Rusted studs 997.2

PJ997 · 29 Nov 2018

Doing a bit of winter refreshing I thought I'd tackle rusted/lose heat shields, coils, plugs as well as upgrade the exhaust header studs to titanium (as they are badly rusted).

Stupidly I thought the Stomski kit currently available would do the trick for any snapped studs (haven't actually attacked them yet - and was about to) . . . . well turns out the 997.2 has a different stud pattern (doh).

Contacted Stomski and they are in the process of designing one and it should be available in a next couple of months.

As I've got the car half stripped, it means the car is off the road of a bit (which is OK as have another car) . . . . . but I wondered . . . . as anyone else tackled 997.2 studs before or know of alternative to stomski.

Cheers
Phil

easternjets · 29 Nov 2018

The garage I use for jobs like this use an inductor heater on any rusted studs, you see them being used on wheeler dealers and the like.
They do work brilliantly, and get a hell of a lot of heat into the studs as opposed to the surrounding area. I know you won't probably have one but you may be able to borrow one or know someone with one.
Saves snapping and drilling which is a time consuming PITA!

deMort · 29 Nov 2018

Im going to havre to start wagging my finger here .. never touch the mainifold bolts .. they almost never leak and whilst looking ugly do the job .

Ok that was the best telling off i can do .. no jig .. difficult .. it can be done free hand but you need someone pretty experienced to do this .. i know i cant !

If you havent yet snapped any then please .. just leave them .. no one will see them .

If you have ..

Try phoneing some local engineering shops .. see if they have anyone whos mobile ..

I say this as in my area we do .. or at least used to (he was getting on a bit ) .. he could easily free hand drill them out ... not used him for a while as we have the gen 1 jig these days .

PJ997 · 30 Nov 2018

I haven't touched them yet. One of the reasons for wanting to take the headers/cats off is to get to the heat shield behind the cat. As you can see in the photos below, it's a bit of a horror story (missing the top shield over the coils altogether!). The corrugated shield over the cat is just lose! I intend to keep the car a fair while, so thought upgrading the bolts to titanium studs would bring some peace of mind (as will only get worse). Perhaps you've persuaded me not to . . . I'm 50/50.

Posting these pictures (I imagine) is a bit like going to the doctor for a bad case of knob rot by the way

Can I get the lower shield off without removing the cat? There looks to be two small torx bolts right behind it. One I can get to, the other I'm not sure about.

deMort · 30 Nov 2018

Aghh yes i see the problem now ..

The cat heat shield from memory is a case of getting the lambda sensor out then undoing the fixings for it .. you dont need the Header off for that ..

If you want to go the cheap option which i have seen customers request then you just cut it off.

Ive not seen a problem with this method over the years but i agree its not the best way forward .

The lower heat shield .. again from memory but im pretty sure one side you can get off but the other you cant .. lever bar on one side on the cat and you can just about get the bolt out .. other side and its too long .

O/s/r rings a bell as the side that will come off .. its basically undo the bolt as far as you can on the lower sheild .. if you can get it off before it jams against the cat then you can get it off !

heat shields are there to give a bit of protection to the coils .. i think its mainly from mud / water and not really against heat but thats my thinking .. Porsche never told us the reason .

Lambda sheild is for heat but again .. ive not seen a problem with those that have been removed .. so far anyways .

To be fair .. Gen 2 mainifold bolts have a good chance of coming undone .... BUT not always .

If you have a plan in case they snap and if they do i expect it will be only one or two then go ahead .. if you will struggle to drill them out then i will have to say leave it .

Im all about saving money and trying to point out .. it may not look pretty but No one will see it other than you and a mechanic serviceing the car .. and we just report the problem and move on .. we have seen far .. FAR worse cars than yours .

Scholester · 1 Dec 2018

All of my exhaust manifold bolts wound out without problem when I swapped my exhaust system last winter. I did however douse them with penetrating oil every night for a couple of weeks (car was up on ramps) which must have helped. It's a nerve racking job but the bolts were in good condition and I was very careful with the level of pressure I was prepared to apply but all went well.
I replaced my bolts with titaninium jobbies and applies the faintest smear of copper-slip to the threads to aid any future work. I had been advised against this as it changes the torque settings but I would not want ever to be faced with snapped bolts/studs at the head as another member on here had a nightmare with this.
I am not sure if the factory fitted better quality bolts to the Mezger lump but they were in good order with no deformation which gave me the confidence to do the job myself. Fingers crossed for you and I hope all works in your favour ðŸ‘

FZP · 1 Dec 2018

OP
When I saw your initial post, it brought memories of everyone I ever spoke about the header bolts, and everyone said the same thing. Back away from the bolts.
I'd actually started writing a response but got distracted. Seeing deMort's response hammers that point home for me.
Fair do to anyone that has a crack at it, but it's a job to far for most.

Counter Of Beans · 1 Dec 2018

PJ997, the driver side cat heat shield on my 2011 Gen 2 had also come loose, and was rattling a bit. You have to remove the lambda sensor to lift off the shield, but apparently that can knacker the sensor. I followed deMort's advice and cut off the heat shield with a Dremel. Took moments and it's been fine since, no ill effects at all. Also, weight saving! (joking)

As for the manifold studs, I'd leave them alone unless changing the whole exhaust including cats. I don't think the effort of changing them is worth it if done purely for cosmetic reasons - although my OCD self does sort of want to do it! mmmm Titanium, nice.........

easternjets · 1 Dec 2018

The copper slip method is a must as it's good up to 550 degrees.
The mention of torque settings being adjusted is correct, we used to use buckets full of copper grease offshore and used to adjust the torque settings depending on the coefficient of friction for each different compound. So if your torque setting is 30 ft lbs and the C/F is 0.5 then that brings your torque down to 15 ft lbs.
TBH we were using massive torque settings of like 15,000 so it made a huge difference, for a benchmark if you can't find the manufacturers spec's id go by .75

I've checked and I'm pretty sure that copper grease is C/F .85, so not a huge difference with low torque settings. A 25 ft lb's torque is down to 21.25.

PJ997 · 1 Dec 2018

So there's no way (I can see) I can get the bolt holding the lower heat shield on without taking the headers off. After everyone's comments I'm thinking -leave them on (although a small part of me wants to sort them once and for all). If I do leave them on, as the rear part of the lower shield isn't too bad I was thinking I could cut off the front part off a new shield and just replace the bit that's rusted away. At least I would them have something to screw the higher shield to (covering the coils). I can get the cat shield on by cutting a slot in it to get passed the sensor (which I've done in the picture below), but I'd have to cut off one of the securing tabs (for the one I can't get the bolt out for) ... but that's got to be better them it just resting on the cat as it is now.

So do I do that ... or do I attack the header bolts/o2 sensors?

Perhaps I use it as an excuse to get new headers/exhaust system? I already have PSE and H&S bypass which sounds great, but I wouldn't be adverse to a little more noise (ideally keeping the switching element of the PSE) ... any affordable suggestions that are MOT friendly?

Cheers
Phil

deMort · 1 Dec 2018

First off .. cutting the lambda heat shield to get it over the sensor ..pure Genius .. i would never have thought of that ! .. i will in the future though should i need to .

Your problem is the lower heat shield bolts .. try useing an 8mm ring spanner to undo them as far as you can .. when slack use your fingers otherwise you can get it stuck against the cat with the spanner still on the bolt .. see how far out you can get them .. if they jam against the cat without comeing out then just refit them.

In this case you are into cutting off that bracket of the lambda heat shield .. the top 2 will hold it but obviously the more you can fit the better .

This is one of those jobs i need the car in front of me to figure it out .. downside of working on all Porsches is i dont remeber what i did last time on these .. and its been a while since i looked at this problem .

The mainifold bolts .. in therory they will come undone .. i use an airgun .. no heat and do them up then undo .. if done by hand you can feel if they are twisiting with a view to snapping .. but im talking as a mechanic here as we have learnt this feeling over many years .. its the Oh crap moment when you know the bolt is not going to come undone !

Cant help with making it louder though .. unless you want to drill holes in it

Top heat shield as im sure you are aware comes out with a bit of bending .

PJ997 · 2 Dec 2018

Well I filed down an old 8mm ring spanner so it could fit in the gap, managed to crack it loose, wound it out at far as I could by hand, then attacked it with a recpricating saw as it was never going to come out all the way. Managed to get the remaining stub with my fingers. Fitted new coils, plugs and heat shields. I cut down a bolt to fit in the awkward spot behind the cat.

Just need to do the other side now.

Phil

montygraphics · 2 Dec 2018

Very nice job - well done

easternjets · 2 Dec 2018

Nice job, saved yourself a small fortune there.

chunkymonkey1982 · 5 Aug 2019

Hi,

I'm looking to do a similar job when I change my spark plugs. Where did you get your heat shields from, and what's the part number?

Thanks

Rusted studs 997.2

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