In The Garage January 2022 issue 14

January 2022 Issue 14 

Welcome to Issue 14 of In The Garage and thanks Paul for our new header logo. We are always looking for content

so please let us know what is going on in your garage especially if you are a new contributor.

Andrew Willmott – TR3 Cable Throttle Conversion

The TR3 has run on its current HS6 SU carburettors for many years and has always suffered to some extent from the common “kangaroo” throttle response. I suspected that the throttle linkage may be the primary cause and so set to converting the mechanical linkage with its myriad of ball joints and bell cranks to a much simpler cable operation. A cable anchor was machined from aluminium stock to clamp around the crank in the accelerator pedal bar and pull a standard bicycle brake cable; a simple hole drilled through the bulkhead with a ferrule fitted provide the outer cable stop with a fabricated post and bracket on the front carburettor providing the outer stop at the other end. A standard SU lever clamped over the throttle link bar with a hastily machined cable clamp completed the conversion.

The completed mechanism appears to be a big improvement in terms of throttle modulation and the “kangarooing” is eliminated unless deliberately provoked. It was also the first step towards a bigger goal...

Fitting Twin Weber 40 DCOE Carburetors

I’d had a pair of 40DCOE twin side draft Weber carburettors sitting in the store cupboard for some time after receiving them a Christmas gift from an old friend. They had been removed from his Racecorp kit car many years ago and he had unearthed them while clearing out his garage. He realized that he could both make some space and provide a Christmas gift for someone who traditionally didn’t want anything, killing two birds with one stone.
I’d picked up a suitable manifold at a good price through an eBay auction and now that I had a cable throttle fitting would be relatively easy.

I’d previously made a simple throttle mechanism and parts to link the spindles across the two carburetors with the carbs mocked up on a spare cylinder head on the bench, so a morning’s work saw them fitted. With various suitable jets and emulsifiers on loan from John Blake and Bob Dove the car started and ran. Initial results were, as expected a bit mixed and the car fluctuated between flat as a pancake, off like a rocket and popping and banging to wake the dead. Different jets and a bit of fiddling with the settings from Bob Dove Racing’s main man saw things running well enough for longer term testing and a drive to the rolling road.

                 
Bob Dove in fettling mode.

The rolling road at SRT in Launceston revealed that our road testing had yielded close to ideal jetting and with the main jet increased by one size the relatively small 30mm chokes fitted were getting close on 120 hp, about 10 more than with SUs.

Further running revealed fuel consumption in the very low 20s regardless of whether the car was being driven like Miss Daisy or in full hooligan mode with most of the extra power only manifesting above 3500 rpm. Some improvement was made by changing the emulsion tubes to a version that passes much more air in the cruise combined with a larger main jet to match, but a gallon of fuel was still disappearing in 26 or so miles although this could now be stretched out by easing back on the throttle a bit.

I’ve popped the SUs back on for the time being but I’ve got a hotter cam in store so the Webers will be making a comeback at some time.

Lazy Starting

For some time the TR3 has been a bit slow to respond to the starter button, sometimes taking a few presses to get more than a click from the solenoid. The fault was very quickly identified as a dodgy solenoid so, with guarantee having expired in the mid 80s and a replacement on loan from John Blake fitted and working, I decided to see if I could repair the old unit.

The components were crimped together so the solenoid was mounted in the lathe and the securing lip turned off. With the lip removed the cap was removed from the housing revealing the problem...

The burned contacts were cleaned and polished and the solenoid was reassembled. The casing was drilled in a couple of places on its periphery to allow two small self tapping screws to be inserted to hold the assembly together and to allow its simple disassembly should the problem re-occur.

Passenger Footrest

Jennie had suggested that a footrest in the passenger foot well may improve her comfort on longer journeys and improve security when cornering at speed. A piece of spare 18mm ply and couple of wooden blocks were quickly knocked up and got the seal of approval. The plan had been to make a more refined version once the mock up had been approved but it worked perfectly in both the TR3 and in the TR4 so the Mk2 comprised the prototype painted black and fitted with some rubber matting.

Andrew Willmott – TR4

Ticking Noise Empties Wallet!

Many of you will know that my TR4 has suffered with a ticking noise at low revs since before I owned it. I took ownership convinced that I wouldn’t have much trouble identifying the source and remedying matters; little did I know!
After hours of diagnosis, part engine strips to examine the shell bearings and borescope probing of the bores and cam I gave up looking, safe in the knowledge that the source would reveal itself in time; which it did. Thanks to the myriad second opinions and help from the usual suspects but we were all wrong!

Jennie and I were on our way home from an afternoon out at nearby Rosemoor Gardens when there was a bang, a tinkling noise and the engine dropped onto three cylinders. A quick roadside diagnosis revealed that the plug on number four cylinder had suffered a forcible closing of the electrodes and that all compression had been lost on that cylinder. As it was obvious that the damage was already done and a rebuild was on the cards, we drove home on the remaining three cylinders.

The cylinder head was quickly removed to reveal impact marks on the piston crown and combustion chamber but no obvious source of debris. Bob Dove was the first to spot the problem; the exhaust valve didn’t look quite right as it was sitting too low. Closer examination revealed that the hardened exhaust seat was missing in action!
The insert must have been jumping up and down in its recess at tick-over making the ticking noise and had eventually given in to the constant impacts, broken up an disappeared out through the exhaust. When the engine was cold and static the seat sat nicely back in its recess. Without stripping the valves out it would have always gone un-noticed.

...Just the excuse I needed to build a new engine.

Paul Gibson – TR6

Paul writes:

TR6 smelly boot!

While putting my car back together after its refresh I noticed the petrol hose from the high-pressure filter felt a little soft and slightly swollen. I’m using a Bosch pump and filter set up in place of the standard Lucas parts and as this hose had never been changed in my ownership. I fitted a nice new piece of good quality fuel hose in its place.

After using the car for a few days I noticed a very strong smell of petrol in the boot. There had always been a bit of a petrol whiff that I considered normal as most TR6 owners report the same problem. The smell was now so strong that I thought I must have a leak. I double-checked all of the fittings and checked again with no joy. The smell was as bed as ever. The only thing that I had changed was the single length of hose so I replaced it with another piece I had of the same spec but a different make. At first there was very little smell but a day or so later it was as bad as ever. Convinced it must be the hose I researched petrol pipe and discovered rubber petrol pipe has a permeability rating mine was R6 the best is R14. Very few manufacturers make R14 and it’s not cheap but I decided to bite the bullet and buy some Gates Barricade. I’ve now changed all my hoses and can report the smell has completely gone.
The hoses were clamped with two eared hose clamps, which are much more secure than worm drive or screwed clamps in higher pressure applications like this. Two clamps were fitted at each union with the ears at 90 degrees to each other.

I used 1.3M for my Bosch set up having bought a 4.57M roll from eBay for around £45. Shorter lengths are available from various suppliers including Moss and the TSSC shop but at a price premium.

Ref: www.gates.com

Gates part no. 27348 product no. 4219-06038 8mm internal diameter 4.57m length (15 ft.) Gates part no. 27340 product no. 4219-06039 8mm internal diameter 7.62m length (25 ft.)

If you're considering changing your hose it maybe worth teaming up with another member to buy some and reduce costs.

TR6 Ballast Resistor

I have been using a 123 Ignition TUNE+6RVG Distributor for quite a while and was using a Lucas Sports Coil. Although I had checked the resistance and was sure it was genuine I decided to upgrade to the Bosch Red coil.

123 Ignition Info:

On fitting the Bosch unit I checked the voltage at the coil this was a fluctuating between 11 and 12 volts when running instead of a steady the 13.5 volts I would expect, very odd. Lots of measuring and head scratching I eventually found the answer. It transpired that my 1973 car is fitted with a ballast resistor wire. This was confirmed by testing. I found only 7 volts at the coil feed with the wire disconnected from the coil and using a 21W indicator bulb for a load. The resistor is not a bulkhead mounted ceramic resistor as some cars had, but a length resistance wire in the loom going from a joint near the ignition switch to a joint in the engine bay just under the washer bottle. Ever since owning the car it has always had a 12volt coil so I never suspected anything. I have now removed the white/yellow feed wire to the coil and run a new wire from the ignition switch to the coil and have full battery supply voltage available at the coil.

The engine does appear to run a little more smoothly but annoyingly I have no idea if this is due to having a good supply voltage or a new shiny Bosch coil. I’m happy to think it’s a combination of both!

Notes:
The ballast resistor was to aid starting. There is a feed from the starter to a 6 Volt coil to supply 12volts while cranking then on 6 volts when running.
The ballast wire is pink/white.
The 12volt feed from the starter is white/yellow.
I believe the ballast system was fitted to UK cars around 1973 onwards.
A good 12 volt coil should have a resistance of approximately 3 ohms.
A 6 volt coil for use with a ballasted system should have a resistance of approximately 1.5 ohms.

Joints under dash and in the engine bay.

John Blake – TR4 x 2

John writes:

Hydraulic handbrake conversion – TR4

The conversion was undertaken at a time when the whole car was undergoing a complete rebuild with the body off, so it seemed like the ideal time to make a few changes.
I’ve always liked the quirkiness of the fly off handbrake and wanted to retain it but found it difficult to use effectively when wearing a three or four point harness. I just couldn’t reach down far enough and found myself holding the car on the clutch more than I liked.

I had already devised a front/rear split braking system with twin master cylinders for biased braking so all that was needed was a secure mounting for the actual lever, a couple of braided brake lines running to a bulkhead adaptor on the vertical panel behind the drivers seat and a couple of new sections of rigid pipe the other side of the panel to intersect the rear brake line running down that side of the car.

The following pictures will help to clarify that explanation:

Reinforcements: I seam welded a couple of 3mm x 40 mm strips of steel to the underside of the tunnel down to the floor pan. Probably overkill but I didn’t want to yank on the hydro in competition and rip the 18 swg prop-shaft tunnel apart.

I made a sturdy plinth with some captive nuts attached to mount the new handbrake. It was welded to the tunnel above the reinforcements:

Welded in place:

With the handbrake was fitted in position I ran braided lines to a pair of bulkhead adaptors (bought from CBS) I wasn’t happy that the vertical panel was strong enough for the brake line unions so I cut out and drilled a piece of aluminium plate which was sandwiched against the vertical panels and removed the possibility of distortion during fitting and in service.

My initial calculations for the size of brake cylinder required indicated that 0.7” was appropriate. However, although this worked well the travel was too little for my liking so I fitted a 0.5” that proved perfect for my needs.

Under the car the lines were connected as seen in the photo below:

It’s just a simple process of connecting the new cylinder in the line to the rear brakes. I’d done the preparatory work whilst the body had been off. The copper brake line shown below would normally connect direct to the bracket holding the red braided line so it was just a matter of terminating it earlier and fitting a straight connector ready for the body to be fitted and the final connections made as shown in the picture above.

The finished product – Total cost including the braided lines and adaptors was about £70. The handbrake unit itself is just a cheapy that is readily available pretty much everywhere. I did have to change the cylinder for a smaller one and I removed the crude ratchet assembly provided so that the hydro cannot be used as the primary parking brake; never my intention on this car. I also removed the adjustable foot that came with the lever, also not needed.

I’ve now completed almost 10K miles with the system fitted and use it frequently, it’s certainly not going to be to everyone’s taste but it suits me and works very well.

Ed: Meanwhile John has set to restoring his second TR4 which although it has been with him for nearly 40 years he has never driven.

Chris Musselwhite – TR6 Exhaust Tailpipes

Those with a sharp eye may have noticed that Chris’s TR6 is now sporting some smart new custom made big bore tailpipes.

Jason Simmonds – TR3

Jason has been beavering away in Croyde to improve his TR3. Having rebuilt the steering and brakes he thought that the car could do with a bit of a visual lift so it is now sporting a set of 60 spoke wire wheels with slightly wider 165 tyres. Having replaced the out of date tyres Jason reports that the road manners are greatly improved, the steering effort is reduced and the previous tendency to follow white lines is eliminated.

Jason plans a re-spray in the near future so look out for a shiny Winchester Blue LHD TR3.

Basil Pennicott – TR3

Basil has fairly recently acquired his green TR3 and it is often seen in daily use around North Devon. He was not entirely happy with the way that the engine was running and the SU H6 carburettors were leaking a bit of fuel.
After visiting a local classic car specialist who tinkered a bit and suggested that the carburettors were worn and needed refurbishing he found that things were worse rather than better and made a call to see if I could help.

We spent an interesting hour or so resetting the float levels, replacing a couple of minor seals, balancing and setting the carburettors and ignition timing. A road test revealed a fundamentally changed car which drove as well any standard TR I’ve ever been in.
Basil has subsequently found that group member Roger Stone had once owned the car. Roger confirmed that the car had been the best driving side screen car to have passed through his hands. We hope to see Basil attending events in the car during 2022.

Richard Osborne – TR3

You tend not to see many TR3s, then, rather like buses, three come along together. Richard had met Basil and group member Steve Williams at a local car show and revealed that he owned a TR3 the engine of which he had recently rebuilt and re-commissioned but...he was having trouble with losing water, stuttering under acceleration, oil fumes from the rocker cover and a few other little issues. Another TR3 found it’s way to my door.

One look under the bonnet revealed that the mechanical work, which Richard had carried out himself, had been completed to a high standard and with a great deal of care so it was unlikely that there would be a great deal wrong with the car.
We found and cured a number of small issues. The front carburettor side was not fully seating and was sticky in operation. It’s common for the needle to catch on the jet, as was the case here. Centralising the jet cured the problem. The 3-In-One oil in the dashpots was changed for specific dashpot oil (I use the Penrite product). 3-In-One is a good substitute used by many but the correct oil was at hand so we used it. The gain would be only marginal but if there’s any gain to be had lets have it. The carburettor linkage was disconnected and the air filters removed to synchronise the carbs. The mixture was reset. With the carburettors fettled we re-set the ignition timing. I always set it at 32 degrees maximum to suit modern fuels; the settings quoted in the workshop manual are not relevant to modern fuels. With the carburettors now behaving and the engine ticking over and picking up nicely we were took a look at the cooling.

Removing the radiator cap revealed that the system was over full so we syphoned some coolant out to bring the system down to its correct level i.e. barely covering the bottom of the radiator extension. At this point we noticed that the coolant was modern red colour rather than the expected blue or green required in a classic car. Use of a modern coolant in our classic engines will soon cause problems; usually coolant in the sump caused by corroded figure of eight gaskets (I’m embarrassed to admit that I found out about this the hard way). It transpired that heater valve had not been opened since the engine rebuild so we opened the valve and with the front of the car jacked up a foot or so and the radiator cap removed we ran the engine to bleed out any air. The adjustable cooling fan thermostat was then set to come on at slightly over the normal running temperature so that it should only operate when in traffic or very hot weather. Richard will change the coolant at the earliest opportunity. Cooling sorted.

With the engine ticking over we could see oil fumes coming from the rocker cover filler/breather and removing it revealed that the cover was flooded with oil and the rockers were running in an oil bath. A look at the rear of the cylinder head revealed the culprit, an external oil feed that bypasses the metering provided by the rear cam bearing robbing flow from the main and big end bearings. Job No2 on Richard’s list....remove and blank off oil line.

A quick road test revealed a much-improved car that now drove very well.
It was interesting that as before, with Basil’s car, all the settings and adjustments were already very close to ideal but that last little adjustment on each variable adds up to make a noticeable improvement.

Look out for Richard in his white TR3 around North Devon and at a few events in 2022.

Below is a picture showing one of my steel figure of eight gaskets that seal between the block and the liners on a 4 cylinder TR. It has been eroded right through after being exposed to OAT (Organic Acid Technology) antifreeze for a year or so. Ed.

Ben and Vicky Freer – TR3

Ben has treated himself to an early Christmas present in the shape of a shiny new four-poster lift. It arrived in kit form so John Blake and myself volunteered to help with the assembly and commissioning.
Believe me when I say that some of the components are very heavy indeed so Bens tractor was enlisted as a crane.

You – Your Car

Thanks to all our contributors to this issue.
Contributions and feedback (positive or negative) are always welcome.

What’s happening in your garage?
Please make a few notes about your garage exploits and email them to me for the next issue. Contributions are best managed by sending in plain text with attached photos or in Word format.

Mail your notes and pictures to: andrewawillmott@gmail.com 

Andrew W