blocks

[debo890]

why is the nubis block coolant hole larger than the other is the blocks are the same? the wider collant passage could cause the bore to be weaker there, dont you think?



nubi(ecotec) engine




c20xe engine



c20let engine
also same as the c20get

any toughts?

[PrecisionBoost]

The C20 series engines may only have the two holes up top on the surface but they converge into a single passage just underneath the top of the block.

So the support is slightly better at the deck but it's identical once you move down a 1/4"

I'd have to think that the Nubira blocks will have slightly more flex due to the missing material but I bet an engineer figured that they didn't need the extra material.

The Nubira block has extra ribbing on the sides of the block.... so it's possible that it might be slightly stronger.

There are a billion different factors that could affect the block strenght.... the quality of the steel might be a big issue.

I think the C20 series blocks were cast in Brazil and they tend to have some good steel.... I'm not sure where the new blocks are cast.

Final assembly is in Australia but I bet they subcontract the casting out to other companies.

[kroz123]

hey Erfinder this may be a stupid question, but thanx for the info if you have it.

What's my engine block (engine) model number? ( I have the 1.8L)

What's my transmission (automatic) number?

Thanx

Arvin

[eljunito]

Sorry for changing the subject. Don't know if anyone has asked about it.

What engine brings this piston? Are this easy to find?

Comparing them to Nubi, we could say that this piston are High.

Does anyone know what's the compression of this pistons?

[Stefan]

The coolent passages in the head are different to the older XEs and OHC heads. Block and gasket is to suit.
Block was designed to be stiffer to reduce NVH. The blocks have undergone several revisions since their introduction in the early 80s. Latest one in the VXR range of Opels/Vauxhalls is stiffer still and has oil jets for under piston cooling.

Stef

[debo890]

The coolent passages in the head are different to the older XEs and OHC heads. Block and gasket is to suit.
Block was designed to be stiffer to reduce NVH. The blocks have undergone several revisions since their introduction in the early 80s. Latest one in the VXR range of Opels/Vauxhalls is stiffer still and has oil jets for under piston cooling.

Stef

so which on is better? the nubi's, the XE's, or the let?

[Stefan]

XE, LET and OHC you can consider the same as differences were/are minor.
Nubi has the stiffer block in the lower half of the engine. It's more open deck may cause problems on high hp engines - worse if they've been overbored a couple of mm.
The older XE, LET and OHC blocks can be made stiffer in the crank area.

The choice of block will be down to what you want to use it for, availability, etc.

The nubi type block hasn't had any issues with outputs around the 300hp mark as yet. Pistons and rods will need to be changed of cause....Steel head gasket is standard fitment on euro turbo version of the nubi type block also....

Stef

[debo890]

so which do you suggest? i am going for an overbore and 250 @ the wheels. i am inbetween buying the non turbo pontiac block. what will you use?

[Stefan]

If a nubi block was available I'd use that. With a Z20LET steel gasket and XE rods it'll handle nearly 300 crank hp with ease. Pistons would need to be around 8-8.5:1.

If all you have is the OHC block, use it by all means but swap out the rods! You may need to swap oil pumps over too iirc.

Stef

[debo890]

thanks alot. is the xe rod same as the lets?
also how much WHP can the early xe crank take?
i see you have one.
who fast does the rpm come up due to them being lighter?

[debo890]

i am taking a poll.
T20sed block for turbo.

or


C20NE(sunbird) block for turbo.

[Efratech]

T20SED with XE/LET rods.

Yes the XE/LET rods are the same.

[Stefan]

thanks alot. is the xe rod same as the lets?
also how much WHP can the early xe crank take?
i see you have one.
who fast does the rpm come up due to them being lighter?

As Efrain said the XE/LET rods are the same.
XE rod compared to 8v/Nubi rod.


Early cranks have taken up to 400hp crank hp.......I've yet to see one break on a turbo car. Some N/A race engines use a steel crank because of the higher max rpm that they run and the higher loads encounted.
I can't say how much faster it revs with the early crank in it. It depends on other components too, like the flywheel.... it will help though.
BTW the early crank is the same as the OHC one except for the extra fasteners for the flywheel and the harmonic damper/accessory drive pulley.

Stef

[PrecisionBoost]

Well... I know what's going on behind the scenes so I will comment on the T20SED vs C20NE

The C20NE is brand spanking new.... why on earth would you overbore it??

Given it's for a newer model it allready has the reluctor wheel for distributorless ignition.

So the question should be....

What's better..... brand new C20NE vs T20SED with 50,000 miles on it.

My vote is to use the C20NE block... swap in some gently used XE rods and pistons and your off to the races.

[Stefan]

Well... I know what's going on behind the scenes so I will comment on the T20SED vs C20NE

The C20NE is brand spanking new.... why on earth would you overbore it??

Given it's for a newer model it allready has the reluctor wheel for distributorless ignition.

So the question should be....

What's better..... brand new C20NE vs T20SED with 50,000 miles on it.

My vote is to use the C20NE block... swap in some gently used XE rods and pistons and your off to the races.

If your not doing any machining work on the new block use that one then.
If you want to do machining work e.g. overboring and the storage conditions of the new one are not known, I'd use the older 50k block if it's serviceable. The older block will have "seasoned" so it shouldn't move around during any machining operations unlike a new "green" casting.

Stef