997 Gen 1 Exhaust Manifolds

[Murv]

Hi All, I'm new to the Porsche club and look forward to joining regional and national events and meetings.
I am very much technically minded and take on all sorts of maintenance and care of my beloved 997!
I recently removed the exhaust manifolds as the bolts holding them in place were corroded. I have replaced all the bolts including having to Helicoil one. The manifolds themselves are very rusty and I am looking to replace them. I have replaced all the nuts and bolts with Stainless Steel. There are a number of manifolds available starting from £100 upwards. my question is; are the manifolds the same across the whole build period of the gen 1 997? some advertisers (on eBay) offer manifolds up to 2005 (997) mine is a late 2007 car. any advice really would be appreciated. I should state that my car is a Carrera 3.6 L.
My previous cars have been 996's and the manifold look very much the same.

Any body got after market manifolds? recommends? I'm not looking for a whole lot of noise I have PSE and just looking for practical replacements.

Thanks Jas

 

[tscaptain]

Hi Jas and welcome to both club and forum. I will move this to the 997 forum where it might get more views!

 

[angusc]

Hi Murv,

What a coincidence! I have just got my 997.1 up on the wheel free ramp at home and noticed that all 12 of my manifold studs and nuts are heavily corroded so much so that the nut sizes are much reduced from their original sizes. I purchased replacement studs and nuts from the OPC but could not bring myself to turning the wrench and for sure shearing off many if not most of them!

So I see that this seems to be a common problem and one that I'm not overly happy about as every Porsche has been serviced during the warranty and later years period to this point. I thin k that the OPC should have that as part of their routine maintenance that the studs and nuts are replaced before they can corrode to such an extent.

Given all that, how did you drill out the sheared stud? Did you drill and pick out the remaining threads of the leftover stud, or did you over drill and hellicoil the hole? Any tips would be greatly received before i embark on the inevitably.

Best Regards
Chris.

 

[Murv]

Hi Chris,

One stud came out with me drilling a centre guide and using an easy-out. The other just plain refused to budge! I started by drilling a guide hole in the centre, I managed to judge the centre I then tried an easy-out but feared it breaking so I progressively drilled using a bigger drill bit hoping, I could pick out the old stud but it was impossible to distinguish it from the surrounding area. I ended up using the drill bit that came with the helicoil kit and tapping a new thread. I have the helicoil kit and if your close to Leicester you are more than welcome to borrow it. I elected not to go for the standard Porsche bolt but, bought studs and copper flashed nuts. I used an anti-seize cream when reinstalling. Everything is now fine no leaks and it looks good. My manifolds however are extremely corroded and I want to change them. I had no feedback from the forum, so have chosen some Topgear SS headers not the cheapest by far but they do have a life time warranty. They were advertised for £399 offered £300 which the seller accepted! Will order this coming week with the plan to install next weekend.

My bolts also displayed major corrosion ended up hammering 12 and 11mm hex sockets on the bolt heads - I did use locktite freeze release and ten came out clean one with more persuasion and one with major surgery!

It's is a difficult job and not for the faint hearted, the car is not my daily driver so I was not stressed in any way. Net result is all SS bolts including the manifold to cats, which were much more difficult to do btw.

Good luck with yours if I can help in any way please don't hesitate to drop me a line.

I also earlier this year removed the Tandem pump which is notorious for rotting through and removed all the surface rust and painted it in a black high temp paint this is another worth while project. I realised the rubber seal between the pump and engine is the very same size as the between the pump housing and body so it's a great seal and you wouldn't know it's been done!

Regards,

Jas

 

[Murv]

Hi Chris,

One stud came out with me drilling a centre guide and using an easy-out. The other just plain refused to budge! I started by drilling a guide hole in the centre, I managed to judge the centre I then tried an easy-out but feared it breaking so I progressively drilled using a bigger drill bit hoping, I could pick out the old stud but it was impossible to distinguish it from the surrounding area. I ended up using the drill bit that came with the helicoil kit and tapping a new thread. I have the helicoil kit and if your close to Leicester you are more than welcome to borrow it. I elected not to go for the standard Porsche bolt but, bought studs and copper flashed nuts. I used an anti-seize cream when reinstalling. Everything is now fine no leaks and it looks good. My manifolds however are extremely corroded and I want to change them. I had no feedback from the forum, so have chosen some Topgear SS headers not the cheapest by far but they do have a life time warranty. They were advertised for £399 offered £300 which the seller accepted! Will order this coming week with the plan to install next weekend.

My bolts also displayed major corrosion ended up hammering 12 and 11mm hex sockets on the bolt heads - I did use locktite freeze release and ten came out clean one with more persuasion and one with major surgery!

It's is a difficult job and not for the faint hearted, the car is not my daily driver so I was not stressed in any way. Net result is all SS bolts including the manifold to cats, which were much more difficult to do btw.

Good luck with yours if I can help in any way please don't hesitate to drop me a line.

I also earlier this year removed the Tandem pump which is notorious for rotting through and removed all the surface rust and painted it in a black high temp paint this is another worth while project. I realised the rubber seal between the pump and engine is the very same size as the between the pump housing and body so it's a great seal and you wouldn't know it's been done!

Regards,

Jas

 

[angusc]

Thanx for the detailed reply Jas. I'm not fainthearted.....but definitely not looking forward to the potential grief that will ensue!

Did you apply any heat on any of the studs and warmed the aluminium heads around the seized studs? Just wondering if that might help get them out. Please could you give some more details about the helicoil kit that you refer to, I think that i would get prepared by buying a kit with 10 x 8mm Helicoil inserts.

Another trick that has worked for me in the past is to drill out the centre of the sheared stud until you break through the bottom of the stud. Then take a 12" Hacksaw blade and using a bench grinder, grind off the back side of the Hacksaw blade to leave just the teeth and a little of the blade behind the teeth. Then using a hacksaw blade handheld grip, you can gently try sawing through the side of the drilled out stud and the aluminium threads (slightly). then try turning or picking out the remaining stud threads. You are left with the stud hole in the aluminium head with a slot cut down one side, but the new stud will screw back in and shouldn't pose any further issues.

All a bit mind blowing on a £100K plus car that the previous owners have paid good money to OPC centers around the planet to offer tip top servicing. The stud bolts in the cylinder heads should always have been stainless steel studs and copper or brass nuts IMHO.

 

[Murv]

Hi Chris, the helicoil kit is from machine mart basic £20 set for m8 threads. It comes with everything you need, the insert is stainless steel. The drill bit is very impressive. Heating up the area; unless you have oxy, a standard blow torch simply cannot get the area hot enough the heads dissipate the heat very quickly. The issue is the corrosion and differing metals reacting with each other that creates a situation where some options such as heat, penetrating fluids and mild heat simply will not yield any benefit. On another car I managed 100% removal, here the car was at working temperature and heat was tremendous, and you could hear the normal cracking of the metals as they started to cool. I wore welding gloves and used the same technique of having to hammer a socket on to the nut.

Not on a Porsche, if there is sufficient stud above surface level. I have used a Drexel to cut a slot then put a bolt on to prevent the expose now slotted stud from just peeling and struck the stud with an impact driver.

I was also concerned about going to far beyond the end of the stud fearing going into the water jacket. There is only some 2.5 mm beyond the stud. Hack saw idea sounds good if you can get sufficient movement, it's only an m8 size, you still have the issue of the two metals having reacted and caused a galvanic mating ( I think that is a right terminology did Metals structure at uni a very long time ago!)
Cheers, Jas

 

[Tamer]

Hi all,
My 997 also has numerous rusted bolts underneath and as stated above I agree, these should be replaced as part of the maintenance service while these cars are under warranty. Why they rust so much is probably a topic for another debate.

Mine (a 2005) is no longer under warranty but has recently had a major service at Porsche Bristol (Dick Lovett Group) where they pointed these rusty bolts out as part of their inspection (similar problem with exhaust clamps further down the exhaust assembly and Ignition Coils - rusty bolts seem to be an epidemic !!). I was quoted £210+VAT and that's just for the bolts.... They also recommended replacing the "rusted clamps". At this stage the problem is nothing more than aesthetic and unless people are crawling under your car to see how it looks under there, this is not an issue, so I told them not to bother and spent the money on having my timing belt AND gearbox oil changed instead, for less than the cost of these bolts.... At that price, I would expect Titanium but judging by the original (rusted ones), they're not even Stainless Steel

The reason why I began writing this response is that many years ago I watched a mechanic address a similar (rusty / tight) bolt problem by literally welding an iron bar to the offending bolt, he then turned / loosened the bolt using the bar, once it was loose, he removed the iron bar and was able to turn the nut using a mould grip...

Unfortunately I don't have a suitable yard, workshop or garage to do maintenance on my car but when I get round to doing this job, that's what I intend to do as I don't like the idea of drilling bolt heads or tapping new threads into the block at all. I would if there was no other choice but in my opinion that has got to be the last resort.

For those interested, here's a link to the video-report provided by the main dealer, which clearly shows the extent of the corrosion. http://video.citnow.com/vtncHtRHhwc

Good luck with solving your manifold problem and thanks for sharing your experience here with us.

 

[Murv]

Hi Tamer,

I've installed new SS manifolds and changed all the exhaust track nuts and bolts for SS. All better than new

Cheers,

Jas

 

[Murv]

Hi Tamer,

I've installed new SS manifolds and changed all the exhaust track nuts and bolts for SS. All better than new

Cheers,

Jas

 

[angusc]

Hi @murv,

Where did you get the SS manifold from please can you provide further details, I have been looking for SS headers for mine but never came across them as yet. I have the sport exhaust installed.

 

[Murv]

Hi, I got my manifolds from Topgear Shop they advertise on eBay also here is the eBay item number 311319149008. They are advertised at £399.00. I offered £300 which they accepted. Fast free delivery, came with gaskets. Direct replacement without any modifications. They add to the great sound in both sport and normal mode. I used new SS bolts and installed header studs and used copper flashed exhaust bolts. Excluding damaged or hard to remove bolts and nuts. The header replacement is an hours job! When ordering just confirm they are for a 997. Regards, Jas

 

[Murv]

Hi, I got my manifolds from Topgear Shop they advertise on eBay also here is the eBay item number 311319149008. They are advertised at £399.00. I offered £300 which they accepted. Fast free delivery, came with gaskets. Direct replacement without any modifications. They add to the great sound in both sport and normal mode. I used new SS bolts and installed header studs and used copper flashed exhaust bolts. Excluding damaged or hard to remove bolts and nuts. The header replacement is an hours job! When ordering just confirm they are for a 997. Regards, Jas

 

[angusc]

thanx @murv,

I have contacted them to see if they also have the chrome tail pipes as well before i make an offer.

 

[Tamer]

or SS

I had a quick look on ebay and these look great.

I now know where to go when mine need replacing.
At the moment mine are faultless although I suspect aesthetically they are probably not eye candy

Very well done!
And thanks for sharing.

 

[RJKflyer]

I have heard of people using EDM to get broken studs and/or taps out of holes, latter where the tap is so hard you cannot drill it.

It's a specialist job though, so only really posting this to point out that if it all goes belly up, and/or isn't extractable, there ARE ways of removing it. (And with little or no damage to the substrate)

This is a random Google find, but coincidentally Porsche related: http://www.pelicanparts.com/techarticles/101_Projects_Porsche_911/95-Tapx/95-Tapx.htm