Day 11: Seats, fluids and Oil Pressure


This was really straightforward, and maybe it’s because there is a little bit more space in a SV chassis to wiggle the runners around.

The weird thing with my kit is that I only had one set of runners. The other set is actually two aluminium box section tubes that you bolt onto the seat and then they fix into the floor.

I did what I thought would be best to get it through the IVA and put the runners under the drivers side as I guess this has to be adjustable to pass.

In reality I think that the fixed seat method may be better for me as I am so tall and I think it takes the seat a little lower and slightly further back.

I may still have problems though. In my old K Series I got very used to sitting lower on a bag seat. I had S-Type seats and removed the seat squab, kept the rear bit, and sat on the bag. An ugly looking solution but the perfect driving position for me.

I was hoping that the composite Tillett would get me low enough and far enough back but I fear I may have to go for a full bag option post IVA.

Either way the drivers side with the seat runners was a little more fiddly because of a really badly designed seat runner adjustment handle. It is supposed to slot under the lowered floor cross member. It does, but you can’t move the seat fully forward because it fouls. Not really a problem for me, as it’s only ever going to be fully back. On this side the bolts drop down through the floor.

On the passenger side the bolts pass up into the threaded holes on the underside of the fixed bracket. Looking at these fixed runners I think alternatives could be fabricated that drops the seat a little lower. Or maybe they could be dropped altogether and then I just use a stack of Tillett black spacers. Not sure whether this would spread the load on the fairly thin floor though. Questions to ask the guys at BookaTrack.

Oil Pressure theory

There comes a point when even I have to stop chickening out of starting the engine. Today was this time. But it didn’t quite work as planned.

On advise I decided to removed the crank position sender at the front of the engine as a way of avoiding a spark. In fact I went one further than that and didn’t put any fuel in.

The objective is to crank the engine over on the starter motor until oil pressure is registered on the gauge.

But before that point we had to fill and bleed both the clutch and brake fluid.

Clutch fill and bleed

Really simple job, pour brake fluid provided into the clutch reservoir, use a bit of flexible tube over the bleed nipple, then into a small container so that fluid covers the tube.

Then undo the bleed nipple and pump the clutch until fluid minus air bubbles is drawn up and out towards the container. A quick tighten of the bleed nipple later and we had a good feeling clutch pedal and we’re playing around changing up and down the gearbox.

Brake fill and bleed

I’ve done this plenty of times over the last 5 years on my old Caterham as I was never quite happy with the feel of the brake pedal, it was always a bit soft.

So this time around I selected the upgraded brakes which comes with an upgraded brake master cylinder plus twin pot callipers.

The only difference this makes is that there are 2 bleed nipples on each side at the front, so the inners need to be bled before the outers.

I used an EasyBleed kit and filled starting from rear LHS, then going to rear RHS, followed by front LHS and finishing up with front RHS, in effect rotating around the car from the furthest point from the master cylinder.

I had a little bit of a leak in the fronts where I obviously hadn’t quite tightened up the connectors inside the body skin. Sorted that, wiped down and squirted ACF50 to dilute and rinse down the inner skin.

I also had the connector to the inner calliper leak a little, and so I nipped that up an checked the other 3 (inners and outers) on the fronts, seeing as these came pre built.

Anyway, to cut a long story short I’ve bled twice since and I’m still not happy. The pedal starts to firm, and then after a few seconds pause goes soft again.

I will have a go using the old fashioned brake pedal pump method and bash the callipers with a spanner to try and release trapped air.

So I stopped faffing with that because I was still, as I said earlier, putting off the inevitable.

Engine oil fill

I made a decision a few weeks ago to get my engine run in professionally at Northampton Motorsport. Basically they put it on their rolling road and during a 2 hour cycle bed the piston rings in properly and leave me with a car I can thrash around a race track without having to mess around for 500-600 miles myself. Seems smart to me, but I know there are lots of differing opinions on this. Either way, to go through this process properly I needed to buy special running in Mineral oil. I bought 10 litres of Millers CRO 10w-40 and this is what I used to fill the car with.

The assembly guide tells us to dump 5 litres in the top of the engine, but seeing as it’s a dry sump system I checked with a few others on this point. Derek, another 420R self-builder had been through a bit of a painful process here, and was eventually told to put 3 litres in the top of the engine and 4 in the dry sump tank. I double checked with ‘Caterham’ Derek and he confirmed this. So that’s what I did.

(Not) Getting oil pressure

So with the crank sensor removed and no fuel in the tank, and oil in roughly the right places I fished out the key, switched in the ignition and pressed the starter button. I held it down for about 30 secs and registered no oil pressure.

Craig then took the cap off the oil tank and witnessed gushing oil re entering the tank from the top inlet, in effect back from the engine. So we had oil flowing and therefore should have been seeing pressure on the gauge.

I kept trying in 20 second bursts but then the battery started fading so I stopped, charged it for an hour on my Optimate trickle charger and then tried again. And again, and again. Still nothing. So the concensus is that I have oil pressure but either a dodgy oil sender or a dodgy gauge. My money is on the sender. Seeing as the gauge sweeps around on ignition as the others do, so it has power.

I was doing all of this on Sunday, so with no Derek to check I didn’t try and start the car properly. I needed to hear his opinion. So I left it until Monday first thing. He agrees with the assessment we made and is sending me a replacement sender and a gauge.

Unfortunately I’m now away in the US with work for the week, so can’t get the engine started until next weekend.

Derek seems to think that we should just start the engine seeing as we have oil flowing around the system. Then see what happens. I’m thinking about this approach and undecided. I may still swap out the sender first, as I have this urge to see the gauge function properly.

potentially faulty sender

So that’s it for now. I have to get the engine going, and it’s all I can think about at the moment.

After that it’s the rear lights, front arches, roof, so fun with poppers again, the tonneau, the doors and mirrors and I think I’m finished. Which means that I potentially will be done 13 days in. My average build day is around the 6 – 7 hour mark based on recorded 60 second interval photos from my go pro. Which works out at an 85 hour build. But my cup is always half full, so we will see, I may need a few more days taking me close to 100 hours of effort. I will report more accurately at the very end!

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