72allblackcoupe

I'm looking for a 70-72 cutlass convertible to restore asap. I have a 72 cutlass supreme . I want to switch bodies.

MDchanic

Are you saying that you want to put a convertible body on a coupe frame?

Bad Idea.

- Eric

72allblackcoupe

Yes...why?

MDchanic

Because a convertible frame is reinforced to add rigidity, due to the lack of the roof and the possibility of frame droop, leading to stuck doors.

A coupe frame will fit a convertible, but you may not like the result.

- Eric

72allblackcoupe

I need help quick. I purchased a 71 convertible. I hope it's not an idiot move. I have a 72 cutlass hardtop. I was wondering can I put the body of the 71 cutlass convertible on the frame of the 72 cutlass without major modifications.

72allblackcoupe

I was wondering can a 71 cutlass convertible body be put on a 72 cutlass supreme frame?

Jonb442

It probably can be but shouldn't be. Convertible frames have boxed rails to strengthen them, and putting a convertible body on an unboxed coupe frame would result in some significant flexing.

MDchanic

There is a chance that creating two new threads for essentially the same question will achieve the goal of producing the answer you want, but it's not a very good chance.

It will fit, but it will be softer than you would like.

GM didn't spend the extra dough to reinforce the frame for no reason.

- Eric

4speed455

The convertible frame is boxed for extra support. You can remove the box sections from the convertible frame and weld them to the hardtop frame. Everything else should be the same.

MDchanic

Those answering, please note threads here and here for others' answers to the same question.

- Eric

4speed455

If your planning on swapping other parts, rear seat, rear door panels and trunk lid are convertible specific. Fenders, doors,and bumpers are the same. The rest of the interior, grills, taillights and trim will fit but might be slightly different depending on year and model.

MDchanic

Those answering, please note threads here and here for others' answers to the same question.

- Eric

72allblackcoupe

Thanks guys.....Eric what's your point?

72allblackcoupe

Only bad idea is the impossible!

72allblackcoupe

Thanks 4speed

joe_padavano

As noted in the threads that Eric linked to above, the convertible doors won't open on the hardtop frame - at least not after the car sags due to an insufficiently stiff frame.

Common sense should tell you that the factory wouldn't use different frames unless there was a reason.

I also merged your identical threads.

72allblackcoupe

I see in answering questions we have an ignorant, arrogant, and child like response. If you had an issue with my question, maybe you shouldn't have responded. I didn't know the site was established by either of you. Nor did I know you were the Oldsmobile police. To characterize a person who knows nothing to very little about cars to," lack common sense, "is colossal Stupidly!

MDchanic

You asked your question in one thread, and it was answered, and the answer was explained.

Then you created two more threads, with slightly different titles, and asked the exact same question again two more times, got the same answer again, and then got mad about it.

I'm sorry if you bought a car with parts that won't work for what you need, but the more you re-ask the same thing, the more hostility you will generate from the people who actually answer questions.

Coupe frame for convertible is a bad idea. Period. Don't shoot the messenger.

- Eric

72allblackcoupe

First off...I got conflicting answers if you can read. Secondly I only post 2 threads. If this is against protocol, surely you should correct before you make yourself look foolish. I'm not mad....that's for kids....also it's possible. ...thanks for nothing.

MDchanic

Well, one of us can read:

What's conflicting in the above?

- Eric

72allblackcoupe

Can you remove the box sections from the convertible frame and weld them to the hardtop frame?

That's what 4speed said and my mechanic agreed!!!!

4speed455

Have it welded professionally. Check the hardtop frame to see if it's straight before you start. Measure carefully. Bolt the convertible crossmember in before you weld it. Don't weld in one place for too long or you can warp the metal. Weld it in small sections apart from each other until the welds meet. It can be done but it's not going to be easy.

MDchanic

Sure you can. With the proper equipment, which most people do not have.

But once you have welded the reinforcing sections onto a coupe frame, it's not a coupe frame anymore, is it? It's a convertible frame.

The responses were completely in agreement - using a coupe frame on a convertible is a bad idea.

There is nothing wrong with creating a convertible frame, but it's likely easier to just start with a convertible frame in the first place, as 4-speed notes above.

- Eric

72allblackcoupe

Your problem is....not knowing how to mind your business. It's not for you to worry about what people have are don't have.....since you're not spending the money. Also, I can do whatever I wish to do... I'm experimenting , maximizing my dollars...it's a bad idea for you....if I interfere with the integrity of the coupe or convertible.....it's my prerogative .

You seem very unhappy....

jharsh

This thread is totally crazy. Do not get me wrong but it appears you have decided on what you want to do, so why keep asking. I have not been on this site very long, but I can tell you there are a lot of great people with a lot of knowledge on this site. Maybe it is the way you are asking the question. In the end if money is no object, I say go for it, what could go wrong?

72allblackcoupe

What's totally crazy is your comment Jonny, come lately. I didn't keep asking anything. And my original question was can it be done. ...not if it's a bad idea....whatever I've decided on....I have the right to ask any question concerning that.

This site is not exclusively yours.......you're right... many good people are and well experienced . Many continue to assist me.

MDchanic

Really? Sounds like what the guy says who's smacking his wife in public.


I don't care what you do. You asked a question and four people answered it. Each said the same thing, though each described a slightly different part of the "elephant," as is common in these cases.
People here are trying to give you advice on the best way to do something. Take it or leave it.


Thank you Dr. Freud. What was that about minding your own business?

- Eric

redoldsman

Eric is one of the most knowledgeable people on this site. I just looked and he has 17,894 posts. If you don't want to listen to sound advice, why the hell did you ask the question. Go ahead and put your convertible body on your coupe frame. Spend your time and money. And then when you can't open the doors after the frame buckles maybe you will realize the advice you got on here was sound. You have had advice from two of the best folks on this site. You should listen to them and get the damn chip off your shoulder. Everybody on here gets along and that is what makes this the best website on the internet for Oldsmobile owners.

72allblackcoupe

I don't care what he knows or you. I don't have to agree. And Eric you may need a good smacking yourself. If you have a problem with most post.....well to bad. I got my answer. Anything can be done to a car. Man went to the moon....and you dispute what can or can't be done to a car.....

Do me a favor. .never responded. ..

Fun71

Well, I think you got the answer to this question.

MDchanic

Oh, a tough guy. I may, may I? And who's gonna do that for me? I'm shaking.

Here's a concept for you: "Knowing when to quit."

- Eric

redoldsman

Other Eric needs to close this thread. It is serving no purpose. What a waste.

Jamesbo

If I were you, I'd quit posting and start welding [or not]

May I be so bold as to ask.Why not look for a convertible frame?

jharsh

I agree, redoldsman this post should just be closed or at least retitled to "If I wanted your opinion I would ask for it.
Oh, I forgot I did."

joe_padavano

In the interest of bringing this back to being an informative thread, let me try this:

The hardtop and convertible frames for the 1968-72 cars are the same EXCEPT for the additional reinforcement sections welded to the convert frames. The outer rails under the rockers are the same on HT and convert frames, and adding the reinforcement sections turns a HT frame into a convert frame. Assuming these parts of the old convert frame are not rusted, they can be cut out and welded to a good HT frame. Obviously alignment and proper weld technique are very important. The best way to cut the reinforcements out of the old frame is to cut into the part of the frame that's common with the HT frame, then carefully grind that away, leaving only the reinforcement.

Since the OP says he has both a convert and HT, simply crawling under both cars and comparing the frames will make the difference obvious.

Bfg

I was thinking of putting my hard top body on my extra convertible frame I have laying around.

joe_padavano

That was the HD frame option on the 1964-67 cars.

MDchanic

And never a bad idea, as the original frame is so soft.

I had been following a guy a couple of years ago, who was building a modern aluminum frame for one of those "C-word" cars, and was considering a production run, but I can't find the link now - that would be ideal and would likely provide far better handling, with improved smoothness and comfort as well.

I guess all you need to do to any problem is add money...

- Eric

joe_padavano

Aluminum has 1/3 the stiffness of steel for the same cross section. How is this an advantage? The side rails would need to be taller and have thicker cap sections to even have the same stiffness as stock.

People don't realize that the specific stiffness (ie, modulus to density) of aluminum and steel are virtually the same. For a part that is a stiffness design, there's no benefit to going aluminum, unless the steel design hits a minimum gauge limit were considerations other than stiffness drive the thickness and weight.

A classic example of this is the original Atlas ICBM. All other launch vehicles are aluminum or now composite. The Atlas was a very thin stainless steel design. The material was so thin that they built the tanks with simple overlap weld joints.

MDchanic

Interesting. As I recall, the frame they were making up did seem to have a larger section size in most, if not all, places, and was far more robust-looking in places where the current frame is not, such as the transverse elements.

Wish I could find that darned thread...

- Eric