924Board.org

[ideola]

Suitable for all 931. Kit contains enough nuts in M8 and M10 sizes for all of the critical exhaust-hanging interfaces, as follows:

• QTY 16: M8x1.25 nuts and E-clips (for manifold-to-head, jpipe-to-wastegate, and wastegate-to-dump pipe)
  
• QTY 9: M10x1.50 nuts and E-clips (for manifold-to-turbine, turbine-to-jpipe, and turbine-to-main exhaust pipe)

$150 per kit. Ordering details...

These locking exhaust nut kits are made from high quality, heat resistant stainless steel (which impacted the cost...). Even when using conventional locking copper nuts, the studs can still back out, particularly on three bolt flange that attaches the turbine housing to the manifold. Once this occurs, one or more studs will often fall out, and are almost impossible to replace with the engine in situ. Loose exhaust hardware leads to exhaust leaks, boost leaks, inefficiency of the turbo due to heat loss, and additional stress on the manifold which can lead to the infamous cracked exhaust manifold on the 931.



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erstwhile owner of just about every 924 variant ever made

[brealytrent]

:thumbup:

Too bad I already bought the outrageously priced nuts though
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1977 Porsche 924 - sold
1980 Porsche 931 - sold
1984 Porsche 928 'S2' Euro - sold
2016 Ford Fiesta ST - sold
2009 Porsche Cayman

[Rasta Monsta]

[ideola]

I also have a source for locking copper nuts. The problem with them (and any other conventional lock nut) is that they won't prevent the stud itself from backing out. On several of the 931s I've seen and dismantled, this has been the problem: the nut stays put (apparently), but the stud itself backs out of the turbine housing...in particular, the one that is upside down on the back side, which is nearly impossible to get to with the engine in situ. I don't ever want to have to deal with this problem again, so all of the fresh motors I'm building will be getting the Stage8 hardware. It's impossible for the stud or the nut to back off with the locking retainer in place. Expensive yes, but worth it in my opinion given the high likelihood of failure with the conventional solution.
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erstwhile owner of just about every 924 variant ever made

[924RACR]

Mmm, good point on the copper nuts.

We ended up safety-wiring mine all up, but again a major PITA...
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

[ideola]

And for what it's worth, I had this happen on one of the studs on my NA (exhaust mani to downpipe)...i.e. used copper locking nuts, but the stud backed out.
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erstwhile owner of just about every 924 variant ever made

[Rasta Monsta]

I'm curious, when you had these back out, had fresh OEM studs been used?

I may have gotten lucky, but all the fasteners I used to refresh Shaggy's turbo a couple years back were fine when I pulled it all back apart(although it did spit off three of the four turbo bracket bolts).
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[ideola]

I don't know because the examples I've seen have all been pre-existing conditions. But I've seen enough of them on my cars and others as well to deem it a problem. OEM might be OK, but then again, there's so many cracked manifolds and known failures, why chance it to a $.50 copper nut? If the turbo were more easily serviced in situ, it might be a different story. But I like the install-it-and-forget-it peace of mind that comes with the locking nuts.
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erstwhile owner of just about every 924 variant ever made