I got to do a bit of engine building over the weekend - about time, because it's been sitting on the bench in the shed for over a month! No matter, I've come back from Bonneville with renewed enthusiasm and I'm keen to get on with it despite knowing that there are going to be a few fitment issues upcoming. Yesterday I fitted the cam, timed it up using a vernier timing wheel and fitted a few components. I've not touched anything car-related in quite a long time so I was being a bit ham fisted at first, plus cam timing is a frustrating job at the best of times and it was trying my patience at times.
First thing to mention when assembling engines is you need to generously oil almost everything and so I thought I'd smugly post a picture of my trusty aerosol can cap I use to hold a bit of clean oil and my 1" brush for painting oil on components, bores etc:
Naturally, it wasn't long before I knocked it over and there was oil everywhere. Predictable. It happens every time and note the lack of a comically placed ironic asterisk, because it's really annoying when it happens.
These are cam lifters, also known as followers or tappets, I don't know which is the correct term and I thought they looked pretty much the same in all engines where the cam is in the block until I looked them up and they don't. But they do the same thing. The lobes on the cam push up and down on the wide pads, the pushrods locate in the other end of them and in turn push the rockers which push the valves open:
They need to drop into the bores in the lifter valley inside the block. You can see here that the far one in the block has had to be clearanced slightly because the cam has a higher lift than standard and the heads on the lifters are slightly thicker than the original ones:
You just oil the stems and drop them in like so:
Then you can carefully slide the cam in, fit the securing plate and timing gear, line up the marks and fit the timing chain and the job is done. On a tuned cam you're not supposed to use the standard timing gear because it can be a few degrees out and it'll affect your power. Instead you use a vernier timing gear which allows you to adjust the cam timing +/- before locking it dead in the correct position. I thought I'd show you the process since it's not every day you have to do this. The process is actually quite simple - you find the exact top dead centre point, you turn the crankshaft round to the angle at which the cam manufacturer has specified that the inlet valve is at maximum lift, turn the cam until maximum lift is found, then lock it all off. You just need a timing wheel and a dial test indicator (dti) to do it.
I set the dti in a magnetic base so that the piston would push the stylus as it went over top dead centre. You can turn the crank back and forth and watch the needle go back and forth as it goes over the tdc point and then you can pick the true tdc in the middle of the dwell where you can turn it a bit and nothing happens. There was no dwell on mine because everything is new and tight, so I just set it at the maximum height:
You then zero a timing disc on the crank, which is effectively making a small pointer out of a bit of wire held down by a bolt somewhere convenient on the engine, then tightening the timing disc so that the pointer points at zero. Mine is a bit of wire coat hanger:
To set the timing you turn the crank in the direction of rotation by the angle specified by the cam manufacturer, in my case 106 degrees:
Then you need to use the dti again to find the point of maximum lift for the inlet valve on no.1 cylinder. I used a pushrod wound in tape to stop it moving from side to side in the bore, because the probe on the dti isn't long enough to reach the top of the lifter:
And that's* pretty much it. Except on a new engine where everything is tight, you can't 'just' turn anything because it doesn't turn doesn't turn doesn't turn suddenly turns and turns past your desired point and you end up doing everything seven or eight times or more before you get it in the right position and it was this that was getting on my tits after a while.
I put a few other bits on, but I spent most of my other time cleaning things. Where the old engine was a bit leaky and oily, it means everything is utterly filthy and needs a lot of scraping and cleaning before it's good enough to go back on. I've decided I'm going to paint the block and head while it's accessible - no point rushing it now to get it back in - and I'll go for a dark grey. I know I could get a few more horsepower out of it by painting it red, but dark grey looks old-timey and doesn't show up the crud half as much. It's one compromise I'm willing to give. I even decided I'd paint the sump, which is a first for me, so here it is after a damn good going over with the knot wheel on the grinder and ready for paint: