Z Blocks

[weldingrod]

Hey Mike, a question. Over how many years was the same engine block used in the 720's It looks like anything bolted to the outside will fit both the 2 litre and the 2.4. I have a 91 D21 and it looks like the same block. I took a 2.4 out of a 4x4 and installed a 2 litre. Just had to change oil pan and pickup and install the bigger clutch pack. Have some engine parts which was why I was wondering. Seems like anything bolted on the outside should fit all Z blocks. Different heads maybe but everything else should fit. What's your take on that?

[datzenmike]

If you have a '91 D21, it should have a KA24E totally different looking in every way. The KA will have 4 spark plugs the Z24i 8.  Maybe swapped? The Z24i will sit in the same orientation and bolt up to the KA transmission.

 

The previous L20B block that was used in a lot of '70s Datsuns was used one year in the 720 (1980) and has same deck height as the '81-'82  Z22, the Z22 having larger cylinder bores. The '83-'86.5 Z24 is similar but 2 cm taller at the very top of the block and even larger bores. Internally the Z24 block is slightly wider to accept the longer stroke crankshaft but externally the same looking a the previous L20B/Z20/Z22, well other than the deck height. Oil pans from the L series will fit, oil pumps/distributors/ heads have same cylinder spacing and bolt pattern, rod bearings, main bearings, water pumps and flywheels all interchange. L series starters will fit Z series but not so well the other way around because of the L series engine lean to the right. 

 

Z20S (car) and Z22 (car and truck) heads are the same with round intake ports with injector notches. The Z24 head is identical but has squarish intake ports and no injector notches. The '84-'86.5 Z20 Mileage Option engine has a unique (W04) head to the Z20S car engine but the combustion chamber is completely different and 9 to 1 compression. The Z20 engine even uses the L20B U60 crankshaft.

 

 

The 86.5- '89 D21 and the '87-'89 WD21 retained the Z24i engine carried over from the 720 before switching to the new KA engine for '90- . It's the same Z24 block just EFI intake.