So the big one. Let's pull out a perfectly good, working, well cared for engine and replace it with another one. Why? Power, that's why. I needed more. Not wanted, you'll notice, this was a definite need!
This 'requirement' started when Mandy and I went on the first Se7en List organised Haggis Hunt in May of 2001. We had a fantastic time, but I could help feeling that I was working harder to keep up that the others in our little group. I started to get an inkling that maybe I needed a little more under the go pedal.
The true deciding factor though was when our main crowd spent the day at Curborough Sprint track, driving each others cars and making notes ready for a comparison article in Low Flying. Here, my car was the lowest powered, with 100bhp, with cars ranging through 155bhp RKE1700's, a 2.0lt Zetec and a 2.0lt VX. Given the chance to drive each car, I soon found that, despite being unfamiliar with each car, and therefore taking it a bit easy, I did enjoy the grunt from the two 2.0lt cars. They really could be driven it two modes, lazy cruiser or full-on blat attack. My decision, it seemed had been made for me.
I did, of course, look into tuning my x/flow. This would have given me almost the same power, slightly less torque, but less weight than the Zetec. The trouble I had with this was that I didn't want a stressed engine particularly. The x/flow as a 1.6 had been reliable and fairly unstressed, with just a pair of carbs bolted on to bump up the performance. The problem with tuning it close to Zetec power levels is that it would require more maintenance and it would have reached it's comfortable limit, beyond which I wouldn't want to go. The Zetec on the other hand, offered more power, more low down torque and all on the standard internals. The Zetec also offered the benefit of being completely modern with widely available spares, 16v flexibility across the revs and better economy - not that that last one is a factor for a sunny day 7. Oh, and if the power wasn't enough in the future, I could go further at fairly reasonable cost. The next factor was cost and to tune the x/flow to a reliable 155bhp would have basically cost not much less than a Zetec swap. Either way, it was going to be a lot of money, and I wanted the result to last a good few years and give good service.
So the search began for Zetec information. Everywhere I looked, Blatchat and the Se7ens List, two companies were constantly mentioned, Dunnell Engines and Raceline Engineering Ltd. As it turned out, Raceline were only about a 30min drive from my place of work so I popped over there one evening and had a chat with Chris Smith about the various options. I had already worked out the various cost permutations, and had decided I would go for a built engine, basically ready to bolt into place. However, Chris talked me away from this route saying that the work required really wasn't very involved and if I'd built my car I'd be more than capable, and I'd save a nice chunk of money at the same time. So this was my preferred route. I would get the engine and then a kit of parts, including the sump, inlet manifold for my carbs, water rail, alternator mounting kit, lightened flywheel, ECU+loom and throttle position sensor. All I'd have to do was put it all together - easy. In addition to the engine kit, I also needed a few other bits that were more specific to fitting the engine in a Caterham. These parts included a new water pump from an 1.8lt engine that pumps water the opposite way to a 2.0lt, the water hoses to mate to the radiator, etc, and a few odds and ends that don't come with a brand new engine. I should mention that I had decided to buy a new engine for two reasons. The first is that I am a bit fanatical about my car so really only a new engine would do for me, and secondly I wasn't really interested in trying to sort out the good engines from the bad when dealing with breakers. A used engine would have had the benefit of being nicely run in though.
Whilst I patiently waited for my order with Raceline to arrive I found an alloy bellhousing which was an RS2000 item and actually had enough time - or was sad enough - to sand back the casting and polish it. To go with this I got hold of a matching clutch release arm as the taper is narrower to suit the bellhousing casting. I also took the car off the road and over a weekend, took the old engine out. This was very straightforward with help from Steve and his hoist. Being the first time the engine had been out I took the opportunity over the next week or so to clean the engine bay and touch up any powder coat with some satin Hammerite paint.
I took a trip to see James Whiting an bought a set of his exhaust pipes. I wanted these specifically as they are designed to mate to a standard Caterham side exit silencer, one of which I had on the x/flow. Again ,whilst waiting, I removed the unsightly welds and then spent a very very very long time polishing it, working through all the Wet & Dry grades up to 1200 grip, before finally putting it on a polishing wheel on my bench grinder. I would not do this again - it was a boring, dirty and depressing job, only bearable for the fact that it was usually cold and wet outside. The result was probably worth it, although I'd happily pay a company to do it for me next time.
The phone call came from Chris sooner than I expected, three weeks after the order, and I hastily arranged to go over and pick my new engine and a large box of bits. Many thanks to Rory who came with me towing his trailer, to which we strapped the engine crate. The major headache of how to get it home solved. The kit of parts included most of the bits I needed with a few outstanding due to longer lead times.
Steve's hoist came in handy again lifting the engine out of it's crate - which became a very useful bin and worktop in one. The first job was to attach the engine to Rory's engine stand. This proved harder than it originally appeared and I didn't quite trust it so I left the hoist in place as a backup. The sump had to be replaced with the nice cast Aluminium Raceline version and this also meant some bolt heads had to be trimmed down to give clearance. The sump had to be sub-assembled first, fitting the oil pick-up pipe and the anti-airation plate. A new sump gasket plus a small amount of silicone in the specified places and the new sump was fitted. This was going to be easy. Next up was to swap the water pump over to the 1.8 version. This required that the cam covers be removed. This was straightforward and as I wasn't going to be re-fitting them I also removed all the backplates and stand-off bolts. They actually weight quite a bit as they are pressed steel. To get the old water pump out and the new in meant that the cam belt had to moved forward. I taped the belt to the cam pulleys and edged it out gradually. Eventually I just had enough room to get the pumps swapped, but the belt was right on the edge of falling off - see later! A breather box had to be fitted to the side of the block, with gasket and three bolts - very simple. Lastly the cam cover was swapped for a nice shiny red one and it was looking good!
I was now ready to put the engine in, as the remaining items like the alternator mounting kit and the hoses had to fitted with it in the car anyway. As with the original build, the bellhousing and gearbox were bolted to the engine before gradually lowering it into the chassis. This was where a slight problem was found. Steve had come over to be part of the birth of another Zetec, and between us we huffed and puffed and had to heave the engine and gearbox so that the mountings would line up. I though this was a bit odd and it wasn't until after Steve and I had got all the bolts into place that I spotted that the 'spare' starter motor position on the bellhousing was now sitting nicely on the triangulation chassis member in front of the drivers footwell. It's not meant to do that, and I suspect that when the chassis was changed that year the tube moved, indeed I have seen them with a 'Y' shaped piece at this point. I therefore spent the next two nights laying on my back with the engine supported on the hoist trying to file away the bellhousing. After 6hrs it dawned on me that this wasn't really working and admitted defeat. The engine would have to come out again. By now, I was getting the hang of it and so did this on my own. A bit more research and I decided to make a plate with a slot for the gaiter that would be fixed in place of the starter position, once cut off. I cut the bellhousing down and then measure the size of the plate required. I had to retain the thin part where it mates to the block as this holds the clutch cable outer, but I did cut it down to give clearance. I was also able to measure the position of the gaiter from the old cast iron bellhousing and then make the slot using a cutting disc in a high speed multi-tool. I used some very strong metal bond to glue the plate into place and the whole thing only took me a few hours to do. This time the engine went straight into place with none of the effort required to line up bolts, which was nice.
With the engine in place, I could then position the wiring loom and sort out the position of the ECU. The now very shiny exhaust could also be bolted into place, with a bit of modification to the side skin required. I also used the opportunity to give the carbs a thorough clean, using cotton buds and white spirit got most of the ingrained dirt off and they looked like new again. These were then bolted to the inlet manifold which was in turn bolted to the engine, having collected a gasket from the local Ford dealer.
There then followed a frustrating wait while I waited for the silicone hoses and the alternator mounting kit to arrive. I had decided to go for the hoses in silicone as the cost difference wasn't that great over the normal rubber and the silicone hoses don't perish - plus they look much nicer. I had also requested these in red instead of the normal blue as I wanted them to match the cam cover. While I waited I carried out the suspension changes, fitted my Christmas present of a battery cut-out switch, fitted and wired in a starter button, installed the electric fuel pump and made a start on the brake modifications. Brent (Zetec owner) very kindly also came over and helped me route my heater hoses, using some copper pipe to line the silicone hose to prevent it kink'ing and giving a very nice bend.
Once the two items arrived I was a) able to stop pestering Chris and b) finish the build. Both items were straightforward to fit and I was just left with little jobs like fitting the throttle position sensor, filling the engine with fluids, etc.

So the time arrived. It was time to see if this thing would run. I triple checked that all the essentials where there, oil, water, fuel, the battery had been on the conditioner all winter. No reason not to then. The spark plugs were removed and I spun the engine over 4 or 5 times in short burst of around 10 - 15 secs until the gauge registered some oil pressure. Steve came over to help with the initial tuning of the carbs and brought over a friend from Sweden, although no literally, of course. So, I jumped in the seat, watched the fuel pump through the filter in front of the carbs and gave the pedal 5 or 6 prods. I turned the key and finally pressed the new button. And away it went, fired first time, but it didn't run very smoothly. Steve leapt into action with his carb balancer, but they were pretty much spot on - the old trick of lining up the butterflies through the progression holes works well. A quick check of the idle screws and it was still running roughly - I think I referred to it as a tractor at the time. Something wasn't quite right. Steve then noticed that there was a large quantity of fuel being thrown back out of the carbs. You could actually see a mist emanating from the trumpets. There was definitely something wrong here.
We called it a night and I retreated to contemplate possible causes. The only thing I could come up with was the cam timing. If the inlet and exhaust cams were out of sink it could be why the fuel was being thrown back out. Brent kindly gave me a suitable piece of flat bar so that I could check the cam timing. The method for standard cams is to place a 5mm flat bar into slots in the cams. The bar will only fit in place with the cams in the right rotation. In the end I didn't need the bar for the initial check - I could instantly see the two slots on the rear of the cams didn't match. Problem found - I just hoped that it hadn't done any damage internally. I had to set the engine at TDC to be able to re-set the cams. To do this Raceline lent me a DTI and some other bits. The technique that I used was as follows:

With the cam cover removed, I fixed a steel plate in the center trough, using the middle cam cover bolt holes. This gives a base for the DTI's magnetic base to fix to. The plate should be flat and have a 6mm hole directly over No.1 cylinder.
I dropped a length of 5mm rod down the hole into cylinder number one. Obviously making sure that the rod was long enough not to disappear.
Positioned the DTI so that the point was resting on top of the rod with plenty of movement in both directions and set the dial to 0.
With an 18mm socket I rotated the engine until the DTI reading reached a peak, at which point it would dwell. I checked that I had the right cam rotation - i.e. not 180 deg out - by seeing if the cam slots are in roughly the right position. Then I re-set the dial to 0.
I rotated the engine backwards (anti-clockwise) around 1/8th of a turn and then forwards (clockwise) until the dial reaches 0 (the beginning of the TDC dwell).
Then I attached a protractor to the main pulley and lined up the 0 with the TDC marker on the engine.
I continued to rotate the engine clockwise but stopped as soon as the DTI started to register a drop of the piston.
I read the amount of rotation on the protractor and make a note of this figure and divided it in half to get the mid-dwell position
Then I reversed the engine, again by around 1/8th of a turn. Bringing the engine forward until the TDC mark is in line with 0 on the protractor. I continued until I reached the mid-dwell position calculated and checked that the DTI still read 0.
This was TDC of No.1 and I marked the pulley for future reference.

With the engine set to TDC I could clearly see that it was the exhaust cam that was out, as the inlet slot was parallel with the head. A few minutes later and the cam belt was slackened off, the offending cam rotated back by one tooth (which equated to around 9 degs) and the belt was back in place an tensioned. I then double checked everything and very slowly rotated the engine by hand listening for any bad noises. None came and I was eventually satisfied enough that I should try starting her again. This time it ran perfectly, so smooth and a rock solid idle, that was more like it!
All I needed then was to finish the brake upgrade, put the rest of the car back together and some descent weather.
Once I hit the road it was pretty clear that my carb set-up was not ideal. It idled perfectly whatever jet we fitted but at around 2750-3000rpm it had a very large flatspot that was quite hard to drive around as I was trying to run it in to begin with. I lived with this until the running-in period was finished (500 miles, upping the rev limit by 500rpm every 100 miles, starting at 3500rpm) and then booked a rolling road session as we hadn't been able to find a solution amongst our collection of jets. On the eve of the session I had an exciting moment which highlighted why it needed to be done. Exiting a local roundabout on a wet, dark night on my way to get a full tank in preparation I had an idiot close behind me. I thought I would pen the gap a little to a safer distance and put my foot down a little more, in 3rd gear still only doing around 40mph. The car picked up, and then went into the flatspot - great I thought, then it came out the other side, hit a wave of torque and the car stepped sideways, by now at about 60mph. Sevens on a wet road deserve respect, but this was silly. The RR session was pretty straightforward, just going through each adjustment in turn. The biggest change was made by swapping the F16 emulsion tubes for F7's. The rest was just minor tweaks from then on.
The drive home was great, no stuttering, just seamless power and totally useable. I sill couldn't bring myself to find the rev limiter - that took a while. What a great engine it is too, I don't want a screaming rev-craving engine as I like to be able to change from banzai blat to relaxed cruise home, etc. The Zetec gives the best of both worlds and the extra grunt over the x/flow (165bhp verses 100bhp, and 146ft lb verses 100ft lb) really brings the car alive, with enough squirt to blow away most cars that are brave enough to try. Of course, I'm now wondering if a little more would be worth pursuing. To this end I have a spare cylinder head ready for porting but I'd then need new cams, verniers and it would need re-jetting again, so I think it would be wiser to go to injection with throttle bodies, but this adds tank, fuel lines, TB's, fuel rail and a new ECU to the list, to name but the main items. We'll see though, it will have to come eventually.

Useful Contacts:
Raceline - 01483 811978
James Whiting - 01784 241466
Clifford Cox Engineering


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