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Cadillac & LaSalle Club Forums => Technical / Authenticity => Topic started by: Gabe Davis on September 18, 2022, 02:36:49 PM

Title: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on September 18, 2022, 02:36:49 PM
Hi all,

I'm beginning to research the exhaust system for my '59 Coupe DeVille. The set that is on there now is from the mid 1990's and I can hear the leaks in the rusted pipes. It also has a Dynaflow muffler which, while not annoying, is louder than I'd like for it to be. There are also no resonators installed.

I have never done any work on exhaust systems and am curious as to how the original was setup on these cars. Was everything just bolted together? Was any part of the system welded? Is this something that I can DIY?

I haven't crawled under the car yet to grab pictures of what is there currently. I have a suspicion though that the original exhaust mounts are no longer there. I'd like to try and put things back as stock as possible. There seemed to be a couple of sources for the stock hangers.

There is one in Finland. Seems like a lot of money.
https://martelius.com/en/cadillac-1959-1960-hanger-set

User Grant Owen out of New Zealand appears to have made reproductions in the past but does not appear to be active here on the forum, at lease recently. I did find his email address on the forum and have reached out. We'll see if he still makes them. He even used pieces of wide white wall tires.

100_1460.JPG

Is there any other place to look for a set of hangers?

One of the other aspects is the flex insulating tubing over the pipes near the engine compartment.

Does anyone have any pictures of what it actually looks like on a '59? I haven't been able to find any pictures of what the original looks like. Did it go up the small section of pipe that comes off of the exhaust manifold or is to only the section between the first small pipe and the muffler? The section is circled in red in the drawing from the service manual.

Pipes-manual.jpg

Is it as simple as sliding a flexible exhaust pipe with the correct ID to fit over the hard pipe like this one? Is this the right type?

https://www.summitracing.com/parts/aph-8859
aph-8859_xl.jpg

Is it common to put the additional flexible pipe over the hard pipe? The lack of photos of it makes me think it is very common for it to be omitted. I ran across a couple of posts about doing earlier cars and a custom 2x4 to aid in hammering on the pipe.
https://forums.cadillaclasalleclub.org/index.php?topic=159035.20

And then there are the pipes themselves. After reading a lot about the pros and cons of stainless vs. aluminized steel, I am pretty sure that I want to go with an aluminized steel system. They are cheaper too. I'd be curious to hear peoples thoughts. This car is a driver and is pretty much original so I'd like to try and keep it as original as possible, within the bounds of a realistic budget.

For suppliers, Waldron's Exhaust seems to have high praise, with a higher cost.

https://waldronexhaust.com/product/1957-60-cadillac-with-4-mufflers-dual-exhaust/
1959-60-Cadillac-Duals-578809.jpg

Any other exhaust suppliers I should be looking at?

I appreciate your thoughts! Thanks!

IMG_3402.JPG
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: fishnjim on September 18, 2022, 03:33:33 PM
I don't think you'll find a OEM steel exhaust these days, they're mostly all aluminized or stainless repro for vintage.  So it's a matter of what you're willing to go with more than getting OEM. 
Any local shop could bend up something, and the custom exhaust people have the OEM bend specs.  I had one made for the P and it fit nice, and was a very tight space in the Xframe.  When I need one for the '58, I'll probably buy a custom and go stainless.  It's got a muffler shop type modified steel system on it since I bought it that way.
If I read this right, you're in Finland, so no idea what's available there.
The potential problem is getting something export and DIY, it doesn't fit, and then your stuck w/o an exhaust, if you don't have the tools of the trade.  Something to ponder before you pull the trigger for big bucks.
I used some universal hangers when I fixed the '58.   I don't know of any that are OEM fit in kits.   You'd have to search around, and probably low chance of any and less Ex-USA.
The shop manual should have the instructions.   The parts list should show what parts came from factory.   I'd guess from memory, so I'm not 100%.  As far as I know the '59 authenticity manual is still nebulous but on the horizon based on posts this summer.  Just a thing with that year.  Plus you're complicated being by off the continent.
ps: back in the day, one used to be able to buy part or a complete steel OEM exhaust off the shelf at the parts store, but those days are kaput with the catalytic exhaust, etc of today.  I might have the Walker catalog listings for that year.  Some have pictures, some don't.  There's been posts here about the double wall, so you can search the posts, but just don't include '59, include years around there.'57-'62
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on September 18, 2022, 10:52:12 PM
Jim, thanks for your insights. No, I'm not in Europe. It's a lot warmer where I am in Atlanta, Georgia.  :)
The one vendor I found with the hangers is in Finland. That is what I was referring to.

As far as material, I'd be fine with the more modern aluminized steel. It does not have to be totally period correct. I would like to have the original hangers though so that part could be correct.

The hangers are briefly mentioned in the shop manual and in the disassembly/assembly procedures but their are no photos of the system other than the diagram I posted earlier. I used a lot of googling to even see what the originals looked like.

The current exhaust was a custom job by a local Midas if I remember correctly. I would hazard to guess it was hastily fabbed up with the cheapest parts they had at the time. If I can save a little money or get closer to original, in this case, I think I would prefer to go with a prefabbed kit.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: dn010 on September 19, 2022, 07:58:33 PM
With any luck, yours is held together with clamps. The joints on mine seem to have been all welded closed at some point in time. In a month or two, I will change mine out and my plasma cutter is waiting to make things easier. I am going with "Classic Car Exhaust Inc."
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on September 24, 2022, 09:55:58 PM
I was under the car today working on the brake lines and got to take a close look at the exhaust system.

There are only the top most hangers above the axle that are original and they aren't connected to the current pipes.

I reached out to Grant Owen and he replied that he does indeed still make the hanger sets and that they would be $300 plus shipping to the US. I'll have to find the correct type of bolts to connect the mounts to the frame. I assume they are similar to the bolts used to hold the clips that mount the brake line. They appear to be a type of self tapping bolt with a wide head. The brake line bolts are 1/2" heads. Are the exhaust hanger bolts the same?

0131-hexwasherheadtypefthreadcuttingtappingscrews1.jpg

The current pipes are almost all welded so I'll have to cut them apart to get them out. They are for sure rusted through in places as I could hear an exhaust leak and was able to confirm it visually.

I'll try and snap some photos when I'm finishing the brake lines tomorrow.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Daryl Chesterman on September 25, 2022, 08:41:34 PM
NAPA has (or can order) the flange headed self-tapping bolts like you pictured.  I am not sure what size you need, but you can go to NAPA's catalog page (link shown below) and in the sidebar on the left, scroll down to Fasteners, click on "Fasteners" and the catalog will appear in the pane on the right.   Click on the catalog icon and the complete catalog will come up.  On page 41 in this catalog it shows the bolt in the upper-left corner of the page, and you can pick the part number that corresponds to the size you need.

     https://www.napaecatalog.com/?market=65&origin=https%3a%2f%2fwww.napaprolink.com%2fecatalogparse.aspx%3fcatid_linecode_partnumber%3d

Daryl Chesterman
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on October 01, 2022, 10:51:53 PM
I was under the car again finishing the brake line project and snapped some photos of what is there currently.

It appears that the original downpipe from the exhaust manifold is still there as it looks like a regular steel pipe given the rust. The rest is aluminized.

IMG_6776.jpg

The muffler is a Dynomax 17732 "Super Turbo"
https://www.dynomax.com/super-turbo-offset-offset-18009.html

While not super aggressive, it is way louder than what stock would be. Even being a "mild" sounding muffler that does sound good, to me, it is loud for the car. This is a Cadillac after all.

IMG_6775.jpg

There is a decent hole blown out. I assume this was the low point where the water collected. You can really hear it especially when pulled up next to another car or wall.

IMG_6773.jpg

No resonators are installed with the current system.

IMG_6769.jpg

All of the original mounts had been removed and replaced with generic mounts welded to the frame. It seems pretty rigid with only a small amount of flex in the system.

IMG_6764.jpg

I have a set of mounts on order with Grant. I'm excited to put the system together with the correct parts.

I'm still on the fence about either going with Waldron or Classic for the rest of the parts.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: fishnjim on October 04, 2022, 04:08:44 PM
I finally looked in my Walker catalog today, and it shows the '59 complete, but I think it was made in more pieces so they can do patch jobs.  It doesn't show the fluted pipe, but maybe just a rendering.   It looks similar to the one you shown.  They don't make these any more.  I can post if needed, but I think you have what you're going to find.
Fastenal is another supplier of those self tapping flange head screws.  I bought from them many times, then they closed my local store during covid.  Now I have to drive 30 minutes one way and if they don't have what I want they have to order, so I just order all my stuff on line.  I get better service out the warehouse.  Just shipping costs have gone wild so you have to buy more to justify.
I suspect the hanger rubber goes and they just lop off the hangers to make it easier to remove.  My '58s were all chopped off and some missing so I repaired the whole length. You probably could've saved a few dinars with a bunch of universals from NAPA, but to each his own.   I remember my friend worked at the local gas station garage and they had to use the air chisel to cut off exhaust pieces and it wasn't timely.
I think the '59 also has the pass through rubber isolators.  I was able to find some high temp belt material by the foot from BF Goodrich, for cheap, so I used that rather than try to find ready made.  Quieted things down no more rattle.
 
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Seville Life on October 05, 2022, 08:09:24 PM
Gabe, that '59, that colour, just stunning, an example of grace, style and elegance. Beautiful motor car and something only Cadillac could make.

I hate this welding of exhausts. Using clamps allows you to fit and line-up the system without building up tension in it which ill produce noise. Likewise using stainless, noisy, I always go for regular steel and just look after it, ie, no short running filling it with condensation.

I'm on the French Riviera, pretty damn hot down here fella?
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on October 07, 2022, 06:09:28 PM
Quote from: Seville Life on October 05, 2022, 08:09:24 PMGabe, that '59, that colour, just stunning, an example of grace, style and elegance. Beautiful motor car and something only Cadillac could make.

Thanks! I think if you are going to have a 1959 Cadillac that Pink is a pretty suitable color! It's the iconic one! ;D
That particular picture was from my brother's wedding photographer who altered the images heavily. The car is a chameleon though. Depending on the light it can be tan, pink, purple or beige. Kinda neat.

Quote from: Seville Life on October 05, 2022, 08:09:24 PMI'm on the French Riviera, pretty damn hot down here fella?

Do you have extreme humidity there too? Gotta love how that makes it feel even hotter!
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: 1957biarritz on October 09, 2022, 08:52:06 AM
try to call or email  0046-706678475 ELLAR MAILA baautoparts@tele2.se
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on October 13, 2022, 10:52:40 PM
I pulled the trigger on a system from Waldron's. The website said 10-12 weeks lead time. I called to confirm this and the lady who picked up, Ruth, was very helpful in confirming the number of clamps and the quality of the system and that, yes, the lead time on the website was correct.

I'm excited to get the new system but the wait until some time in January is going to feel like a long one!

Grant in New Zealand shipped out the set of hangers so I should have them well before the rest of the system.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on January 04, 2023, 06:09:49 PM
I got a couple of boxes from Waldron's last week! Their estimated lead time was exactly right, coming in at 11 weeks. The parts look great and I'm excited about getting them installed. The hangers from Grant also look great. I have ordered the bolts and washers from McMaster-Carr and those will be here tomorrow.

What I did not realize is that the pipes are two different sizes. From the manifold to the muffler inlet is 2 inches and from the muffler outlet to the tail pipe is 1 3/4 inches.

The last piece I need is the flex pipe to go over the solid pipe from the manifold to the muffler. Does anyone have any size recommendations? If the OD of the solid pipe is 2", what would work best for the flex pipe? 2 1/4"?
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on January 09, 2023, 09:02:20 PM
Time to play!

I got started installing things today. The last piece of the puzzle I needed before getting going though was the flex pipe. I found a chart from Walker exhaust that showed what was available by part number. Walker is carried by Advance and NAPA.

Screen Shot 2023-01-09 at 7.59.53 PM.png

I ordered 46974 (2 1/4") and 46975 (2 1/2") from NAPA. Total was 6' needed to cover both of the front pipes from the downpipes to the mufflers. Those sections of hard pipe are 2" and the rest of the system is 1 3/4".

IMG_7695.jpg

The flex pipe was pretty evenly split between the left and right sides. The left side was 1" longer that the right.I cut it with a Dremel. I attempted to get the 2 1/4" flex over the 2" pipe but it was not possible to get it to bend around the tighter sections of the hard pipe. The 2 1/2" was doable but still put up a fight. I got it on there though.

IMG_7696.jpg

IMG_7697.jpg

IMG_7698.jpg

IMG_7699.jpg
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on January 09, 2023, 09:08:17 PM
Once I had that sorted I started taking apart the old system. It was welded in place so I had to cut it with a sawzall.

IMG_7700.jpg

The aftermarket mounts were welded to the frame and had to be ground off. I hit the bare metal with a bit of paint to stave off the rust.


IMG_7703.jpg


The old system was full of holes and had an aftermarket muffler and no resonators.


IMG_7702.jpg

The mounts from Grant Owen are extremely well made.

IMG_7706.jpg

The only two originals on the car were up in the well above the axle. Comparing them with what he made shows that they are very accurate.

IMG_7714.jpg

IMG_7715.jpg

The holes all lined up except for one on the rubber anti rattle mount but that was easy to modify with a new hole in the rubber.

The bolts to hold them to the frame are 5/16-18 x 3/4. The originals were self tappers but I used regular bolts as the threads were already in the frame. I also added a lock washer to each new bolt.

IMG_7708.jpg

Each of the anti rattle mounts requires 4 washers and the front most rubber mount before the muffler requires one each. These are 5/16" screw size, 0.344" ID, 1.25" OD, 0.120"-0.130" thickness.

The hardware all came from McMaster-Carr and is zinc yellow-chromate plated except for the large washers which are black oxide. They are Grade 8, massive overkill, but were what I could get with that plating. Military grade stuff, so it should last.

IMG_7711.jpg
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on January 09, 2023, 09:14:09 PM
I was very lucky that the nuts came off of the exhaust manifold studs without too much of a fight. The nuts were rusted and partially stripped so I replaced them and the lock washers behind them. I had forgotten to order new ones from McMaster-Carr. The nuts are 3/8-24 and the only ones I was able to get locally were stainless steel and not as tall as the originals so I doubled them up.

IMG_7722.jpg

IMG_7723.jpg

IMG_7725.jpg

IMG_7726.jpg

As far as the pipes them selves, they are very well made. Not a burr on them and the bends are clean and accurate. The fitment was perfect and I did not have to force anything together. The included gaskets and clamps look to be high quality. I highly recommend Waldron's exhaust for these parts.

I did have to remove the rear shock to get the curves pipe up over the axle.

IMG_7727.jpg

IMG_7732.jpg

IMG_7733.jpg

IMG_7734.jpg

This car has two exhaust systems and I only got the left side installed today. I have time tomorrow to get the right hand side installed and then I can make comments on how it all sounds. But if it sounds as good as it looks it should be amazing!

More to come!
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on January 10, 2023, 08:56:44 PM
I got the right side installed. It went the same as the left with great fitment and everything bolting right up.

Except for the exhaust manifold studs. Apparently in the past a repair had been done on this side and the studs were replaced. They were two different sizes and one of the studs came out when removing the down pipe. It had been tapped with a 3/8-16 thread and the stud was very rusty. I ran a 3/8-16 tap through it to clear the threads and installed a new stud but it was still loose and would not clamp down.

When trying to tighten the other stud it gave and is now loose too. So both holes in the manifold for the studs are toast.

What was the original stud size? If I helicoil the holes I'd like to install the correct studs if they will fit. I was reading it may make sense to go to the next closest side up in metric to keep as much material on the manifold holes as possible. I assume the originals have fine threads like the left side did. It looks like I may be able to drill and tap them in place. I really don't want to have to pull the exhaust manifold out to do this.

Has anyone ever done this job with it in place in the car? Any clues on the original stud size? Is helicoiling the holes the way to go or is there another repair process that would be more suitable?

I want to get this fixed so I can hear the new exhaust system without a massive exhaust leak!
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on January 15, 2023, 09:38:04 PM
Updates!

After reading a lot about helicoils I decided to re thread the holes to 3/8-16 instead of trying to directly tap m10 threads. I also already had the 3/8-16 studs from the earlier repair attempt.

IMG_7777.jpg

IMG_7778.jpg

I had to drive to a couple of different Ace Hardware stores but eventually found a Helicoil brand thread repair kit. It comes with the specific tap, install tool and coils. It did not include a drill bit which in this case called for a 25/32. I picked up one of those too.

IMG_7779.jpg

There is plenty of room to get a straight shot to both holes in the exhaust manifold from under the car. I had to use about a foot of extensions but was able to get the bit to go in straight and bored out the old stripped out threads. The rear hole opened to the outside on the top. I don't know if it was this way when new as the old repair may have drilled it all of the way through. The front hole is blind but the bit went all of the way to the bottom without issue.

The next step was to tap the threads. Again, I used a long extension and attached a ratchet as there was no space for a tap handle. The process was slow but both holes tapped cleanly.

IMG_7756.jpg

In the rear hole I stacked two coils so the thread was the full length of the hole. The front hole only had room for one coil.

IMG_7758.jpg

Once the holes had the new threads I trimmed the stud length with a Dremel so they would catch as many threads as possible in the holes and have the unthreaded portions of the stud land flush with the manifold. They feel super strong and are tight and straight and true.

IMG_7762.jpg

The down pipe bolted right up and the nuts with lock washers were torqued to the 20ft lbs the shop manual called for.

IMG_7774.jpg

Needless to say, I was quite relieved that the repair process went well and everything came back together cleanly. No more exhaust leak!

IMG_7772.jpg

IMG_7770.jpg

IMG_7765.jpg


So how does it sound? I was surprised that at idle from the outside of the car the exhaust note is pretty deep. Similar to what the Dynomax mufflers sounded like. It sounds like what a large displacement V8 should sound like. Yet, it is more refined sounding than the Dynomax. The most marked difference is while driving. It is much more quiet. Yet it sounds nice. Smooth and even. I think the correct exhaust mounting system made a huge improvement as well as the amount of vibration went way down. That makes sense as there was very little compliance in the aftermarket hangers that were there before.

Overall, I am very very pleased with how the project came out. I like the fact that the car is closer to how it came from the factory as the rest of it is a very original car. I very highly recommend Grant's reproduction mounts. They are accurate to the originals, high quality and bolted right up easily. The pipes, mufflers and resonators from Waldron's exhaust are also very highly recommended. The fitment, quality of materials and customer service are all top notch.

Anybody interested in some lightly used Dynomax mufflers?  ;D
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: TMoore - NTCLC on January 18, 2023, 12:42:01 PM
Beautiful work and a great write-up - thanks for providing this.

Title: Re: 1959 Coupe DeVille Exhaust System
Post by: 59-in-pieces on January 18, 2023, 04:24:38 PM
Gabe,

Sorry for arriving late for this string - just missed it way back.

But, I couldn't agree more with TMoore - great job.
Love it when a guy does his own work and gets his hands dirty.

Here is a pic of an original cold rolled 59 wrap, to help document your journey.

Have fun,
Steve B.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on January 22, 2023, 08:01:02 PM
Quote from: 59-in-pieces on January 18, 2023, 04:24:38 PMHere is a pic of an original cold rolled 59 wrap, to help document your journey.

Steve, thank you for sharing the picture of the original pipes! I searched the web high and low and was not able to find any.

It's interesting how tight the flex pipe is around the hard pipe. I wonder if they had a process that had both layers together before bending or if it was a slip on over the hard pipe. I'm sure they had some kind of jig or machine to do it.

I tried to get the 2 1/4" flex pipe on the hard pipe but the tighter bends kept it from going on. I would have had to cut slits in the flex to have any hope of opening up the radius. It had not been cut or modified in any way so I was able to return it. The 2 1/2" flex still put up a fight but I got it on.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on January 22, 2023, 08:08:23 PM
I have been reading this thread here:

https://forums.cadillaclasalleclub.org/index.php?topic=166634.0

It discusses drilling a small hole in the muffler and/or the resonator to drain water from the system. I could see that for the resonator for sure. According to that thread there were even Cadillac service bulletins instructing to do so.

If that is done to the muffler is there any chance of hearing an exhaust leak? After removing all of the holes I'm a little hesitant about adding them back!  ???
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: bcroe on January 22, 2023, 08:35:22 PM
Just a comment, when I started building custom
SS exhaust systems to avoid that maintenance,
those straight rubber strap hangers supporting
a pipe seemed to transmit a lot of vibration. 
Seen in the foreground of the picture.  I
changed to OEM hangers which all seemed to have
some curves (background), with better results. 
Bruce Roe
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: jwwseville60 on January 26, 2023, 09:58:10 AM
I have a Waldrons dual exhaust on my 59 flat top.
Its worth the wait. Perfect sound, factory specs.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Clewisiii on June 16, 2023, 11:03:20 AM
Gabe, showing my ignorance. What is your reasoning for using the flex pipe shielding. 
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on June 16, 2023, 08:54:17 PM
Quote from: Clewisiii on June 16, 2023, 11:03:20 AMGabe, showing my ignorance. What is your reasoning for using the flex pipe shielding. 

It actually came with that covering from the factory. If you look at the diagram of the exhaust system, you can see it on the first set of pipes has it.

Pipes-manual.jpg

59-in-pieces posted a photo of an original exhaust with it:

Exhst wrap atbrace to bell housing.jpg

Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Clewisiii on October 10, 2023, 08:21:23 PM
Bump
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Cadillac Jack 82 on October 11, 2023, 10:57:02 AM
This is a great post and its helping me understand my exhaust completely.  Mine was replaced by Kmart November 1968 by the original owner.  They obviously cut corners but some of the original components remain.  I'm looking forward to getting this completed over the holidays.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Cadillac Jack 82 on October 11, 2023, 03:48:54 PM
Okay I'm having a hard time understanding why the steel part that Gabe listed earlier costs 60 while Mastermind wants 350 for their stainless one?  They look as if they're the same?
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on October 11, 2023, 04:01:58 PM
Quote from: Cadillac Jack 82 on October 11, 2023, 03:48:54 PMOkay I'm having a hard time understanding why the steel part that Gabe listed earlier costs 60 while Mastermind wants 350 for their stainless one?  They look as if they're the same?

Which part? The flex tubing?
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Cadillac Jack 82 on October 11, 2023, 04:36:10 PM
Yes.  I love your post because its very detailed.  Mastermind has the stainless version of the flexpipe but they want a hefty price for it.  The items you ordered from Napa appear to be almost exactly like the originals from what I can find.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on October 12, 2023, 08:50:29 AM
I opted for aluminized steel over stainless for the whole system after weighing the pros and cons. I like that it is more technically correct and sounds original. So in doing that the flex pipes are galvanized steel as that was what I was able to find easily. I'm sure a stainless version will be pretty expensive. I think the galvanized was about $40 for the 6' length.

I do have an update I need to make to this thread when I get a chance to confirm the details. Basically, on the rear most hangers for the resonators the threaded holes in the frame are a different size than the rest. They are smaller I think by one size. I didn't realize it when installing as I figured the threads were just rusty and the bolts were difficult to get started but they are actually smaller.

When I find that info I'll see if I can find the part numbers for McMaster-Carr that I used as well.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Cadillac Jack 82 on October 12, 2023, 11:13:09 AM
Thank you for the information!  I'll just opt to do the route you went and save myself 200+ dollars for more Cadillac goodies.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on October 12, 2023, 12:51:36 PM
Quote from: Cadillac Jack 82 on October 11, 2023, 04:36:10 PMI love your post because it's very detailed.

I'm happy to help! I'm glad others are finding this useful. I looked around but didn't see a lot of info about the hangers specifically. They are only mentioned in passing in the service manual. As they say, a picture is worth a thousand words. So I intentionally posted a lot. I find it useful to be able to compare visually with others cars. I've only personally seen two other 1959's in person so photos really help!
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on October 13, 2023, 02:28:19 PM
Adding some specifics about the bolts for the hangers to the frame.

All of the hangers except for the resonators are 5/16-18. The resonator hangers are 5/16-12. The last page of the Fuel & Exhaust section of the shop manual has a handy chart:

1959-SM-FnE-Chart.png

The McMaster-Carr parts are here:

5/16-18 3/4 long Zinc Yellow-Chromate bolts - Part Number 92620A581
https://www.mcmaster.com/92620A581/

5/16-24 3/4 long Zinc Yellow-Chromate bolts - Part Number 92620A606
https://www.mcmaster.com/92620A606/

They were not present originally but as I was re-using the holes in the frame I added lock washers:

5/16 Zinc Yellow-Chromate Plated Steel Split Lock Washers - Part Number 91104A030
https://www.mcmaster.com/91104A030/

And the large washers for the anti rattle rubber bushings and two mounts up by the mufflers:

Black-Oxide Steel Oversized Washer for 5/16 bolts - Part Number 92140A116
https://www.mcmaster.com/92140A116/


Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on October 29, 2023, 12:05:13 AM
So I had the car out today on a beautiful fall afternoon and decided to go for the resonator drain hole. The earlier cars had the resonator tilted at a pretty extreme angle downward toward the front of the car. The '59 is much closer to being parallel with the ground so I decided to measure it to see where the hole should go.

IMG_0832.jpg

While the car was on level ground, I put a small magnetic level on the resonators to get a sense of which direction they favored. Unlike the earlier cars, these actually tilted down slightly rearward.

IMG_0834.jpg

IMG_0836.jpg

Using a 1/8" drill bit, I drilled into the resonator, at its low point toward the rear of the car, inward enough from the edge to clear the crimp and its inset.

IMG_0840.jpg

The results were immediately clear as water came spitting out at cold idle.

Video here:

https://www.dropbox.com/scl/fi/274g1u6h2eb0as6v7vuy9/1959-ExhaustDrain.mov?rlkey=5sevk5xtgjcgrjjdna6wvi9te&dl=0

IMG_0841.jpg

I repeated the hole for the other side. There was a very, very small difference in sound but you would have to be underneath the car right at the resonators to be able to hear it and even then place a finger over the tiny hole to A/B the sound. It really made no appreciable change and no change at all while driving.

Hopefully this will help to increase the longevity of the resonators!
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Cadillac Jack 82 on October 29, 2023, 03:11:57 PM
I ended up buying the Mastermind kit but lordy....its just precut flex tube.  Also bought the bolts you recommended.  Hope to have it done in early December.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on October 30, 2023, 04:33:23 PM
Quote from: Cadillac Jack 82 on October 29, 2023, 03:11:57 PMI ended up buying the Mastermind kit but lordy....its just precut flex tube.

I was curious and looked up the Mastermind exhaust. Found it here:

https://mastermindinc.net/Exhaust%20System.htm

"57ZB23-004   1957 - 60 EXHAUST MANIFOLD TO MUFFLER GALVANIZED EXHAUST SYSTEM DECORATIVE FLEXIBLE METAL SHROUDING    250.00
    For that factory fresh look! Includes installation instructions, which you will need! 4 Piece Set."

Has yours come in? Is it just the flex tubing or are the hard pipes already wrapped in it? I found the receipt from NAPA - I paid $30 for 6'. Almost 10x less than what they are asking!

Interesting that they describe it as "decorative". Seems like it has more purpose than just looks. The cryptic hint about the instructions too. "Beat the tar out of it with a custom cut 2x4" is my guess.

Also, for correctness, I should add the flex over the passenger side down pipe. The photo that was shared by 59-in-pieces shows it there too. And Mastermind says that for '59 it is a 3 piece set in the description of the stainless version.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Cadillac Jack 82 on October 30, 2023, 04:38:48 PM
Hopefully it works because it looks just like standard flex pipe.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: 59-in-pieces on October 30, 2023, 08:00:23 PM
Once again late to the party.

The first picture showing the wrap seemingly short around the exhaust brace to the bell housing is shrink and wiggle.
Originally, the wrap would have been close up to the brace clamp.

I also posted another area around the pan that had original wrap.

I don't know what the reference was to the 3"?????
But perhaps, they were referring to the asbestoses wrap that crumbles away over time, and is illegal nowadays, see the posted pics below.
So instead of asbestoses, steel wrap could go there?????

Have fun,
Steve B.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: 59-in-pieces on October 30, 2023, 08:08:07 PM
Oh, I forgot to post this exhaust diagram which I used for more detail.

Have fun,
Steve B.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Gabe Davis on October 30, 2023, 08:38:40 PM
Quote from: 59-in-pieces on October 30, 2023, 08:08:07 PMOh, I forgot to post this exhaust diagram which I used for more detail.

This is great! Thank you for sharing the diagram and the additional photos.

Where would that diagram of the exhaust system have been originally published? The master parts list? A service bulletin? It is for sure not in the shop manual.

Very interesting about the wrap around the drivers side down pipe. It looks like there was the asbestos fiber blanket held together with metal bands. Any idea if these are reproduced? I'm not looking for a 100 point show car so I'm not sure I'll pursue that, given the asbestos and all (even with modern equivalents), but it is good to have that information.

Were the Cadillac engineers that concerned about heat? Or sound levels? To help the function of the heat riser? What is the thinking behind adding all of those extra layers?
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: David Greenburg on October 31, 2023, 03:30:39 AM
Wow, Steve. You really do have pictures of everything!
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: 59-in-pieces on October 31, 2023, 08:30:05 PM
David,

Thanks for commenting.

Most of my pictures came out of working on my own cars.
But, that wasn't enough by a long shot.

During my searches for parts over the years it also put me in touch with folks which were parting out cars.
In the beginning, I wanted to get the cars back to original or as close to it with the experience I had and the money I never seemed to have enough of.

Fanatically, I chased the hardware - bolts, washers, lock washers and screws.
And often I had to wait for the weather to change back east so the owners could - maybe not literally dig the cars out of the snow - but close to it.

I hope the pics help, but I can tell you I sure wish I had taken more when I went to put the cars back together.

Have fun,
Steve B.
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Cadillac Jack 82 on November 01, 2023, 11:11:04 AM
Question about the clamps.  In the photos they look like standard clamps however I notice that Caddy Daddy has special 59-60 exhaust clamps.  Does it really matter?
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Clewisiii on November 01, 2023, 11:40:38 AM
Quote from: Cadillac Jack 82 on November 01, 2023, 11:11:04 AMQuestion about the clamps.  In the photos they look like standard clamps however I notice that Caddy Daddy has special 59-60 exhaust clamps.  Does it really matter?

I don't think they would be unique. The 61 uses three of the same hangers as the 59-60. It is just normal clamps but two sizes are used .

IMG_20231101_113821414.jpgIMG_20231101_113844621.jpg
Title: Re: 1959 Coupe DeVille Exhaust System
Post by: Cadillac Jack 82 on November 01, 2023, 12:12:48 PM
Wonderful thank you!