thezonster

'86.5 928
Ive pulled my intake to repaint and also change all seals and gaskets.

There was a pretty fair amount of oil pooled under my intake in the vee area around the throttle body.

At this point I think that it was probably from a bad seal at the oil filler.

But I'm wondering about the three plugs in the floor area of vee, under the intake. What are they for and could the oil have come up through there?

I dont want to have to go back in here again, later.

Speedtoys

The plugs dont go into any passages...its that filler neck, to be sure.

Avar928

If that's your car in your avatar, I have the same one...except without the .5...and the rub strips...but with a dent on both sides in the rear...

Very nice.

hacker-pschorr

Contrary to popular belief, most cars suck oil into the intake, it's all part of how emissions systems are designed. The crankcase breather systems on all stock cars is routed to the intake so a vacuum is drawn on the crankcase. This is good for the engine (helps the rings to seal better) and insures no unburnt fumes from oil vapor goes into the atmosphere. This means on all cars, oil vapor is going through the intake manifold at some point.

One of the problems with the 928 is the inverted nature of our intakes. Over time oil trying to go straight up through the throttle body goes from a vapor back to liquid and settles in the valley.

There is a laundry list of issues that can increase the oil injection above what is considered "normal" Everything from worn piston rings, to bad gas causing it to detonate (detonation causes bad blow-by).

One popular solution is to install some kind of air / oil separator between the crankcase and the intake. That is where the Sharkvent from 928 Specialists comes into play. Not the only way to accomplish this, but one of the only "plug-in-play" options that I know of:

https://rennlist.com/forums/928-foru...ight=sharkvent

Another option is to simply vent to atmosphere instead of the intake. But to do this, you should still install some kind of air / oil separator to pull the oil from the crankcase air. Some route this to the exhaust to be burnt off there.

Mrmerlin

What the Op is talking about is oil in the V of the block,
this is caused by a leaking oil fill tube connection where its bolted to the block
928 Intl has an oil block off plate to install under the fill tube to reduce oil splash from the #2 rod .

If you dont choose to use this plate then clean the parts you have,
NOTE you have the metal fill tube and it should have a metal plate with a set of louvers in it and a seal thats bonded to the plate.

Clean this up as best you can then get some Hondabond 4 and put a generous coating on both sides of the plate then connect to the block,
if you choose to use the 928 INTL plate put the Bond on every face that seals.
this should prevent any future leaks till you loosen the bolts.
If you have the new style plastic fill tube use the HB on the O ring and be generous with it on the sealing face of the plastic tube face then bolt it onto the block

NOTE make sure you have installed the water bridge first before installing the fill tube

hacker-pschorr

Yea....noticed that after I posted my response.......oh well.

Landseer

The two crankcase breather hoses on the early 32V cars that run to the passenger cam cover get sticky soft, break down and get holes in them. Check at the base of the oil filler area. Will spray engine compartment with oil and fill below the throttle body and the cavities closer to the water pump / front of engine. I've got an 85 and an 86 that both had this happen. Could be something else, but that's what fixed mine.

ramcram

I had exactly the same problem with my 94 GTS. Removed the filler neck and the 'O' ring had shrunk and leaked oil into the valley.
I don't know when Porsche moved from a gaket to an 'O' ring?
Simple fix though.

thezonster

I see that the black o ring that is built into the baffle plate/seal at the bottom of the filler neck, is completely flatened out and must have been leaking. I also have to wonder if the baffle at the bottom, may have caused the oil to back up and spill over the top, into the vee area, when filling the oil, over the years.

The vent hoses were good. So I think this seal must have been it. I have gaskets and sealant to repair, and will be carefull when filling the oil in the future.