Exhaust Removal...

[Mitch Leland]

Howdy,

Man do I have a lot of questions... I'm going to replace my muffler and have the rest of the exhaust system coated. Since I'm dropping the engine anyway would I be better off removing the exhaust system before dropping the engine, rather than have it hanging from an engine hoist while doing the work?

Thanks for your help...

[azasadny]

I found it easier to drop the engine last summer after removing the muffler, but the heat exchangers were a pain in the a** to remove with the engine in the car. With the muffler off, you get better access to the bottom of the engine and it's not hard to do. I replaced the bolts and put copper anti-seize on the threads so it will be easier next time. Good luck!

[Mitch Leland]

Thanks Art... That's what I'm going to do. I think it will be easier to un-do the header bolts when the engine is still in the car as opposed to swinging around on an engine hoist.

[84porsche9113.2]

I don't know if this is what everyone else would do, but when you drop the engine it is usually resting on some kind of dolly or cart with the weight of the engine resting on the exchangers and muffler. If you removed the exhaust while still on the car, you'd have to get the exhaust studs out as well before dropping the engine if you planned to rest it on a cart, otherwise you might break or bend the studs. If it was me, I wouldn't want to have to mess with the bolts unless I had to. And the thing is messing with those can be a real PITA because many times they are frozen to the nut as well as they are brittle from the heat and may break. All in all another good reason if you are not doing a substantial upgrade, or there's no real problems with the exhaust, not to mess with it because it could cause some real headaches.

I couldn't say which is easier since when I dropped mine I never worked on the exhaust and didn't have to put it on a stand (I also did the clutch at the time). For me getting it from the ground to a stand off the ground would have been a challenge since I didn't have a hoist at the time. If you had the ability to raise the engine on to an engine stand anyway (the kind that rotates when doing engine work), I would think it would be much easier to remove the exhaust when it is out of the car since you have more room to work than when it is still in the car (not unless you also have a vehicle lift).

It might be easier to remove the muffler when in the car (maybe it does provide more clearance?), but I think azasadny was also saying that it is harder to remove the exchangers when the engine is still in the car.

[Mitch Leland]

Thanks 84P, I'll noodle on that. I am going to change the muffler as well as clean or coat the heat exchangers so one way or another I'll end up removing the exhaust system.

I had thought about making a wooden cradle that would support the crankcase center seam and the heads. I would attach this cradle to a steel flange with a 1" pipe nipple that goes through the lifting head of the floor jack. I'll have a engine hoist so I can move the engine around for cleaning and detailing.

I appreciate your good thoughts... Stay tuned, film at eleven.

[84porsche9113.2]

Forgot to mention, when I changed to headers I pulled the originals when the engine was still in the car (like you had planned to). It was pretty much a bi*ch. I remember I had to make some kind of special tool to reach one of the nuts. I also think one or more of the studs broke too. The clearance was pretty limited, it's hard to see even with a drop light, and very awkward in general trying to manuver around under there with a creeper board.

In retrospect, I think it would've been much easier if I had the engine out on a rotating stand and I was sitting on a bench while pulling the exhaust.. But unlike you, I did my exhaust and clutch at separate times, so I really didn't have the choice. Somehow I still did manage to get the job done that way, for whatever it is worth...

[Mitch Leland]

Thanks for the heads up... I might see how far I can go with the muffler and HE removal, then finish it after the engine is on the bench. I don't have a engine rotary fixture so what ever I do it's going to be a "job".

See ya,

[azasadny]

Use PBBlaster and lots of heat to loosen the nuts. Don't force anything, take your time and reapply PBBlaster and heat as required. Be sure to take frequent refreshment (German beer) breaks and wear goggles to keep the stuff out of your eyes!!

[azasadny]

Use PBBlaster and lots of heat to loosen the nuts. Don't force anything, take your time and reapply PBBlaster and heat as required. Be sure to take frequent refreshment (German beer) breaks and wear goggles to keep the stuff out of your eyes!!

[silverc4s]

I have never actually removed heat exchangers with the engine still in the car - but the reading I have done here & elsewhere says it is a real bear on our older cars.
If you have access to a lift, I think that would make all the difference.
I have always removed and reinstalled (or installed new SSI's while the engine is on a stand - inverted. It is VERY simple this way, and I have always felt that when I was done, everything was lined up well and I could do a final inspection before flipping the engine over to put the intake / cooling / alternator stuff on.

Muffler - definitely with the engine in the car for me - on or off.

EDIT: Just recalled another lesson I learned in this area> with the engine on a stand inverted, HE's installed but not torqued down yet - install the muffler you will use and snug up the mounting bolts, no gasket needed. THEN torque down the HE bolts. Remove the muffler, and reinstall once the engine is back in the car. This will give you good alignment for the actual muffler install in the car.

[Superman]

For many reasons, the following would be my method: I would drop the engine like normal, resting on the heat exchangers. No need to remove the muffler. Put a yoke on the engine and mount it on an engine stand. Again, there are a number of reasons for this. I would soak the fasteners with Maltby's penetrating oil (PB Blaster is most peoples' favorite) for as many days as time permitted. Then I would use the "blue torch" to remove them. Heat is your best chance. And.....I would be very patient and careful. You do NOT want to snap an exhaust stud.

[84porsche9113.2]

PB Blaster helps... But it is still a b*itch. Which is why in my opinion if you are just removing them to clean them or refinish, it's simply not worth it just to clean them up....You may run into problems or break a stud. Even if you're very careful, doing everything everyone else suggested, depending on the condition of your exhaust, problems may be inevitable.

I would try to figure out a way to clean them up when still mounted if possible, so you woudn't have to deal with the removal. If you had to fix or upgrade the exhaust, then I think it would seem to more justify the difficulty of the job.

If you're committed to refinishing though, then I guess that's what you gotta do... Even in my case, I think I might have just left it alone and not even changed the exhaust if I knew it was going to be as difficult as it was.

Then again, you'll have your engine out, so it could be much easier that way than trying to work from under the vehicle. Maybe i'm also just lazy or too practical. I did get the job done, but now that I know better, I probably just wouldn't have messed with it.... I don't think the little HP increase or the time and $$ spent was worth the little increase.... I also probably spent more in parts and upgrades than what I bought the car for, and that is not including any labor on my part... Which is why in retrospect, my quest to upgrade may have been a bit overkill and I could have saved a ton of $$ (and time) if I left a lot of stuff as-is because a lot of things were working fine but just being upgraded. Although I probably wouldn't do everything the same way on another project, it was a fun process (and a learning one too)...

[Mitch Leland]

Exhaust update... I've been soaking the header bolts and all the connection bolts with Knocker Loose penetrate for 3-4 days. So far all the bolts and nuts have come off pretty easily. The nuts at the studs for the headers came off with a box wrench and a dead blow hammer.

Question, what size allan does it take to remove the allen bolts, what is the best way to get at the allens? A long allan wrench or can you get a 1/4" drive with a allen/socket on it to remove the allen bolts?

Will a 13 mm socket on a wobbly get the nuts at the headers? Doesn't look like enough room for that... I have SAE socket wobbly combination, maybe they make the same combination in metric?

Maybe only having 48,000 miles on the car and the soaking of the hardware with penetrate was the key...

Thanks,

[84porsche9113.2]

That's good news! I guess I wasn't so lucky...

It's been a long long time since I removed the bolts so I couldn't answer your question very well. As I recall, most of them come off with regular tools, but as I recall, there was one or two where there wasn't enough clearance to use regular tools, i.e., I think the exchanger was direclty beneath the bolt and in the way. I think I had to weld a really short piece of allen wrench to a socket and use a box wrench around the short allen wrench part to grab it, or something like that... I have the tool around somewhere. If I find it I'll post a picture.

Although I haven't read it in detail to see if it answers your question, I took a quick look over in the tech section and it seems the procedure is pretty well documented. I would assume it covers everything step by step from beginning to end. Did you see this?

http://www.pelicanparts.com/techarticles/911_1974_heat_xchangers/911_1974_heat_xchangers.htm

[Mitch Leland]

Thanks for the heads up, another great technical article... The up grade was completed on a 3.0, I'm guessing that the 3.2 didn't need it? I hate myuself for asking, but what does the SSI stand for? Is it an after market heat exchanger? Will it improve the performance on the 3.2 over the stock set up?

Questions, questions...

Thanks,

[84porsche9113.2]

Yes, SSI is a set of performance after-market heat exchangers. They are supposed to improve exhaust flow as does headers. The primary difference is that SSI has heat capability and headers do not. SSI are stainless steel. Conversion to SSI will be like going to the old dual outlet style exhaust so you would basically do away with the cat and have to buy a 2-in muffler. Right now with stock, you basically have the exhaust from the right and left sides combining into one pipe before the cat. SSI will change that and go straight out the back into the muffler so it is more of a true dual exhaust type system. SSI may have equal length tubing as well, not sure. BTW, many of these questions you ask could be solved by first looking in the tech section and/or doing a search for SSI at pelican parts sales pages... I just checked and indeed pelican does have a very detailed description/explanation of SSI. I usually try to solve my stuff by doing a lot of my own research, looking in repair manuals, tech articles, books, etc. Only if I find stuff that isn't covered, I'll usually try to find help on the internet...

http://www.pelicanparts.com/cgi-bin/ksearch/PEL_search.cgi?command=show_part_page&please_wait=N&make=POR&model=911M&section=EXHprf&page=1&bookmark=42&part_number=SSI-911-32L

I'm not sure if there are any big differences between a 3.0 and 3.2 exhaust. Since I did mine a long time ago, I'm not much help as far as remembering exactly how I did the removal on my 3.2, or how a removing a 3.2 exhaust compares (or differs) to removing a 3.0 exhaust as stated in the tech article.

By the way, when you say the 3.2 didn't need it, that's an incorrect guess. The 3.2 like the 3.0 has a 2 into 1 exhaust system so a 3.2 would also benefit from an upgrade to SSI as well. Also, if a 3.2 wouldn't beneffit from exhaust changes, I wouldn't have installed headers on my 3.2 (which gives similar perfomance increase to SSI's). The person who did the upgrade just happened to have a 3.0 car and not a 3.2 so that is the only apparent reason why the article is written specifically for a 3.0 and not a 3.2.

[Mitch Leland]

Thanks, I'll look harder next time, but thanks for clearing that up. I need to find out whether part of our annual County Safety Inspection includes a visual for CATS. I'm not a track guy so between the noise and inconvenience of having to change out the CAT every year to complete the inspection just isn't worth it for the way I use the car.

Also I bet that the straight through CAT by-pass pipe does more good than than changing the headers/heat exchangers. The stock headers and heat exchangers look pretty straight forward. Although I imagine having the direct two out system also is a big performance booster.

Anyway I think I now know what I want to do for my car, I really appreciate your sage words...

See ya,

[84porsche9113.2]

No problem. I don't mind helping if I can because I've recieved a lot of help from this board and I'd like a chance to give back. I don't mind the simple questions personally but I know there are those who think simple questions that could be solved on other areas of this website (parts listings, tech articles), or even previous threads for that matter, is just taking up unnecessary bandwith.

Anyway, you might try the bypass and like it. I started with inexpensive upgrades myself like the bypass first. I pretty much always do things like that. Usually what happens though, is after a while, I end up wanting more so I would've saved more $ had I just got the good upgrade to begin with... And the exhaust was no exception. So I think I've learned my lesson and try to get more than I think I need from the beginning. You might want to also consider since you have the engine out and are removing the exhaust anyway, if any time was the right time to change exhaust systems, now is the time!... You wouldn't want to put in a bypass, change your mind, and then do extra work later...

Good luck with your exhuast! (btw, I'm not a track guy either...)

[Mitch Leland]

First off I hope I'm not beating this to death and using up your valuable time. Different from some other up grades the muffler system can be abstract in its conclusion depending on the performance and noise levels of your expectations. I'd like a muffler that at cruise wouldn't be much louder than the stock muffler.

Here's what I think I want to do:

1. Install a sport muffler, 1 in, 2 out with the ability of capping off the right outlet if the noise level is too high... The choices of mufflers makes this difficult since I have no way of seeing or hearing the mufflers first hand.

2. Remove the HE's and CAT and have them Jet-Hot coated.

3. If I don't need the CAT for annual inspection I'll go with the by-pass pipe. I assume removing the CAT in favor of the by-pass pipe would increase the noise level?

Considering my thoughts and your experience what would you recommend?

Thanks,

[84porsche9113.2]

I think I was looking for the same as you when doing my exhaust. Increased peformance/hp with minimal noise. There is a tradeoff between the two and usually the more exhaust you flow (performance) the more noise you will get. You just need to find the right balance.

To give you some background. I first started with a bypass & stock muffler. Then I bought a bursch sport muffler to use with the bypass. Then I tried a B&B dual outlet. Eventually I switched to headers and a 2 in 2 out. Then my final configuration after switching mufflers again, was headers and a 2 in, 1 out Dansk stock type SS muffler. I found that a bypass will increase the noise level and mufflers will make a big increase in sound volume, especially if it is 2 out vs. 1 out. Unlike you, I tried them all and sold the parts when I outgrew them or changed my mind. You can always get a used muffler to try out, or sell it if it is too loud. You'll never know for sure, unless you try.

1. There are previous threads on this. Somene has made a muffler with an exhaust cutout that could be electrically operated from inside the car. I thought about this too but never got around to it. Note you would have to modify the rear valance for the 2 out.

2. no comment.. short of changing the exhuast system, I personally don't see much value here..

3. the bypass in conjunction with a 2 out will definitely be very loud. in my experience, i think a header/ssi system with a 2 in 1 out stock muffler is perhaps around the same volume if not a little less noise, but better performance. the other issue is that cats can get clogged so if yours is clogged you could be loosing hp. but switching to a bypass would solve this.

"I'd like a muffler that at cruise wouldn't be much louder than the stock muffler." -- I don't think this is possible if you are considering a 2 out muffler and a bypass. If you want something quiet and you want to try the bypass, then just go with a bypass & a 1 in, 1 out stock type muffler (or keep your old muffler if nothing is wrong with it). The bypass will already increase the volume, so if you go with a 1 out sport muffler, or 2 out sport muffler, it will be substantially louder than stock in my opinion. Apparently a stock type muffler reduces noise the most, but is not known as a performance type upgrade. So you have some tradeoffs to make. If sound is more important to you than performance, I'd say stick with stock or make as minimal changes as possible. If you are concerned about noise, the bypass and a stock muffler is good because it is a minimal change and you can easily go back if you think it is too loud.

Also, if you are staying with your original exchangers, then it's not reallly a critical decision you need to make right now. Mufflers can be installed when the engine is in the car, so you could try the bypass for now with the stock muffler, and if it wasn't too loud, then you could try going with a sport single outlet or dual outlet muffler. The key here is trying things in small increments if you are concerned about the noise. You'd have to install the bypass with the stock muffler and run the engine first to see if it was too loud or not. If it wasn't, you could then move up to a 1 out sport for the next volume increase, and if that wasn't too loud, a 2 out sport... Or you could try to get a 2 out with a cap so you'd have control over the volume as you mentioned. But I would still try the bypass with stock and run the engine so you can find out for yourself if it is too loud or not. If it is already too loud, then muffler choices become irrelevant, because you'd then know that you'd probably want to stick with a single outlet stock type muffler to keep the noise down.