmosphere - the vent explains why you no longer have vacuum at the filler - You can vary the size of the hole that vents the catch tank to regulate the amount of vacuum the PCV gives to the engine but it depends on what it does to upset the engine running at idle which it can have a tendency to do. You also need to make sure that the inlet to the PCV is protected from oil splashing / mist otherwise it will just draw oil into the catch tank as the vacuum is increased.
	Last Edit: Aug 23, 2019 18:43:08 GMT by Darkspeed '70 Ginetta G15 998cc '76 Autotune Gemini 1660cc & 3900cc '93 Litton Corse I Strato's Replica 2700cc '95 Ginetta G27 4500cc Flowbench Thread

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vader Part of things Posts: 425 Club RR Member Number: 93	Stag with pcv vader @vader Club Retro Rides Member 93
	Aug 23, 2019 19:00:03 GMT Select Post Deselect Post Link to Post Back to Top
	Ok thanks for the info, the pcv is between tank and inlet manifold. Tick over was a little up and down when cold but evened out. Of course the vent will reduce the vacuum, didn’t even enter my head! I’ll blank it off and have to trial and error the system!
	Last Edit: Aug 23, 2019 19:04:28 GMT by vader Triumph Stag Ducati Supersport Shanks’s Pony

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vader Part of things Posts: 425 Club RR Member Number: 93	Stag with pcv vader @vader Club Retro Rides Member 93
	Aug 28, 2019 20:19:57 GMT Select Post Deselect Post Link to Post Back to Top
	So I’ve ran the stag with the with the filter blanked off, in less than 100 miles the catch tank was full of oil? I’m going to try it with the filter on to see what happens but something is amiss? Does it matter where the PCV is fitted? I have it between the tank and the intake but should it be between cam cover and tank? Thanks for any and all advice
	Triumph Stag Ducati Supersport Shanks’s Pony

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Darkspeed Club Retro Rides Member Posts: 4,885 Club RR Member Number: 39	Stag with pcv Darkspeed @darkspeed Club Retro Rides Member 39
	Aug 28, 2019 22:38:29 GMT Select Post Deselect Post Link to Post Back to Top
	The issue you have is that the connection on the engine is not in an oil free area - it needs to be in a part of the engine free from oil mist and splashing - Generally they are fitted to a crankcase "breather" that houses a vapour trap of some sort that prevents oil carry over, If fitted to a rocker cover then the rocker cover has an internal baffle arrangement as explained by scimjim above. The key is air velocity. The PCV must really be fitted to an area with low oil mist/splashing and have a large enough volume that the air flow through it is slow so as not to entrain the airborne oil vapours and mists.
	'70 Ginetta G15 998cc '76 Autotune Gemini 1660cc & 3900cc '93 Litton Corse I Strato's Replica 2700cc '95 Ginetta G27 4500cc Flowbench Thread

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vader Part of things Posts: 425 Club RR Member Number: 93	Stag with pcv vader @vader Club Retro Rides Member 93
	Aug 29, 2019 7:07:35 GMT Select Post Deselect Post Link to Post Back to Top
	The cam cover has a flame trap, which is basically like some wire wool type stuff where there is an outlet. This outlet used to go directly to the Stromberg carbs just under the butterfly. The outlet from the cam cover is the only breather so I’m limited to where I fit the valve. Maybe I should try the valve between the cam cover and can? I ran the car for year with the breather just connected to the air filter, I would get a build up of oil after a good while but the engine always leaked oil, I was told by many the leaks were due to the positive pressure built up because the engine wasn’t breathing properly, hence why I’ve now tried to fit the PCV because I was getting fed up of my drive looking like an oil slick! Thanks for the replies, I will persevere
	Triumph Stag Ducati Supersport Shanks’s Pony

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ChasR RR Helper motivation Posts: 10,309 Club RR Member Number: 170	Stag with pcv ChasR @chasr Club Retro Rides Member 170
	Aug 29, 2019 18:18:50 GMT Select Post Deselect Post Link to Post Back to Top
	You'll need a PCV of sorts as the Stag breather system is compromised as it is in stock form. This is why they leak with just a catch can plumbed in or a pipe to the air filter. Does your cam cover outlet still have the baffle on the back? Most go missing and will spray oil up the pipe. You can always fit a baffle to it .
	'79 Honda NC-50 '02 Mercedes R230 SL500 '03 BMW M3 Coupe '08 BMW E91 325d M-Sport Touring Pre-LCI '16 Yamaha XSR700 My car history and exploits: leylandlegends.com

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vader Part of things Posts: 425 Club RR Member Number: 93	Stag with pcv vader @vader Club Retro Rides Member 93
	Aug 30, 2019 6:39:17 GMT Select Post Deselect Post Link to Post Back to Top
	Aug 29, 2019 18:18:50 GMT ChasR said: You'll need a PCV of sorts as the Stag breather system is compromised as it is in stock form. This is why they leak with just a catch can plumbed in or a pipe to the air filter. Does your cam cover outlet still have the baffle on the back? Most go missing and will spray oil up the pipe. You can always fit a baffle to it . Hi, cam cover still has the flame trap, although I’ve never actually checked the medium! Ever since changing to the Weber it’s leaked oil, I don’t remember it leaking with the strombergs, that was 9 years ago and I struggle to remember breakfast!
	Triumph Stag Ducati Supersport Shanks’s Pony

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ChasR RR Helper motivation Posts: 10,309 Club RR Member Number: 170	Stag with pcv ChasR @chasr Club Retro Rides Member 170
	Aug 30, 2019 21:49:28 GMT Select Post Deselect Post Link to Post Back to Top
	Strombergs have a partial vacuum on the breathers, hence why it didn't leak . Stags don't have many vents to vent from regarding crankcase pressure, and that is part of the problem.
	'79 Honda NC-50 '02 Mercedes R230 SL500 '03 BMW M3 Coupe '08 BMW E91 325d M-Sport Touring Pre-LCI '16 Yamaha XSR700 My car history and exploits: leylandlegends.com

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Bullstarz Part of things Posts: 402	Stag with pcv Bullstarz @bullstarz
	Aug 30, 2019 22:30:55 GMT Select Post Deselect Post Link to Post Back to Top
	Try a catch tank, I have two in my Stag. You would be surprised how much sihte they collect, this would allow you to blank off the rest of the hoses.
	Last Edit: Aug 30, 2019 22:31:38 GMT by Bullstarz “It Doesn’t Feel Pity, Or Remorse, Or Fear, And It Absolutely Will Not Stop, Ever, Until You Are Dead!”

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