The V8 Owners Forum -

Hi, I am new to the forum and new to V8s and need some help. Yesterday I noticed that my air filter was saturated with oil. Any ideas what this could be?

The car is a Mark 1 Sierra with a Rover V8 engine. Any help or advice would be really appreciated.

Thanks
Steve

Most likely blocked flame traps and or hoses to them and where they go into the rocker cover and carbs. Check all the breather system is clear - including the air input to the crankcase.

If they are all ok, it's sadly likely down to engine wear.

Thanks mate the engine only has 6k on it so I really hope its not not wear lol I changed a breather the other day I think maybe the breather I changed might not be up to the job il change it back and see what happens thanks for the reply
Steve

They tend to be quite sensitive to having the correct crankcase ventilation - which can sometimes be a problem with aftermarket carbs.

Hi
Ive changed the breather back but still no joy its still throwing oil into the air filter. Ive searched the web and I keep seeing this pcv valve but I cant locate it. Anyone have any idea's any info is appreciated.
Thanks steve

rs_v8 wrote:Hi
Ive changed the breather back but still no joy its still throwing oil into the air filter. Ive searched the web and I keep seeing this pcv valve but I cant locate it. Anyone have any idea's any info is appreciated.
Thanks steve

Could you explain the layout of your breather system,
and are you using SU carbs or a holley or injection ??

Any idea if it's a 'standard' engine, i.e from an SD1, lock stock and barrel?, or is it a mixture of all sort of bits.

Chris.

rs_v8 wrote:Hi
Ive changed the breather back but still no joy its still throwing oil into the air filter. Ive searched the web and I keep seeing this pcv valve but I cant locate it. Anyone have any idea's any info is appreciated.
Thanks steve

Take a look here.... http://www.locostbuilders.co.uk/viewthr ... tid=158499 a bit further down the thread is another pic from the front.

Hi guys its a 4.6 rover v8 its had various modifications im going to put a picture on here when I get home to give you an idea of my breather set up. I have a small filter on the right and on the left there is a pipe that runs into my air filter.the air filter is a flat pan type sits on top of a holley carb.

Thanks gor the reply
Stevr

I think I have managed to upload a pic
if this has not worked could you copy and paste the address into your search bar please.

thanks steve

You have no flame trap on the right hand rocker cover breather pipe. Also those rocker covers dont have an internal oil deflector plate. So it will chuck oil into the filter pan, especially when using nitrous

The old style flame trap is just a small can full of steel wool, but it does hold back the oil mist.

The pipe from the left hand cover no doubt dips down behind the carb and then turns up into the plastic hose barb in the base of the filter pan. This trap will fill with oil until a big glug of oil gets chucked into the filter housing when you give it some beans.

If thats another breather with filter on the right hand cover I dont think its any good. It looks like it has fine foam as the filter media. Better off to covert this to a large breather with stainless steel mesh. And either fit a vertical flame trap to the other one or blank it off.

Is the filter on the right hand cover fitted to an oil filler hole or just a small 1/2" pipe connection?

From what I can see the breather system is too small, and therefore the velocity of the escaping fumes is too high which is giving oil carry over.

I've ditched all my small breathers and have rockers covers with a filler hole in each. These are my breathers straight to atmosphere. You may get the odd smell of engine when using on the road but at least you are not clogging the block up with vapours !

Hi thanks for the reply, the filter on the right hand side is on a small 1/2 inch hole held with a jubilee. so I need a flame catcher on the right and this will solve the issue?

The other option (which is what I did on my 4.6 in my Landie) is to get a PCV valve like this:
http://www.ebay.co.uk/itm/Jeep-CJ5-7-8- ... 4d0b2fb9f1
And stick it between the flame trap on one of the rocker covers and the port on the carb. I suppose a port in the air-box should work as well.
Then you need one of those little K&N filters or similar on the other rocker cover.

The theory is that air is drawn into one rocker cover, through the crankcase, then out via the flame trap and PCV to the inlet. The PCV stops too much being drawn out.

Chris.

rs_v8 wrote:Hi thanks for the reply, the filter on the right hand side is on a small 1/2 inch hole held with a jubilee. so I need a flame catcher on the right and this will solve the issue?

It should make a bit better. But I still suggest converting the filler oil hole to a large breather. And the flame trap needs to go on the rocker cover with the hose to the carb. The flame trap would need to be fitted straight onto the pipe and then take the hose off the top and loop it gently up and then down with no kinks so it forms an arc of hose that will come level with the top of the air filter and then down and back up to the tail on the filter plate.

Or go for the full PCV set up. But the PCV valve needs to be fitted upright as its not spring loaded. the one Chris showes is the ones I used to use, they are dead weight valves so need to be upright. And they wont work properly if fitted to the air filter housing as there is not enough suction on the over run when you need it. Actually it will sort of work if fitted to the airbox, but only by being lifted from excess pressure in the rocker box under load. And if thats happening you will still get oil being shot into the filter housing. The bore in those valves is a lot less than the 1/2" pipes you have at present. But that because its supposed to be connected under the carb for max evacuation under decelleration when your foot is off the pedal or at part throttle when you have vacuum in the manifold sufficient to lift the weight in the valve so the engine can suck the vapours out.


Where are you based? I think I have a couple of these flame traps rolling around under my drivers seat in the truck (dont ask) and I think I have a spare oil filler extension tube that I could convert to a large breather for a few quid. This would screw on in place of your oil filler cap.

I'm quite happy to do this and bung them in the post for you if you want me to. Send me a PM and we can discuss delivery and price if you want to try this idea out.

Perry