In order to know how extensive the damage was, I needed to test the
compression for each cylinder. A compression test is done using a gauge that can
be bought at any autoparts store for about $25 (see picture).
After removing all of the spark plugs, you plug the tester into each of the spark plug holes, one at a time. I
put on a new timing belt, complete with a new tensioner arm bolt, and lined up
the timing on the crank and camshafts. My 6 year old son happily turned the key
for a few seconds at a time as I watched the compression tester. I wrote down the
results and repeated the process for each cylinder until all 8 were tested.
Three of eight cylinders (one on the passenger side, two on the driver's side) produced no compression whatsoever, meaning that valves in at
least 3 cylinders were damaged. The only way to pull the heads off of the engine
is to pull the engine out first. It's not possible to pull the heads with the
engine still in the car, at least for an '85 928.
Another Rennlist member, Keven ("86.5_Tiburon") kindly offered to help out
by rebuilding a set of heads he had on hand. Once I receive them, I'll be able
to pull the engine, pull off the old heads, and install the rebuilt ones.
At this point, I'm going to have to do the following:
