300ZX Turbo to Downpipe Bolts
#1
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300ZX Turbo to Downpipe Bolts
I've recently torn down my install after about a year and a half and 15000 miles of driving. A head gasket with 200K miles on it was the catalyst.
In addition to the head gasket, it became obvious that I need to change my hot-side connectors. The mild steel bolts that I had used for manifold to turbo were completely inadequate. On had sheared in use. The other three had bad cases of thermal creep (turbo was loose) and sheared during removal. Only the safety wiring was keeping things together. TSE's M10 x 1.5 Inconel studs are now going in to take care of this area.
I used similar safety-wired mild steel bolts for the turbo to downpipe connection. These held up, were tight and came out undamaged, although the zinc corrosion coating was long gone. They see a lot less heat than the manifold to turbo area. Nevertheless, I'd like to upgrade these as well and have been looking around for suitable bolts. During my internet searching, I came across the factory early-90s Nissan 300ZX turbo to downpipe bolts. Supposedly, these were Inconel. Does anyone know anything about these particular bolts? Material (for certain)? M8, M10, other? Thread pitch? I can't seem to find these details anywhere.
Thanks in advance guys. If these really are Inconel M8 x 1.25 for $5 each, it would seem like a sweet solution.
In addition to the head gasket, it became obvious that I need to change my hot-side connectors. The mild steel bolts that I had used for manifold to turbo were completely inadequate. On had sheared in use. The other three had bad cases of thermal creep (turbo was loose) and sheared during removal. Only the safety wiring was keeping things together. TSE's M10 x 1.5 Inconel studs are now going in to take care of this area.
I used similar safety-wired mild steel bolts for the turbo to downpipe connection. These held up, were tight and came out undamaged, although the zinc corrosion coating was long gone. They see a lot less heat than the manifold to turbo area. Nevertheless, I'd like to upgrade these as well and have been looking around for suitable bolts. During my internet searching, I came across the factory early-90s Nissan 300ZX turbo to downpipe bolts. Supposedly, these were Inconel. Does anyone know anything about these particular bolts? Material (for certain)? M8, M10, other? Thread pitch? I can't seem to find these details anywhere.
Thanks in advance guys. If these really are Inconel M8 x 1.25 for $5 each, it would seem like a sweet solution.
#3
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Bolts Came In
So, I ordered the bolts (1990-1996 Nissan 300zx OEM Turbo to Downpipe Bolt).
$3.50 each!
The picture shows what I got. M8x1.25x28mm. Inconel. Nissan OEM. I think these are going to work really well. Happy with the purchase.
Easily drilled for safety wire, so long as your drill bit is sharp. The bolts do dull the bit quickly. Once it starts chipping rather than cutting, toss the bit. I've been using about 1.5 bits per bolt (I ordered 8 bolts).
Wouldn't use these on the manifold to turbo connection -- you want studs there for disassembly (got TSE's kit). But these should be just the ticket for the turbo to downpipe.
$3.50 each!
The picture shows what I got. M8x1.25x28mm. Inconel. Nissan OEM. I think these are going to work really well. Happy with the purchase.
Easily drilled for safety wire, so long as your drill bit is sharp. The bolts do dull the bit quickly. Once it starts chipping rather than cutting, toss the bit. I've been using about 1.5 bits per bolt (I ordered 8 bolts).
Wouldn't use these on the manifold to turbo connection -- you want studs there for disassembly (got TSE's kit). But these should be just the ticket for the turbo to downpipe.
#4
Bump
Great information Rick. +
Encouraged by your success I went to my local Nissan dealer and ordered some 300zx studs. It seems in addition to the bolt you ordered there are 2 additional types of inconel studs used on the 300ZX turbo setups.
1406440P01 is around 31 mm long and is the one used on the t2 flange. 1441417F00 is around 35mm long and is the one used on the downpipe flange. As far as I know they are inconel as
1) The Nissan man said the are
2) They are non magnetic
Originally the t2 side nuts look like they were locked in position with lock tabs. This shows the 1406440P01 part mounted on a t28 manifold.
I will test these and update with the results.
Great information Rick. +
Encouraged by your success I went to my local Nissan dealer and ordered some 300zx studs. It seems in addition to the bolt you ordered there are 2 additional types of inconel studs used on the 300ZX turbo setups.
1406440P01 is around 31 mm long and is the one used on the t2 flange. 1441417F00 is around 35mm long and is the one used on the downpipe flange. As far as I know they are inconel as
1) The Nissan man said the are
2) They are non magnetic
Originally the t2 side nuts look like they were locked in position with lock tabs. This shows the 1406440P01 part mounted on a t28 manifold.
I will test these and update with the results.
#5
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I should add that long-term, I've had good service from the Nissan turbo-to-downpipe bolts. I've disassembled/reassembled easily a couple of times over the last two years and been able to reuse the hardware with no issues.
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thanks for the long term report. i am in the middle of trying to find cheaper alternatives to TSE, and finally just broke down and bought some inconel bar and im having it machined by a friend. i may still get some of these for the DP though
#10
95 Rx7 Large Exhaust Manifold to Turbo Stud...
If M10 x 1.25mm pitch is needed then Subaru 800910340 are an option.
#12
Good information Vlad. I guess the part no for these Mazda studs is 9YA9-21-003? They look like they are regular M10 x 1.5 mm thread pitch.
95 Rx7 Large Exhaust Manifold to Turbo Stud...
If M10 x 1.25mm pitch is needed then Subaru 800910340 are an option.
95 Rx7 Large Exhaust Manifold to Turbo Stud...
If M10 x 1.25mm pitch is needed then Subaru 800910340 are an option.
And yes on the subaru studs too - I've actually used those too with no issues before. Though I'm not sure those are inconel - at least I never noticed that word in any of the part names or descriptions.
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12.9 steel is very brittle and would do very poorly in a high temperature, heat-cycled application. It also has a very different coefficient of expansion than the cast steel it is being used to retain. See the 70 page thread where this has been beaten to death for years on this forum. Inconel is the droid you are looking for.