Header reinstall help

[Bala]

Finally located the exhaust leak that was coming from where the header attaches to the engine. All 6 bolts came out fine, whew! The PO had put whatever M8 bolts he could find. some were shorter than the other. The gasket was a POC.

Anyway, ordered the gasket, bolts and also the bolts+nuts for the other triangular end of the pre cat.

Question is do I need to prep the surface of the header and the engine side before I put it on and bolt it? Like sanding down the surface smooth maybe? The old gasket seems to have fused a little bit on to the headers and I'm concerned that the seal may not be good enough. Do I have to use any kind of sealant around the edges of the headers? Thanks.

[san rensho]

I would try a scotchbrite pad lubed with brake cleaner first. If that doesn't do it, then maybe 320 wet/dry paper and brake cleaner.

And I would oil the fasteners if you want to make sure they come out again in the future.

[stateofidleness]

Hey Bala,
How did you locate the exhaust leak? Do you think the header(s) could be removed with the car on ramps? Where did you order the bolts from?

[Bala]

Originally Posted by san rensho

I would try a scotchbrite pad lubed with brake cleaner first. If that doesn't do it, then maybe 320 wet/dry paper and brake cleaner.

And I would oil the fasteners if you want to make sure they come out again in the future.

Will definitely do that. The surface feels like it could use a little rubbing. Thanks

[shadrach74]

The correct acronym is POS! If it were me and I wanted to ensure a good seal, I would do the following.

1) clean as much debris form the mating surface as possible using penetrant and elbow grease. Any stubborn pieces of old gasket should be carefully removed with a steel bar or utility knife.

2) tape a large piece of P220 sandpaper to a plate of 24*24" piece of glass (I use a spare from our greenhouse but it shouldn't be to hard to come by).

3) Secure the "sandpapered" glass to a sturdy, flat surface. Place the mating surface of the header flat on the sandpaper surface and move the header in an orbital motion.

4) Pause and verify that all of the surface is in contact (the sanding marks or lack-thereof will tell you).

Continue until the mating surface is smooth and uniform.

This will ensure a tight seal for the reinstall. It's not nearly as much work as it looks like in my instructions... Good luck!!!

[Bala]

Originally Posted by stateofidleness

Hey Bala,
How did you locate the exhaust leak? Do you think the header(s) could be removed with the car on ramps? Where did you order the bolts from?

I bought the stethoscope from Advanced and it didn't help. Couldn't hear a thing and it broke too easy. I went the hose to the ear way. Took a long 3/8 (or 1/2") clear flex tube, stuck one end in my ear and the other end as a probe. With the engine running started from the manifold side and probed every joint and bolt hole. Pay dirt right away.

As for the ramps, I jacked up the rear, put them on stands, removed the wheels (for other rotor swap work) and then put 2 more stands at the rear by the suspension and also the rear wheels as a added safety. For some reason I wasn't comfortable leaving the car on the sloped driveway with the front wheels held by 2 bricks! With that I was able to slide underneath and get a good view and hold of all the bolts. Where the cat end is, it is good to have the wheel out to access the 3 bolts.

I ordered the gasket and the bolts from local stealership. Looked at Pelican but some items like bolts are not in stock so it would take almost a week. Price came pretty close but these are genuine parts.

All the 6 header bolts were rusted at the head. Not taking chances. I have limited luck when it comes to bolts and screws on the Boxster.

[stateofidleness]

Awesome, thanks! I've had a "ticking" sound for a long time now and haven't found the time to take it to an exhaust place to have them "smoke" it. Let me know how the re-install goes? What's the torque spec on the header bolts?

[Bala]

Originally Posted by shadrach74

The correct acronym is POS! If it were me and I wanted to ensure a good seal, I would do the following.

1) clean as much debris form the mating surface as possible using penetrant and elbow grease. Any stubborn pieces of old gasket should be carefully removed with a steel bar or utility knife.

2) tape a large piece of P220 sandpaper to a plate of 24*24" piece of glass (I use a spare from our greenhouse but it shouldn't be to hard to come by).

3) Secure the "sandpapered" glass to a sturdy, flat surface. Place the mating surface of the header flat on the sandpaper surface and move the header in an orbital motion.

4) Pause and verify that all of the surface is in contact (the sanding marks or lack-thereof will tell you).

Continue until the mating surface is smooth and uniform.

This will ensure a tight seal for the reinstall. It's not nearly as much work as it looks like in my instructions... Good luck!!!

Thanks bud! Definitely up for the elbow grease as I do not ever want to hear the farting sounds again.

[Bala]

Not sure of the torque value. Have to look up the manuals. Will let you know tho.

[Meir]

Hi Shadrach.
Just out of curiosity. Why use glass? Is it consider to be the most leveled surface?

[Meir]

One for you Bala.
What headers are going on?
After market, or OEM?

[Heiko]

I think 17 ft/lbs is what the book calls for...
Use a little of the copper colored anti seize paste on each and they will come out like butter next time

[Bala]

Originally Posted by Meir

One for you Bala.
What headers are going on?
After market, or OEM?

stock header. jut fixing a leak.

[Bala]

Originally Posted by Heiko

I think 17 ft/lbs is what the book calls for...
Use a little of the copper colored anti seize paste on each and they will come out like butter next time

The bolts i removed had anti seize on them. The first bolt - where the leak was- was not tight. Came off too easy. rest were torqued. Anti seize wouldnt aid in the process of bolts coming loose would it?

[Bala]

Originally Posted by Heiko

I think 17 ft/lbs is what the book calls for...
Use a little of the copper colored anti seize paste on each and they will come out like butter next time

i could not find the torque value on the workshop manual. But every post i came across says 17lbs.

[Heiko]

No the antiseize wont make the bolt loose it just makes it easier to get out later. If someone previously over torqued the bolt though it may have damaged the threads in the head which will cause a loose fit (which could cause the bolt to come loose). 90% of the time you can re-use old header bolts but if there is/was a lot of corrosion, I would use a new set of bolts.

[Bala]

Originally Posted by Heiko

No the antiseize wont make the bolt loose it just makes it easier to get out later. If someone previously over torqued the bolt though it may have damaged the threads in the head which will cause a loose fit (which could cause the bolt to come loose). 90% of the time you can re-use old header bolts but if there is/was a lot of corrosion, I would use a new set of bolts.

I ordered new ones as some of them had severely rusted heads- might break off during install. Some were not the right length and looked like Ace Hardware bolts. Not willing to wake up the bolt demons!!

[Heiko]

Took this out of the manual for you

"5. Fit exhaust manifold with new gaskets. Fit the gasket in the correct position between
the exhaust manifold and cylinder head. The bent-up sheetmetal tab must point
upward toward the cylinder head. Tightening torque: 25 Nm (19 ftlb.)

Parts book calls for Hexagon-head bolt M8x28 Quantity 12 (6 per side) PorschePart# 900 378 131 00

[shadrach74]

Originally Posted by Meir

Hi Shadrach.
Just out of curiosity. Why use glass? Is it consider to be the most leveled surface?

Precisely. A plate of glass for all intents and purposes is completely flat. It's also completely inert, so the surface will never rust, pit or scale off. The downside of course is its fragility. I keep a large plate of 1/8" tempered in my hangar (which serves as my shop area). I have used it to prepare the mating surfaces on things like cylinder heads on motorcycles, the old Amal 900 series concentric carbs on my 40 yr old Triumph, aluminum oil pans on aircraft engines and more.

Sand paper works fine for lighter jobs or aluminum pieces. Emery paper or cloth is more robust and better for steel.

One caveat. This method is only usable for very light removal of material, as in fractions of a millimeter. A situation where a mating surface is truly warped should be sent out to a machine shop.

[Bala]

Originally Posted by Heiko

Took this out of the manual for you

"5. Fit exhaust manifold with new gaskets. Fit the gasket in the correct position between
the exhaust manifold and cylinder head. The bent-up sheetmetal tab must point
upward toward the cylinder head. Tightening torque: 25 Nm (19 ftlb.)

Parts book calls for Hexagon-head bolt M8x28 Quantity 12 (6 per side)

Thank you sir!