Smog Pump Piping

Guardsred911 · 08-17-2017, 08:13 AM

I still have the piping from the smog pump on my '77 911S with the 2.7L engine. Pump has been long gone, but the pipe that goes around to the 6 cylinders and the injection ports are all still in place. What do folks do with these? Looks like you could remove the pipe and leave each port per cylinder? The piping is open ( at least covered with tape from the PO).

Thanks!

J

T77911S · 08-17-2017, 08:19 AM

remove all the piping then plug the holes in the heads with plugs you can get here.
backdate exhaust, upgrade fan to 11 blade if not done.

75 911s · 75 911s's Garage

PB blast all the nuts at the end of the air injectors.
Buy the plugs as stated above
remove the muffler, blast the check valve in the engine tin as well, boy is it really on there and it's hard to fit a wrench in there.
The injectors and piping can all be taken off without removing the HE/headers. Get creative with small adjustable wrenches and leverage.

ossiblue · 08-17-2017, 08:25 AM

Quote:

Originally Posted by Guardsred911

I still have the piping from the smog pump on my '77 911S with the 2.7L engine. Pump has been long gone, but the pipe that goes around to the 6 cylinders and the injection ports are all still in place. What do folks do with these? Looks like you could remove the pipe and leave each port per cylinder? The piping is open ( at least covered with tape from the PO).

Thanks!

J

I had the same set-up on my '75, which I removed. If the pump is gone, you likely still have the check valve in place which prevents the exhaust gases from leaving the pipe. The check valve is located at the tin, in line where the smog pump had been attached. Tape alone will not plug the pipe. You will have no change in operation by leaving the plumbing in place or removing it. Removing the old plumbing will make the underside look cleaner, obviously, and you will eliminate the possibility of a failed check valve.

If you choose to remove the plumbing, you may run into difficulties in that removal of the heat exchangers is not necessary but makes it easier, and that can often result in destruction of the exhaust studs. Once the exchangers and plumbing is removed, the holes where the pipes tapped into the exhaust head must be plugged--plugs are offered by our host.