A series valves

Adrian is sorting out the reconditioned cylinder head for my Austin Allegro. He's made up a mandrel that fits inside the new silicon bronze valve guides and drifted them into the head but when I dropped in the other day he told me that the old valves weren't quite as good as they might be. If we looked closely at the end of the valve, the area where it meets the rocker was slightly warn. I could actually see fine lines running across the surface and if I ran a finger across the valve I could feel them too.

Adrian didn’t like the look of these. He said that these imperfections could lead to the valve being pushed over sideways, as the rocker levers it against the valve guide whilst the valve is off its valve seat. This would have increased wear on the valve guides and before long oil would be seeping passed and the engine would start smoking again.

One solution would have been to clean up the end of the valve but when I saw that valves were only a few pounds each from Minispares, I opted for new ones.

I asked Adrian if the rockers themselves would have a similar problem on their contact pads but he said he would have a look and dress them up on a stone if necessary.

I also bought some new valve springs because they're only £1.60 a go.

Now that we have the valves, the valve seats themselves might have to be re-cut because British Leyland valve guides were notorious for being so eccentric. Aftermarket valve guides are made to much closer tolerances than the rubbish the factory turned out but, once fitted, new valve guides can cause the valves to no longer fit properly on the valve seats.

When I arrived with the new parts, Adrian was involved in some displacement activity. This wasn't surfing the Internet when he should have been doing something more practical. He was boring out the block for another A series engine, this particular one having originated in a Metro Turbo. He was doing it with a boring bar and I found the operation quite fascinating. Once setup on alignment of the cylinder bore and switched on, the boring bar moves the cutting bit down the cylinder at a predetermined rate.

I asked him if he was going to do a really big bore but he said no, it was just a 20 thou over bore.

We had a brief discussion about doing a big valve head for the Allegro but, when we remembered what car is going into, we thought better of it. One day, it might be fun to do a really fast Allegro, but that day has not yet arrived. I just want my standard Allegro not to smoke like a two-stroke on start-up.

I quite fancy my own boring bar, though. Apparently, they come up on eBay fairly frequently.