Outer Limits 4x4 Board

currently have the early 3.5 rover cover's on there. with the breathers going through PCV's to a catch can and then to the TB

my local wreckers swears that I need the slightly later rocker covers with the breather/fire trap on it other wise I will blow out rear mains like there is no tomorrow.

Is he spinning shit or telling me the truth?

Cheers

Simon

I can't see how you'd get excess pressure in the crankcase with the arrangement you have.

My question is do you need a breather on both rocker covers or is one enough?

yea same, but apperently I will.

rocker covers are a lot easier to swap than a rear main seal so that's why I'm asking

now for more confusion... one breather to my throttle body for breathing out. and one to my air cleaner for breathing in... or am I way off?

I think it makes sense, i had the twin strombergs and twin filter cans on my 81 3.5 that had a single breather on the RH side that went to the carbs and a small single intake to the filter housing. When i went to a holley and had a pcv off the large round flame trap going to the base of the holley but it seemed to be able to force oil thru the timing cover even though i fitted a new gasket and oil seal with speedy sleeve. The later hicomp twin flame traps off the r/covers worked better but i think the efi covers with a small filter on the LH side work better again.

shakes wrote:currently have the early 3.5 rover cover's on there. with the breathers going through PCV's to a catch can and then to the TB

my local wreckers swears that I need the slightly later rocker covers with the breather/fire trap on it other wise I will blow out rear mains like there is no tomorrow.

Is he spinning shit or telling me the truth?

Cheers

Simon

Hi Simon

I assume that you have a 4.4 leyland motor fitted with 4.4 heads and alloy 3.5 rocker covers? If so then the reason you are getting oil coming out the breather pipe is that the 3.5 heads have an oil shield fitted to the rocker gear and therefore no oil shield inside the rocker covers. Whereas the 4.4 heads have different rocker gear and don't have the oil splash shield fitted to the rockers rather it is fitted inside the steel rocker covers.

So if you've got the 4.4 heads and the 3.5 rocker covers, then you have no oil splash shield and you will get oil "pumping" out of your rocker covers and making a hell of a mess. All motors have some sort of crankcase pressure, a worn one much more than a good one (that's what the breathers are for, to stop your seals from geetting blown out or oil forced out them at least).

If my assumption is correct then he is telling you the truth. Hope this helps.

Cheers
Simo

simo that wasnt exactly what he told me but pretty damn close.

thanks

I got some late ones here you can have, not even for beer, for free

the rover breathers are connected to manifold vacuum, some carb fittings are not full vacuum, so you wont get enough vacuum to remove the crankcase pressure, shouldnt matter which covers you use as long as they are connected to the right vacuum source.

the rover breathers are connected to manifold vacuum

AFAIR I do not think so. I believe that the inlets to the carbs are before the throttle butterflys. There is probably a little bit of vacuum due to the constant vacuum of the pistons.
Certainly in an injection car the breather inlet is before the throttle, and there is a very small bleed into the vacuum area of the Plenum .
On a carby car you would be pretty safe betwwen the air cleaner and the carby.
Regards Philip A

cloughy wrote:I got some late ones here you can have, not even for beer, for free

Cheer's man. will cost me more in juice than it will to exchange mine over!