Rebuilding Austin Healy Sprite Engine No 9C-U-H 619
948cc A-series BMC
March 29, 2003
Initial work on the engine:
I took the engine apart over the same winter and brought all the parts to the
machine shop.
Here's a summary of what was done:
Block: There was a bit of a lip at the top of the cylinders and they were overbored
0.020". The block was tested for cracks, all plugs removed and replaced.
Head: All new valves and valve guides. The exhaust valve stems were a little
too large for the guides that were provided (both from Moss Motors) and the
machine shop had to go and buy a reamer just for my job. A couple of springs
were broken and I will need to replace those. The head was completely cleaned
and machined flat. No porting was done (that I know of). The cylinders I got
were 8.3:1 and I had the shop skim a little extra material off the head to bring
compression back up. We will see how that turns out.
Bottom end: line-bored 0.010" oversize and all the rotating parts balanced.
The flywheel was resurfaced. Crankshaft magnafluxed polished and balanced.
Camshaft: The early camshafts ride in only one soft bearing: the middle and
rear saddles do not take a separate bearing and the shaft rides diectly on the
cast iron of the block. The camshaft itself was reground.
Everything was cleaned and sandblasted. I bought: gasket sets, new oversize
pistons, all new bearings, new oil and water pumps, new valves, valve guides
and seals.
As an example of the work done by the machine shop, here is a shot of a rod
cap that has been ground down to make its weight equal to that of the others.
Seeing the amount taken off, it must have been pretty heavy. I don't think physical
integrity is jeopardised in any way, even by this much grinding.