Orange620 Posted June 27, 2009 Report Share Posted June 27, 2009 I have a 78 620. I'm removing the smog hardware and when I got the manifolds off, I noticed the engine is stamped Z20. Is this not the orignal engine? I thought Z engines sat vertical. This one is inclined toward the passenger side like my other 620s. Quote Link to comment
athoose Posted June 27, 2009 Report Share Posted June 27, 2009 Not original. The block are similar. Is it an L head? Could just be the short block got changed. Post a photo. Quote Link to comment
Orange620 Posted June 27, 2009 Author Report Share Posted June 27, 2009 Yes, I'm pretty sure its an L head. Where are the numbers on the head stamped? Quote Link to comment
athoose Posted June 27, 2009 Report Share Posted June 27, 2009 If the intake and exhaust manifolds are on the same side of the motor its an L. Z's have them on different sides of the head. Quote Link to comment
defdes Posted June 27, 2009 Report Share Posted June 27, 2009 Yes, I'm pretty sure its an L head. Where are the numbers on the head stamped? Under the spark plug #1 if it's an L. Quote Link to comment
datzenmike Posted June 27, 2009 Report Share Posted June 27, 2009 The Z identification is always on the left side of the block at the top roughly in the middle. L ID is on the right rear about where the dip stick handle is. The Z block is almost identical to the L20B with slightly different casting ridges beteween cylinders on the sides. The two that I have taken apart had the fully counterweighted L20B crank in them. The Z20E and Z20S have different rod piston heights from each other and from the L20B but will fit the L20B if kept as a set. The Z20E uses long 152.5 rods and a flattop piston compared to the L20Bs 145.9 rod and 11 cc dished piston. This would give a high 9s compression when used with a pea nut L head and high 8s with the open chamber head. Engine 'tilt' is determined by the motor mounts used. To have make it work in the L20B position L20B MMs, oil pan and pick-up, timing cover, chain and head were used. If a '78 you probably have a W-58 head on it. Quote Link to comment
420n620 Posted June 27, 2009 Report Share Posted June 27, 2009 this is where the Z engine ID = like mike said.. this is where the L engine ID = like mike said.. Quote Link to comment
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