very low compression on 72 alfa 2000 spider

[ramiroflores]

Hello everyone. I'm a newbe to this chat but I need help.
I have a 72 alfa 105 spider 2000
ground up resto.
did not fight me one bit....... Til now
rebuilt head.
new bearings everywhere.
new gaskets everywhere.

before intalling the engine in the car I thought i do a quick compression test and even go as far as firing up the engine just to check for any leaks. Didn't want any surprises.
torque down the head to 67 ft/lb.
took out the cam shafts so all valves are shut. I thought i'd do the timing later. This was purely a compression test.
and no compression.

well
1-30psi
2-40psi
3-50psi
4-55psi
I put a little oil in the cylinders and did a wet test. No change.
I took the head off and had it on the bench upside down. put some fuel in the semi spheres to see if there is a valve issue. no issues. fuel stayed there for a day. I had to clean it up. so no leak there.
I put the head back on and did a leak down test.
It seemed that air was escaping from everywhere but mainly from the crank case and water ways. (this is with wet pistons)
I read somewhere that the cylinder sleeves must sit proud of the block bu about 0.03-0.05mm. so i checked that. the sleeves are not sitting proud. they are level with the block edge.

could this cause the low compression?
do i now have to take out the sleeves and replace the O-rings?
Or is it possible to put shim spacers between the sleeve top and the gasket. (i read somewhere that this is a possible remedy. bit dodgy but i don't know.)

please help.
Thank you

[KevJTD]

Hi.
First of all to get a compression reading you can't do it with cams out, air needs to get in via the valves as the piston goes down, all you're doing is creating a vacuum as the piston goes down then as you go back up the pressure will stabilise, a bit of fluctuation as air will get past the piston rings in both directions of stroke.
You can't test compression in that way.

As for the liners they do need to sit proud. Flush isn't good enough. You may get away with it but to be correct the liners need pulling out and spacer shims fitted.
Had to do this on my Flavia engine, some copper sheet is the simplest solution as they need to have just enough but not too much height above the block face.
It's available fairly cheaply in differing thicknesses. Make sure to clean the sleeves and seats in the crankcase well though.

You may be lucky and get away with it in the hope that the head gasket has enough depth to make a seal, but it's a pain to remove it all and start again if it goes wrong once all is back in, worse if it results in a warped head or water contamination into the oil damaging bearings etc.