Eng​ine first start, the big day!

16th February 2019 was the big day, the day we first started my Caterham 7 420R. A week has gone by now and it's time I blog one of the most important milestones in the build.


Overall it was a fun day, which went well, considering how nervous I was about the whole process. The only tension occurred towards the end of the day when trying to get the radiator fan to start. If you've read my previous blog you'll have some insight into that! My mate Mark came along to provide is support, expertise and usual frustration at my procrastination.


Preparation for the day was fairly straightforward, I performed a nut and bolt check if you will on all the coolant and oil hoses, plus a check of the various senders.


On the day the first step was to add coolant to the cars cooling system, unfortunately I'd not spotted the supplied coolant was concentrate. A trip to a motor parts supplier was therefore required to pick up some deironized water to mix with the concentrate. Once obtained the coolant concentrate was mixed 50:50 and added to the system. From memory, the system took approximately 7l of mixed coolant fluid.


Next up was the car's oil. I'd previously sought advice from Caterham Cars and also BlatChat regarding the ratio of oil to be added to the car's dry sump reservoir and standard fill point. In the end I went with Caterham's recommendation, 5L into the reservoir and 2l into the standard fill point.


Of course fuel was added too, I went with a recommendation from BlatChat, a minimum of 15L, we added approximately 20L to the fuel tank.


Mark and I debating how to pour fuel. Or may be the quality of his jerry cans!

Once the fluids had been added, we were ready to start!


The process of starting the car is fairly well documented, simplified the process is essentially;

  1. Disable the fuel pump through disabling the inertia switch.

  2. Switch the ignition on, crank the engine over via the starter button and starter motor until oil pressure develops, as shown on the pressure gauge.

  3. Re-enable the inertia switch.

  4. Crank the car over in short bursts using the starter button until it starts.

I'd previously sought guidance about the startup process from BlatChat, and I'd received some excellent input. Notable comments were to watch the heat generated in the starter motor when cranking the engine over, and also to remove the spark plugs to reduce the pressure in the engine when cranking over, and subsequently give the starter motor an easier time.

Above photographs taken removing the spark plugs.


We heeded the advice, so before we started cranking we removed all 4 spark plugs, it certainly helped the engine spin quickly and developed oil pressure after approximately 15 seconds which was fantastic. Don't forget we'd previously disabled the inertia switch.


Now that oil pressure was present, the 4 plugs were added back and the inertia switch reinstalled and reset. The moment had come! Cranking the car over to actually start.


We cranked the car over using the starter button in 5 second bursts for quiet a while, well what seemed it. It was certainly long enough to exhaust the reserves in the battery, so I had to grab my booster pack. Unfortunately the car wouldn't fire. We were suspicious it wasn't getting fuel. To check we decided to remove one of the spark plugs to see if it was wet with fuel. So we removed one, it didn't seem wet. We also checked for spark by grounding the plug, sure enough it was getting spark. Following our checks we put everything back and tried again. We still struggled, unfortunately the little booster pack couldn't cope either. Given this we were forced to put the car's battery on charge and wait for the charge to build.


After a small wait, I left the charger connected and went for a start again. This time it fired, and burst into life. I'm not sure why this time over other, but it was running. We quickly spotted the idle was a little high so halted the engine and adjusted the idle on the intake plenum. Once changed, the engine was started again, and once more she fired without issue. Great, we were truly on our way.


I have some GoPro footage taken from the side which I'll post at a later date, for now footage of the big moment from a mobile phone.

Our focus then turned to bleeding the cooling system and that was a confusing process, but thankfully BlatChat came to the rescue. The issue was that the assembly guide implies a temperature in the mid 90c should be used when bleeding the system. Unfortunately on a Duratec such as that in the 420 the thermostat doesn't open until much later. We spent a lot of time trying to bleed the car and getting concerned the temperature was getting too high, but it wasn't It was fairly obviously the thermostat wasn't opening as the bottom hose wasn't getting hot. Eventually we moved passed this and got all of the hoses hot, we then released as much air through the bleed port on the top of the radiator. We also lifted the car at the front to help ensure the radiator and expansion tank were higher than the heater matrix. Finally air ceased to appear, we had hot hoses and heat coming out from the heater, so all good. Along the way we did pick up a number of leaks from hoses where I'd not tightened the jubilee clips sufficiently, for example around the submarine connections. These were pretty easy to fix, a quarter turn here and there.


I mentioned previously we still couldn't get the fan to start, and this was a problem.


A huge amount of time was lost gradually trying the car at increasing temperatures, but eventually we conceded and accepted more research was required. I eventually found the issue, which was faulty wiring on the fuse board. Details of which are available in my earlier blog.


All in all then a good start! She even had a small drive to the bottom of my driveway and back as we tried to solve the fan issue.


At the bottom of the drive, just on the street.

You'll have to excuse the questionable dress sense, it was a cold February Saturday, and I was layered up.

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Meet Mark
Loves cars, light weight specials, jDM, Lotus, Caterham, Rallying and Trackdays