some engine questions
 

I just did a top end overhaul on my 2.4 L engine and it drives as if I have no power.
The serial number says its a "T" motor. But Im spectulating that the motor was upgraded to a "S". What are the comparisons between the looks of a "S" piston and a "T" piston. I plan on doing a compresion check, Does anyone know the values I should recieve for a "T" and a "S" motor 2.4L using a pump up compression tester. Also what are the cam timing measurements for a "S" motor.
Im sure I will have plenty of more questions, trying to trouble shoot my problem.
Thanks Eric Leach

it's always a good idea, on an unknown engine, to do a cam timing check before teardown. who knows what's in there.
T pistons have a slightly rounded top, not quite flat, with slight valve reliefs, while S pistons have quite a tall dome with deep valve reliefs.
T timing is 2.60mm
S timing is 5.20mm
the factory cams are also marked on their ends. most cam grinders will mark their own code.
hard to tell an S from a T with a compression check because valve overlap on the S keeps the cranking compression readings down.