Jonathan Fry: Alvis TA21

>> Listen to this Article or Add to Podcast

I was asked last week if I would recommission a 1951 Alvis TA21 which had been garaged for the last 20 years or more without being moved or started.

It had been bought recently by Bob who already owns two vintage 1946 Hillman Minx and a vintage MGB GT. The previous owner had garaged it after the death of his wife and there it had sat until Bob discovered it.

Now this is the kind of job I love and I just wish on such occasions dad was still alive as this 1951 Alvis TA21, 3000 Straight 6 would have been right down his street! In fact with dad present I wouldn't have even needed to check any technical data as he would have known all the settings and pretty much everything else about the car after working on them for years.

It's important to approach the recommissioning of vintage vehicles in the correct way, especially when they have not operated for a number of years. In the case of this Alvis we estimate over 20 years and when it was last used it didn't benefit from modern lubricant, coolant and fuel additive technologies. Failure to assess every action before proceeding may result in damage being caused which often is irreversible and many components are no longer available for such vehicles to correct this damage.

Over the years corrosion will have caused deterioration to many components and especially electrical components, cables and connectors which did not benefit from modern water resistant multiplugs and silicone insulations. Components such as the commutator / slip rings in the generator will have corroded preventing contact from the brushes and the contacts inside the regulator will also be subject to corrosion. The list of possibilities is endless and each must be assessed subject to the vehicle's individual circumstances.

The one thing that does need to be controlled more than anything else is human nature. The excitement and anticipation of hearing the engine running again after many years idle can lead to bad decision making and costly, if not irreversible mistakes being made during the recommissioning procedure. It's good practice to encourage the vehicle's owner to keep clear while the assessment is being carried out but in this case the owner is Bob who I've worked with for years on such projects; Bob knows how I work and I know how Bob works and time isn't a factor, only quality and accuracy.

The following few paragraphs detail only some of the steps we carried out in the recommissioning process. Many of the more boring but essential tasks have not been included in this article to keep it to an acceptable length. If you are planning on recommissioning a vehicle which has not been used for a period of time I advise that specialist advice is sought before starting and preferably the job is entrusted to a professional with experience in recommissioning vintage vehicles which is exactly what Bob did in this case.

The first thing we did was to remove the spark plugs and inject a small amount of new engine oil into each bore through the spark plug hole in the cylinder head. Introducing oil into the bores helps to protect them during the cranking phase which is likely to be long considering the length of time the vehicle has been left. The oil also improves cylinder compression until the oil pump can take over. Any oil which was left in the bores from its last run will be long gone and there's a good chance the piston rings will be stuck in their grooves.

With the spark plugs removed we connected a new, fully charged battery and operated the starter switch on the bulkhead. With help from a few well aimed taps from a small ball pein hammer the starter motor turned and engaged the flywheel ring gear. Because we had left the spark plugs out there was very little load on either the engine or the starter motor and we soon achieved an acceptable cranking speed helping to distribute the engine oil we introduced into the bores. We allowed the starter motor to operate in small bursts to ensure everything was OK and after a total cranking time of about 30 seconds we disconnected the battery and carried out checks to the engine and electrical system.

During the cranking phase we noticed fuel coming out of the float chamber overflow pipes. You would expect to see this if the needle valve or float had stuck so we dismantled both float chambers and stripped them down on the bench for a quick clean. The rear carburettor float chamber float assembly had stuck in the chamber and everything we tried to get it to move failed. Because the float is delicate and hollow it's not possible to apply too much force otherwise damage will occur. In the end and after trying everything else we applied some heat to the base of the float chamber which melted the tar like substance which was holding the float in place. I wouldn't recommend anybody applies a heat source to a fuel storage device but we had little option and put in place safety measures prior to doing this. The tar like substance was the remains of the fuel from the float chamber which had slowly evaporated over time leaving the sticky compounds and impurities behind.

At the same time as servicing the float chambers we also removed the dash pots, dampers and pistons and cleaned them using carburettor cleaner before refitting and renewing the dash pot oil. The viscosity of oil used in the dash pots is critical to correct operation. Unfortunately we did not have the correct grade available and phoning around all the local motor factors revealed they no longer stock it either. Waiting a few days for the correct oil to arrive was not an option at this stage so we mixed some 10W/40 engine oil with some light penetrating oil which worked well and will be replaced as soon as the correct grade arrives.

During the cranking phase I also checked for a spark by installing a spark tester to number one cylinder high tension lead. No voltage was present in the lead so after the initial cranking phase I removed the distributor cap and tested the coil primary circuit, contact breaker points, rotor arm and distributor cap. The king lead between the distributor cap and ignition coil was broken so we replaced this and there was a high resistance between the moving contact and the fixed contact of the points. We removed these and cleaned the contacts until the new ignition parts arrived and this gave us an acceptable spark at the spark plugs. We had new spark plugs ready so a small amount more engine oil was injected into the cylinders and the new spark plugs were gaped and installed.

We had ensured that the three main elements a four stroke internal combustion engine requires were present. We had acceptable compression in all six cylinders, we had fuel delivery to both carburettor jets and we had an acceptable spark at the spark plugs. The vehicle had been driven into the garage where it stayed for over 20 years so we also knew there was a running configuration the last time it was started therefore no need at this stage to make any service adjustments.

A towel was placed partly over the air induction pipe to throttle the air flow and therefore increase the depression in the inlet manifold. This would help to draw fuel through the jets and would compensate for my decision to start this car without choke which may have resulted in a flooded engine. After about 45 seconds the engine started and idled for about 15 seconds before stalling. This was good news as we knew everything must be OK to achieve this brief idle. After adjustments to the level of throttle we was inducing using the towel the engine restarted and we ran it at a fast idle for 2 minutes before turning the engine off and removing the battery lead. Following this we restarted the engine and ran for longer periods up to an hour duration after 3 hours of successful stop/starts.

The work on this Alvis has only just started and so has my involvement as there's plenty more work and recommissioning to do before we are satisfied it is ready to hit the road.

Related Articles: