924Board.org

[numbbers]

Hey guys, I know in the past there was a thread about the mod Porsche made to the series two cars to reduce the amount of oil vapor that came through the oil seperator. I cannot find the thread.

I would appreciate it if somebody would describe the mod, and maybe post or email me some pictures, as I have an early '80 series one, and since I am fixing my oil leaks, I would like to reduce crankcase pressure. I may want to make the mod on my engine.
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1980 924 Turbo

[MikeDanger]

Yes id like to know too. My 80 has the head with the port but my 81 head doesnt. Sine im making equal length headers that pipe may get in the way, and id like to remove it if i can.


Hey Im moving to Denver !!

[gohim]

All 931 cylinder heads have the undrilled block where the oil breather hose is connected.

One of the Porsche Factory Tech Bulletins (Reprinted by year in bound form) cover the installation of the Breather Modification. I found the instructions in in the Tech Bulletin Reprint Volume labeled "Prior To November 1984". The TB number is #83-01

The instructions even show how, where, and what size hole to drill in the head for the breather hose.

At one time there was a kit available from Porsche with all of the parts included. Unfortunately, I believe that the kit #000.043.017.00 was discontinued some years ago. I think that all the parts may still be available, but you would have to buy them separately. The cost of the parts is probably going to be in the $300-$400 range.

[924 turbo]

Gohim provided the kit's part number, but here are the individual parts:

1 End plate 93110404100
1 Gasket 059127311A
2 Plain washer N 011 525 13
2 Socket head screw N 014 710 3
1 Pipe 931 107 219 01
1 Foam rubber hose 477 209 303
1 Shaped hose 931110 181 00
3 Hose clamp N 0245101
1 End cap 930 110 256 01
1 Round seal 999 701 477 40
1 Valve cover gaskets 060 198 025

Basically, the Series 2 turbo had a vent in the oil return line from the turbocharger. In the original factory installation, this vent line was connected to a Y in the crankcase-breather-to-oil-separator line. The upgrade kit basically just changed the connection to the cylinder head.

For an '80 car, you will need a vented oil drain line (931.107.108.08) from a 1981/1982 model in addition to the above parts.

FWIW, the factory supposedly installed the kits from VIN 93CN150503.

A couple pictures from the factory literature:








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Jon Furst

[CMXXXI]

Hmmm, interesting. Someone here on the Board did a rebuild maybe a year ago or so and posted a photo that showed the tube/pipe running to the head. I asked about it saying I'd not seen that before and have half-heartedly attempted to find a source for second-hand parts to do that mod. I finished reassembling my engine this weekend (except for clutch-related stuff) and note that the "breather" off my turbo dumps directly into the bottom of my intake manifold - no oil seperator on the '79 Euro model.
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'79 Eurospec 931

[924 turbo]

More likely, that line is the vacuum line for the bypass valve in the turbo compressor housing. Your breather line (from the engine block) should go straight into your air filter box if you don't have an air-oil separator.
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Jon Furst

[MikeDanger]

my 80 appears to have both, one line from the crank case breather goes into the collector(?) the purolator thing. but has 2 hoses exiting it, on going into air filter housing and the other going, uh, somehwere.. the hose was laying behind the thermostat housing.(wait, maybe that line went into the CIS meter??)

there also apears to be a pipe/hose comming from somewhere under the alternator mount that connects to the under side of the intake manifold


PS i have all the fuel and ignition parts forsale, from both 80 and 81 model cars.


BTW, how is this a mod, since my 80 had it but my 81 didnt?

[Paul]

The mod was to supply a better vent for the turbo oil return line.

[numbbers]

Thanks guys. Looking at the diagram, I can't see where this mod would have any effect on crankcase pressure.
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1980 924 Turbo

[Paul]

I've thought about putting a T on the hose that runs from the head to the turbo oil drain and routing it to a T on the crankcase vent hose that's connected to the separator.

[MikeDanger]

Well what can i do? since im going to need to move this set up?
remember im making equal length headers, they will go forward.

[CMXXXI]

[Lizard]

hmmm, according to that diagram all the turbos I have seen have had that mod, done including Kenodogs, it must have only been early 1980 931 that didnt have that
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3 928s,

[-nick]

CMXXXI-
I've got the same early setup as you. This mod changes the drain line from the turbo to the oil pan. The other two turbo lines remain the same.

Just how important of an update was this?

-nick

[CMXXXI]

I read somewhere here on the Board a while back that the mod had something to do with preventing or reducing the amount of foam/oil as it came out of the turbo shaft housing. Maybe something about the foam "backing up" preventing decent oil flow across the bearings? I haven't gone back to look for the post. I was under the mistaken impression that the mod didn't entail tapping into the existing oil line draining from the bottom of the shaft housing into the sump. Perhaps because <almost> everyone else has a "T" in the return line going to the air/oil separator to begin with.

Like I said, I half-heartedly looked around to find some second-hand parts so I could implement the mod, but I guess it's just as well I never found them. I suspect that unless I found a complete scrap engine with the mod already applied, it'd be pretty tough getting all the necessary hoses, pipes and fittings.
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'79 Eurospec 931