Thursday, 12 June 2014

Two heads are better than one?

After some rotary wire brush action the valve heads and combustion chambers looked much better.
The plan was just to stem the oil consumption so I wasn't going to dismantle the valves at all.

Pi heads have double valve springs with two piece valve spring caps, the idea I am reliably informed is that the two parts can rotate separate to each other. I spotted something strange on one of the exhaust valve caps. You can just about make out a hairline crack in the picture below.

So now I had a valve out and curiosity got the better of me. I found that there was a fair bit of wear in the guide............. The solution was sitting on my spare mk1 pi engine at the side of the garage. After stripping all the valves out of the spare head, I found 3 cracked exhaust valve caps but minimal guide wear. Round 2 of rotary wire brushing of a head was completed and I got ready to lap the valves in.
To my disbelief I then noticed something on the exhaust valve seat of number 1.

At this point, reverting to the original but more worn head was the only solution so I consoled myself with removing the front subframe, steering rack and sump. All six pistons followed and at least the news was better this time. The crank had been ground to +10 thou. I had some NOS glacier bearings in just that size.

The big end shell bearings weren't in bad condition and the crank journals although a little marked would polish up fine.

More to follow.......

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