Rust inside the steel frame
Discussion
Okay, opened the bottom, and had a first look inside the pipes with a probe.
Situation is as follows (so far):
As supposed, it looks like the bottom 4 pipes only are affected
(red cross in the screen).
Their inside is connected.
So what ever came in, could spread from one to another, but not any further.
Tomorrow I will bring a piece of the corroded steel to a laboratory.
I am confident the analysis will tell what's responsible for the corrosion.
Situation is as follows (so far):
As supposed, it looks like the bottom 4 pipes only are affected
(red cross in the screen).
Their inside is connected.
So what ever came in, could spread from one to another, but not any further.
Tomorrow I will bring a piece of the corroded steel to a laboratory.
I am confident the analysis will tell what's responsible for the corrosion.
When you get the rear section replaced, get the fabricatior to put in "crush-tubes" (solid tubes welded in to the box section for the bolts to go through) in where the gearbox mount is.
this will seal off that area and stop the box section from crushing (like it has in your picture).
the deformation of the metal around those bolts would be enough so that water could be let in, but not let back out.
this would be my number one cause for the rot before anything else was considered. Other factors previously discussed in this thread should not be ruled out, but that is your main problem.
this would be.my number one
this will seal off that area and stop the box section from crushing (like it has in your picture).
the deformation of the metal around those bolts would be enough so that water could be let in, but not let back out.
this would be my number one cause for the rot before anything else was considered. Other factors previously discussed in this thread should not be ruled out, but that is your main problem.
this would be.my number one
I have not seen that type of 'box mount before so suspect it was fabricated by the builder. If you look at the centre of that rear tube you can see the Factory gearbox mounting hole complete with its welded in crush tube.
Agreed that looks to be a strong favorite for the ingress of water most likely from above where water can sit on top of the tube until it seeps under the mount bracket. Once inside, the crush of the tube will prevent its escape.
Steve
Agreed that looks to be a strong favorite for the ingress of water most likely from above where water can sit on top of the tube until it seeps under the mount bracket. Once inside, the crush of the tube will prevent its escape.
Steve
Steve_D said:
I have not seen that type of 'box mount before so suspect it was fabricated by the builder. If you look at the centre of that rear tube you can see the Factory gearbox mounting hole complete with its welded in crush tube.
Agreed that looks to be a strong favorite for the ingress of water most likely from above where water can sit on top of the tube until it seeps under the mount bracket. Once inside, the crush of the tube will prevent its escape.
Steve
Strange, I don't think ours has a crush tube for the gearbox mount.Agreed that looks to be a strong favorite for the ingress of water most likely from above where water can sit on top of the tube until it seeps under the mount bracket. Once inside, the crush of the tube will prevent its escape.
Steve
honestly ultimas are not made to be driven in daily wheather conditions, the frame will not last too long (in its original shine and develop surface rust), since it is not protected enough (from stone hits and water spray) and the quality of steel is not up to it (with lost powder coat) my opinion. my car shown no sign whatsoever since dry is all he has seen in his life.
if you driving regularly in the rain i would expect corrosion sooner or later. Steves GTR was showing a good amount of it when i saw it at stoneleigh and he had made 15k miles at this time.
if you driving regularly in the rain i would expect corrosion sooner or later. Steves GTR was showing a good amount of it when i saw it at stoneleigh and he had made 15k miles at this time.
Edited by spatz on Wednesday 21st November 13:33
ok i stand corrected, maybe steve can add a comment, however certified quality gives no information at all about the steel quality, even the most simple steel could be certified. Driving the car in winter on salted roads will do not much good and i assume there is not much salt used in england.
Just to chime in... I have a small amount of surface rust on the chassis tubes around the rear suspension. I stress that this is light surface rust and would be easy to sort - this on a 21,000 mile, 11 year old chassis. I have used in very wet conditions and once on salted roads when taking the car to the Autosport show a few years back (although the salt did more damage to my ally rocker covers 
).
I had to store the car outside for a number of months and that did cause rust to develop inside the cockpit, where my flat floor pan meets the sides. That was, I assume, my fault and have since drilled some drainage holes into the bottom of the sidepods close to the chassis rails!
So, when you build, think about where water can sit. Overall though how good can an old car look, the Ult a lot better than most IMO!
).I had to store the car outside for a number of months and that did cause rust to develop inside the cockpit, where my flat floor pan meets the sides. That was, I assume, my fault and have since drilled some drainage holes into the bottom of the sidepods close to the chassis rails!
So, when you build, think about where water can sit. Overall though how good can an old car look, the Ult a lot better than most IMO!
spatz said:
ok i stand corrected, maybe steve can add a comment, however certified quality gives no information at all about the steel quality, even the most simple steel could be certified. Driving the car in winter on salted roads will do not much good and i assume there is not much salt used in england.
Not sure what you want me to comment on, however,I'm guessing the steel Ultima use will be Mild steel ERW tube. This will be the same tube we use in the manufacture of our kitcar and likely the same used by all kitcar manufacturers. It is definitely the tube used by TVR and by us for the repair of rusted TVR chassis. There may well be British Standards covering the product but I have never seen it specified nor have I seen different grades on offer so have to assume it is all to the same standard.
All these steels will rust and no matter how well the powder coating (or any other painted coating for that matter) is applied it will fail eventually allowing the surface to rust.
This particular issue appears to be rust from the inside. There will be no rust protection on the inside and there would be little need for it as the tubes are welded closed until a builder starts to drill holes in them. The Factory say they have never seen this before which I can well believe as there is no reason for it to happen.
As an aside, and this may be of interest to the Factory, we are just about to have a repaired TVR chassis finished with a new process. I say new simply because we have not done it before. The chassis will be grit blasted then hot metal sprayed with zinc before powder coating. This should not only improve the resistance to rust it also helps key the powder coating as the Zinc process is slightly porous.
Steve
Storer said:
Steve
When they spray the galvanising is it electrically charged as well as hot metal (I asume the chassis is baked prior to spraying) applied?
Paul
My understanding is that the process is a gas burner with the zinc wire fed into it so the zinc is melted and blasted onto the steel. I suspect compressed air may be part of the process. If an electrical charge was used then you would need an earth which I'm not seeing in this video link.When they spray the galvanising is it electrically charged as well as hot metal (I asume the chassis is baked prior to spraying) applied?
Paul
http://www.youtube.com/watch?v=e_QrrVWet4M&fea...
Steve
The top-end weld through primers (frequently zinc based too) are very good in repair or general tube fabrication.. But internally treating each member in a whole chassis would be quite time consuming and very costly. Worth considering for the chassis modders or during the OP's repair.
If the chassis is properly internally vented, then internal protection can be done at time of manufacture.
If the tubes have a vent hole at each joint, it is possible to spray a cavity wax in to one area of the chassis and "push" it along with some compressed air. although this coverage will not be comprehensive, it will be better than none.
maybe the factory could comment on whether or not the chassis are vented in this way to make this possible.
If the tubes have a vent hole at each joint, it is possible to spray a cavity wax in to one area of the chassis and "push" it along with some compressed air. although this coverage will not be comprehensive, it will be better than none.
maybe the factory could comment on whether or not the chassis are vented in this way to make this possible.
Ultima factory said:
We feel it is worth pointing out these facts regarding this thread:
1. It appears to be 99% certain that the corrosion occurred in this instance due to a non factory transaxle mounting method being used. Furthermore it crushed the chassis member due to poor design as shown in the pics.
2. A typical year 1998 GRP bodied Ultima holds up far better in terms of rusting than a typical year 1998 production car such as a BMW 740 or Ford Scorpio both of which we have as tow cars. Both of these tow cars have a large amount of unsightly body rust and also required their cills welding to pass an MOT several years ago. We have recently inspected a 1998 Ultima Sports that has covered 100,000 miles as a daily driver which doesn't require any chassis tubes replacing.
3. We use a thorough powder coating process- preparation is the key.
Does anybody actually own an Ultima that would fail an MOT Test due to corrosion?
Regards to all
your getting overly protective here... quite clearly the OP had an issue that would cause an MOT fail, but its also very clear this is an isolated issue.1. It appears to be 99% certain that the corrosion occurred in this instance due to a non factory transaxle mounting method being used. Furthermore it crushed the chassis member due to poor design as shown in the pics.
2. A typical year 1998 GRP bodied Ultima holds up far better in terms of rusting than a typical year 1998 production car such as a BMW 740 or Ford Scorpio both of which we have as tow cars. Both of these tow cars have a large amount of unsightly body rust and also required their cills welding to pass an MOT several years ago. We have recently inspected a 1998 Ultima Sports that has covered 100,000 miles as a daily driver which doesn't require any chassis tubes replacing.
3. We use a thorough powder coating process- preparation is the key.
Does anybody actually own an Ultima that would fail an MOT Test due to corrosion?
Regards to all
I dont think anyone has suggested there is an issue with the build quality of the Ultima chassis... its just like any other kit in that its powder coated, so if it scratched or hit it will flake and rust regardless of preparation.
If you use it daily in rain like the BMW it would rot just as much... but thats hardly relevant either as it wont rot any more or less than a Lamborghini or TVR and is hardly going to be used in the rain as much as a production car so should way outlast it.
To put it in persepective, the complete rear subframe of my Noble was rotten when I bought it.... underneath like the OP issue... I cut it out an replaced it... its also a common issue as the rear defuser traps water against this subframe if used in the rain so is a design flaw IMO
Cant see any similar design flaw in the Ultima that would have caused this... its a one off that others need to learn what caused it and not make the same mistake.
BTW, my ultima chassis also had the gearbox mounting with a welded in anti crush thread...
I remember painting on some wax oil, over the welds in the engine bay. This just covered areas that you can't easily see and seems to have stopped any rust in those areas (that is if they rust there anyway!)
I also did more on the chassis rails inside the sidepods and inside the front radiator part that gets double skinned. Basically anywhere water could sit for a while against a metal surface. That was 11 years ago, and in general still looks like a new-ish car (IMO anyway).
I also did more on the chassis rails inside the sidepods and inside the front radiator part that gets double skinned. Basically anywhere water could sit for a while against a metal surface. That was 11 years ago, and in general still looks like a new-ish car (IMO anyway).
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