Its Alive…

I am pleased with the recent work, the engine is back in, fully connected up and all the bodywork has been put back on. I will admit to mild trepidation with the very first start up but a little diligence with ensuring I had a good fuel supply and the ignition was producing a spark – all that was left is getting the ignition timing ‘about right’. That is not so easy on vintage cars – they dont have any timing marks and in the good old days you just rotated the dizzy until the car started then locked it in place. But initially I had to guess the setting which to be fair was close and it resulted in the engine trying to start so I tweaked the ignition until it DID start. I had forgotten how loud the car was but it was firing on all cylinders and the oil pressure quickly came up to 55psi (I will adjust that later).

I had been given a ‘running-in regime’ by the engine builder which was simple to follow – start the engine and let it run for up to 1 minute then turn it off. Do this a few times until the engine has got a reasonable amount of warmth into it. Torque all the head nuts down to the factory setting of 45lb per square inch. The next step is to fill the engine with coolant, start it up and bring to running temperature, keeping an eye on the oil pressure and the water temperature.

Okay easy enough – garden hose goes into the top of the radiator [oh pants the water pump is leaking profusely again]. Quick fix then – bypass the water pump and simply allow the engine to thermo-syphon (hot water rises, cooler water drops – this creates a natural flow of cooler water through the engine. This is why vintage cars had such large radiators because thermo-syphoning is not a fast flow

[tighten a few more nuts until the leaks stop]. Start the engine again. Oil pressure good, temperature coming up, a few minor water leaks which a coolant seal like rad-weld or similar will cure. At this stage the engine could easily overheat, which is highly likely with a new tight engine, no radiator fan and a lower rate of coolant flowing, with the water temperature reaching 85 degrees, I turned the engine off and again rechecked the torque of the head nuts – a few needed a tweak. So before taking the car out for a drive, there were a few things I wanted to put right first. The waterpump leak was found to have the carbon seal spring missing and with no pressure against the seal – water was free to flow past it – i put that down to a schoolboy error, i have had the water pump off enough times to know I need that spring!

But the next thing needed a bit of creativity. The exhaust manifold was custom build and when it was made – insufficient room was left between the pipes and the studs that bolted the manifold to the engine. This meant that it was literally impossible to put the retaining nuts onto the studs. Previously I worked around this by using high tensile steel hex head bolts which require an Allen key to tighten them up. The heads of these bolts are much narrower than the original brass nuts so the solution worked but over time they rusted and were a real pig to remove when I took the engine out. My new solution was to make some brand new studs, seal them into the cylinder head plus manufacture some special brass fixings that would be sized to ‘just’ miss the pipes. I got the idea from the nuts that hold the valve covers on – although they do have hex sides for a spanner – they are installed into a confined space making the use of a spanner rather difficult so they ALSO have a slot cut in the top so that you can actually tighten them with a large screwdriver… that was my eureka moment.

The good part of all this is I get to play with the lathe AND make some more bits out of brass (which doesn’t rust so wont seize). I needed 4 brass ‘nuts’. Below you can see what I produced, 2 of them are upside down so you can see each end.

The screwdriver slots are 2mm wide and about 5mm deep. The base is intentionally wider than the top to cater for the slight angle of the exhaust pipes and there is plenty of meat in the tops for the screwdriver to get a good purchase. They do not need to be tightened too much so I know this will work.

To cut the slots I went old school and used the lathe as a milling machine. Usually the part to be machined is placed in the lathe chuck and you move the cutter across it forming the shape you want. To convert it to a milling machine you insert an end-mill cutter into the chuck of the lathe and move the part to be machined across the cutter. Holding the part to be machined is the tricky part – it needs to be held very securely so this does need a special holder which to be fair I had from my old lathe but never used. Nothing like learning new skills as you go along.

A 2mm end-mill is fragile – if you apply too much sideways pressure onto it – it will snap. Larger diameter end-mills are of course much stronger… below you can see the milling clamp in the centre of the lather and in the picture below the end-mill in the lathe chuck

My Myford ML10 with milling adaptor.
Close up of the 2mm end mill and the brass component waiting to be worked

The milling clamp allows me to move the component to be machine up and down until the brass bar was in the right place for the end-mill to cut through the centre of it. By using the lathe cross-slide, I could now move the brass towards me so that the end-mill touched the side of the brass bar and then onwards to cut a slot. I took this slowly and carefully but it was fun to do and its a pretty decent job.

Below you can see one of the new brass nuts in place and you can also see what the challenge was. There were another 2 ordinary nuts on the manifold which were perfectly fine as-is but they now looked different to the ones I had just made so I manufactured a slightly larger pair of brass nuts to replace those too – they do not need a slot because you can pop a spanner on them.

I am rather pleased with the outcome – most people will never notice but they do the job just fine and look nice. I think I might replace all the steel valve cover nuts to match when I get some free time. You can never have too much brass on an engine.

So the engine was now almost leak free (vintage cars always leak oil), it has decent oil pressure and the moment had come for it to be tested on the road. This is always a nervous time, what if it seizes up – how do I get it home? So i nervously drove it up the road a few times first. My confidence quickly grew so I drove it around the block, then 2 blocks, then a 5 mile round trip. Coming home I re-checked the oil, water, fuel, head nut torque, slightly adjusted the timing and the carburettor mixture and the engine felt good to go out again. So all in all – we covered 15 miles today in ever increasing circles.

I am pleased to say the rebuilt and modified engine is so far noticeably more responsive, it definitely has more torque and very easily keeps up with modern traffic even at the reduced ‘running in’ speeds. After 100 miles I will change the oil and the oil filter. After 500 miles I will again replace the oil and filter but this time also remove the sump and give it a good clean out. Refill with new oil again and simply drive the car as normal after that…

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