Roger King

Yup

In essence, a 244 camshaft, forged pistons, better advance curve (or even better, 3D mapped ignition) and competition valves (which are lighter and flow better) with bronze guides or guide inserts will do the job. But there are lots of other things needed to ensure reliability - tufftrided crank, better big end bolts, steel rocker gear, carb re-choking and jetting, etc, etc. You would not believe the difference compared to a standard Supersprint.

If it's actually connected I would remove it. It's not necessary for starting (a few pumps of the throttle will do the trick) and is just something else to go wrong. It's not even very effective. Just as a point of interest, it's not actually a choke. A choke works by literally restricting (choking) the air flow through the carb, thus making the mixture richer. On DCOEs, the device works by opening up additional fuel jets to allow more fuel into the engine, but without restricting air flow.

What is the spec of the engine? I might be able to get you fairly close as a starting point.

It's a personal opinion, but I feel that a turbo is the worst possible way to go in a Caterham, whatever the engine. Aside from the inevitable heat management issues and extra weight, you are also losing it's instant throttle response

Yes, I'm afraid it's head off to establish the facts. Just as a point of interest, it's perfectly possible to have a 1700 engine (1690 actually if it's Supersprint spec) that is registered as a 1600. The Supersprint has a +.090" bore which is a standard oversize for a Crossflow rebore (standard pistons are easily available at this size) so it's perfectly possible to have fitted an exchange engine that is +.090" when the original engine was a standard 1600, even in a Ford Cortina. I don't recall anyone claiming a claiming a capacity increase under such circumstances.

Absolutely anything is more reliable than that particular Lucas item, but seeing as the gauges failed as well it sounds far more like a power supply issue.

Wear nitrile pervy gloves and you won't need Swarfega; with the added bonus that oil is not good for the skin.

The jetting Andrew has highlighted above is pretty much where I'd start. Bear in mind that it's impossible to give a "correct" setting without testing because lots of factors can vary between engines - cam, exhaust, etc.

Mechanical pump was the std fitment.

Compressed air is fine so long as the pressure isn't silly high. But are you sure this is a blockage? A common cause of your symptoms is an air leak at the carb mounts or the inlet manifold. A quick check is to spray WD40 or similar over the mounting and gasket of the affected cylinder. If it momentarily improves matters that is the problem.

Just a change of dizzy - which was completely unnecessary and lost a lot of performance.

Check that you get a spark from the coil lead to earth. If you do, the problem lies in the dizzy/plug leads/plugs (unless the engine isn't earthed but you seem to have dealt with this). Is th distributor actually turning? Has the carbon electrode in the dizzy cap fallen out I don't know what ignition you have, but there is a possible failure there, particularly if you have the abysmal Lucas system supplied by Caterham. The clue is that if you have, your rotor arm will have a steel skirt with four slots on its underside and the whole system is very unreliable and prone to failure. If nothing else works, disconnect the ignition from the car and power it via an external battery to see it that works. It could be lots of other things as well but you have to start somewhere.

I can't tell you what the noise is, but Accralites don't normally make any unusual sounds cold or warm if they're running the correct clearance (around .0045" to .0055"). Are you certain that the valves aren't clashing with the piston pockets? It's a long time since I installed any Accralites but back in my day it was necessary to increase the diameter of the piston pockets if using valves much larger than std; they may have changed by now.

Just fit it as high as is reasonably sensible under the bonnet and you'll be fine. You are correct about the water pump plumbing.

Has the cooling system pressure cap failed?

Hi Alan, Note that in my notes there is a slight difference in valve size but it's not much.

Generally, you wouldn't use anything on the head gasket. The exception to this is when you have a copper/asbestos (or asbestos substitute) gasket because they tend to leak around the waterways. However, I have never encountered such a gasket for the Crossflow so the answer is almost certainly to fit it dry. What make is it?

Sprint engine is completely standard except for an A2 camshaft (later ones used the standard Ford camshaft) and a pair of 40DCOE carburettors. It is sometimes fitted with Caterham's own (excellent) lighter flywheel. The Supersprint is completely standard with the following modifications - bored to + .090", fitted with 1300ccm pistons (which are identical to the 1600ccm pistons apart from a smaller combustion bowl) to increase compression ratio, 234 camshaft, double valve springs with Mini stem seals (that don't work in this application), a little work on the porting, slightly larger valves in better material (which is incompatible with the cast iron valve guides and wears rapidly) and a pair of 40DCOE carburettors (larger chokes and different jetting compared with the ones fitted to the Sprint). That's pretty much it unless I've forgotten something - oh yes, Caterham's own lighter flywheel. Later versions of both types were fitted with Caterham's so-called "unleaded" distributor which simply reduces the ignition advance at higher revs and loses up to 10bhp. The irony of this is that everything we tested on 95 Octane unleaded ran fine on the original distributor type. As a rough guide (not infallible), an orange dizzy cap indicates a Bosch dizzy (leaded type) and a black cap indicates a Lucas type (unleaded). If you have the latter, a distributor change is the cheapest way to get extra power, but whatever dizzy you have, the Caterham supplied electronic ignition is utter rubbish and needs changing if only for the sake of reliability; something like a Lumenition kit would do it, but other systems are available. If I have forgotten something, please let me know!

I'm assuming this is a factory supplied Supersprint. The official Ford seals will only fit inside single valve springs and are a bit like an umbrella. They don't attach to the valve guide and can move up and down with the valves. They work by having such a large diameter that by the time the oil drips off them it completely misses the guide. This is obviously less than perfect but works reasonably well. From memory, the Supersprint was fitted with Mini stem seals. These fit inside the inner spring and have a lip which is meant fit into a retaining groove in the top of the Mini guide. This locates them in place, but, the Crossflow guide is integral with the head and has no such groove - which means that the seals are not properly located and just go up and down with the valves, often getting chewed up in the process. They are almost worse than useless. The solution we used was to machine the top of the guide to the correct o/d to press fit Vauxhall XE stem seals. This works perfectly. Other stem seals are available! I'm afraid there is no satisfactory answer without doing a bit of machining.

Sounds about right though I've never used running in oil. Cam won't need bedding in so long as you have kept the followers in the same order that they were originally installed. If you haven't, you have a small chance of catastrophe whatever you do. I don't know if you have a plateau honed bore finish but if you have it won't take too long to bed in. If you haven't it will take a little longer, but it's not like the "old days" when you really did have to run and engine in gently or you'd destroy the bore finish and the rings. Don't thrash it, don't labour it and don't hold steady revs for long periods - but you've pretty much said that anyway.

That one's quite a rarity. It has a semi-chambered cylinder head and no valve pockets in the pistons.

The ring on the oil separator is actually made of rubber.

Looks like it could be a crushwasher of some sort, so I'm still suggesting sump plug washer. Although it's a little odd in black. They're usually copper or aluminium.

It's not the seal ring for the sump plug is it?