Safe to leave 'spider' in heads without smog air pump?

KobaltBlau · 02-13-2011, 12:07 AM

Hello all, I searched around on this and didn't come up with much.

I'm removing the air pump from my 78 SC. I know our host has plugs that can be screwed into the head to replace the air injectors, but what I'm wondering is if I can safely leave the 'spider' (the distribution manifold from the pump to the air injectors, below the tin) on, and simply remove the pump.

I'd then probably remove the spider down the road when I make an exhaust change.

If I can leave the spider on safely, I can get the car back on the road tomorrow, if not I will probably wait for parts. Not critical to get me to work, but you know how it feels waiting for parts

Thanks in advance!

James Brown · James Brown's Garage

souldnt' be a problem as long as you plug the end. Or just take the belt off and wait till you want to remove it all.

KobaltBlau · 02-13-2011, 02:48 AM

Thanks, James. I guess this was the post that had me worried:

Quote:

Originally Posted by Rex Walter

T1R1,

I have heard that leaving the air injectors in the head, without air going through them, can cause them to get hot, and possibly break off in the head - not a god thing. John Walker has pointed out in the past that 914 rear brake bleader plugs work perfectly. Part No. PEL-BRC-02 comes with plugs and copper seal rings. I just got some.

Rex

From this thread: http://forums.pelicanparts.com/porsche-911-technical-forum/239213-help-id-these-cause-concern.html

Rex hasn't been active on the board since 2006. What he heard might be just somebody's worry of what might happen. This problem doesn't seem likely to me...

Aurel · Aurel's Garage

I had the tubing left on mine for years before I plugged the holes when I rebuilt the motor. This did not cause any problem other than knowing it was useless.

ossiblue · 02-13-2011, 08:30 AM

You will not need to plug the end of the spider tubing, even if you remove the pump. There is a check valve just before the tubing drops below the tin that prevents exhaust blow-back from entering. If you remove the pump but leave the check valve, you are good to go.

fanaudical · fanaudical's Garage

When I got my 75, the PO had removed the air pump and capped the pipe to the spider. I found the tips of 4 of the 6 injectors somewhat melted, but no evidence that the molten parts made their way into the head. The only place for pieces to go when the break off is into the exhaust system.

scotricker · 02-13-2011, 09:03 AM

You are right that the exhaust needs to come off to completely to get those air lines removed and plugged. I removed the air pump and a few of the hose thingeys in the engine compartment awhile ago. I couldn't get the bracket off though. Not enough clearance to get one of the bolts out. I just capped the two air tubes in the engine compartment that go to down below with rubber caps like for a chair leg. I, too, will take the rest of that stuff off later someday. I carefully boxed up all those parts that I took off, for just in case, someday. What if I sell, and the next owner needs the pump to pass smog, etc... These pumps are hard to find later, so you might want to keep yours if you can.

KobaltBlau · 02-13-2011, 08:14 PM

Thanks, all. You are a great help.

L.J., I do see the check valve, so I'm good there. I may throw something over it just as a dust cover.

fanaudical, that's very helpful. I guess my biggest risk is that I damage the air injectors, which isn't a problem unless someone wants to use them again (California, perhaps). The melted tips didn't cause any issues getting them out?

Scot, yeah. Not looking to remove heat exchangers on this round. I'm in the same boat on the bracket too. I will definitely sock the parts away for the benefit of future owners.

Dang, I didn't find this thread before, because I was searching for 'air pump' not 'smog pump' but for future searchers it should be helpful:

http://forums.pelicanparts.com/porsche-911-technical-forum/568494-smog-pump-removal-next-steps.html

Also, from Scot regarding leaving the bracket on - I would love to remove it too but no luck:

http://forums.pelicanparts.com/porsche-911-technical-forum/503034-air-pump-bracket-removal-stuck.html

If you are able to remove the bracket, you'll either need spacers or shorter studs, more info here:

http://forums.pelicanparts.com/porsche-911-technical-forum/101554-smog-pump-removal-what-length-chain-cover-studs.html