924Board.org

Vince Ponz · Joined: 02 Nov 2002 Posts: 3581 Location: Florida

I have a 79 turbo and need an exhaust manifold. There are three numbers on Pet for the part. Anyone know if they are all the same?

Got one? Let me know.
_________________
"Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock

924guy · Posted: Wed May 05, 2004 12:12 am Post subject:

vince,

The only difference i could find between the years is the required sealing gasket configuration. i dont know if the flange mating surface is actually different or not. hopefully someone here will know more.

ill be swapping my exhaust manifold soon, as i just found a "new " one.. my currently installed manifold may or may not be cracked (ill know more once its out), and its an 82' , but if itll work with your 79' and can be repaired (if needed) your more than welcome to it if you want it..just cover the shipping and remember me in our future "parts exchanges" and dont expect it quickly...

_________________
Eric
78 924
82 931 SE "smokey"
99' VehiCross
Y2K Honda Insight
http://www.cardomain.com/id/924Guy
Performance by Pasha

CMXXXI · Joined: 05 Nov 2002 Posts: 1939 Location: Vicksburg, MS

Vince, I've got an "early style" one, but it has the hairline crack on the #2 runner like just about all of them do. I got this off e-Bay, and the guy had acutally plugged off the J-Tube end of it, so he wasn't running a wastgate at all! (see left hand photo below). I don't know if the turbo I got is shot or if it's rebuildable. Who knows what sort of stress (?) it's been subjected to running in that configuration.

If no one else can help you out to meet your timetable, let me know.

(click for larger images)
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'79 Eurospec 931

Paul · Posted: Wed May 05, 2004 9:29 am Post subject:

From the FAQs:

Modifications to turbocharger on production cars were introduced in stages:
Version I = exhaust in and out connections without recess, with gaskets
Version II = exhaust in with recess and fill-in gasket seal, exhaust out without recess, with gasket
Version III = exhaust in and out connections with recess and fill-in gasket seals
Note
Flanges from exhaust manifold and tailpipe to turbocharger have not been modified

CBass · Joined: 03 Nov 2002 Posts: 2807 Location: Vancouver, Canada

I have two manifolds from '80, but they're both the seal ring type, so I don't think they'll be compatible unless you're running an '80 turbo. Coincidentally, I just happen to have a good '80 turbo I'm looking to sell

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'81 931 in various states of assembly

Vince Ponz · Joined: 02 Nov 2002 Posts: 3581 Location: Florida

Thanks everyone. It is a small crack about 1/2 in between the first and second cylinder on the top of the manifold. Are your cracked in the same area. I may have my friend try to weld it closed.
_________________
"Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock

CMXXXI · Joined: 05 Nov 2002 Posts: 1939 Location: Vicksburg, MS

Vince, I'm not sure what the differences would be for three different part numbers. As noted, the flanges on the actual manifold didn't change to accomodate the flat gasket vs sealing ring. All I've ever seen or heard of is that the early types didn't have the reinforcing "ribs" cast into the underside (see photos in my first post), whereas the later ones did.

I've always found this nugget of information puzzling, as my '79 has the "late style" manifold. I have all service records from day one, and there is no mention of a manifold replacement.

Well, now that I think of it, the manifold--->J-jube joint calls for different gaskets, doesn't it? Some need the flat one, others call for the same sealing ring as is used at the manifold--->tubo joint. Maybe somewhere along the line there was a production run of ribbed manifolds that used the flat gaskets, and then another run that used the new sealing ring. Still, this is conjecture on my part...
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'79 Eurospec 931

-nick · Joined: 16 Nov 2002 Posts: 2699 Location: Cambridge, MA

Wow no wastegate! vroom vroom!

Vince, my manifold had a small crack under the #2 running also. The welder charged $75 to blast the manifold and weld up the crack. I'm not sure what the process was, but I know I couldn't pick it up for a few days because it was "cooling" down.

-nick

Vince Ponz · Joined: 02 Nov 2002 Posts: 3581 Location: Florida

I will keep asking for one. Right now I have to replace both motor mounts. Boy does it sound bad on startup. Sounds like marbles inside the oil pan. Scary.

Keep me in mind everyone. And thanks.
_________________
"Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock

CBass · Joined: 03 Nov 2002 Posts: 2807 Location: Vancouver, Canada

Vince, if you're going to have the manifold welded, have it welded by a professional with lots of cast iron experience. The stuff can be tricky to weld, especially since you can't actually see the weld puddle through the flux.

IMO, a nickel electrode weld is the best way to go, as it has good expansion properties for use with cast iron, and likely won't crack in the future. It also means that the manifold can be "cold welded", that the welder can clean up the manifold, grind a small groove into the crack, run a quick weave pass and give you back the manifold.

The other alternative is to torch weld it. The torch weld will probably look nicer, but it requires the manifold to be slowly preheated before welding, and very slowly cooled, or it will crack. If it's not done properly, it will crack again anyways, and it's going to cost more to have it done in the first place.
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'81 931 in various states of assembly

Vince Ponz · Joined: 02 Nov 2002 Posts: 3581 Location: Florida

I will look into it. Thanks. Maybe in Australia I can pick one up. I leave thursday. May say hello to Peter Au.
_________________
"Never let them see you sweat"
77.5 924 modified track car
79 931 Euro stock
88 924S SE
87 911 Targa stock

welder · Joined: 16 May 2003 Posts: 158 Location: cumberland,maine

Hey Vince have it welded, its cheap and permanent.(I wonder why I feel that way)
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I have a 78 n\a currently under restoration.

CBass · Joined: 03 Nov 2002 Posts: 2807 Location: Vancouver, Canada

Or upgrade to an '80 manifold and turbo, come on, you know you want to

But seriously, have it welded. It's cheap, and like Welder said, it's permanant. I've only seen one weld fail on a welded manifold, and it was because it was a bad weld.
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'81 931 in various states of assembly

John Brown · Joined: 07 Nov 2002 Posts: 903 Location: Leesburg VA

Vince, mine is welded too. Same spot. Technique was actually a combination of the above. Preheated with a torch (lacking an oven) then used high nickel content electrode to arc weld. The electrode was specificaly for welding cast iron.

Apparently the special electrode material is very ductile allowing the casting to expand and contract without putting further stress; while at the same time holding everthing together.

The fellow who did this (actually the local VOTech teacher) told me that in his opinion it was superior to other methods we could have used.

The info on the 3 types of manifolds is in the back of the Parts pamphlet. Note 5 I think.
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John
80 931 - #931 44Cup
99 Escalade - tows track cars
gone but not forgotten: original 924.org car - 82

924guy · Posted: Tue May 11, 2004 12:03 am Post subject:

why does this happen? is it just a product of aged parts and fatige or is it a flaw in the design? since this is such a common issue im almost thinking i should have my "new" manifold reenforced to prevent it from splitting down the line..maybe have a bead weld burned onto sure up the common failure area.. would it do any good though, or will it just split someplace else?
_________________
Eric
78 924
82 931 SE "smokey"
99' VehiCross
Y2K Honda Insight
http://www.cardomain.com/id/924Guy
Performance by Pasha