Breather Tube - Oil dumping in air filter and carb

[TrevorJ]

Hello,
I have a 1967 Healey 3000 MKIII BJ8....the breather tube that comes out of the valve cover and connects to the air filter of the rear SU HD8 carb....keeps dumping oil into the air filter and then into the carb.

Someone recommended that I take an empty quart of oil and attach it to the rubber hose...and let the oil drain into the empty quart.

Would anyone have any suggestions? Is it bad to have the oil in the air filter and then burn thru the carb?

Thanks!

 

[HealeyRick]

Sounds like you need a new rocker arm shaft and bushings for the rocker arm pedestals.

 

[TrevorJ]

Thanks Rick. The entire engine was completely overhauled 1,600 miles ago.
Would that have been done during overhaul?

 

[TimK]

I agree, this is the classic symptom of a worn rocker shaft. Easy to confirm by taking off valve cover and observing whether oil is dribbling out of rocker arms or spraying out. Dribbling is correct.

 

[TrevorJ]

Sincerely appreciate the advice. Thanks!

 

[HealeyRick]

Sincerely appreciate the advice. Thanks!

Used to be the place to go was Rocker Arm Specialists in SoCal. They've since sold out and become rockerarm.com I don't know if they still are as good as they once were.

 

[Keoke]

HEY Trevor !!!
Try this under the tube coming out of the valve cover is a baffel. If the T shaped tube is screwed down to close to that inside baffel you can get the problem also. So try repositioning the tube to a higher level--Fwiw--Keoke--

 

[RAC68]

Hi Trevor,

My first thoughts are that since you have recently completed a full engine rebuild, there are three things that may cause this problem. First, if components such as rings and bushings have not seated correctly, or are yet to fully seat, you could have this type of problem. For example, shortly after rebuilding his engine, a friend added Slick 50 to his oil and the engine never did work in properly.

The second possibility is quite the opposite as it is the result of oil starvation causing excessive ware to some components (i.e. valve train bushings). In this case excessive ware was caused during engine break-in which, again, resulted in sloppy sealing.

The third cause could be a take-off of the first in that you are experiencing heavy combustion blow-by. In this situation, your rings are not sealing against the cylinders and, during combustion, excessive gasses are expelled into the crankcase. Excessive pressurized blow-by gasses, mixed with hot splashing oil, is pushed through you vent tube to escape into your rear carburetor[s air stream.

Although all three, and many more, could be a cause, the only way to identify the true problem is with some diagnostic engine excavation.

One way to relieve the oil from venting into your rear carburetor is through the implementation of an oil catch can. Consisting of a container that has been ¾ divided internally to form two chambers connected by a steal wool filled path across the bottom, this container will take in your crankcase output and condense and capture oily vapor prior to passing these crankcase gases on to your carburetor. A drain installed at the bottom of the oil catch can is provided for periodic elimination of the captured oil.

Good luck,
Ray (64BJ8P1)

 

[Randy Forbes]

 

[Randy Forbes]

Yep, looks like my days of adding pictures to threads here is over (all I see are the url links to the pictures, not the pictures themselves).

Must be something about the way Basil has it set up here, because I can post (and see) pictures from my new website/server on the BMW forums.

Sorry guys...

 

[Randy Forbes]

LOL! See... https://www.bimmerfest.com/forums/showpost.php?p=6051105&postcount=2

 

[57_BN4]

Randy, seems like your server is down... Also, [ img ] has to end in .jpg

Andy.
PS TS gapless rings on their way, thanks.

 

[RAC68]

Hi Trevor,

The following is a depiction of an Oil Catch Can that can be easily constructed or purchased.

Hope it helps.
Ray (64BJ8P1)

 

[richberman]

Here's one that AHSpares sells.
https://www.ahspares.co.uk/products/productdetail.aspx?GUID=03746a82-886c-4589-870d-86fd2d50aa9a

 

[Legal Bill]

Trevor, call your rebuilder and ask if he replaced the rocker shaft and rebushed the rocker arms. Also, as I recently discovered, the oil line to the rocker assembly might be leaking.

 

[Randy Forbes]

Randy, seems like your server is down... Also, [ img ] has to end in .jpg

Andy.
PS TS gapless rings on their way, thanks.

Server's online, but adding ".jpeg" made all the difference here (not required on the BMW forums...).

Thanks for the tip!

 

[Keoke]

Tre adding just JPG might even work bettter----Keoke--- :laugh:

 

[AUSMHLY]

If I should start another tread, I'd be happy to.

What should we use to clean the mesh in the air filters and after they are cleaned, should anything be applied to them after?

 

[Keoke]

Naw it fits here OK. Generally any good parts cleaner like Gunk etc that you can soak them in then wash thoroughly with water. Mask off the screen and repaint. Fwiw--Keoke

 

[AUSMHLY]

After the mesh has been cleaned, should the mesh be coated with anything to help collect the dirt? Example, K&N has a spray for their air filters.