Frame Sag

[vette]

I would say, jack it up, make it straight then box the frame with plate. It's never going to be concours now. OR! buy a new frame from Martin.

If the car has just begun to sag it is possible to extend the life of the car by plating it from the inside. I've seen this done with 3" square tubing inside the frame. By cutting open the top of the frame from inside the cockpit area and folding it open you can insert a box tube inside, then cut circles about 3/4" round on the original frame then weld the old box frame to the new box frame from the outside around the circles. Then seal up the top opening and you are good to go. It is virtually undetectable unless you look under the car and up the side of the frame. Does any of this make sense?

I think we all/mostly agree that the big Healey has a weak frame. Especially after about 50 or 60 years. The car was built light. And we can reenforce the frame but that is not a prefect answer. A new frame is the best answer. But can we or will we all go that far. I would not cut the frame apart to try to hide the repair because ultimately you probably won't be hiding it anyway. So hears my answer in leu of a new frame, Think street rod. On an earlier project I boxed the inside of the frame on a Model A Ford. Those old frames were an open C Channel with the open side towards the middle. You would weld plate to the inside of the c channel to box it closed so that you could weld in new cross members for newer suspensions. The advantage to the Model A frame was that it was open and you could scrap it, clean it, and paint it. One of the bad things about a Healey frame is that it is completely closed in and almost imposible to treat. And guess what? It ain't going to get any stronger. If you want to attempt to repair an existing frame, you can buy replacement main channels. Or they can be made from approprately sized rectangular tubing. Thant's still a chalenge getting them in right and will certainly have an effect as to any originality or concours. Thats why I would give consideration getting them up and straight and precisely cutting and fitting plate to the sides of the main rails and "Welding Plate".

 

[EV2239]

FWIW here's John Chatham explaining how to brace a chassis. You can see the U section he's welded to the underside of the frame.

 

[RAC68]

Hi All,

It has been a common thought that injecting high density catalyzed foam into a chassis has the potential of increasing internal structural corrosion. However, since no one seems to have offered anything more than conjecture, I fail to understand why this feeling should thwart anyone from further evaluating this approach.

I, for one, would prefer not to eliminate the potential to weld onto the frame for, if my frame was foam filled, I would not have been able to repair the tare I addressed this summer. But, after the application of reinforcing gussets originally applied to the Healey rally cars, I do not anticipate any need to weld the frame further. And, would I have sustained the tare if my frame had been foam fill enforced?

In a twin turbo 300Z article describing the application of the same catalyzed foam used in structural members of the present Q45 (https://www.modified.com/projectcars/0006scc_project_nissan_300zx_part_5/), both application and actual result are presented. I am not saying chassis foaming is the answer but that it is an approach that poses a yet-open potential. It seems to me that foaming the Healey chassis has the potential of stiffing and strengthening the Existing frame, IN PLACE, and Could be a viable alternative to applying metal on the outside of the frame or replacing the full chassis.

Ray (64BJ8P1)

 

[Frameman]

I am not a fan of foaming the inside of the chassis for the following reasons: the foam may cause the chassis rail to sweat due to temperature differences, foam may cause the chassis to split at the seam while the foam is curing and expanding which would leave you with a big problem as you could not weld because it would compromise the foam, once the metal has been fatigued it has a new memory and when straightened the metal will return to its fatigued state- the foam may slow this process but will not stop it, the foam does not address the torsional loading of this design, outriggers weld to the chassis and with foam in the chassis you can't do this.
A Healey's chassis design cannot be compared to 300ZX and Q45. They are very different designs.
In Canada, a car having chassis damage then repaired has to be disclosed and the ownership becomes branded warning all potential owners that the chassis is damaged.
Insurance allow body shops to use adhesives to replace quarter panels, I wouldn't do that it either.
Marty

 

[Hoghead]

I am interested in the structural foam idea and look forward to what you find out

Any Mechanical Engineers in our group?

 

[BigGreen]

... If anyone is interested and I go back I'll get pictures.

Please ask if its oké and show us the magic

I have seen a Triumph Spitfire eat its own body after using PU Foam. PU needs moisture (water) to get hard. Also any leaks will give a problem. No go in my opinion.

Hans

 

[bob hughes]

Not Sure if JC advocates this method now, but in 1974 he strapped my old 100/6 down front and back and jacked the centre up to straighten the chassis.

The channel method of beefing up the chassis is much used here with restorers but you need to get the door openings right otherwise you are locking in the problem.

Me - I've modified the top of the rear wing on the passenger side a tad, driver's side to follow. Then I will get the channels fitted to the U/S of the chassis.



Bob

 

[Stretch]

Check the frame rails that go beneath the rear axle. It's possible that jacking up the car from the rear crossmember or more likely, a severe bump that bottomed the axle caused distortion of these rather slender frame members (as happened with my Mk2). The center frame rails and side rails all work together to support door clearances. Some have reinforced the rails that go under the rear axle. I crossed my fingers after re-setting clearances and now have a driver door with too little clearance at top rear.

 

[pkmh]

Now I know it would be a challenge to coat the interior of any rusted frame, and I do mean coating with POR-15, but I have heard from some who were successful in doing so.

So, just as a thought, if it were possible to first apply a rust coat such as POR-15 and then use this PU Foam, would it or could that work in preventing moisture or further corrosion.

I have done some POR15 in specific areas of my rocker panels, but not all the way through (just yet). Just curious to know how the circumvent or make more successful the application of PU Foams.

Any thoughts??

Paul

 

[healeyblue]

Best way is to completely dip the frame to coat inside everything. We has our chasis acid dipped to remove any rust, then we repaired the rust and then dipped again followed by a thorough rinse. The final dip is called E-coating. It is like a powder coating only it is dipped in a liquid solution. ALL new auto manufacturers use this process on their new bodies and it is very good at preventing rust. On our car with much less use than originally intended, it should last another 50 years before it even starts to show any rust.

 

[Randy Forbes]

VERY commendable Jim, bravo! There's a former Redi-Strip place in Toledo (American Parts Cleaning is what I think they're called now) and they do the "alkaline immersion" process, and the metal comes out spotlessly clean.

While they did not offer an E-coat process in house, they claimed there was a place around Detroit that a lot of people took their dipped cars to.

I had wondered how they did it on cars post manufacture, so thanks for clearing that up!

 

[Lotuswins]

This has been an interesting thread, and I've learned much about the frame specifics that I hadn't known up to now. One thought occurred to me though when reading through this information. Wouldn't significant bending rigidity, and for that matter some torsional also, be gained by either welding in a replacement transmission cover/tunnel or replacing the fiberglass unit with a latice unit that could be shimmed to provide the additional compressive strength to allow for the slowly deteriorating frames? The second option would allow shimming to correct the door gaps in-situ.

From looking at the design, it appears the front of the frame is hingeing just aft of the firewall? Would that seem logical since in front of that the firewall is triangulated downward with the struts that double as pedal boxes.

Has anyone tried or heard of such a modification??

Just curious,

 

[57_BN4]

I don't mean disrespect to this guy but this is the sort of frame repair that makes me very nervous about recommending somebody to purchase a 'restored' car. Given the OP stated that the car is previously restored, I wonder how similar the chassis condition is to this one.

This chassis has lost a lot of metal to corrosion and no amount of patching is going to fully restore its strength.

The other issue that hasn't been discussed is that the frame sag isn't the only problem with the chassis. Stress cracking around the engine mounts and front suspension points will exist on all vehicles of this age to greater or lesser degree and this was the final deciding factor in replacing my chassis.

The foam-filling idea has got me thinking too, not so much to increase static stiffness but to raise the natural frequency and possibly add some damping. As I have a spare chassis that will soon be scrapped I'm thinking about doing some before and after comparisons when foam filled.

Andy.

 

[Brinkerhoff]

I agree Andy. The inside of the main frame rails will look exactly like the outside. This car is a problem "down the road" for someone.

 

[vette]

I agree also Andy, That's why I said that if you can't go the full route with a new frame, you might as well start welding in reenforcing plate. You can design it any way you feel appropriate but what else are you going to do? But also, you can replace every piece one section at a time if you wanted to.
I think it is good to have this discussion. I haven't seen a discussion on this subject to this level in a long time. this exemplifies the concept of "buyer beware". Knowledgable owners and buyers will hopefully make the best decissions.
Dave.

 

[rjc157]

wow how much would that metal work cost thats why these restorations cost more than what the cars are worth that is some project

 

[HealeyRick]

RATCO makes replacement frames for Triumphs and offers a foam-filling option:
https://www.sites.google.com/site/tonyratco/frames/Finishes Talks about rust proofing and sound absorption but doesn't mention strengthening.

 

[drambuie]

Well, In response to your original post,You never stated the overall condition of your existing frame in terms of frame "rot" As long as your frame and outriggers are solid, and you have reasonably good sills, Just have the doors and body panels adjusted to your tired frame! All our vintage cars are subject to metal and structural fatigue. My BJ8 has only 42,000 Original miles on it and is extremly solid everywhere! However, My door gaps are all over the place! Most likly due to the shear age of the car and some structural weakness. Before i do a repaint someday, I will simply get the door gaps adjusted close as i can and shoot the new paint. Come to think of it the factory door gaps where nothing to write home about! Personaly, I don't think filling the frame with foam would do much for the resale value! Like i said, as long as you have a reasonably solid Healey i would just adjust the doors and be done with it! Michael, IL.

 

[emgeetf]

Sometimes it is better to start with the small stuff like checking the wear on the door hinges/ support pin to see if they need attention. Healy doors are relatively heavy and the way they are installed there is a lot of wear and tear on the hinges specially on the roll up window cars. yes by all means check the frame and the outriggers but start with the basics like door hinges, and the pins and adjust or replace if worn. why do frame repairs if all that is wrong would be a door hinge wear that needs replacing. Just my 2 cents worth.

 

[Patrick67BJ8]

I don't mean disrespect to this guy but this is the sort of frame repair that makes me very nervous about recommending somebody to purchase a 'restored' car. Given the OP stated that the car is previously restored, I wonder how similar the chassis condition is to this one.

This chassis has lost a lot of metal to corrosion and no amount of patching is going to fully restore its strength.

The other issue that hasn't been discussed is that the frame sag isn't the only problem with the chassis. Stress cracking around the engine mounts and front suspension points will exist on all vehicles of this age to greater or lesser degree and this was the final deciding factor in replacing my chassis.

The foam-filling idea has got me thinking too, not so much to increase static stiffness but to raise the natural frequency and possibly add some damping. As I have a spare chassis that will soon be scrapped I'm thinking about doing some before and after comparisons when foam filled.

Andy.

Anytime you do the amount of welding this type of frame damage needs, you'll probably warp the frame. The warp may not be where you weld, but at the other end of the frame. The Healey frame metal is "thin"! This info is from experts I talked to before deciding to have a new frame made.