A "different" sort of chassis sag problem

[wvukidsdoc]

I've had a look through the forum a few times and am need of suggestion despite my search. I have a rather different sort of problem with the frame on my 4A.

 

History: I purchased the car on a whim last year as I'm in AK, always wanted a TR3 in the day, and the price was right and ....

 

So the car is a true CA one owner (well until 3 years before me when a local Triumph nut bought it to make a racer out of then couldn't do it because it is so original) car, brought to AK about 10 years ago, but mostly from sunny southern CA. Never used more than as a summer driver here, and garaged its whole life. I've been a car guy all my life, knew well enough how to look for rust, and this car has not a spot on it, nothing on the body or frame, nothing. One cheap MAACO repaint 20 years old but it hides nothing.

 

Now knowing nothing about 4A's at the time, and taking the immediate previous owners word for it, what I did not realize was the significance of the slightly expanding door gaps. He suggested perhaps merely some shimming was in order, which seemed reasonable at the time to me. Of course as I bought the restoration books and started getting into the car I became more and more nervous about the condition of my IRS frame.

 

Over the past week though, I've had an extremely careful look, and the thing is, nothing new has come to my attention, the frame is truely solid, rust and accident free, probably looks the same as it did in '66 give or take, exactly what one would expect for a true CA frame. It actually has some of the front pivot gusset stiffeners installed, probably long, long ago. The rear is immaculate, the bridge holding the springs and diff pins, the rear diff bridge, the pins themselves, the frame box sections coming together, the T-shirt plate, all unrusted virgin steel. However this car has an honest 255k miles on it, all meticulously documented. As the rear of the frame rails are slightly visible under the rear valance (down 5mm perhaps), I assume though without rust the frame has simply succumbed to a slow creep of plastic deformation (I used to be a mech engineer) over the years and the end result is somewhat the same as if it had simply rusted.

 

So my quandry is what to do with it. I have no structural concerns whatsoever. I'm going to install the rest of the front gusset stiffeners and have a careful look around up there, hopefully without separating the chassis and frame while I have the drivetrain out. The big question is can I just shim the body to account for and correct my door gaps as long as I don't run into issues with the bumper supports in the rear, or perhaps even with a little clearancing on them if I do? I mean even if I pulled the chassis off I can't really see cutting apart a perfectly solid rust free frame to restore it back to an undrooped condtion. The work I do not fear, I MIG, I TIG, I sandblast, I just can't bring myself to do it. This is a driver, will never be concours, nor competition, just reliable and fun.

 

Thoughts, opinions, or a point in the right direction appreciated.

 

Thanks

John

[littlejim]

Think it will come down to personal choice.

My 4a had rust in the dreaded part of the chassis under and round the 'T' shirt. I learnt how to MIG weld, repairing the rusted bits. Early on I found the chassis was distorting as I welded, despite following all the recommendations on the order to do the welds. I bolted the chassis to the cement floor to do the rest. Thought you can't distort now, you beggar. When I got the tub on, now the other way up, it looked like Mr Williams description of 'hogging', a bit of chassis showing under the rear valance. My reaction was b*ggered if I'm going to redo all that again, I'm going to live with it. The bottom of the rear valance varies just as much as the chassis anyway.

Haven't got to the doors yet, but if they are out I'm going to heed Stuart's advice on making them look nice with 'leading' on the door edges.

 

Hopefully the real experts will tell you if I'm a wanker barking up the wrong tree, and whether you should actually redo the whole lot.

[BrianC]

If the doors open and close OK in normal use, then I'd leave well alone. They may well be a problem if you have one end of the car jacked-up, but this is 'normal' for a TR (and most convertibles).

 

It may well be worth adding or removing packing pieces if the doors are difficult to open and close, but try adjusting the locks, striker plates and anti-burst restraints first.

 

Be warned that once you start cutting and welding, or removing the body, you will almost certainly be into a long, tedious and soul-destroying rebuild, especially since your car sounds like an ideal everyday car. Just drive it and enjoy it.

[TR 2100]

I did not realize was the significance of the slightly expanding door gaps.

 

Hi John,

 

It doersn't sound like you have too much to worry about.

After 255K miles, it would be surprising if the body mounting rubbers had not

perished and settled a bit, but you don't say whether it's sagging in the middle

(i.e. door gaps greater at the bottom) or the other way around.

 

There's nothing wrong with jacking the body up from the chassis and putting in

a couple of extra rubber pads.

 

And don't worry when the door gaps change, and maybe the doors won't shut

properly when you jack up the chassis in the middle. Perfectly normal.

 

AlanR

[wvukidsdoc]

Thanks to all the suggestions so far. The gap issue is the "typical" one shown in Williams book, the gap on the tops are probably 10-11 mm on both sides, at the bottom 4-5mm on both sides. The doors do not close particularly well because of it, though they haven't popped open on me yet... Oddly, or perhaps as I surmise because of creep on a non-rusted chassis, jacking does not change anything. As an experiment I have had the rear frame up on jack stands at the extreme rear just at the bumper (fender to you guys eh?) supports with the front on the wheels for the last week. The gaps have not changed or improved/closed as one might expect they would if there were much flex in the frame. It is solid just solidly changed, vs the packings (which are all terrible) are the issue. I guess I will reshim to improve slightly and leave it at that. The whole thing is being incited by my changing the steel brake lines as I fear a single circuit on 40 year old steel (let alone original rubber) lines as I prepare for summer use.

 

Any other thoughts still appreciated but I guess I shall leave well enough alone.

 

John

[stuart]

I have lost count of the number of times I have had to add a few mm of lead to the top section of the leading edge of rear wings to cure this so called "Problem." A very high percentage of cars from the factory suffered this problem so unless you fancy the fun of re-shimming the whole shell or the expense of having the leading edges redone then I believe the expression is "Live with it!"

Stuart.

[ChrisR-4A]

Hi John, there is one other thing you could look at once the chassis shimming has been fixed, that is adding shims to the door hinges.

Assuming that the worst gaps are only at the rear of the door then it is possible to add shims to the hinges and therefore move the door back 3 or 4 mm.

It's a case of trial and error, but by varying the shims top and bottom it is possible to make considerable improvements.

 

I often wonder if most of the cars I see with the "perfect" (2mm) gaps all round have all been fiddled by lead loading, looks ok at a car show but how durable is it for a 5000 miles a year club car?

 

Chris

[TR 2100]

The gap on the tops are probably 10-11 mm on both sides, at the bottom 4-5mm on both sides.

 

A little surprising the gaps are higher at the top - not the usual, I think.

Also surprising that the door gaps don't change when you jack up the

car in the middle of the chassis. You really do have a one-off!

 

No matter - it's just a question of adding some shims front and rear.

You may even find that the shims on the front suspension member

(where the original thinbkness was greatest) have been left off at

some time.

Geometry will tell you how much to add by way of shims.

 

AlanR

[i8pig]

A little surprising the gaps are higher at the top - not the usual, I think.

Also surprising that the door gaps don't change when you jack up the

car in the middle of the chassis. You really do have a one-off!

 

AlanR

 

John,

I'm afraid it's a "two off", before you put the car on e-bay as being unique and therefore as priceless as an ex Tony Pond TR8, my TR4 is the same. I simply got fed up with fiddling about with spacers and stuff so got the gaps as best as I could, which was nice and consistant at the leading edge and bigger at the top at the trailing. I felt it was important to be consistant left side to right and that is what I achieved. I just live with it and my gaps are bigger than yours at the top. It does offend me from time to time and I am resolved to fix it someday, it's just so cold in my garage then I use the car through the warmer bit of the year then it's just so cold all over again, and I don't live in Alaska!! My car is red, was green and I intend to return it to green one day, that's when I'll take the body off and make sure the chassis is right. I'll do the gaps then, I,ll be retired and have the time.

Have fun but remember life is just too short for TR4 door gaps.

Steve

[mandarawessels]

Hi John, there is one other thing you could look at once the chassis shimming has been fixed, that is adding shims to the door hinges.

Assuming that the worst gaps are only at the rear of the door then it is possible to add shims to the hinges and therefore move the door back 3 or 4 mm.

It's a case of trial and error, but by varying the shims top and bottom it is possible to make considerable improvements.

 

I often wonder if most of the cars I see with the "perfect" (2mm) gaps all round have all been fiddled by lead loading, looks ok at a car show but how durable is it for a 5000 miles a year club car?

 

Chris

 

Chris,

 

I think you'll find that there is a 'minimum' gap for the door - front wing gap.

anything less then 7 to 8 mm and you won't be able to open the door without damaging the wing!!

John.

Edited March 10, 2009 by mandarawessels

[Dave Seer]

Hi John,

 

As most other members have said, tapering panel gaps are nothing unusual or troublesome on a TR, however you can get an idea of how well shimmed your body is by looking at the shims at the B Posts and the rear. As a rule of thumb, the floors should have sufficient shims to just be clear of the chassis frame. Obviously if the middle of the car is over shimmed, you'll have more clearance than you need, your handbrake cables may not fit well, and the door gaps will be difficult to adjust. Another rule of tumb (and as a guide to initial set up of the body) is that when the rear of the car is somewhere near correct the botto of the spare wheel well will be roughly parallel with the tops of the rear chassis legs.

 

When I fitted the body of my car to the chassis, I put in only as much packing amidships as I needed - and as little as I cold get away with, and simply packed the front and rear as needed, whilst trying to maintain the parallel between the spare wheel well and the rear chassis legs. A lot of the remaining adjustment can be done in the engine bay.

 

Cheers

 

Dave