810 L24 240z parts compatibility-zero compression in one cylinder

[jackfruit]

I have a 78 810 sedan, stock L24 (same/similar as 240z). one cylinder has zero compression. can only find 240z engine rebuild kits. question is piston/ring/head/intake/exhaust manifold component compatibility with 78 240z engine components?

year:78

model:810

transmission:4 speed manual

Engine manufacturer:Nissan L24

Engine type:spark-ignition 4-stroke

Fuel system:gasoline indirect injection

naturally aspirated

Valves per cylinder:2

Cylinders alignment:line 6

Displacement:2393 cm3 / 146.1 cui

[banzai510(hainz)]

look at this firest,

make sure the rocker arms is adjusted or the lash pad didnt fall out on the bad cylinder,this will give a bad compression reading

[datzenmike]

The 240z engine is not the same as the 810 engine. Both are L24s but the 810 does not have a 240z engine.

 

 

To have zero compression and it be the rings then something catastrophic like hole in piston... unlikely.

 

As stated look at the rocker arms on the bad cylinder. Valve clearance may be too tight, rocker arm may have jumped off and jammed the valve open.

 

Was engine over heated??? May have dropped a valve seat. If so head can be replaced.

 

 

[jackfruit]

51 minutes ago, banzai510(hainz) said:

look at this firest,

make sure the rocker arms is adjusted or the lash pad didnt fall out on the bad cylinder,this will give a bad compression reading

will do. thanks.

[jackfruit]

18 minutes ago, datzenmike said:

The 240z engine is not the same as the 810 engine. Both are L24s but the 810 does not have a 240z engine.

 

 

To have zero compression and it be the rings then something catastrophic like hole in piston... unlikely.

 

As stated look at the rocker arms on the bad cylinder. Valve clearance may be too tight, rocker arm may have jumped off and jammed the valve open.

 

Was engine over heated??? May have dropped a valve seat. If so head can be replaced.

 

 

thanks. will check. I've been able to use some 240z parts so didn't realize especially since the original commercials advertised it. there were a few instances of overheating within a week. I fixed it, but clearly too late. 

[datzenmike]

Overheating MUST be avoided. Seat and head are an interference fit. The head is heated to 400F to expand the hole and the valve seats cooled with liquid nitrogen to shrink them and installed. Once head cools and seat warms it cannot fall out. Overheating the head can loosen the grip. 

 

L24 blocks are different. The oil pick up is at the front. I think the block is fine.

 

L24s in the 240z had flattop pistons and 8.8 compression. I'm guessing the 810 had some small dish pistons.  Best find an 810 head and be done with it.

 

 

[Z-Gad]

Have an 810 N47 head off of my 78 wagon if you need one. Did an L28et swap, so it’s available. Engine ran perfect before the swap.
regards, Mike