Technical Library
Andrew Turvey's Technical Topics
The E-type Fan club!
By Andrew Turvey of CMC
It’s the time of year when the cooling system on your E-type is working at full stretch. Often those of you who are running strictly original examples are driving with one eye on the temperature gauge and the other on the road. However, some of you have fitted an extra electric fan and drive with a watchful eye on the ammeter instead. With this article I do not wish to contradict anyone’s personal experience, I will merely add my own ingredients to the cooking pot!
Unless you are blessed with infra-red sensitive vision, you will be relying on the dash-board temperature gauge to tell you that all is well under the bonnet or, as our American friends say, hood. The first thing to note is that the ‘Temperature’ Gauge is not always strictly accurate. We are, in the main, talking about electric units. It is often the case that a gauge will read +/- 10 degrees C, and 10 degrees is a critical amount.
The only way to check it is to put a digital probe on the radiator or thermostat. ‘Knowing’ the gauge is reading high or low by X degrees is a huge step forward. It may even be correct! Generally speaking, the earlier the E-type, the higher is the likelihood of an inaccurate reading.
This is often due to a variety of causes. It can be the result of an alternative temperature sender being fitted to the engine at some stage, faulty or incorrect gauge calibration or a faulty instrument voltage stabilizer.
Having a slightly inaccurate gauge can be a problem if you are unaware of it. But if it is consistent, and you can mentally compensate X degrees, then you could stick with it.
Temperature sensors are colour coded to get you into the right ball park. But individual sensors do vary when it comes to the gauge reading. Buying a replacement gauge and sender as a pair is one option, or, better still, replacing your electrical gauge with a non-standard capillary temperature gauge.
On the road
Once we have a tangible reading from the temperature gauge we can monitor the engine temperature in relation to its circumstances. Water temperature of 75 degrees centigrade is normal on E-types and should be reached in approximately 10 to15 minutes of motoring. It takes a little longer for the oil and other ancillary components to reach temperature. In 25 minutes this should be extended to the whole car.
Engine temperature readings can be split into two categories: on the move at 35mph plus and idling-stationary but not parked against the garage door.
Whilst the car is doing 35mph, the wind speed through the radiator should be more than enough to keep the engine at a stable 70 degrees (the electric cooling fan should not be running). If not, your radiator/cooling system is not behaving efficiently enough. This may be due to a lack of water circulation through the radiator and block. Air not flowing through the radiator correctly is another possibility. Other contributory factors are: retarded ignition timing, weak mixture and even sticking brakes. Modified engines are also big heat producers.
Like most designs of purpose the E-type was not intended to stand still! It was so conceived to shed its heat with forward movement. All versions have air outlets in the top of the bonnet which allow a lot of the heat radiated from the block and exhausts to escape, along with hot air from the radiator.
Whilst idling in traffic we need to push as much air up through the bonnet vents as possible. So an electric fan has two jobs: pushing air through the radiator and blowing air around the engine and out again. Later E-types, such as V12 or S11, are ahead in the electric fan department. They have two good fans that are capable of moving plenty of air.
Switching from Otter
Their only shortcoming is the unreliable Otter switch that controls the fan. In the V12 it is located in the bottom radiator hose. These switches are often replaced by a more reliable alternative from Renault or Kenlowe. Also, during the summer these fans can be wired to run constantly with the ignition on or through a redundant dashboard rocker switch. This keeps the under-bonnet temperature down very effectively. On V12s do not neglect to keep the rubber flaps on the radiator cowl in good order. They act as a one-way valve to stop air being drawn backwards into the cowl when the car is stationary.
Originally designed with a more thermo-efficient aluminium radiator, a standard S1 E-type has a small fossil of an electric fan. Its priorities are to ‘not cause trouble’, i.e. flatten the battery or get in the way. The standard dynamo cannot keep up with an electric fan that is capable of lowering the engine temperature significantly. The standard S1 fan may take the edge off, but it will not pull the temperature down from 95 degrees to 75 degrees centigrade. It is possible to run something like an after market 16in Kenlowe fan and retain the dynamo. But prolonged use in heavy traffic will flatten the battery. You will have to consider the merits of pulling over and switching off to conserve the battery instead of eating your sandwiches.
A fitting fan
Compare the picture of the 16in Kenlowe with the smaller type of fan, which is also by Kenlowe, that we regularly have to remove. These small fans units stand proud of the radiator and aren’t up to the job!
The 16in Kenlowe (puller) fan fitted on the inside of the radiator is a solution for S1 cooling problems. Fitted in place of the standard electric fan, and coupled with a 55 amp alternator conversion, this will indefinitely draw considerable quantities of cooling air into the engine compartment. The standard radiator cowl should also be removed at the same time; this allows greater air flow on the move.
The Kenlowe thermostatic switch also proves to be very reliable if fitted correctly. Remember to get your big electric fan wired through a relay. Some of these fans have a 50 amp start-up current. This is where the ‘competent auto electrician’ comes into his own.
Setting the electric fan cut-in temperature
Set your electric fan to come on as early as possible, that is to say 75 to 80 degrees centigrade. Once the engine pushes over 85 degrees C, it becomes increasingly more difficult for the fan to bring the temperature back down. 85 degrees is only fractionally past the normal 70 reading on a standard gauge. Also very important! Check that the fan is blowing towards the engine.
I often see small electric fans fastened to the stone guard in front of the radiator which can present two problems. Firstly, the fan blocks air flow to the radiator on the move. Secondly, the stone guard is one inch away from the radiator, a gap which allows the air to disperse in front of the unit. Only a small amount of air passes through. What we want is positive air displacement through the radiator and also to push all the hot air out of those bonnet vents.
The right radiator?
As for the radiator itself, the existing core can be replaced with a ‘tropical core’ which retains a standard appearance and improves cooling.
Another popular solution is the aluminium radiator. So E- type radiators have come full circle. They are costly though, ranging from £350 upwards, but do give very reliable results, are stronger and more thermodynamically efficient than the originals. Running temperatures often fall by as much as 10 degrees centigrade, when compared with a copper radiator.
But heed a word of warning when buying an aluminium replacement radiator. Make sure you check the dimensions and bolt holes carefully. The people who make the radiator have no idea how tight a fit it is! If you are having one made, ensure that the dimensions you supply are five mm smaller throughout. You can be sure it will fit and the cooling will still be fine.
Before you fit your new radiator take the time to flush the rest of the cooling system out with a hose pipe. Ideally you should remove the core plugs prior to cleaning sludge from a six cylinder block. But that’s a job for an expert.
Capping it
Then there’s the radiator cap. The E-type one should generally have a 7lb yield pressure for a S1 and 11lb for a V12. I often see caps set to 15lb fitted but this is demanding on older water hoses and water pump seals. So at least make sure you have cotton-reinforced hoses, and monitor the pump. I do not fit hoses if they are not reinforced. Some new Kevlar ones don’t have any cotton at all and I have seen them burst!
A higher pressure cap will allow the engine to run hotter without boiling over, but be vigilant. I would also recommend carrying a can of Bars Leaks in the spares box; this will seal many Jaguar engine weeps and not block the radiator.
Above all, keep your eyes on those gauges!
The Slammed Doors
“Your E-type should have flat metal door drains attached to the underside of the door. If yours does not – oh dear!”
Hopefully, we have the original specification seals. The shape and material should be as good as, if not better than, original. Be sure to fit the seal the correct way round and use the correct adhesive: self-adhesive rubbers almost always fall off. If restoring a car, keep samples of your original seals as a reference of size and flexibility. When the car is built up in bare metal, fit the new seals and keep them in order until final assembly day. Door gaps and seal channels should be made generous enough to suit your seals before the car is finally painted.
Many shining E-types suffer from ill-fitting doors. Doors often will not close without slamming them so hard that you risk shattering the glass. In some cases, this is the fault of the seals, but not in all. If the cause of your woes is not readily obvious, then a methodical approach is required. Look into obvious problems first.
Door strikers move or just come loose, the door catch may fail to latch every other time or the inner door panel may hit the trim somewhere around the door aperture. Trim issues such as new thicker leather on door panels instead of vinyl can cause major door closing problems.
If the seals are to blame, the method is to remove all the door seals and start building up the door and seals gradually. Try closing the door at each stage.
First set the hinges and door strikers with no seals in position. Then mark the door hinge position and remove it in order to fit the A-post seal. Fit one seal at a time, rather than spend hours fitting and removing all the seals at once.
The door often has to be removed to change the A-post seal, even on a built-up car, as it is trapped out of reach. In this case, if the seals are already fitted, remove all but the A-post seal and work from there – that is, if the door closes successfully with the A-post seal in place…
Assuming the hinge is not bent or distorted, it should be possible to set the door in its best condition, i.e. the door panel should have an even gap all the way round and be relatively flush with the A-post and B-post panels. It should not touch the door aperture when pushed closed at least 1/32in past flush with the B-post. Incidentally, an E-type door needs to go over-centre when closing in order to make the latch operate correctly.
When fitting seals on a freshly-painted car, begin by fitting the seal dry i.e. no adhesive. The plain seal often holds in the channel temporarily with a little tape , for example. Series II-on cars require the A-post seal to be worked into the holding track and the upper cant rail seal for the window frame left dangling loose inside the car.
When closing the door, the seal should be soft enough to compress without pushing the door skin away. If the door does not close easily, the seal may be too firm or too deep for the channel. This will require cutting material away from the back of the seal – or consider finding an alternative, softer seal from another supplier. If the door closes well with no hindrances, the next step is to fix the seal, using the correct contact adhesive.
The sill seal is next. Your E-type should have flat metal door drains attached to the underside of the door. If yours does not -oh dear! This pressing allows rainwater to run past the sill seal and out at the bottom of the door. If the door drains are not fitted correctly, the water will run over the sill into the car so, if you haven’t any holes in the footwell, you soon will have.
Series I and III cars have small cut-outs in the sill seal to clear these door drains. You will have to align these when first fitting up the sill seal. Series II cars do not tend to have cut-outs unless there is a clearance problem.
The vinyl sill coverings often fill the sill seal channel with excess soft material. Look in the channel hidden below the level of the chrome trim piece. It is necessary to trim this away and allow the seal to sit deep and adhere directly to the paint in this channel. Removing the old glue is essential.
The lower inside edge of the door or drains may hit the chrome trim piece if it is not pushed on to the seam far enough. In extreme cases the sill chrome has to be removed and a few millimetres of material ground away from the steel seam.
Again, trim the sill seal to length and place it into the channel. The SI and SIN seal lip points down when fitted. The Sll seal lip points upwards. The SI sill seal can be thinned down by sanding or cutting material off the back but this is rarely necessary. Glue this seal in place with contact adhesive, only once the door is closing very easily.
The B-post seal should be tackled next. This seal is often the most troublesome. If not glued on well, it will get pulled off regularly as the driver climbs in and out of the car. Even when the B-post seal just becomes a little insecure it will cause door closing misery. Again, first try fitting the new seal ‘dry’, you may have to trim some off the length, but it should hold in place well enough for you to get an idea.
The B-post seal material needs to be extremely supple or soft. We have less leverage over this seal than any other, so it is the hardest to compress when closing the door. This is particularly the case on SI roadsters which have very lightweight doors. The seals are supplied for left- and right-hand sides. Shaped like a hockey stick, they have a section that is ‘corner’ shaped. The open side of the seal should face towards the rear of the car.
If there is any excess of seal when the door is shut, it is usually forced out of the door gap. When the seal is forced out like this, it may be an indicator that the seal channel is too shallow for the seal. If the seal proves to be holding the door away, we could remove material from the back of the seal. If this is unsuccessful, alternative rubber sections are available. Though not concours, they do get the job done; for axample, a hollow-section square seal can work just as well. Sticking with the original SI type seal, a little superglue is often used at the very ends if you have to stretch the seal. Cutting this seal short and then slightly stretching it does have the effect of reducing its section.
Superglue will pull the paint off if you change your mind – you have been warned. Contact adhesive should only be applied over the full length of the seal on one side. If the channel is prepared correctly, contact adhesive should be all that is necessary to secure the seal. It is not uncommon to have to remove and refit this seal a couple of times to get it just right – so don’t be in a hurry with the B-post seal.
The door glass and frame are the next contestants. The adjoining seal is the Cant Rail seal. This seal runs along the top of the door aperture and down the A-post on a FHC. On the Roadster it is in many sections, attached to the hood frame. The Roadster’s upper A-post seal (fixed to the windscreen pillar) differs from that on the hood and is the same section as that used by a FHC.
We use contact adhesive Martrim A2338, which is available from CMC. This glue should not be applied on top of existing adhesive. All original glue remnants should be removed with white spirit. It is sometimes necessary to soak a cloth with white spirit and wedge it into the seal channel for 10 minutes: this will eventually soften the old glue. Plenty of white spirit will be required if the glue is particularly stubborn. Patience and elbow grease will win the day. Scrapers may damage the paint, so use with care. Always apply a little primer to bare metal if the inevitable happens.
New rubbers should also be cleaned with methylated spirit to remove the release agents that are present. They can also be abraded on the adhesive face only, using coarse sandpaperto aid adhesion.
Applying the glue is done in three steps.
1. Apply a thin even layer of glue to the rubber seal and set this aside.
2. Apply a thin even layer of glue to the channel in which the seal sits; allow this to dry until tacky.
3. Re apply a second layer of glue to the rubber seal once the first layer has gone tacky.
4. Allow this second layer to go slightly tacky before you push the seal home into its channel.
Use a small plastic scraper or blade to push home the edges of rubber that drag behind. Pulling the seal away and refitting it again is possible if left no longer than a couple of minutes. The general finishing off of seals does leave a little to artistic licence, but just remember that rainwater always needs an escape route to the outside of the car. Small holes and gaps can be finished off with a black body sealant, wiped over with white spirit whilst tacky.
“Getting some hood frame advice from CMC will help with many issues-just ask!”
The FHC cant rail seal sits in a metal track that is painted body colour and pop-riveted to the door aperture. The seal is best pressed into the seal track 5mm at a time using a blunt plastic putty stick. Many use a screwdriver, but that is not for the faint-hearted. Little can be done with the size or shape of the ‘original’ type seal here. The top of the FHC door frame is adjusted from below. The height and angle should match that of the seal. In extreme cases the frame and seal are too far from each other to be overcome by frame adjustment. As a compromise, the seal track has to have packing strips placed behind it and long pop-rivets used to hold it in place. Though it is difficult to make this look neat, it can be a way out of trouble. Wind noise is one of the main reasons for getting the cant rail seals to work and it is rare for this seal to be too tight against the door frame. This will be a very time consuming job to get right, but patience will be rewarded. No adhesive need be applied to this seal.
Fixed-head E-types have a secondary seal around the exterior edge of the door frame.
Sometimes this seal can be too tight on the door aperture. If too tall in section, this second seal will give headaches when opening the door. The new seals available seem to be too rigid for this job. It is often wise to fit a good secondhand seal in this channel or try trimming down a seal that is too firm, so that it is not overly tight in the door aperture.
The same seal is also used on the Roadster drop glass pillar, again it should be fitted the right way around and extend down below the top of the door. This should then drip rainwater into a special drip tray on top of the doorjamb.
Roadsters’ cant rail seals: for those with hoods. Getting a good seal when the glass is wound up to the top is a priority.
This is where the glass meets the cant rail. The only successful seals are the hollow-section ones or very soft examples. Hood adjustment should be carried out first and then the drop glasses adjusted to match. The drop glass needs to slide up and put a little pressure on the seal. The Drop glass should not make contact with the metal hood frame as this eventually chips the glass. There should be a stop inside the door to prevent this. The metal segments around the hood frame should be adjusted to match the shape of the glass. Getting some hood frame advice from CMC will help with many issues-just ask!
The individual seal segments should not be cut too short either, as they need to butt together tightly. Also note that: small strips of rubber can be inserted behind these rubber window seals to make up the small deficiencies in the rubber thickness or angles. All extra rubber strips should be glued up individually and allowed to dry before continuing. Again we should be closing the door and glass in between gluing individual segments of rubber to make sure of a perfect fit.
No two doors are ever the same!