How To Test Piston Liner O-Ring Seal

[Caxambu@xxxxxxx]

Slowly reassembling the engine after opening it up to replace the head gasket 
(symptom was increasing quantity oil in radiator). Turned out to be a small 
crack in the head, No. 2 cylinder, from exh. valve seat across to the water 
passage. It was beautifully welded up and a new seat installed. New exh. valves, 
guides, seals, valve adjustment. Everything else checked OK. I also installed 
new pistons/rings/liners to cut down the oil burning. The old pistons and 
liners were in quite good shape, but the old rings were very worn. I had the rods 
rebushed and the big ends measured and recut round. They were straight.

So now I am in the reassembly process. It felt so good to turn the ratchet 
wrenches to "tighten."

It wasn't so easy installing the pistons into the liners. First I tried using 
my hands, but found the rings too difficult to compress sufficiently. I ended 
up using a "wavy" ring compressor tool, which didn't work so great, but 
eventually got the job done.

After installing the piston liners into the block and locking them down I 
figured I should do a basic test of the liner-to-block seal by filling the block 
with coolant and watching for leaks from below (the oil pan is off). I filled 
it a bit, looked underneath-- no leaks, so I filled it more, to about 3/4 full 
to the height of the block. Then I heard the unmistakable sound of liquid 
hitting the garage floor--a lot. I was immeditely discouraged until I realized 
the radiator hoses were still disconnected and the coolant was pouring out of 
the lower inlet. The liners still appear to be sealing well. I will recheck it 
again tomorrow morning. I realize this test does not take into account the 
pressure that will build when the engine is running but at least now I feel more 
secure that there is no gross leak. Those liner o-rings seem so thin.

--Caxambu
1969 Spider Veloce 1750
Seattle WA
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