Welcome to 911UK
The only place for Porsche, 911uk is the definitive enthusiast and resource site for the Porsche 911.
Registration is fast, simple and absolutely free, so join up today for full access to the site and benefit from latest member offers.

Porsche Classifieds
Porsche Buyers Guides
Sell Your Porsche on 911uk
Create a Free Classified Advert
Search Ads
Classified Adverts FAQ
Trade Classified Information
Buyer & Seller Fraud Protection
Consumer Rights Act
Pre Purchase Inspection (PPI)
Porsche Car Sourcing
Porsche Cars Wanted
Official Porsche Centre Reviews
Model
Stock
Porsche 911
991 : 2011- 22
997 : 2004- 84
996 : 1997-2005 47
993 : 1993-1998 5
964 : 1989-1993 3
Carrera 3.2 : 1983-1989 0
Carrera SC : 1977-1983 2
930 Turbo : 1975-1989 0
Early 911 : 1964-1977 3
Porsche Other Models
Classic : 1950-1965 0
Boxster : 1997- 14
Cayman : 2005- 16
Cayenne : 2003- 8
Macan : 2014- 0
Panamera : 2009- 1
912-914-924-928-944-968 1
959 - CarreraGT - RaceCar 1
Car Parts For Sale & Wanted
Other Items For Sale & Wanted
Wheels Tyres For Sale & Wanted
Number Plates For Sale Wanted

Porsche Services
Porsche Body Shop Repair
Paint Protection & Wrapping
Porsche Classic Insurance
Porsche Classic Parts
Porsche Classic Restoration
Porsche Design Collection
Porsche Engine Gearbox Rebuild
Porsche Heritage & History
Porsche News
Porsche Picture Gallery
Win a New Porsche 911

Porsche Parts
Body Parts, Body Styling
Brakes, Clearance
Electrical, Exhausts
Engine Cooling, Engine Electrical
Engine Rebuild, Heating Cooling
Interior Incar, Lighting
Rubber Seals, Service Parts
Steering, Suspension
Transmission, Workshop Tools
Early 911, 911 - 930, 928 - 968
964 - 993, 996 - 997, Boxster
Cayman, Cayenne, Panamera

Porsche Model Range
911 [991] 2011-Current
Porsche 911 [991]
911 [997] 2004-Current
Porsche 911 [997]
911 [GT] GT1-GT2-GT3
Porsche 911 [GT]
911 [996] 1997-2005
Porsche 911 [996]
911 [993] 1993-1998
Porsche 911 [993]
911 [RS] RS-RSR
Porsche 911 [RS]
911 [964] 1989-1993
Porsche 911 [964]
911 3.2 1983-1989
Porsche 911 3.2 Carrera
911 SC 1977-1983
Porsche 911 SC
911 [Early] 1964-1977
Porsche 911 [Early]
Boxster & Cayman
Porsche Boxster & Cayman
Cayenne & Panamera
Porsche Cayenne & Panamera

911uk Site Partners

Post new topic   Reply to topic

Should I replace my rusty manifolds?
Yes, the car is going to be much better with new
15%
 15%  [ 3 ]
No, you won't really notice any difference
84%
 84%  [ 16 ]
Total Votes : 19

Author Message
ragpicker
Estoril


Joined: 14 Apr 2013
Posts: 3676
Location: North East England


PostPosted: Sat Apr 14, 2018 8:30 pm    Post subject: Reply with quote

INWB wrote:
alex yates wrote:
The clue's in the name - Stainless, not Stainproof.


Thanks Alex. Smile I'm not that good with stuff like that. Can I get bolts that don't corrode? The new ones already have surface rust.


Yep, titanium ones. Poppopbangbang on here sells them Thumb
_________________
996 turbo - slightly modified....
986 S - usually in pieces: http://911uk.com/viewtopic.php?t=112626
 
  
View user's profile Send private message
   
alex yates
Brands Hatch
Brands Hatch


Joined: 06 Mar 2014
Posts: 14298
Location: The Ribble Valley, Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sat Apr 14, 2018 8:31 pm    Post subject: Reply with quote

Marine grade Stainless (A4 I think) is probs the best.
_________________
2000 Manual 996 C4 Arctic Silver Convertible


 
  
View user's profile Send private message
   
alex yates
Brands Hatch
Brands Hatch


Joined: 06 Mar 2014
Posts: 14298
Location: The Ribble Valley, Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sat Apr 14, 2018 8:34 pm    Post subject: Reply with quote

I fellow Engineer (Aerospace Quality Engineer) was telling me the other day not to mix Titanium with Aluminium as they react with eack other and corrode. Don't know how true this is, only found out on Thursday.
_________________
2000 Manual 996 C4 Arctic Silver Convertible


 
  
View user's profile Send private message
   
Bluebird911
Nürburgring


Joined: 29 May 2010
Posts: 417



PostPosted: Sat Apr 14, 2018 10:09 pm    Post subject: Reply with quote

alex yates wrote:
I fellow Engineer (Aerospace Quality Engineer) was telling me the other day not to mix Titanium with Aluminium as they react with eack other and corrode. Don't know how true this is, only found out on Thursday.


Your fellow engineer is correct Alex.

The Galvanic Series Chart explains that the "anodic" or "less noble" metals at the negative end of the series such as magnesium and aluminium will be subjected to bi metal galvanic corrosion when in contact with "cathodic" or "noble" end of the series materials such as gold or titanium, in the presence of an electrolyte. Salt water is a particularly effective electrolyte, so consideration of metal combinations is particularly important in Marine engineering for example. Better to choose material combinations that are closer together in the series and stainless steel is a good example of this. The potential (voltage) difference of Al v Stainless Steel is much smaller than Al v Ti. Heat also promotes this galvanic corrosion

That is the theory out of the way. An electrolyte has to be present for corrosion to take place, and would suggest that the screws into the head is potentially dry, though any dampness in there will cause corrosion and seize the stud. This is more likely to happen with a Ti stud. In theory, it should also accelerate corrosion around the stainless steel flanges / fasterners.
 
  
View user's profile Send private message
   
alex yates
Brands Hatch
Brands Hatch


Joined: 06 Mar 2014
Posts: 14298
Location: The Ribble Valley, Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sat Apr 14, 2018 10:14 pm    Post subject: Reply with quote

worship

Yep - I totally get all that and understand the Chemistry of it (working in Cathode manufacturing for TVs and also spark and wire eroding in the Toolroom). Usual case of good stuff used in the wrong application with regards to ti and Ally.

My Stainless bolts have now been in there 3.5 years but look like they were fit last week.
_________________
2000 Manual 996 C4 Arctic Silver Convertible


 
  
View user's profile Send private message
   
wasz
Magny-Cours


Joined: 28 Dec 2012
Posts: 2627


1999 Porsche 996 Carrera 2

PostPosted: Sun Apr 15, 2018 7:50 am    Post subject: Reply with quote

Yes pure titanium is more reactive than stainless.

However both stainless steel and titanium form a passive oxide layer when freshly cut, it is this that protects the metal and resists corrosion.

Titanium's oxide layer is more protective than the layer that forms on stainless. This oxide layer also insulated the titanium from other metals in contact.

This is why medical implants use titanium, it is least prone to corroding because the inert oxide layer protects the rest of the metal.
_________________
My special order Vesuvious Charcoal 996 | Clutch, Fly RMS IMS AOS Job |
Steering Rack Hard Lines | Air Con Compressor / System
 
  
View user's profile Send private message
   
alex yates
Brands Hatch
Brands Hatch


Joined: 06 Mar 2014
Posts: 14298
Location: The Ribble Valley, Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sun Apr 15, 2018 8:05 am    Post subject: Reply with quote

But wouldn't the layer get sheared off when torqueing the bolts up?

As a side note, I have Titanium implants in the front of my face. The pain when they drill and tap into the bone is purely excruciating........like a teet I had the operation done whilst conscious nooo

They use Titanium because the bone fuses with the metal and locks it in place.

Its ability to physically bond with bone gives titanium an advantage over other materials that require the use of an adhesive to remain attached. Titanium implants last longer and much higher forces are required to break the bonds that join them to the body compared to their alternatives.

Source: https://en.m.wikipedia.org/wiki/Titanium_biocompatibility
_________________
2000 Manual 996 C4 Arctic Silver Convertible


 
  
View user's profile Send private message
   
alex yates
Brands Hatch
Brands Hatch


Joined: 06 Mar 2014
Posts: 14298
Location: The Ribble Valley, Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sun Apr 15, 2018 8:28 am    Post subject: Reply with quote

I hope I don't have to have mine removed.......that will be excruciating!!!! Neutral
_________________
2000 Manual 996 C4 Arctic Silver Convertible


 
  
View user's profile Send private message
   
Dammit
Kyalami


Joined: 23 Sep 2016
Posts: 1842



PostPosted: Sun Apr 15, 2018 8:55 am    Post subject: Reply with quote

I've got titanium Rawl plugs in my jaw as well, did they tell you how it was discovered that bone bonds onto Ti?

It was a researcher who was working with Rabbits - something to do with blood chemistry IIRC. Anyway, the experiment (for a specific rabbit) was over so the researcher decided to "recover" the titanium capsule that was inside the rabbit - and made the discovery that the rabbits bones had bonded to it.
 
  
View user's profile Send private message
   
alex yates
Brands Hatch
Brands Hatch


Joined: 06 Mar 2014
Posts: 14298
Location: The Ribble Valley, Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sun Apr 15, 2018 9:00 am    Post subject: Reply with quote

Thumb Kool.

I know I also had a bone graft as a lot of the bone had rotted away. They used cow bone to do the graft then cover it in pig skin while it knits, stitching the flesh up over the top. Then 3 months later, open me up and remove the skin.
_________________
2000 Manual 996 C4 Arctic Silver Convertible


 
  
View user's profile Send private message
   
Bluebird911
Nürburgring


Joined: 29 May 2010
Posts: 417



PostPosted: Sun Apr 15, 2018 1:24 pm    Post subject: Reply with quote

wasz wrote:
Yes pure titanium is more reactive than stainless.

However both stainless steel and titanium form a passive oxide layer when freshly cut, it is this that protects the metal and resists corrosion.

Titanium's oxide layer is more protective than the layer that forms on stainless. This oxide layer also insulated the titanium from other metals in contact.

This is why medical implants use titanium, it is least prone to corroding because the inert oxide layer protects the rest of the metal.


Hi Wasz,

You are correct about the oxidation layers and they form a protection to environment conditions, but these layers are not an electrical insulator, so will not prevent bi-metal corrosion when the joint between the metals contains an electrolyte. Remember, bi-metal corrosion is an electrical process.

If oxidation layers prevented galvanic corrosion, there wouldn't be the sophisticated inhibitors or sacrificial annodes that have been developed to manage this type of corrosion.

Because of its good oxidation corrosion properties, titanium is a really good material for use in the body such as the application you suggest. Ti is not used in bodies because its oxide layer prevents galvanic corrosion, this is not true. When in the body, Ti will not come into contact with another metal via an electrolyte; unless you are Iron Man!!!

Cue Black Sabbath!! Grin

Alex, I recall studying this stuff at Uni many years ago, but it appears you have practical experience of the principles!! However, I have seen and worked on some ropey early Land Rovers (Aluminium body panels on Steel chassis constructed using steel fastners) before the motor industry took bi metal corrosion seriously!!
 
  
View user's profile Send private message
   
X51 996
Trainee


Joined: 14 Nov 2016
Posts: 89
Location: Surrey


PostPosted: Sun Apr 15, 2018 1:52 pm    Post subject: Reply with quote

It seems that no matter what type of fasteners are used there’s a downside!

Isn’t stainless lower in strength than the regular steel bolts used? And what about the repeated heat cycling?

Always a hassle with steel/alloy fixings on these cars - which is pretty much everywhere, and as they’re getting older there’s more and more trouble waiting for the future.

Have to say the quality of the factory fasteners can’t be all that. I’ve worked on loads of cars over the years - many much older than 996s and have never seen such badly rusted exhaust fixings as you see on these.

What are the typical exhaust studs used on most alloy heads made of? Black steel or coated steel with the copper/copper coated nuts - never had any trouble with removing either the nuts or the studs even on cars twice the age and mileage of most 996s.

I think going back to the OP’s question - personally I’d leave alone. There’s a good chance you’ll never need to remove the manifolds in situ, and if you do it now you’re still going to have hassles anyway. Save the cash towards other contingency work or something Cool

If you need to remove them in future just use a proper jig and take your time or let a specialist do it if required.
_________________
2003 911 Carrera 2 coupé, Arctic Silver - 3.6 manual, X51 Carrera PowerKit, X74 Suspension, Sunroof delete, PSM delete. Black leather crested sports seats (XSC), XAG rear spoiler, 5-spoke 18" Carrera Alloys, Xenons.

2011 Mercedes E63 AMG Wagon
2004 Mercedes E55K AMG Wagon
1988 Mercedes 190E 2.3-16
1988 Mercedes 190E 2.5-16
 
  
View user's profile Send private message
   
alex yates
Brands Hatch
Brands Hatch


Joined: 06 Mar 2014
Posts: 14298
Location: The Ribble Valley, Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sun Apr 15, 2018 1:56 pm    Post subject: Reply with quote

The problem with a 911 is the engine's almost scraping along the floor hanging out the back end and subject to everything off the road unlike most other cars.
_________________
2000 Manual 996 C4 Arctic Silver Convertible


 
  
View user's profile Send private message
   
eabeukes
Silverstone


Joined: 30 Jan 2018
Posts: 119
Location: Aylesbury

1999 Porsche 996 Carrera 2

PostPosted: Mon Apr 16, 2018 5:20 pm    Post subject: Reply with quote

I have a pair of old manifolds that were blowing that I have cut the pipes off - they make a perfect drilling jig. Feel free to PM me is you (or anyone) wants to use them for such!
 
  
View user's profile Send private message
   
Gooey36
Trainee


Joined: 23 Aug 2017
Posts: 81



PostPosted: Mon Apr 16, 2018 8:28 pm    Post subject: Reply with quote

I’ve bitten the bullet as the cars a keeper for me and it’s booked in with my local Porsche specialist tomorrow for drilling/helicoiling worse case. It does have a slight blow on it though...The rest of the exhaust is new so the old rusty manifold just looks ‘orrible as well.

I had/have opted for Ti fixings over SS given the threads in the head should be “dry” and a galvanic cell will not be created. Any residual moisture in the heads should disappear with heat from the head I would’ve thought. I do have some tef-gel which we use at work to prevent galvanic corrosion - not sure I need it though

I’ve used Ti fixings in many road and track sports bike engine applications in the past and some car applications and never had any galvanic corrosion issues in the past. Have had a few stainless fasteners sheer though!

What I am sure of, not putting mild steel in again!
_________________
Current: 2003 996.2 C2
Daily: 2016 Audi A4 Avant S-Line TDi
 
  
View user's profile Send private message
   
P911X50
Monza


Joined: 03 Jan 2017
Posts: 213
Location: Hertfordshire


PostPosted: Mon Apr 16, 2018 9:09 pm    Post subject: Reply with quote

Hi Gooey36,

Mine a keeper too and I am also considering getting it done. Has your specialist indicated likely costs??

Thanks
_________________
Porsche 996 Turbo X50 with 9e exhaust,
BMW M6 V10,
Previous
Evo 4 with Evo 8 MR Engine 360 bhp - Road Legal Track car
Previous
MR2 Turbo 280 bhp - Road Legal Track Car
 
  
View user's profile Send private message
   
elwyn
Newbie


Joined: 03 Mar 2018
Posts: 8



PostPosted: Tue Apr 17, 2018 6:41 am    Post subject: manifold Reply with quote

i have been thinking of stripping mine also, at the moment no leaks, just know from prior experience they will be a bas.'#d, has anybody the jig for hire, they are expensive for one time use, regards to all
 
  
View user's profile Send private message
   
rdodger
Monza


Joined: 08 Apr 2018
Posts: 150
Location: Cheshire


PostPosted: Tue Apr 17, 2018 7:51 am    Post subject: Reply with quote

alex yates wrote:
Thumb Kool.

I know I also had a bone graft as a lot of the bone had rotted away. They used cow bone to do the graft then cover it in pig skin while it knits, stitching the flesh up over the top. Then 3 months later, open me up and remove the skin.


This deserves it's own thread!

I have 2 Ti implants. I also had a bone graft but from my hip. They did say at first they would use bone from my skull form the non dominant side. I thought the hip would be the safer option.

I too had mine done under sedation rather than GA. Not fun!
 
  
View user's profile Send private message
   
Gooey36
Trainee


Joined: 23 Aug 2017
Posts: 81



PostPosted: Tue Apr 17, 2018 9:14 am    Post subject: Reply with quote

P911X50 wrote:
Hi Gooey36,

Mine a keeper too and I am also considering getting it done. Has your specialist indicated likely costs??

Thanks


Yes - looking at £37 a bolt to remove and helicoil. Most I rang local to me (Notts) wanted between 350-700 worst case.

He said that he’s never known all need drilling..so fingers crossed.
_________________
Current: 2003 996.2 C2
Daily: 2016 Audi A4 Avant S-Line TDi
 
  
View user's profile Send private message
   
Paynewright
Trainee


Joined: 17 Apr 2018
Posts: 52
Location: Nr Lutterworth Leics


PostPosted: Tue Apr 17, 2018 1:10 pm    Post subject: Reply with quote

Another newbie here - owner of a 996 C2 3.6 manual since October 2017!


Already done the manifold to cat bolts. Fortunately they had been replaced with nuts and bolts previously rather than the press fit studs which are a challenge to remove. I've just used steel but purchased 3 sets so they will become a service item.

I plan to do the manifold bolts November time, when it will see a lot less use. I've already purchased poppopbangbang's TI stud set and picked up a Stomski jig from ebay. Thinking is if I have the kit to drill them out, they'll all come out easy!

Plan is heat the bolts up with a blow lamp and quench. Plusgas for a couple of days then use a hex socket (6 sided) to work backwards and forwards slowly.

I keep looking at the cheap stainless Chinese manifolds on ebay for around 150 a pair, as whilst its in bits??

Regards

Ian
 
  
View user's profile Send private message
   
Display posts from previous:   
Post new topic   Reply to topic   All times are GMT - 12 Hours
Goto page Previous  1, 2, 3  Next
Page 2 of 3

 
Jump to:  

You cannot post new topics in this forum
You cannot reply to topics in this forum
You cannot edit your posts in this forum
You cannot delete your posts in this forum
You cannot vote in polls in this forum
You can attach files in this forum
You can download files in this forum
You cannot post calendar events in this forum