86.5 Oil Filer Neck and WYIT TB/WP/Etc.

[Crumpler]

I couldn't handle the oil filler neck leak anymore. The valley full of oil was keeping me up at night.
Figured I would hit a lot of other issues while I was in there.
Needed to do my first TB/WP anyway.
I decided to rebuild the stock tensioner, mostly because I wanted to learn the system but also because there is no porken option right now.
Plan to rebuild water bridge and replace T-stat as well as all hoses and belts.

Started the tear down this week.
For a change I went slow and bagged and labeled everything.


Only issue getting water bridge out was managed to strip a hex bolt at driver's side rear.



The filler neck was pretty nasty.
Not bad to get to, but hoses to neck were brittle and fell apart.



I couldn't even find evidence of a gasket...not even residue.

Plenty more to come.
Tips to the rookie are welcome.

[Alan in AZ]

Well - that could explain the giant mess - uggh, it looks like an o-ring is in there but very flat looking - can't really tell...?

Are you going to strip & refinish the filler? At least with the metal oil filler (and new o-ring) you should get a reliably good seal when it all goes back together - the plastic ones can warp.

If you have any thoughts of changing crankshaft oil control configs - now is the time to configure for it...?

Alan

[Crumpler]

Alan, if you have time, can you tell me more about options to re-configure or send me a link?
Thanks.

[Alan in AZ]

Well its a complicated question and there are many opinions of what to do. The oil ingestion into the intake is a bigger issue for later engines (esp. GTS). If you have no concern on oil usage or oil in the intake - no need to do anything. if you have excessive oil usage or a very oily throttle body you may want to think about it...

If so a part of the oil ingestion is from the breather ports on the oil filler.

General options are to add a baffle down in the crank vent below where the filler goes, and perhaps to relocate the breathers from the bottom of the filler - which means they need to be capped off down there - this is all harder once the water bridge is back on... so the question should be asked (and answered) now...

Alan

[Danglerb]

Google provent and 928, but the baffle does a lot.

[Crumpler]

Thanks, I will read up on it.
Appreciate the help.

[Alan in AZ]

For me even a Greg Brown crank vent baffle and a Provent helped not that much - its a GTS, used lots of oil (1 Quart / 400-600 miles maybe) and ran poorly at times as a result (knocks /power loss).

I am still working at it but currently run a vacuum pump and two AOS elements (second is a Provent). I think I'm close to having this thing licked..

When you drive a GTS hard I think they all use a lot of oil... Porsche screwed up big time, some of the changes to the oil control system for the GTS actually made things worse...! Of course stroking the engine for the displacement and using a higher windage crankshaft design didn't help matters either...

For earlier cars - especially if you don't drive very aggressively - you may never see much of an issue - but on the track you likely will.

Alan

[Landseer]

On 85/6 cars the hoses at base of that filler neck harden, crack and then spray oil mist across top of 32V engine. Replace them and the gasket, should be good to go.


Those same vent hoses, if original, will also be nearly dissolved and soft on the approach to the cam cover. At base, they crack.

Its one of those items on the permanent refresh list that must be changed on any 85/6 that you bring home.

[Crumpler]

This may become an interesting thread. Thanks again.

I have not had time to look at a provent but a baffle might help. I certainly do have a lot of oil in the intake. I don't have plans to track this car.

I've got so much junk in there, I made a modified cap to avoid a FUBAR while cleaning.



The filler neck is being prepped, but I do have a concern about the metal baffle/O-ring combination.
The components aren't secure to each other and I had heard it is now NLA.
I measured the opening on the crankcase and the metal baffle overlaps the hole. I assume it would be stable when I button it up, but I certainly don't want it to shift around.

[Dadddio]

Possibly clean the groove really good.
Then apply a small bead of silicone sealant in the groove.
Leave it stand a little proud of the surface.
Let dry.

[Alan in AZ]

The baffle I was talking about is not that one. You can get a baffle box that drops down into the crank vent... you can ditch this baffle plate then and use a stock gasket above/below.

Greg Brown & John Kuhn make them - do a search

Alan

[Danglerb]

Like a lot of things on the 928, oil where you don't want oil isn't from a single issue, more like a handful of problems that show up depending on how you drive and which model you have.

[Crumpler]

I have been looking at the aftermarket baffles. The Kuhn system looks like more then what I would need in this car.
I repaired the stock baffle just in case.
The filler neck went well and the clean up is in progress.

[Landseer]

The oil is highly likely just from the breather hoses.

You do good work, BTW!

[Alan in AZ]

I think its more likely from the base of the oil filler where there was no gasket

Alan

[Crumpler]

Long day, I might need one of those New Hampshire sleep-aids that Pete mentioned.

Thanks Landseer, that means a lot coming from a veteran. And Alan, thanks for run down -- I'm enjoying learning the system.

I'm going to try the stock baffle first with these gaskets I got from Roger, and see how it goes.
I love the concept of the aftermarket baffle upgrade, however.



The filler neck went well enough I decided to pull the air boxes, etc.

[Landseer]

Well, you are right Alan, gotta have the gasket.

[Danglerb]

Its a slippery slope, cad plating is just a couple steps away.

[Crumpler]

Would love to but starting to bleed money on this job.

If my ship comes in I would call Mr. Kuhn for a twin turbo conversion!

[Crumpler]

Got some work done today, but not much.
I'm doing the waiting game for parts.

Cleaned and rebuilt the water bridge with new gaskets and T-stat.
Inner gasket was essentially cooked off.




I also had been missing anything resembling these gaskets as well when I did the tear down last week.


Moved on and started to take off belts and clean in preparation for TB/WP.



(wish I could identify object trapped behind power steering belt, could not even tell you what it was after I pulled it out.)