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Struts under the hood of the 1965-66 Cadillacs

Started by J. Douglas Bailey, July 18, 2019, 12:17:02 PM

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J. Douglas Bailey

My Eldorado convertible does NOT have the two struts that run from the tops of the wheel wells to a center point on the firewall. Neither does ANY OTHER convertible of this era I have ever seen. There are plugs in the holes where those struts would have bolted on. I used to own a Preservation award winner (a '66 SDV) that DID have those struts.

In Louisville this year I was on pace to lose points for not having those struts until I protested (mildly because the point was not going to make that much difference - however, when I'm right I can dig in my heels). I was told by the judging team's leader that the burden of proof was on me. I had to show them a photo from the Authenticity Manual. Nope, it's not covered in the AM. We checked the body and main Shop Manuals. Couldn't find anything there either. I carry a salesman's Data Book with me, but believe it or not there was no photo showing the engine bay in there.

The judges' team leader at one point explained that because her '67 convertible has the struts it seemed reasonable to their team that my '66 should have them too. As if someone in its history had TAKEN THEM OFF... Lars Knellar was in the vicinity, and as one of the primary authors of the Authenticity Manual, was asked about the struts. He indicated that they probably didn't belong in a '66 convertible, but acknowledged that it's not covered in the Manual. A fellow two spots down the row with an all original '66 Eldorado showed us his engine bay - minus the struts - and tried to help. Not good enough... The '66 coupe next to mine had the struts, of course.

Eventually Chief Judge Bill Anderson intervened and applied what I believe is the "go-to" rule: In the case where there's no evidence that an item is an authenticity deduction the judges are to accept the explanation of the owner. Bill asked the judges to award the point.

Here's my question: Do any of you stacked headlamp guys know where the evidence is buried in Cadillac documentation about whether there are supposed to be struts under the hood of the '65-'66 convertibles? And here's a follow-up: Why would Cadillac NOT use struts in a more flexible convertible and USE them in a hardtop sedan or coupe? 
Director, Peach State region
1958 extended deck sedan touring badge; 1st Touring '07
1966 Eldorado Senior Touring badge; 2nd Primary '19
1996 Fleetwood Brougham, 2nd Primary '12
2013 XTS

"Cadillac Kid" Greg Surfas 15364

Coupes (and sedans) had them, Convertibles did not. Counter intuitive but so.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

cadillacmike68

And it does not appear to be documented anywhere. I added them to my 1968 for stability.

And this is why I have skipped the last several GNs...
Regards,
"Cadillac" Mike

wrefakis

no struts due to frame being stronger on convert ,100 % no struts ever why did they think they had plugs in fender wells?
only way convert had struts is if car cam with level ride then one strut to hold tank
tes I have had them both ways still do

MikeLawson

I asked the same question about the missing strut rods on an all original 1967 Deville convertible I bought a few months back. Here is a response I got that helped to answer the mystery:

Ralph Messina CLC 4937
Posts: 1275

Re: New Member 1967 DeVille Convertible
« Reply #10 on: March 08, 2019, 11:38:11 PM »
Quote
Gentlemen,

The following is from the Master Parts List. The right and left  ¾-1”strut bars (Rod-Wheelhouse; Groups 8.155 $ 8.141; Part number and specs differ by year) is used as follows:

Group 8.155
65 Exc. Convertible & 75
66 Exc. Conv.
67 Exc. Conv & Eldo
68, 69 & 70 Exc. Conv & Eldo
71-76 Exc. Eldo

Group 8.141- Different rods and mounting location
67 & 70 Eldo
71-76 Eldo use four support rods.













J. Douglas Bailey

Thanks MikeLawson! Well, there you have it, and from the horse's mouth, I would say. Ralph KNOWS these cars inside and out, and apparently the doc as well. I'm going to suggest to Lars and Jeff, who were the primary authors of the Authenticity Manual (and who own stacked headlamp cars), that they add that information to the AM. My line of relief is highlighted below:
Group 8.155
65 Exc. Convertible & 75

66 Exc. Conv.              THAT IS, FOR '66 the Deville and Eldo convertibles were EXCLUDED from using the struts. Probably as wrefakis says, because of the stronger frames.

67 Exc. Conv & Eldo              NOW, this makes me wonder about that judge's '67 convertible that HAS struts. Apparently someone made her car non-authentic by adding them! ;-) 

68, 69 & 70 Exc. Conv & Eldo
71-76 Exc. Eldo

CadillacMike, I understand about skipping the judging. I actually entered my car for display only, and found out there that it was in for Primary! I decided to go forward and see if they saw anything I didn't know about. That's when the struts thing came up. I didn't bother to hide my Pertronix ignition or coil, and I had an aftermarket battery in there. In fact, all my authenticity deductions but one were for concessions I had made for driving. I drove from Atlanta to Louisville this year, and to San Marcos last year. Take those points for radials and headlamps! I was amazed to receive a second place in class in Louisville, so something was decent about the car!

Thanks guys for the help!
Director, Peach State region
1958 extended deck sedan touring badge; 1st Touring '07
1966 Eldorado Senior Touring badge; 2nd Primary '19
1996 Fleetwood Brougham, 2nd Primary '12
2013 XTS

klinebau

I am curious to know how the frames or body are stronger.  I own a 70 convertible, but have never tried to compare the differences.  Unfortunately, I don't have a non convertible to compare.  Would be interested if anyone knows.
1970 Cadillac Deville Convertible
Detroit, MI

Ralph Messina CLC 4937

#7
Gentlemen,

Let me add the following observations to the conversation. I’ve worked on  Broughams, Eldorados and a Coupe de Ville. I’ve seen no discernable difference in the chassis of the three models and I’ve not found any published data pointing to a difference in them, other than the longer wheelbase for the Brougham. The same statement can be made for the coupe and convertibles. The differences of note in the body structures related to the convertible top mechanism, not any structural buttressing. I believe the idea of  “extra strength added to the chassis” might relate to ’57-’64 cars with the “X” frame.

Yes, it is counter-intuitive that closed cars would have the brace, but convertibles do not. I have a feeling this relates to masking the flex in the convertible body. Engineers / designers want to minimize noise, harshness and vibration in the passenger compartment. Adding the braces to a convertible would amplify NHV from the front end by transmitting it directly to the cowl, without the reinforcement benefits of the structural roof.

I'd be interested in hearing from anyone who installed braces in a convertible whether they had any effect.

Mike Lawson: Thanks for relaying my post. I totally forgot about it…..

Ralph
1966 Fleetwood Brougham-with a new caretaker http://bit.ly/1GCn8I4
1966 Eldorado-with a new caretaker  http://bit.ly/1OrxLoY
2018 GMC Yukon

savemy67

Hello all,

My '67 shop manual indicates sedan, coupe, and convertible frames are the same.  However, convertibles use one additional body mount at each side.  I suspect that this is true for '66 cars as I believe the frames are the same since '65.  This provision goes back to the X-frame chassis. 

My Fisher Body manual shows an "A" body with a large buttress at the forward portion of the rear quarter - near where the convertible top cylinder is installed.  The buttress spans the space between the floor and the forward portion of the rear quarter.  I believe the buttress was in place for larger car series ("A", "B", and "C" bodies), but not smaller cars ("F" bodies).  The manual shows an "F" body car without a buttress.  This makes sense as the longer the assembly, the more subject it is to torsion.  Removing a roof drastically reduces the stiffness of the body.  To compensate, GM applied the buttress to the longer bodied convertible models.

My shop manual references removal of the cowl to wheel housing strut rods in the chassis sheet metal section.  There is no call out for convertibles lacking the struts, probably because it was obvious to the mechanic that if the struts were not present they need not be removed.

Do the struts do anything?  Perhaps so.  In Hendry's book there is a picture of a '66 Cadillac sitting atop a massive test fixture utilizing four large hydraulic pistons that simulate bad road conditions, and which could easily reproduce conditions that would flex a fully assembled body.  I speculate that this testing demonstrated a need for the struts in the closed body cars, but not the convertibles.

The shop and body manuals combined with the Master Parts manual should be sufficiently definitive for any authenticity questions.

Respectfully submitted,

Christopher Winter
Christopher Winter
1967 Sedan DeVille hardtop

"Cadillac Kid" Greg Surfas 15364

Chris,
It is the wheel housing to radiator support struts that are in question.
Greg Surfas
Cadillac Kid-Greg Surfas
Director Modified Chapter CLC
CLC #15364
66 Coupe deVille (now gone to the UK)
72 Eldo Cpe  (now cruising the sands in Quatar)
73 Coupe deVille
75 Coupe deElegance
76 Coupe deVille
79 Coupe de ville with "Paris" (pick up) option and 472 motor
514 inch motor now in '73-

STS05lg

Doug, don't feel bad, at one recent GN I had a judge ask me when I had the custom interior put on my Talisman. He added that even though it's looks nice it will cost me a lot of points. After I picked my self up off the asphalt, I explained to him the interior was original to the car. He then asked if I had proof. Lucky for me I had a 1976 Full line catalog and thank goodness Cadillac had a picture of the Talisman front 40/40 front seat in the catalogue. Did not need to call Bill over. The catalog convinced the judge not to deduct point... Honest this really happened. Sorry you had to go all the way up the chain of command to not lose points.  :D

cadillacmike68

Quote from: Ralph Messina CLC 4937 on July 18, 2019, 05:17:36 PM
Gentlemen,

Let me add the following observations to the conversation. I’ve worked on  Broughams, Eldorados and a Coupe de Ville. I’ve seen no discernable difference in the chassis of the three models and I’ve not found any published data pointing to a difference in them, other than the longer wheelbase for the Brougham. The same statement can be made for the coupe and convertibles. The differences of note in the body structures related to the convertible top mechanism, not any structural buttressing. I believe the idea of  “extra strength added to the chassis” might relate to ’57-’64 cars with the “X” frame.

Yes, it is counter-intuitive that closed cars would have the brace, but convertibles do not. I have a feeling this relates to masking the flex in the convertible body. Engineers / designers want to minimize noise, harshness and vibration in the passenger compartment. Adding the braces to a convertible would amplify NHV from the front end by transmitting it directly to the cowl, without the reinforcement benefits of the structural roof.

I'd be interested in hearing from anyone who installed braces in a convertible whether they had any effect.

Mike Lawson: Thanks for relaying my post. I totally forgot about it…..

Ralph

This might have been the primary reason. If ALC was optioned, then one brace would have been necessary though.
Regards,
"Cadillac" Mike

Gary McKinney

Mike, the ALC compressor was mounted down low in front of the engine in '66, not on the strut as in later years - thus, no struts at all on any of the convertibles.
Gary McKinney

1950 Cadillac Series 62 Coupe
1966 Cadillac Eldorado

J. Douglas Bailey

Great conversation guys! I learned a ton there. Would love to hear more from a Cadillac engineer about the reasoning behind the strut decisions and extra body mounts.

I laughed at your judging experience with the Talisman, STS. I could tell a few stories like that one. Here's one, shortened: New judge in St. Augustine asked what that ugly after-market switch was hanging below the dash of my '66 SDV. Wanted that point extra badly. ;-) I showed him the Options brochure with the headrests, over-the-hump trash receptacle, and the FIRST-YEAR lighted four-way hazard switch. He was so excited to get that information that he promptly went to the car beside mine, a perfect '66 Fleetwood, and tried to ding him for NOT having the OPTIONAL hazard switch. Chief Judge Carl Steig eventually sent me an apology, advising he had vacated all that judge's scoring sheets... Ego will get you every time.

Thanks for all the great information guys. By the way, I heard back from Jeff Shively and Lars Knellar. They indicated they will make sure this adjustment for struts gets reflected in future Authenticity Manuals for the '65-'66s.
Director, Peach State region
1958 extended deck sedan touring badge; 1st Touring '07
1966 Eldorado Senior Touring badge; 2nd Primary '19
1996 Fleetwood Brougham, 2nd Primary '12
2013 XTS