Emission Control System Advise

[visualfx]

Hi,

Has anybody deleted/blocked/welded the O2 (lambda) sensor holes on 912 heads?

I’m in the process of rebuilding my engine on my 1968 SWB and this emission control system is not required in the UK, just looking for anybody’s solution or experience in the past?

[Peter Graham]

These holes are easily capped with proper fitting plug; the plugs I just used just last week are BMW oil drain plugs (17mm ATF) with copper sealing washers. I wish I had a photo to post but these heads went to the engine builder last Thursday.

The tapped holes were actually used to inject air into the exhaust stream to complete combustion and reduce emissions.

[visualfx]

Thanks Peter that’s exactly the info I was looking for much appreciated.

Off to source some plugs :-)

Thanks Again

[Peter Graham]

I should add some information conferred to me on the 912bbs about these ports:

I have a 356 racer friend who prefers the '68 heads! He installs a pyrometer probe in each of the air injection ports, routes the signal through a 4-way switch and then to a pyrometer. He can read the exhaust temp on any single cylinder accurately. He seem to have no trouble rejetting when altitude or weather changes dictate.