A20NFT Astra J vxr engine

vocky

Staff
I think it might have been poor mapping, it was over 350bhp, however it has been pointed out that some A20NFT engines have forged pistons, this one clearly did not.

Perhaps GM are trying to save a few quid and now use cheaper pistons (n)
 

vocky

Staff
it's been a while but I have made a start on porting the A20NFT cylinder head and inlet manifold

inlet manifold done :)
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I have seen a few threads about porting the LNF head and it seems to be a bit 'hit and miss' with opening up the inlet ports

So I made a start on the inlets, if it works great, if not I will stick the original head back on :LOL:
SAM_5309.JPG
 

vocky

Staff
so three years later the cylinder head is finally finished :LOL:

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head had a light skim to clean it up, they also did 3 angle valve seats and lapped in the valves

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brand new OEM valve stem oil seals fitted

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and complete

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evocarlos

Stupid Bollocks
Staff
This will now be fitted to my vxr, got to purchase a few goodies before it can be fitted, like pistons and rods :D
im saving up for bigger valves and bronze guides will be aiming for 450bhp with an efr and 4x4 :) got a head from a astra vxr but it needed some cleaning :confused: and it got 2 bent valves in #1
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vocky

Staff
I think 425-450 would be perfect.

My plan is a hybrid turbo, ported head and inlet, ported throttle body, ProAlloy chargecooler and a 3" non-res exhaust system. Coupled with my Courtenay intake and Cobra downpipe. Stage 3 clutch will also be needed. Plus Wiseco pistons and Molnar steel rods.
 
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Hallo,

does anyone know the Differents between the b207 Block and the a20nft ? Are there only the castings at the Cylinders or are there any more differents ? Can ist use the z22se internals as in the b207 ?

Regards
 

corsaZ22se

Senior Member
Hallo,

does anyone know the Differents between the b207 Block and the a20nft ? Are there only the castings at the Cylinders or are there any more differents ? Can ist use the z22se internals as in the b207 ?

Regards
Yes you can use Z22SE internals in the B207. I have done this in mine.
The A20NFT i believe is the Gen 3 block and has more strength around the top of the cylinder liners over the Gen 2 B207 block. This is sometimes referred to as a closed deck block.
 
Thx for your reply.
I use the z22se internals too already in my b207 supercharger build.
Question is if i can use the same internals 1:1 in a a20nft Block ?
And does the b207 Head fit the a20nft Block ?
 

vocky

Staff
the z22se internals will fit and so will the b207 head.

I have built that spec engine before.

for info: the vvt head does not fit a B207 / z22se block, due to the oilways for the vvt solenoids in the vvt head.
 

evocarlos

Stupid Bollocks
Staff
for info: the vvt head does not fit a B207 / z22se block, due to the oilways for the vvt solenoids in the vvt head.
Unless you have a 2007> b207 that's gen2 and has the blanking parts for the vvt oil ways at the chain end.
ive already converted a gen1 to use as a a20nht replacement aew years back :) i guess you do the same welding on a z22se but then be stuck not having any way to control the solanoids
 

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Hey guys.. having a night mare with my astra j vxr.
Wondering if anybody has any ideas.
Its got a loud whine sound once warm from top left side of engine bay but only on idle or very low rpms. Checked belt pulley tensioner and its not that.
Don't wanna replace timing chain as everyone's saying as it sounds nothing like a chain issue.
No power loss/ problems at all, still drives perfectly Other than ridiculous loud idle. Sound like a bus when warm
 
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