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Old 10-24-2020, 02:33 AM   #1
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2003 Boxster S Sheared Exhaust manifold bolt

I had a sheared bolt on the right side from the previous owner and it was blowing ever so slightly. I finally bit the bullet earlier this year and tackled the job.

I should have done a detailed write up and have them on other forums so will paste in below this as it may help someone.

As we were in lockdown I decided I would also have a good a making a video. Needless to say that didn't turn out as well as the actual job and I need some serious work on my camera, script, production and editing skills. Actually its fairly crap but there may be a few bits of info to help others if they are facing the same problem.

https://www.youtube.com/watch?v=quSp8ZQ8EIs&t=8s

I'll add more posts now that I will copy from the Irish Porsche club forum so excuse the dates and some of the context as it was being updated as the job progressed over a few days / weekends.

Before anyone asks - I did consider welding on a nut in the hope that the heat would break the broken bolt loose. I know this has worked for many but I decided against mainly because I would be hardening the bolt and if I had to drill it would be more difficult. I try and do things once and do them right.

text version below:

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Old 10-24-2020, 02:35 AM   #2
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I’ve been planning the next job after the previous exhaust one. In the process of sorting the blow between the manifolds and cats due to rusted bolts I could hear another slight blow and on investigation there’s a sheared bolt into the head.

Much googling over the summer has not inspired confidence in this being a straight forward job so I’ve decided to prepare to do it right as being ready for the worst case in my experience usually means things go smooth.

So I invested in a Stomski Racing tooling jig. I’m in the US for a weeks hols so had it delivered to where I’m staying and it arrived this morning. Quality looks great so let’s see when the time comes. Pic for ref

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Old 10-24-2020, 02:36 AM   #3
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Well I never got a chance to do that job and the car got very little use last summer. I don't think I actually made it to any event.

So time to drag this project back up for everyone else's amusement. I shall keep the profanities to myself as I am sure it will get very colourful.

I started the car today for the first time since October and turned her round. She's now up on the lift with the rear section of cover removed.

When I looked last season there was one bolt on the right that was obscured by the thermostat housing. I figured to have half a chance of getting that bolt out I'd need straight on access. So I parked the job.

Fast forward and now that we are under house arrest I've overdosed on the brave pills and intend to get stuck in. As in getting in there I figured it was a good time to install a new pump, stat, gaskets and new coolant. Hopefully when I get the pump out I'll be able to get a camera up in there and check the engine mount as now would seem like the logical time to change if needed.

A few pics and as there is no sport on feel free to place your bets via Paddy power on how many bolts will shear and how many knuckles will be maimed.

A few pics of today's efforts. It will a case of slow and steady.
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Old 10-24-2020, 02:37 AM   #4
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I knocked off about 3 this afternoon and thought I'd be able to amuse myself for hours.

However here I am less than 90 mins from starting with phase one complete and less drama than I expected. I only sheared two bolts out of 11. So not quite an A but definitely a B+ for me!!

So coffee now while I decide if I go home and wallow in my glorious victory or get the drill out and start phase 2.

Here's how it went. I've been spraying the bolts with PB Blaster for the last few days and letting it soak. This is an American product and I found it via some US muscle car stuff where lads swore of its miracle properties in terms of rusted exhaust bolts and stud's. Did it help? No clue but it did seem to wick under the heads and up along to bolt to where it threaded into the block. So I suppose it did help with release from the manifold itself.

The car was cold. I had suggestions of run the engine and get it heated up a bit. Others said weld another nut onto the bolt and that would heat the bolt. Others just suggested the blue spanner and heat the bolt. I figured you can argue plus or minus for each of these so I just went cold as less chance of burns or worse a fire.

Initially I tried one with a breaker bar. There was no budge so I tried another and it was the same. I felt I'd definitely shear them right off so abandoned that plan. I have a crap air impact driver so got that out. I set it to the lowest torque it has and that's fairly low. Even at its highest it won't open a wheel bolt.

So on with the ear muffs and tried a bolt. Didn't leave it long, move to another. I kept checking the bolt and the socket for heat as I thought if I was heating the bolt I was probably stretching it.

So with a bit of patience most went on the low setting one. Two sheared on that setting and two needed a move to the second setting. I was glad I'd done the previous job last year and even with the new bolts connecting the manifolds to the cats they put up a bit of a fight.

I think I'll just trim the broken bolts while I have the air line out and take the victory. Live to fight another day and all that.
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Old 10-24-2020, 02:38 AM   #5
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Here's a few pics of the right side gasket. This was the original broken bolt at the rear.

Looking at the gasket it would seem that there was a leak as there is carbon and soot on both sides of it right out to the edge. I could only here it at low revs or when labouring pulling off.
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Old 10-24-2020, 02:39 AM   #6
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I started cleaning the block and I think it feels fairly good now. How clean does it need to be?

There is still some discolouration but I don't think it should be polished flat? Making a coffee now and will clean the headers next. Should be an easier process.

All going well I might have a crack at drilling them out before the weekend if I have time. The one on the left side is a bit long so I might shorten it to reduce the amount of drilling.
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Old 10-24-2020, 02:42 AM   #7
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Just finished the last one, what a major pain in the buttocks job.

I've been at this on and off for the past few weeks with being busy at work so been tackling one task at a time when I had a few hours run at it.

I am glad I had prepared by picking up the jig. It contains locators, cobalt bits, hardened steel drill guides etc for on a trip to the states. I saw it as an insurance policy and might save a lot of money in the long run. The kit has a machined locator that is shouldered to sit perfectly over the remaining knub of the broken bolt. The main locating frame is then clamped in place by two other machined locators.

You drill a small indentation then swap out that locator for a hardened steel drill guide and drill dead center through the bolt. Remove it and jump to the larger bit which is sized to leave the male parts of the bolt threads in the female thread part on the block. Sometimes most of it will come out on others you just needs to dress it with the tap and clean it. Three targets and three times it worked perfect. No stripped threads and no need for helicoils.

Its still not an easy job ,very time consuming as its a slow and easy type approach that works best. Each bolt probably took 3 hours from start to finish. Having said that though you do end up with the original threads in perfect nick so its very satisfying and should it have to come apart in future I know what I am dealing with.

I've cleaned off the gasket surface with steel wool, dry 240 and wet 240. It feels smooth but I'm not sure if I should keep cleaning or if its good enough to start reassembly which I'll do next week. I'm also putting new sleeves and clamps on the u bends at the back box so will fire her up to see what a straight pipe flat 6 with just the manifolds and cats fitted sounds like. I'm guessing loud.

Advice on the surface cleaning welcome. Before and after pics:











The threads on the last one to be drilled out and was also the original broken one. That pic makes me smile!



I'll update more next week when I get it back together assuming I have the time. I have also recorded various bits so may stitch it together on youtube at some stage in the hope that it might benefit someone else or convince them to take it to an indy.
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Old 10-24-2020, 02:45 AM   #8
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I gave it all another quick clean of brake cleaner and blew it all out with an airline. Buttoned it all back together with new gaskets and hardware. I also used some ceramic high temp grease on the hardware. It will be interesting bro see if it makes any difference in future. It's also inert or so the story goes so should reduce the galvanic corrosion process between the steel and aluminium but then again who believes the marketing waffle anyway. It's rated for up to 1500C so I suppose time will tell. I keep an eye on the torque just in case it does cause any issues.

I was curious to hear a straight piped flat 6 so I fired it up without the u bends and all I can say is it's loud. It's a distinctive sound. Snarling and popping. I had a mic on the camera and I think it even got overwhelmed with the range and pitch. An interesting experiment all the same.

Any all is back together and the blow is gone. Now I await the next oddball sound that I'll latch on to and torment me into doing something else.

Although if I left it straight piped I might not hear anything again. Here's a sample for your aural pleasure or not!

https://youtu.be/_GVLTgNWGLc

Onto the next job now - new stat and water pump.

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