Ignition timing

Its funny I have always taken the setting of the ignition timing to be a thing of simplicity; read the manual to see what the timing should be (lets say 8 degrees before the piston is at top dead centre). Attach a strobe light to spark plug number one, start the engine, turn the distributor until the pointer points to 8 BTDC. Done, have a cup of tea.

Vintage cars, no surprise had not evolved to the point where they had timing marks. Okay step one, read the manual – nope I don have one of those so revert to the internet. Zero degrees before top dead centre. Really? Okay i can live with that. 0 BTDC with the ignition fully retarded – oh thats the lever on the steering wheel, i remember. ok done. now what… of how do i know when the piston is at TDC? Back on the internet… use a ‘timing stick’. Oh one of those things that no one has seen in donkeys years – a tool that is screwed into spark plug socket number 1 and has a rod in the centre that is pushed upwards by the piston which then rotates the built in dial gauge so you can see down to one thousandth of an inch when the piston is at the absolute top of its arc.

Well I have a dial gauge that measures thousandths of an inch – and the race boys set the ignition at 5 degrees before TDC so a bit of simple maths taking into account the length of the piston conrod, the arc rotation of the crankshaft and some black magic means that i am looking for 8.5 thousands of an inch before TDC. Got it. but i still don’t have a timing rod – perhaps a bit of wood? Nope it wobbles in the plug hole, an 8mm brass rod? Better but still no. Oh bother lets make one properly…

FatBadger Garage timing stick instructions:

  • Take one spark plug
  • Remove all its internals
  • Fill the inside with a drill-able material (metal filler will do it)
  • Drill a hole a smidge wider than a rod of suitable length – beware of dropping the rod inside the engine!
  • insert new tool into spark plug hole no.1
  • rotate engine using the starting handle (i knew it would come in handy) until the engine is in the right place.
  • Rotate the engine until the points just open. Doh! I have rebuild the distributor so that it no longer has points…. umm
  • Rotate the engine until you get a spark at the end of the lead that would have gone to plug 1 – yep that’ll work
  • Robert is apparently now my  uncle

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Yes – i know… the dial gauge is showing 4 not 8.5 – i don’t seem to have a photo at its correct position and i am not going to do it all again. Whilst the valve covers are off, i will clean up the cylinder head a bit and replace the cork gaskets etc… onwards and upwards.

I have only one month before the car goes to the coach builder – i have some detailed design stuff to do…

Frost damage repair

Going back a couple of posts you may recall i had a small hole in the side of the engine caused by water freezing and expanding with such force that it blew out the side of the block.
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You will remember I had left the metal filler to dry thoroughly before attempting to drill and tap the holes for the bolts. The brass plate was already the right shape so I now measured out a neatly spacing row of  punch points around the plate and drilled a 4mm pilot hole wherever i wanted a bolt to be. Using these pilot holes as a guide, I then drilled a 4mm hole into the side of the engine. Most of the holes were made as you would expect, a cobalt drill making short work of the cast iron. BUT 2 of the holes needed to be where the previous owner had applied weld to his patch panel and his ‘repair’ had made the metal so hard that it blunted TWO brand new cobalt drills whilst barely making any impression. It was with some sadness that i was now forced to drill holes off line with the other bolts to avoid this super hardened material. This results in a job that is less neat and certainly not what i had envisioned. Never mind – such is life. A repair that holds back water is more important than the asthetics of having 2 bolts slightly off line. The exhaust manifold hide the repair anyway – but i like a ‘proper job’.

The next challenge was making a gasket that was waterproof. Obviously i can’t buy a ready made gasket for this but manufacturing one is not so hard. I just had to find the right material. This part of the excercise was a little silly… I found a company that made said gasket material in 1m square sheets and i needed around 120mm x 120mm maximum. They said they could provide a sample which seemed like a good idea so i asked for a price. £10 they said plus £10 shipping. Seriously £20 for sample? I popped onto your favourite online auction site, found someone selling an off-cut of the same material and bought a 200mm x 200m piece for £6.50 delivered. How can eBay be so much cheaper than buying direct from the supplier. The salesman is missing a trick i think and £10 to put a flat sheet inside an envelope is just taking the proverbial.

So below is the gasket cut to size and held in place using blue Hylomar – my favourite sealant. The holes were made with a punch, intentionally slightly oversize because you can’t see where the middle of the hole punch is
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It was then simply a case of bolting the panel into place. I had thought of keeping it natural brass, but i didn’t like the fact the bolts were not neat so it got a coat of paint to match the engine. I then filled up the engine with water and left it a week – no leaks. So thats that job done. Moving on…

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