Porsche 944 - Exhaust Manifold Replacement Tutorial

[@rrassoc]

Three of my studs broke since my R&R for the oil cooler O-ring replacement on my S2. Honestly, I am loathing the idea of doing that job again. The headers on the 16 valve motors have almost zero clearance, 3 studs, and sealing rings (instead of gaskets) that don't like to stay in place while refitting the headers and new studs. Nightmare! -Especially reaching the nuts back on #4. I'll do my best to not over-torque the nuts this time! Theres no way to get a torque wrench on them, but I love the technique you used to mimic the job across all the studs!

[@NC944er]

@@rrassoc That’s crazy! Exhaust work in general is not one of my favorite things to do. It’s possible to get a crows foot socket with a short ratchet extension on most of the fittings, but I feel like the torque value gets thrown off because the wrench is leveraged off the side a bit. Anyway, I figure my human torque wrench is at least 80% accurate. 😂

[@stephengawlik3033]

Terrific video. I’ve watched it several times. Question: would there be any reason to not bead blast and POR 15 the entire exhaust from the header down to the chrome tip on the tail pipe?

[@NC944er]

The rest of my exhaust system wasn’t oxidized like the headers were. Also, the POR-15 coating hasn’t held up the best, you may want to look at ceramic powder coating.

[@stephengawlik3033]

Thanks. Can I ask: did you bake those parts prior to installation? Thanks for all you do, man. Love your channel. Learned so much.

[@NC944er]

@@stephengawlik3033 Yes, they were baked per the manufacturer’s specifications.

[@jondavidmcnabb]

You should have those cast iron units "extrude honed" which will make them flow much better... It won't hurt them and they will be just as reliable.

[@NC944er]

That’s a great idea! 😁

[@victorcoiciu576]

Which model years should i be looking at to source a replacement from? Also, are these interchangeable with the 1989 2.7 litre motors?

[@NC944er]

@@victorcoiciu576 Porsche switched to stainless steel in 1987, so anything earlier than that would be cast iron. Exhaust manifolds from the 2.5L engines will fit the 2.7L.

[@victorcoiciu576]

​@@NC944er did you replace the manifold pre-emptive or were you having symptoms of a cracked manifold?

[@NC944er]

@@victorcoiciu576 My stainless steel one was cracked in a couple places.

[@victorcoiciu576]

​@@NC944er my final question - with the cracked manifold, were you noticing fumes/vapours entering the cabin through the vents? Thanks for taking the time! 😊

[@NC944er]

@@victorcoiciu576 No exhaust odors detected inside the cabin, but visually noticed some carbon deposits surrounding the cracked sections of the steel tubes.

[@ndj4267]

How did you torque the Rennbay exhaust studs? Double nut? Also, did you use antiseize on the studs?

[@NC944er]

I wasn’t able to get a torque wrench down in there to truly measure the value during installation, so I did them by hand using an allen tool on the end, basically hand tight as far as they would go until the tool flexed a bit. I did not apply anti-seize to the studs… you’ll probably see mixed opinions on that, some say its use can lead to over torqued installation and striped threads in the block, while others will argue that not using it will result in seized and snapped studs that require invasive measures to correct. There is a general consensus that they can back out over time, so some even apply loctite instead of anti-seize. I just put them in clean and dry, and have easily removed them a couples times since for other work on the car.

[@HighOnFlying1]

Hey, sorry hopefully last question to bother you with during this rebuild! Ignorant question, but which way do the exhaust gaskets go in? I see one side is metal and the other is not - does the metal touch the block side or the header side?

[@NC944er]

Hey! The smooth metallic side should face the exhaust manifolds and the coarse composite side will face the aluminum cylinder head. The smooth surface allows the manifold flanges to slide as they expand and contract during heat cycling from engine operation.

[@HighOnFlying1]

@NC944er awesome, thanks so much! So just to make sure my still very novice brain is processing correctly: when installing, I should see the metal side right? Because I would slide the gasket onto the studs with the non-metallic side facing away from me to contact the head?

[@NC944er]

@@HighOnFlying1 Thats exactly right! 😁

[@HighOnFlying1]

@NC944er thanks so much! New engine in the car and it started on Sunday for the first time in 3 months... only problem was the belching of white smoke on the exhaust side so now trying to troubleshoot that :) thanks again for all your help.

[@notny411]

did you chase the threads in the head with a tap before reinstalling the studs? Great video by the way! Thanks for making it!

[@NC944er]

Hey, thank you! In this case I did not. They were surprisingly clean and I was able to hand-thread the new studs most of the way without issue. If there was a bunch of oxidation debris I probably would have.

[@HighOnFlying1]

Hey, yet another great video! Sorry to hassle you again, quick question: did you do anything to polish the mating surfaces before putting the new gaskets and new manifold on? Do you do anything similarly when you did the intake gaskets in your other video?

[@NC944er]

Hey man! I generally use 600-grit sandpaper on a block sander to remove old gasket material and smooth out the mating surfaces. The paper intake manifold gaskets tend to bake on more junk than the metal exhaust ones. You can also use a razor blade to carefully scrape off larger deposits.

[@HighOnFlying1]

@NC944er that's a big help, thank you! Don't have a block sander yet but sounds like I should definitely use some 600 grit at least by hand. Thank you for all you do for the community - I run a 944 racecar on a pretty severe budget and am having to go through an engine swap at the moment, your videos have been a huge help.

[@Riddler0115]

Do you need to drain the coolant before removing the heater pipe?

[@alecmajor9]

Coolant runs through there so yes

[@NC944er]

Yes and no… as someone replied, there is coolant in the pipe, so if you disconnect it, coolant will drain out, but you don’t need to drain the radiator and the entire system just to replace the heater pipe. You would need to top up whatever drains out and vent the system after reassembly however.

[@paaf5547]

I have a 944S2 - will the cast iron manifold fit that also?

[@NC944er]

The flanges on the S2 manifolds are different from the early NA cars, three bolts instead of two, so my guess would be no, they are not compatible. Lindsey Racing offers a 4 into 1 header for the S2 for $750.

[@paaf5547]

@@NC944er thank you

[@HighOnFlying1]

Hey, I'm so sorry to bother you again, should have asked this at the same time but I thought the other gasket was symmetrical. The downpipe gasket that goes between the header and the cat - it's metal on both sides, but one side has a slightly raised ring around the opening while the other is flat. What's the right direction on that? I don't see anything online and don't want to mess it up for a third time! Sorry again

[@NC944er]

Hey, that one is steel on steel, so there is no difference in the way it’s installed.

[@HighOnFlying1]

@@NC944er oh perfect, the little ring threw me off. Really appreciate it - promise to leave you alone now!

[@marcosrosado7043]

Great work and tutorial as usual, do you have a shop or you work on your own car only.

[@NC944er]

Hey man, thanks! It’s just a side hobby I do in my home garage.

[@marcosrosado7043]

Awesome,appreciate your work

[@jimigucio]

in what order did you tighten the screws? especially on 1-4 part.

[@NC944er]

There isn’t a factory recommended tightening sequence for the manifold, just a specification that the hardware is torqued to 15 ft/lbs. As I recall for this one, I installed a stud at #4 to hold the left side in place while I installed another stud at #1, followed by the remaining studs. Once all the nuts were installed finger tight and the flanges were flush with the head, I just went down the line and torqued everything.

[@nathanlink4926]

Damn I didn’t realize that the late cars had stainless manifolds

[@artmchugh5644]

If you want to make it easier, remove the motor mount bolts , then with a piece of wood on your hydraulic jack slowly lift the engine up by the oil pan !!!😄😄😄😄😎😎😎😎🍺🍺🍺🍺

[@NC944er]

Thanks for the tip good sir! Lots of various tricks out there, thanks for sharing. Do you own stock in a brewery?

[@artmchugh5644]

@@NC944er 🍺🍺🍺 😎😎😎 see I'm cutting back! !! Would you like a link to video of my 951 ??

[@NC944er]

I did man! Did you use Glasurit 22 on your Mexico Blue demon?

[@artmchugh5644]

@@NC944er not sure, just dropped it off at the body shop !😎😎😎😄🇺🇸🇩🇪🍺

[@artmchugh5644]

@@NC944er yo yo !! It runs pretty good too !!😄😄😄🇺🇸🇺🇸🇩🇪😎🍺🍺 kzbin.info/www/bejne/mWjEaqOtfbGKa9E