Gen 2-3 blocks

[haggi961]

Hey everyone,

I've been doing a lot of research and speaking to different people about the Gen 2 and 3 blocks. Just seeing if anyone else has anymore information then what I already know.
From my understanding they made a stronger version of the gen 2 block almost like a gen 2.5 the LE9, the LAF, LEA and LUK versions. This model block is the later ecotec 2.4 engines from 2013 onwards i think. Then there is a 2.0 litre A20NHT from the insignias and the A20NFT from the Astra turbos. On the internet the A20NHT, A20NFT and the LE9 engines are all Gen 2 blocks. From what people have said is that the A20NFT is a Gen 3 and has a stronger block then the A20NHT/LE9 engines. Anyone know where there is evidence to say this is true?

Another question is speaking to a friend he said that the A20NFT has some special coating on the bores so it's not wise to fit oversized pistions. Can anyone confirm this?

Basically the reason I'm asking the questions is that I have a A20NFT gen 3 block and not sure if I still should look to buy the 2.4 ecotec LE9 block. I'm looking to find out what the strongest block is and if the LE9 blocks are the same as the A20NFT then it makes sense to go with the 2.4 engine for more power.

Thanks for any help

 

[figo126]

I too have been looking , the a20nft is the same engine has the a20nht , which is the same has a b207 ver.2 , which have the extra casting around the top of the bore, so the block you have should be the uprated one , has to the le9 blocks not sure pal ???

 

[vocky]

The LE5 blocks are GEN 2 and do not have the additional cast cylinder braces / ribs, which the GEN 3 blocks have.

When you search the internet for the a20nft it is mostly referred to as having the GEN 3 block, probably because it has the extra braces / ribs which the GEN 2 don't.

zzp use the same photos for both the gen 2 and gen 3 blocks, so difficult to give a 100% correct answer.

 

[vocky]

As a rough guide

GEN 1 - 2000 - 2006 z22se, z22yh

GEN 2 - 2007 - 2011 L61, LE5, LAP, LNF.

GEN 3 - 2011>

If you look at the casting of the A20NFT engine it is the same as the advertised GEN 3 blocks



zzp GEN 3 block

 

[vocky]

2010 B207 top + LE5 below, both look like the same block - GEN 2

You can clearly see that the block castings are different to the A20NFT

 

[haggi961]

The 2.4 ecotec LE9 has the same design block as the A20nft so this is classed as a gen 3. So does this look right.

Gen 1, Z22se:


Gen 2, B207, A20NHT, LE5:

Gen 3, A20NFT, LE9:

 

[haggi961]

Thanks to the person who sorted the pictures for me.

 

[White estate]

So Not knowing much about these blocks yet and just by looking at the pics i would say the gen 2 engine is the strongest due to the closed deck nature of the block ? Im probably wrong though lol

 

[vocky]

GEN 3 is regarded as the strongest, due to the extra ribs keeping the cylinders in position. What happens on high bhp engines is the cylinders move and then break, the extra ribs stop the movement.

LE9 does look like the same style block as a A20NFT, so both GEN 3

 

[evocarlos]

gen 1 and 2 are the same (lost foam casting)
gen 3 have lower and upper cylinder support (sand cast)

gen1 are strong but suffer porosity
gen2 have deeper wider water jackets and suffer with lower water jacket failure filling the sump with water there a close approximation of the gen1 but with vvt oil support holes
gen3 strong with the upper and lower supports capable of 550hp improving the power handling over the previous gens there is also no way to replace the liners like gen1 as there ribbed on the gen3

 

[White estate]

So A gen 1 block is good to use but possibly get a sand cast head rather than the lost foam one fitted ?

 

[evocarlos]

yes the saab/z20net head is a better choice over the z22se head but even then the z22se head is capable of more than we can make with out a huge turbo