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Discussion Starter · #1 ·
Hi all
I have had a problem for a while which seems now to be getting worse.
I had been noticing smoke coming into the car from where the gearshift gaitor is missing.
On investigation I have found that it is smoke being forced out of the breathers and out the back of the air filter which then finds its way under the car and through the gaitor.
I have checked this out and cleaned the breathers themselves which are fine, so I removed the rocker covers and run the engine to find that smoke seems to be coming out through the valve stems.

Question:

does this mean the valves/guides/oil seals are gone?
Should I have the heads rebuilt, or is there a more serious problem?

Any help will be much appriciated, many thanks in advance:tup:

Woz
 

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Discussion Starter · #2 ·
Sorry forgot to say its a Rover 3.5:slap:
 

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Do a compression test,1st without oil in cyl,take reading if low put some oil in the cyl if it raises then it the rings if stays it's valve's,there is a way of changing the seals with the heads still on ,you make an adapter to put in spark plug hole and fill with compressed air then remove spring then change seals.Might be someone on youtube showing how to do it.
 

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Discussion Starter · #5 ·
Thanks Paul I'll check it out
 

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Worn Out Fanny Magnet.
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I have a Rover 4.6 V8 lump, which has only done around 5/6k since being fully rebuilt, including having the Bores Honed & New Rings etc, etc, and it still Breathes a bit. Is your Breather system on the top end set up correctly ?. As you look at the front of the engine, the smaller diameter breather on the R/Hand Rocker Cover should be open, with just a small K & N type Filter, to stop any crap going in. This will then suck in air. The L/Hand Rocker Cover should have a larger diameter breather, and you should have a pipe from this, with an in line Fire Trap, then if you have a 4 Barrel Carb an in line PCV Valve as well, then if you have say an Edelbrock 1404 Carb, the pipe should then be connected to the PCV Port at the front, which creates a "Circuit" around the engine. If you have twin S.U`s, then there should be splitter, and a pipe to each carb. This allows a partial Vacuum to be created in the Crank Case, and any Oil Vapour is sucked back into the engine, burnt, then discharged via the Exhaust Ports. If you dont have a system like this, this Partial Vacuum will not be there, Crank Case Back Pressure will build up, and Oil Vapour will get up past the Rings from the Crank Case, and out of the top of the engine to Atmosphere. The more worn the Engine, the worse it will be. I hope the way I have written this is understandable !!.
 

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Discussion Starter · #9 ·
Thanks Guys.

Mike, my system is definatley not like yours.

It has two rear breathers one from each cover, they tee together and then into the filter base.
Because of the pressure and the angle of the drilling in the filter base the smoke was being force back out through the filter. What I have done to stop this is to use metal tape on the inside of the filter for approx 4" opposite the drilling to stop the smoke blowing straight out and to give it time to be drawn back into the engine.
I know this is just a band aid, I was more worried about the smoke appearing from the valve stems when the rocker cover was off.

Again thanks for your thoughts

woz
 

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Worn Out Fanny Magnet.
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Mike, my system is definatley not like yours.

It has two rear breathers one from each cover, they tee together and then into the filter base.
Because of the pressure and the angle of the drilling in the filter base the smoke was being force back out through the filter. What I have done to stop this is to use metal tape on the inside of the filter for approx 4" opposite the drilling to stop the smoke blowing straight out and to give it time to be drawn back into the engine.


Woz,

That aint right mate !!. You need to create a "Loop", with one Breather Sucking in Fresh Air, and the other Breather discharging any Vapour which has buillt up via the Crank Case etc, back into the engine via the Carb Base or Inlet Manifold, so it gets burnt up, and discharged via the Exhaust Ports. Its a bit like Syphoning Liquid, i;e - Once the Flow has started, it will remain constant until the "Circuit" is broken. If you have both Breathers from your Rocker Covers feeding straight into your air Filter, all you are doing is pumping any Oil Vapour that the engine chucks out, straight into your Air Filter, which will foul it up in no time, and you will have manky oil running out of it before too long !!. Also, you are making the Breathing worse, as your C/Case Pressure will be well up, due to not having this PCV, (Positive Crank Case Ventilation), Circuit in place. Some people sometimes set up the 2 x Breathers from the Rocker Covers correctly, then feed the "Outlet" Pipe either back to the Air Filter, or to an Oil Catch Tank. This wont work either, as you need the Vacuum from the Inlet Manifold or Carb Base, which is obviously connected to the I/Manifold, to suck any Oil Vapour back into the engine. If you attach either both breathers, or even the 1 x correct outlet pipe to your Air Filter, there is insufficient Vacuum/Suction to draw the Oil Vapour back into a Downdraught Carb, plus, you are passing nasty Oil Contaminated Air/Vapour/Smoke straight into your Carb, and this will Gunge up the Internals in no time !!. Once your Breathers are Plumbed properly, any Breathing will reduce straight away, as your engine is then set up properly with this PCV Circuit, but being a Rover V8, you will probably always get a little bit of breathing anyway. :tup:
 

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Discussion Starter · #11 ·
Many thanks for your time in explaining this to me Mike I really appriciate it mate.
I will now look into getting the right parts and getting it plumbed in properly over the winter months.

regards

woz:tup:
 

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Worn Out Fanny Magnet.
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Many thanks for your time in explaining this to me Mike I really appriciate it mate.
I will now look into getting the right parts and getting it plumbed in properly over the winter months.

regards

woz:tup:
No probs mate, I have a habit of Prattling On a bit once I get started, but I hope its been of at least some small help to you !!. :tup:
 

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You can buy pretty slip-in billet rocker cover oil filler caps with or without built-in pcv valve. Non-pcv version has foam and vents allowing clean air to be drawn in in rocker cover and crankcase - the other cap with the pcv valve sucks via engine vacumn the excess oil vapour into tapping in inlet manifold. You HAVE to use them as a pair or it won't do the job.
My new 'stroker' BBC had plain vented valve cover caps and 'coz there are a few grommets missing in the bulkhead I was getin' pissed with the smell of oil fumes when steppin' out out bit. So converted it (with some of the bits shown) back to stock PCV format - job done!
Billet Specialties 21120 - Billet Specialties Valve Cover Breathers - Overview - SummitRacing.com
Billet Specialties 22120 - Billet Specialties PCV Valves - Overview - SummitRacing.com
Billet Specialties 20120 - Billet Specialties Valve Cover Breathers - Overview - SummitRacing.com
 

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The best way to ventilate the crank case is PCV (air in one cover and the other cover connected to manifold vacuum) for a road car and for a performance built engine open crankcase if maybe better as oil fumes dont get sucked into the mixture and reduce octane rating and maybe cause detonation.
Regarding valve seals on a 3.5 Rover, unless the engine has had a performance rebuild most engines will only have a rubber washer on the valve stem inside the spring, and not a proper modern type oilseal on the end of the valve guide, (and if any aftermarket cam has been fitted the extra lift has chopped these up and they will be in the sump!)
If you nare right and I suspect you are that the valve guides are shot ( as this is the only way you will get exhaust smoke in the rocker covers) you will have to remove the heads to have new ones pressed in and then the valve seats recut, if you have to do this consider shortened bulleted ones and having them machined for modern stem seals. Indead it may be an idea to consider an exchange set from one of the specialist Rover re-builders if you are thinking of getting a performance increase as well as just maintainance
 

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Forgot about that,don't think the p6 rover even had valve seals.
I'm sure I read somewhere they didn't fit them till 1993.
 

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when you connect one of your breathers to inlet vacuum make sure you fit a pcv valve inline, either in the valve cover or in the pipe to the inlet.
 
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