911 2.7l Running Problem

adb · 06-18-2006, 10:31 PM

HELP!!!! I am a newbie, just purchased a '77 911, with 2.7l motor, last week. I have read about the backfires that could cause airbox damage, so i decided today to put in a 'pop off' valve (from Pelican Parts), after gluing the valve in and putting the airbox cover on, i started the engine, and it runs really rough, almost stalling on occasions, there seems to be a popping sound coming from the airbox. The engine ran beautifully before i put this darn valve in, so i am tipping it may have something to do with that! Vacuum leaks around the valve come to mind, but how can i check, if this is the cause? Please help me!!!!!

adb · 06-19-2006, 01:21 AM

My nightmare just got worse! I attempted to start, started fine until the epoxy glue was sucked down the hole!!! hopefully i have not done any major damage! Not a good day at the office!!!

kach22i · kach22i's Garage

I had to re-glue my pop off valve, I had air leaks around it and it was forced out of the hole several times by pressure. Any leak around that seal will mess things up (starting/ running).

When I took a vaccum cleaner hose attachment in there to clean out all the old glue, I must of bumped the air intake plate, I had to fiddle with it (no adjustment) and get it unbound before it would run right again. Maybe the cloth I had tangled up and caught the plate. One guy left his cloth in and it got sucked down when he started up- be careful in there.

You should cover the intake before working in there to keep debris out. You might be able to suck debris back out with a shop vac and long flexible attachment - although I never had to go that far myself.

adb · 06-19-2006, 03:12 PM

Cheers, I actually re-glued the valve late last night, left it overnight and just started it then, IT RUNS!!! I reckon i still need to ad more glue around the edges, just to make sure that the seal is 'air tight'. I have included some pictures of my new girl!