LZ22 W/ 4 speed?

[Vandy893]

I really want to turn my Z22 into a LZ22. My truck (1982 720) has the Z22 mated to a 4 speed. First how hard is swapping the L20B head on, Second can I keep the 4 speed or will I need a 5 speed? Thanks.

[datzenmike]

The Z series engines sit very slightly tilted to the left, or driver's side, of vertical leaving lots of room for the spacious intake on the right side. The exhaust manifold is small and does not need much room on the left side. The L series is tilted about 12 degrees to the right of vertical leaning the engine and leaving room on the left for both intake and exhaust. The difference is roughly 18-20 degrees. Putting an L head on a Z series block will be a tight fit on the left side for the manifolds. I doubt it will even fit with the steering column in the way. The intake will be tilted down to the left and the carb not sitting level.

 

If you were to get L series engine brackets that position the Z engine to the right, the transmission will not allow this as it is bolted in the Z position. The L series and the Z series transmissions have the same bolt pattern but is 'clocked' be this 18-20 degree difference.

 

 

This is the position of an L series 4 or 5 speed. The two top holes are the bolts into the top of the block, the long rib is the center line. You can seethe engine is off to the right.

 

 

This is a Z series transmission. Rib is still the center line but the engine bolt holes are over to the left. Trying to force a Z series transmission over to the same position of the top picture is just not going to work.

 

So... if I were doing this...

 

I would re-position the engine in the proper L series position with engine brackets from a 620 L20B.

 

For the transmission, you could get an L series 4 or 5 speed. OR You could get the L series front case from a 4 or 5 speed and swap it onto you transmission.

 

 

Now the head swap.

I would find an old L20B engine (that has the engine brackets still bolted to it) It does not have to run, and better and cheaper if it doesn't, as all you want is the head and manifolds, engine brackets, oil pan and pick up tube, front timing chain cover, timing chain, tensioner, oil pump, distributor... basically everything but the block crank rods and pistons. Again basically you are exchanging everything but your block and everything in it. Better use a new Z22 head gasket and trim the front off around the timing chain. Trim the old L series head gasket and graft it together. The front around the timing chain is differently shaped and why the L series is needed. Don't worry it only has to seal in oil spray and fumes. Why not an L series head gasket" The L series cylinders are 85mm and the Z22 are 87. The L gasket would stick out too far into the bore and would erode away from the heat.

 

An open chamber L series head such as a U67 or a W58 will raise the compression from 8.4 to 9.47

 

You can use either a 4 or a 5 speed as long as the front case is an L series or you swap an L series onto it.