A Guide To Modifying A 100e

This has been put together by our very own Jan, due to concerns that have recently been raised, it is just here to help one and all

A Modifier’s Guide
Both Graham and I have some concerns regarding the modifications being posted on this and other sites. Now this isn’t an attack on those who take a 100E and then make it into something old Henry would never recognise, and there are many, many people out there who have built wonderful vehicles which combine good looks and much higher performance with safety; unfortunately there are also some who pursue only the first two attributes and either don’t concern themselves with safety, or produce a potentially lethal vehicle through simple lack of knowledge.

Two things recently have prompted this article. Most of the British members will have heard of the man who lost control of his Land Rover, thereby killing three of his children who drowned when it left the road. When recovered, the vehicle was given a police examination and the unanimous decision by the police technicians was that none of them would have dared to take it on the road. The owner had ‘improved’ the vehicle in such a away that it was just a matter of time before the accident occurred. This man is now serving a gaol term, but that will never equate with the loss of his children.

This sad result was undoubtedly due to ignorance, but there are other reasons why people ‘improve’ their cars to dangerous levels: lack of cash is one. This is a hobby, and like all such needs a financial input. If you can’t afford do what you want, either don’t and rethink your plans; or save up until you can. Simply taking the cheap and nasty option will not produce a car with the good performance / handling / braking that you desire, but one where all these are inferior to the bog standard system with which the car left the factory. You end up with about a ton of steel capable, even in standard form, of 70 mph and possibly much more. That can cause an awful lot of damage, injuries and deaths unless you get it right.

Unfortunately, there is another reason, and that is stupidity. This isn’t the same as ignorance, which can be corrected. Here is the second inspiration for this article, and while I haven’t read anything quite so stupid on this board, there have been comments which approach it. Someone stated that he wished to lower his car and would cut two coils from each front springs. Many others wrote in, and there are many serious modifiers on that site who know what they’re talking about, that was not the way to achieve this and he needed to fit shorter stroke dampers as well, or there was the possibility of the springs become displaced from their cups and causing a loss of control. He didn’t wish to go down that route – the dampers were too expensive – but was determined to carry on with the coil cutting. In the face of much more advice he finally announced that he didn’t mind if the car was dangerous; he just wanted it to look nice. Hopefully, there aren’t many like him around.

Quite apart from the possibility of causing an innocent person to lose his or her life, there is knock-on effect from things going disastrously wrong: legislation arises to prevent repetition. This might, as a result of the Land Rover accident, be at a planning stage. Before a heavily modified vehicle is allowed on the road, it must gain a certificate over and above an MoT to state its roadworthiness, all at the owner’s expense. It’s something I can see happening.

What follows is a brief, general outline showing how things interact, and why it is necessary to plan what you want, and how to achieve it. There is no ‘How to’ instruction implied; I don’t have the experience of much of the work, and that will vary from person to person anyway. Once you know what you want, see how it can be achieved. Unless you know for certain that your ideas are viable, ASK. There are people on this and other sites who have done almost everything at some time and will know, so ask their advice. If nothing else, it might save your scrapping a previously good shell, having wasted a lot of hard work and money beforehand. Eventually you want a car that looks and performs how you want it to, but does so safely. There is no alternative; ask the man who killed three of his children.

Planning.
This goes as follows: what do I want; what work do I need to do; what parts do I need? These need to be considered in total and taking the entire vehicle into account. Your knowledge of how to do it (welding, for example) must be up to the job and what the consequences of the work will be must be considered. If you are unsure, post up your ideas and see what others say. Ignore those who obviously made it all up last year and the car hasn’t fallen apart yet. But you must get this bit right at the start rather than improvise as you go along.

Structure.
The 100E was Ford’s second unitary constructed shell, as opposed to being built on a separate chassis, and, in view of the lack of experience with this type of body, Ford’s over-engineered it considerably. It is therefore very strong and will accept some mistreatment, but there are limits. The point with unitary construction is that each part is structural, even if only to transmit stress flows from one strong point to another. Ad-hoc cutting of apparently simple components can disturb these flows, which now need to find another path through components already stressed for different purposes.

Changing the gauge of metal can also effect the shells structural integrity. Certain parts of it are designed to distort to absorb road shocks (try placing your hand where the door meets its aperture as you drive along and see how much movement there is). If these are replaced by thicker gauge steel (“That’s better; it’s much stronger now!”), these parts won’t distort so others, which are NOT designed to distort, must do so instead. This gives rise to fatigue, followed by fatigue cracks, which can be hard to find and repair.

One issue with the 100E is that, with few exceptions, any engine change requires the bulkhead and gearbox tunnel to be cut. The gearbox / prop shaft tunnel is a major structural area of the floor and resists much of the bending stress in the longitudinal direction. Now if, after cutting the tunnel, you repair the cuts with sound metal welded in, the strength is restored. The same applies to the bulkhead. I don’t know if anyone has ever blocked the splits with glass fibre matting, but if they have, they’ve left the shell considerably weaker. What’s more, even a 1600 crossflow will deliver almost three times the torque of the original sidevalve unit, and will feed the torque reaction into an area that has had its strength seriously reduced. And that’s before considering a V8!

Then there is the addition of mounting brackets for, say, suspension mods, which must be thought through in relation to the strength of the shell at the new mounting point; the magnitude of the forces it must restrain; and the direction of those forces. I’ll use Dan T as an example of what I mean, basically because he obviously has thought it through and come up with neat engineering solutions. He intends locating the rear axle by a four-link system in the longitudinal direction and a Watt’s linkage (not my first choice, but each to his own!) in the transverse. Many people would have welded or even bolted simple brackets to the underside of the floor. The floor is a large, relatively flat area and will not accept great vertical loads, but will accept them in a horizontal plane. The brackets I mentioned might be quite small since the weight of the car isn’t transmitted through them, but driving and braking forces and the axle’s torque reaction are, so the forces are high. The contact area between the new brackets and floor might be quite small, leading to high stresses (Stress is Force / Area. The smaller the area therefore, the higher the stress for a given force). The result is that the brackets are ripped away from the floor under harsh braking or accelerations, with consequences too easily imagined. This is not the case with Dan, who has not only provided adequately strong box sections each side, but given sufficient length to ensure a large contact area with the floor and low stress levels at the welds.

Brakes.
Fitting a servo does not improve braking performance, at least by much; what it does is allow a similar performance but with reduced pedal effort. Adding a servo to standard brakes will not achieve anything, although insurance companies might insist on one. They do come into their own if a conversion to discs is made, for reasons now to be explained.

Everyone knows that fitting discs automatically gives improved braking – and they’re wrong. A good drum set-up will outperform a mediocre set of discs, and drums have one major advantage: with twin leading shoes you get a self-servo action. This means that as the piston and shoe move outwards from the wheel cylinder as the pedal is pressed, the drum at that point is moving in the same linear direction, and friction between the drum and shoe help pull the latter further in the desired direction, so increasing the shoe’s force against the drum and giving enhanced braking. With a disc, the rotation of the disc and the pads’ directions of travel are perpendicular to each other, so there is no self-servo action; it’s all down to the pressure you apply at the pedal, augmented by the vacuum powered servo. That though is drum brakes’ only real advantage; as to servicing, discs are much easier, and far less prone to fade.
Any moving body, including a car, contains Kinetic Energy; if it is stationary, KE = zero. It stands therefore that to bring a moving car to a stop, all the Kinetic Energy must be lost. Energy can be neither created nor destroyed, it must be converted to some other form, such as heat. This is what the brakes do; friction between the lining and drum / disc convert the Kinetic Energy to Heat Energy, and so the car slows to a stop as the KE reduces. But as the KE reduces, heat rises, and brake linings work well only up to a certain temperature, after which their Coefficient of Friction begins to fall, eventually to near zero if their temperature rises high enough. The effect is that you notice that, although you’re pressing the brake pedal, the car isn’t slowing down so you press harder, putting more heat into the linings and getting less braking effort, until it disappears altogether.

This is a particular problem with heavily used drum brakes: the shoes are inside an enclosed drum / backplate so the heat cannot escape but builds up. A disc rotates in relatively free air, so loses heat far more readily, resulting in a delayed onset of brake fade and less severity if it does happen. Vented discs improve the heat dissipation properties. That’s the advantage.

Of course, you can fit bigger discs to improve the braking effort, in the same way you can fit bigger drums, but there are two issues. Firstly, if you improve the braking at the front end of the car, you must make a proportionate improvement at the rear. Too many people have upgraded the front brakes with no corresponding improvement at the rear. While most braking is done by the fronts, unless there is adequate retardation at the rear the back of the car won’t slow down with the front end but try to overtake it: the car will spin.

Another issue with discs is that as pads wear, the fluid level in the reservoir falls. The same happens with drum brakes, but not to a noticeable degree so the reservoirs are small – too small to accommodate the drop with a disc system. So either fit a larger reservoir or check and top up the fluid regularly. But if you do top up as the pads wear, fitting new pads will force more fluid back than the reservoir can hold so it will overflow. You takes your money…

Suspension.
Most people want to upgrade their suspension to improve road holding and handling, but this is a very subjective topic: ask two ‘experts’ and you’ll get two different answers, sometimes telling you absolutely opposite advice. Some things need to be understood though, particularly suspension angles, what they do, and what effect changing them will have.

The most common modification is lowering. This is a matter of taste (and not mine!) but needs to be done right with an appreciation of what the effects will be. Firstly, as mentioned above, simply cutting coils from the front springs is not a good idea: the 100E leg extends a long way on rebound and shorter springs can come loose or even out of place. The MoT tester should, if he’s doing his job properly, fail the car and I certainly would. You must fit shorter stroke inserts, and no, wiring the coils to their pans is not an acceptable substitute.

Bear in mind that lowering the front will have two effects on suspension geometry: camber will be reduced (heavier steering) as will castor (less self-centring action). Before doing any front suspension modifications, look up: Castor; Camber; Swivel pin inclination: Offset; and Centre point steering. All these inter-relate, and you do need to know what they are, what they do and what effect changing them will have.

At the rear, lowering blocks provide an easier solution, but bear in mind that torque reaction of the axle and spring wind up under braking and acceleration will both be increased, especially in conjunction with a more powerful engine (Torque is Force x Distance, and you’ve increased the distance from the axle to its controlling influence, the leaf spring). You might find that anti-tramp bars are needed, which takes us back to adding brackets to the floor.

Steering.
Rack and pinion systems are much better then steering boxes. I’ll agree to that, but just throwing a rack on to the existing system will give a very unpredictable vehicle subject to bump steer, i.e. on striking a bump, it shoots off in any direction of its own choosing, without any input from the driver. Simply welding brackets to the 100E crossmember and bolting on an Escort rack - a not-uncommon bodge – will give exactly these results. To see why, we need to consider Ackermann’s Principle whereby the inner front wheel is steered through a larger angle than that on the outside of the turning circle. This is because the circle the inner wheel travels is smaller than that of the outer, and the steering arms at the bottom of the struts are so angled that, if extended, they would meet at, or just in front of, the rear axle. As a result, if you turn one wheel outwards through 30 degrees, its partner on the other side will have turned inwards by only 22 or 23 degrees. This setting is known as the Toe-out on Turns. It must be maintained at this; if you run the car with the tracking toeing in, you’ll find the steering unresponsive. If you run with the front end toeing out, it will be wildly unpredictable. It is possible to get the tracking right in the straight ahead position, but wrong when the steering wheel is turned, giving these results when cornering.

If a vehicle has a solid beam axle, there I no change in track – the distance between the wheel centres from one side to the other – as the suspension rises and falls. With independent suspension, the track is constantly varying with suspension movement, and to maintain a constant toe-in, the steering must mirror these changes in length. The 100E’s crossmember has two longitudinal holes to which the track control arms attach; they are a set distance apart. The drag link – the steering link between the steering box and idler – has two similar holes to which the inner track rod ends attach. Because these distances match, toe-in is maintained at all suspension angles. On an Escort, the drag link is replaced by the rack, and the holes by ball joints to which the track rod ends joint it. The distance between those ball joints matches that between the holes in the crossmember so once again, equilibrium is achieved. But the distances between mounting holes on the Escort is far greater than on the 100E, so much so that the Escort’s TCAs are much shorter than the 100E’s, despite the wider track. If you fit the Escort rack but retain the 100E suspension, everything will be out of phase. The outer TCA ball joints will be moving in and out at a different rate than the outer ball joints of the track rod ends, so the toe-in changes every time there is any suspension movement. So as you drive along the toe-in might be correct, or toeing in too much, or toeing out. And this will effect the car’s behaviour, but in a constantly changing way as you travel along. So yes, you will have lighter, more precise steering, but a car which does what it wants rather than what you want. This might include ramming an HGV head on! I’d prefer to stay with the steering box, or fit the full suspension from the Escort. That though will give you a wider track, negative camber, etc., so you need to think the whole thing through.

Wheels.
Simply fitting wider wheels sounds fairly innocuous, but again there are consequences.

The 100E has a fairly short wheelbase compared to its track: this allows good turning but it tends to wander when travelling in a straight line. Extending the track will exaggerate this, admittedly minor, problem. The main issue though is wheel bearings. Have you noticed that the inner front wheel bearing is considerably larger than the outer? Have you ever wondered why? Well, it’s because the centre line of the wheel and tyre runs through this inner bearing – more or less – which means that it is through this bearing that the car’s weight acts; the outer doesn’t carry much weight but is there to stop the wheel falling off. Now consider what happens when you fit wide wheels, whose centre has moved outwards, towards the small outer bearing. Basically this will now carry the cars weight, for which it isn’t really adequate, especially if you’ve replaced the little sidevalve unit and three-speed box with a V6 or V8 coupled to a Borg Warner autobox…

Another issue is that the wider wheels will alter the offset – the centre line through the strut top mount and bottom ball joint (Swivel Pin Inclination) is continued downwards and intersects that of the wheel and tyre at a point below the road surface. The distance between these lines at the surface is the offset, and has consequences for the steering and suspension. If the offset is zero, (known as Centre Point Steering) the wheel scrapes around over the road as the steering is turned; as offset increases, the wheel rotates through an arc. However, the wheel is pushed along by the car, the force pushing it forward acts through the SPI as above, but acting though the wheel’s centre line is the tyre’s rolling resistance, pushing the wheel backwards. So you have one force forward and one rearward, acting through these centre lines. If the offset is zero, the forces are equal and opposite so cancel out, but the ‘couple’ rises as offset increases. The effect is to cause the wheel to steer outwards each side, and while the two wheels trying to steer in opposite directions will be contained by the track rods, it will give rise to heavy steering and component wear. Fitting wider wheels increases the offset, and so the couple, etc.

Conclusion.
Modifying a car takes in many of the problems faced by the original designers: each part of the car interacts with the others. From your point of view, all your modifications need to be in harmony with each other, and with what you have retained from the original 1950s’ car. If you get it right, you will have a car that is nice to drive and give you all the attributes you were looking for. Get even one bit wrong and you will have a dog that will drop you in serious trouble. Plan what you want, ensure that you know what these will do, and what knock-on effects they will have, don’t be afraid to ask others for advice – and don’t discard that advice just because it isn’t what you wanted to hear – collect the parts and do the work methodically, taking the time it needs – don’t set unrealistic deadlines.

And good luck with your project.

I have to agree with Graham and Jim with everything said. Before i modified my Prefect i had been reading the Likes of Custom Car, Hot Rod & Custom UK, Hot Car. I found as many features on 100e's as i could find to see what people had done to there's, this firstly gave me an idea into what i was letting myself in for, this being the first time i had done anything like this before. The first thing it taught me was not to go over my head, to do what i felt was within my capability and the tools i had. Reading the features i could find out the short comings of certain parts fitted, some good and some not so good. I also went to Custom Car shows so i could see peoples cars in the flesh, this gave me the chance to talk to others and view the cars more closely. I can remember seeing a steering rack fitted with the T.C.A's bolted to a section of square tubing bolted to the engine crossmember, not sure now whether or not this was in one continuous length or not, one thing for sure i didn't like it. Things have changed a heck of a lot since then as there is more companies out there involved in the scene, speck to them, say to them what you want to do, they have the experience to say whether or not it is possible.

One concern i have seen posted is the cheap way of lowering the front end by cutting the coil springs downs, this was an old hot rod trick to lower the car, many tying the springs to the seats with wire, to try and avoid the springs from jumping out of there seats. If you look at a spring it's made to sit flat on the ends, cut the spring down then it doesn't, this will affect the way the spring compresses, the exact same way a playing card will fold when compressed. People have heated the spring till it's white hot and then flattened it so it sat right, this can change the way that part of the spring reacts, the worse case the spring breaking through fatigue.

The dampers in the strut are designed to work with the springs, reduce the spring length, you remove the safe distance the insert can travel without bottoming out, i have heard of the inserts being forced out through the strut tops, this might sound excessive but think about it, the insert hits the bottom of the strut, the weight of the car pushing down on the spring, the insert will either bend or push up through the top mount, then through the strut top.

Lowering a car will alter the camber angle, as the T.C.A's will level out pushing the struts further out, the first thing you will notice at speed the car is a bit twitchy over bumps, this is because the car has the weight on the inside edge of the tyre, over a period of time you will notice the inside edge wearing down quicker than the rest of the tyre. I've found this to my cost with my Prefect, at the time you couldn't get adjustable T.C.A's, this has now been rectified, having been done prior to me buying it back. Also lowering a car also affects the caster angle, the standard roll bar can be made adjustable to overcome this problem, again this wasn't available when i did my Prefect but again has since been sorted.

With my Thames i have gone for a steering rack, using the 107e Prefect crossmember, which my engine bolts straight on to. I went to Old Ford Auto Services and told them what i was doing, they designed additional sections to the crossmember for the new T.C.A mounts which would marry up with the chosen steering rack to be used, they also made new adjustable T.C.A's, they also converted my anti rollbar to make it adjustable for caster.

I felt this was beyond me, involving too much guess work, which i wasn't happy with, yes it cost me a lot of money, but peace of mind knowing it will work properly was important to me.

Another i found was the fitting of wider wheels on the front, was the increase heaviness in manoeuvring to park up, something i have learnt to live, this can be reduced in the fitting of alloy wheels, this i have found out when i had my Wolfrace wheels fitted.

Brakes, i wanted to reply to this as i didn't want people thinking that i hadn't thought about this and that as i had just posted on my Thames about the rear disc brake conversion i have fitted.

When i did my Prefect, i converted it to disc brakes on the front, using Mk 2 Cortina discs and calipers, i also used the same master cylinder as well, knowing full well it would be up to the job, having a large enough reservoir to cope, i also fitted an in-line servo which helped with the ease of braking.

With My Thames, it will have the same Mk 2 Cortina front calipers, but with disc brakes to the rear, again the master cylinder has been upgraded and a large enough reservoir will be fitted. Another thing you have to remember with disc brakes on the rear will have a far greater ability to lock the rear wheels than drum brakes under hard braking, to reduce this, there is two options, the first is to fit a bias peddle box, a lot of work if you are running the same peddles, the other option is an in-line bias valve, which like the bias peddle can be adjusted to suit. My Thames has a non standard peddle box, i choose to fit a servo which meant a bias peddle box was out of the question, so i have gone for an in-line bias valve to the rear brakes.

With bigger engines being fitted the addition of anti tramp bars will help stop the axle twisting, it also reduces the side ways movement, a 'A' frame probably does this better than tramp bars. This was another problem i found when i fitted wider wheels to my Prefect, sideways body movement meant the body was rubbing on the outside of one of the tyres when cornering, another problem that has been sorted with the addition of tramp bars, as you may well have seen with my Thames an 'A' frame has been used, in some ways i feel better as it gain a little bit more space for the exhaust and saves fabricating something as there is no steel floor to attached to.

I wanted to post this so everyone can see that i have put a lot of thought into what i am doing with my Thames, it also shows i have learnt lessons from my Prefect, which i hope will improve my Thames, take your time, speed is not important, your and others safety is.

Regards

Andrew

Explanation of SVA and why:-

If you are still unsure PLEASE ask on the forum as someone will be able to help..

the single vehicle approval scheme

In depth SVA detail here ,especially re goods vehicle interpretation.:-

sva technical standards explanations

SVA manual can be ordered from here

publications and guides

All online download SVA manuals are out of date , Latest manual is April 2005 and closes some of the loopholes ,like getting away with pipe lagging on sharp edges ,and it also introduced the ESVA for certain vehicles.

This is a 'quick version ' that appeared in The Gasser and is currently held on UK Hotrods site..
rodding and the law

Comparison of requirements for SVA test between commercial vehicles and cars.

the single vehicle approval scheme

Don't think you can pull a fast one :-

Click Here...

Clarification of testers interpretations.

sva information bulletins

Clarification to testers of parts of SVA manuals to acceptable parts:-

sva technical standards explanations

Requirements to qualify for commercial SVA:-

Click Here..

And taking your bootlid off won't work :-

Click Here

Link to kit car site with info on SVA plus one article re sorting the registration on an incorrectly registered 'kit'.

Use the info carefully and wisely!!

www.totalkitcar.com

SVA is changing to a new test, BIVA, in April 2009.

VOSA check the VIN and security marking at SVA and MoT testing

How to register a rebuilt,radically altered vehicle

Vehicle Registration Certificate


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