Do I Dare???

[n/a]

Dear Guys;
I've spent the winter doing all the rust repair on my 280SL, now finishing some paint and color sanding. Next are some mechanicals that need attention, and the car is ready for some long awaited Spring driving. However, the exhaust is getting on the noisy side. I'm an engineer with many years auto experience, have many tools, welders, torches, you name it, AND enough common sense to ask you guys, the experts who have spent lots of time with the SLs, for your advice; Question...DO I DARE try to do this exhaust system now or wait until the Fall? Long experience tells me I could begin a nightmare...imagine trying to separate the front pipe from the manifold and cracking it...now I would probably have to remove the intake to get at the exhaust manifold, break something else, have to find another manifold, etc. etc. meanwhile, the summer goes by. Is replacing the system a **** or fairly straightforward? Any idea of cost for parts? Recommended vendors? Appreciate your kind input. Thanks in advance.
Regards,
Joe Bango

[cth350]

do you have the short cast iron manifolds or the sexy headers from the early 230sl?

If you don't have then, it sounds like a great excuse to get them.

-cth

[J. Huber]

Hey Joe. One way to approach this is to figure out just what part of the exhaust is giving up. It could turn out that it is just the muffler (rear) or the resonator (center section). In other words, you might not even need to mess with manifold stuff. I have replaced my rear muffler (1988) and my resonator (2001). I think the front pipes are originals. No problems at the moment.

James
63 230SL

[n/a]

Gentlemen;
Manifold is standard cast iron....no doubt problem is either resonator or muffler...pipes seem good. But I don't like doing jobs half way...Jim....did you have a problem welding in the new muffler and resonator? I fear that if I start hacking the pipes apart, they will crumble or will not easily MIG weld. Are the pipes heavy gauge? Are they known to rust through readily? Metallurgy has a lot to do with micro galvanic cells having some material rust away real fast. I presume original system are pretty contaminant free good mild steel?....
Regards,
Joe

[George Davis]

Joe,

several guys have had problems getting the head pipes loose from the manifolds.  Typical solutions involved removing all hangers then moving the entire exhaust system from the rear to get enough leverage to break the pipes loose.  I don't recall any reports of broken manifolds.  Go easy and be patient.  My pipes came loose without a problem, but I'm guessing they aren't original.

George Davis
'69 280 SL Euro manual

[Jonny B]

Just be careful when lining this up and tightening everything down. Last year I had to replace one of the cast iron manifolds when it cracked on the underside just before the exhaust system connection. We tried to have it welded, but no luck. There was just enough tension on it that it led to the cracking.

Jonny B
1967 250SL Auto

[Vince Canepa]

In the bad old days it was standard practice for the dealers to replace only the bad component.  Most techs used oxy/acetylene gas welding rigs.

I replaced my entire system quite a few years ago, using all factory parts.  I gas welded it.  I tack welded everything with the wheels carrying the weight of the car, then dropped the system down a bit to complete the welds.  The following hints might help.

1) Supporting the chassis and letting the wheels hang tends to result in the system touching the body in the rear.

2) Make sure you allow just enough room under the right axle tube so it doesn't hit the system with the right axle tube at full extension.  Hang the pipes under the axle too low and they will drag on bumps that fully compress the rear suspension.

3) Make sure to position the rear muffler carefully so the the rubber bumper on the body hits the tab welded onto the muffler (near the rear hangers).

4) I plug my tailpipes with rolled up rags when I shut the engine down.  The old steel systems would rot out internally from moisture that was pulled in when the system cooled.  It wasn't uncommon for components to last only 3 years or so.  My system is 20 years old now and doing fine.

Vince Canepa
1967 250SL
113.043-10-001543
568H Signal Red
116 Caviar MB-Tex

[Khurram Darugar]

Joe,
    I recently removed my exhaust system and found that while the pipes  were solid, the muffler sheet metal had thinned over the years and was not suitable for welding repair.  Im also going to replace the manifoold gaskets which i would imagine would be a real pain once the exhaust is fitted.  

A local shop has told me they can replace the exhaust in 4 hours with an after market SS clamp on system.  So in my case multiply by 5  :?  and your still looking at a weekend jobbie.  

Kay

Kay
Euro 280sl LHD Auto.

[J. Huber]

Joe, I can't really help as far as the actual installing stuff -- I tend to pay my way out of trouble! For the muffler, it was just a matter of driving into Midas and saying I think things are getting loud. Couple hours later I was back on the road. With the resonator, I discovered a hole forming, and used Ray at the old Star Quality to purchase a resonator (Eberspaecher?) -- then had it installed at a local tire/muffler place. Again, seemed like a smooth fix.

James
63 230SL

[Cees Klumper]

I replaced my old (welded) system with a stainless one, new front to back (including the downpipes) in about two hours if I recall correctly, two years ago. The new system is clamped. This to me is the way to go: easy to install, no leaks, easy to position and reposition if necessary, easy to remove (part or whole) if necessary. Getting the downpipes separated from the manifolds was not an issue for me. What DID cause some headache was getting the old welded system out from under the car (I don't have a lift in my garage).

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic

[ted280sl]

Joe,
  There was a thread some time ago about the tendency of the bolts which hold the exhaust pipe to the manifold. These bolts should be fastened with brass nuts. I promise I am not joking about this. The previous owner of my car had installed a stainless steel exhaust system but, he did not have brass nuts. If you are going to change the exhaust system I suggest moving to aluminum because I understand that the pitch of the muffler leads to condensation standing in the system and rust. Obviously this does not happen with a stainless system. The brass nuts make a huge difference as my exhaust system bolts would become loose periodically. Now that I have brass bolts they have not required tightening in years.
Ted 1969 280SL w/ brass bolts & stainless exhaust

[n/a]

Joe, I have done most of the work on my 68 myself. I rebuilt the motor, and had the FI redone while I had the motor out. The exhaust was shot but I couldn't get the down pipe to release from the rest of the system. My solution was to take it to the local muffler shop and for $100 they had my new exhaust, which I supplied, on in 2 hours. Well worth the bucks as I hate working under cars. By the way I bought the exhaust system on ebay and it was very reasonable, but it is a little louder than I would like and my stock exhaust tips were slightly small so I had to go back to the vendor and get his chrome tips. But it works OK for me. John

[rwmastel]

quote:Originally posted by cees klumper

Getting the downpipes separated from the manifolds was not an issue for me.

Cees,
What was your solution to your long running problem of the bolts & nuts that hold the downpipe to the header?  Am I even recalling the problem correctly?  Was the problem related to SS instead of normal steel exhaust pipes?

Rodd
Powell, Ohio, USA
1966 230SL, Euro, Auto, Leather, both  tops
1994 E420

[Cees Klumper]

Good memory Rodd.
The problem with my downpipe-to-manifold bolts, that kept working themselves loose (I must have replaced both the bolts and the brass/copper nuts at least three times) was that there was no tension on the fit between the downpipes and the manifold. Without this tension (which is created by the shape and length of the downpipes vis-a-vis the manifolds) the nuts work themselves loose. I even resorted to trying two nuts per bolt, but to no avail.
My new exhaust system is properly designed, so that there was (and still is) tension in the connection. Bolts have stayed tight for the past two years without any retightening.

Cees ("Case") Klumper in Amsterdam
'69 white 280 SL automatic

[n/a]

Dear Gentlemen;
Good info here, thanks. Vince brings up a good point in not jacking up the car and letting the wheels hang down, as the clearance is different then when the suspension is loaded. I think I'll put the car up on ramps fore and aft, whic will give me room while under the car yet load it as if it were on the ground. I'll have to play with the rear to get the wheels to camber properly though. And good note about the brass nuts. These are used on Rolls-Royce as well. (now those systems are a bear to work on!).
I think I'll try to find a used exhaust manifold before I start just to be safe. Stainless, like Borla systems, tend to be a thinner gauge and can sound "tinny", thus prefer mild steel. Anyone recommend where to buy a system or what make? How much are they? Little gunshy with Ebay hacks selling junk unless someone has had good luck with a particular seller. With all parts on hand, I may try the muffler - resonantor replacement alone approach. If I can't weld, will be forced to do the whole deal.
Regards,
Joe :?