MistaX

Serious question:

If my upper balance shaft rear seal is wrecked, can this cause a major vacuum leak?

It's losing oil down the side already, and this seems like I need to order things and that's going to take time I don't really have.

It's extremely loose and the hoses don't seem to be the issue. Can blow smoke into the AOS and smoke comes out the seal. It's pretty bad.

V2Rocket

Yes...
Crankcase should be under partial vacuum, hole in that seal could be pulling air into crankcase, out the AOS and into the intake manifold post-MAF (unmetered).

Van

Sure that'll cause a vacuum leak. The hose from the AOS goes right into the intake pipe... so, sounds like your seal problem would be just like if you left the oil cap off.

BTW, the upper and lower balance shaft seals are different diameters...

MistaX

Well that's my leak then.




Going to attempt to pop the cover off and RTV it to death without removing any belts.



I don't understand why I can't have normal 944 problems instead of breaking spring plates and major vacuum leaks from nonsense oil seals.

fwb42

Just remember a temporary fix is just that. You'll be doing it again.

V2Rocket

no RTV...
popping BS belt off is trivial for this repair.
total time to remove BS belt, remove pulley, replace seal and reassemble probably under an hour.

MistaX

What do I win?

(Had to take the alternator belt off, not exactly no belts removed. Bracket blocked the cover by a hair)

Van

Oh, the rear plug. Those are the same size for both covers, but they are different sizes for early and late engines.

V2Rocket

^^ early/late in this case is 82-86 vs 87+

MistaX

I'll do it right since the original one made it 32 years after all.
Ordered one with 1 day shipping, hopefully I get this stupid thing tomorrow for what that cost.

At least I can spend the rest of the day putting the door handle on.

924srr27l

How's your Progress any luck?
R?

MistaX

No. A certain vendor still hasn't shipped the seal. Apparently having items listed as "In Stock" on their website does not actually represent reality.

Of course next day shipping means from them to me, but not their supplier to them.



Edit: Now, magically, it shipped. Quite the coincidence.

MistaX

Okay it's back together again and runs again.


AND IT STILL ISN'T FIXED. Runs different, exhaust note is different, revs freely, idle is crap. I think the vacuum leak is now smaller.

V2Rocket

Try something...
Put pliers/vise grips/hose pinch clamp on the fuel return line (after the fuel pressure regulator - it's the smaller of the two engine bay fuel hoses). Clamp as tight as you can...

Then start the car...does it idle any better?

MistaX

Tried that, no noticeable change. Put the vac gauge back on it, ~50in/hg so now I'm really sure there's no leak.


I drove it around, it backfires on every shift, which is cool in a bad way, but it has a major hesitation getting back on it, and some misfire/bucking issues at low throttle input. There's a delay in throttle response in general.