SSI, M&K swap-out and oil return tubes, in one day

[James Brown]

Hey, like always, never enough time to do things right. So I had this one day window to pull the old heat exchangers off and put a set of SSI's on and fix some nagging oil leaks. It all sounds good but there is always something more than meets the eye, especially on these Porsches.
So lets dive in. First, make sure you have all the parts and tools you need or think you need. Don't worry too much as there is always something you forgot or broke.

The 30 year old system is, well, done and disgusting.


No way those are coming off without a fight!

All 4 tubes are leaking this makes for a major mess

So started with heat, penetrating oil, cold water, more oil, more heat. Nothing, snapped off 4 studs, all the barrel nuts on one side. So the next side, out came the die grinder and cut off the nuts, much better.

nut bodies, no match for air tools!

Finally, there off!!

And off with the old oil tubes

The new tubes are a lot easer to put in with the heat exchangers out of the car but can be done. The hard part is expanding the tubes in that tight space, my hands are hurting. But there finally in and somewhat cleaned up under there. No concourse for me, I need my driver fixed today! part two will address the stud replacement.

[Carrerax]

Remember that you need to flatten the flange on the drivers side SSI to clear the omega spring. They use a screwdriver to pull it (spring) back while you put the SSI up.....

[James Brown]

So, the tubes are in and looking good.
Now on to the studs, I didn't have a jig and they are several days away (remember the things that you always forget? yeah, this is one). So, lets do it the old fashion way, drill out and re-tap. Make sure the broken studs are flush

Center punch them and drill a small pilot hole. the drill will brake through the back of the stud into the stud hole so you know you have drilled far enough. Try not to drill all the way through the head! I used HSS bits and re-sharpened them after each hole with my handy dandy drill doctor. If you don't have one of there, get one. Worth there weight in gold. Nothing like a sharp drill bit to make the job easer.
Drill right down the center. Eyeballing this is important.

Then, switch to the final drill size, for M8x1.25 tap use a 17/64th drill (info on the tap) and make sure your right in the center of the stud, drill away.

Then run the tap in the hole and your done, clean out the hole and screw in the new studs.


Oil lines are next, I used a big Ford wrench and a extension to break those oil lines free, not a lot of room at the thermostat but manageable.

On with the new ones, this step is easy and fun!


The M&K slips right in, no problems

There you have it, about 10 hours of work, lots of back time, several Aleve the reward is the most pleasant sound you have heard from a flat 6 in a long time! and the amount of heat coming out the defrosters is incredible. No idea what Porsche was thinking when they changed from the old 2-in system. As far as performance, the rain is still coming down so I hade to not push it. After a re adjusting of the carb jets, I took her out and for the first time spun the wheels for about 30' off a stop light! I have never experienced this in my porsche before! Didn't realize what was happening. It raps right up to redline fast and makes this great sound. It's a 4th gen muffler and there is no drone spot anywhere. In fact, it's quieter than the old muffler. So in conclusion, more power, better sound, improved heat, way better looks, lighter weight, cooler running temp, better fuel economy. Why haven't YOU switched?

[James Brown]

I used a BFH to massage the heat boxes around the omega spring.

[James Brown]

Got this great set of SC heat exchangers along with a euro pre muffler and Dansk sport muffler if anyone is interested...

[9er]

Nice work Mr. Brown, was the outlet on your old dansk 3" and is the M&K 2 1/2" ? I am asking because I have a Dansk sport with 3" outlet and I am thinking of going to an M&K. You mention 4th gen. what does that refer to? The M&K mufflers I have seen appear to be perfect cylinders whereas your picture clearly shows it shaped through the middle section.

[James Brown]

Yes 3" on the old and 2-1/2" on the M&K. they keep upgrading there mufflers. The first generation were round. Also note the strapping on the inlet flanges to prevent cracking. ask RARLYL8 on this forum about M&K's or ask at there web site.

[steve911T]

Mr. Brown, very impressive in 10 hours. I have been working on the SSI replacement only (on and off) for about 2 weeks. Luckily, no broken studs, just trying to get the time to finish the job. Steve

[Neel]

Don't forget to check on shipping of the Dansk for me per PM yesterday.. Thanks..

[Carrerax]

Can I ask why you guys want to get rid of the Dansk sport mufflers? I just got a new one and you are scaring me....

[James Brown]

Carrerax, it came with the car. They are the best without changing everything else. With that big 3" outlet, they flow almost as much as the SSI/headers, M&K combo, but with out the hassle of changing all that stuff that will break. Keep yours, it works fine.

Neel, Haven't made it back to the hangar to get that thing weighed, but I have not forgotten about you!!

[James Brown]

This is a comparison of the two mufflers, note the big tip on the Dansk, nice!!

[Carrerax]

Ok, gotcha. The Dansk is a 1 into 2 and wont work with your SSI's. Thanks, Mark

[9er]

Cheers, I'm only replacing my dansk because it is very old and something seems to have broken inside.

[snbush67]

You make this stuff sound too easy!

Looks great. What happened to your #3 flange on your old exchanger, it looks like it spun? Also did you use thick flanged SSI's?

[WIL84911]

Beautiful. Great job!

[Scott R]

Those are thick flange SSI's, and his #3 what you're seeing is the old gasket sitting on top of the flange.

[dtxscott]

Is there a way to mitigate the broken stud issue?

Can you use a penetrant oil and/or heat?

Edit: I re-read James' post..... Looks like Heat/cold/oil didn't help much

[snbush67]

Originally Posted by Scott R

Those are thick flange SSI's, and his #3 what you're seeing is the old gasket sitting on top of the flange.

Thanks, I fixed resolution on my monitor and can see it better now.

[RarlyL8]

Impressive work James!
You can get a 3" tailpipe as an option on any M&K. Standard issue is 2.5" as it further helps keep the noise level down.