[kai.spencer]

So ive had a 92 leafy for a while now and they guy who sold it to me said he engine swapped it but told me it was still just a stock G13ba with lower kms. So i didnt think much about it and wanted to eventually put a 13b in it. Well i just recently was given a g13a and i thought i might be able to use it as a spare for mine. So i did a check on mine and it turns out it actually is a g13b block with a 8v head, and if it helps ive just got a webber on it.
So my first question is: ive done a bit of research and found that g13b’s can have either a 16v or 8v head. Is this true?
Second question: will i still be able to use the 13a as a spares engine that i can swap parts from and if so what parts are the same.
Cheers heaps

[Gwagensteve]

Are you basing the g13 on the casting or the engine number prefix?

[damø]

The g13 b and ba block are the same, which is why they are all just stamped 'g13b'. obviously the head and internal mechanical components are different. The g13b is the fuel injected swift gti engine with 16v head, the g13ba is the carburetted 8v engine (in Australia anyway). i would imagine the 8v head would be the same for the g13a and g13ba, but from memory the g13a block is slightly taller due having a slightly longer stroke than the g13b motors.

[kai.spencer]

So am i able to just put a 12v head on and then all the efi, loom and computer shit with it? Or is it more complicated?

[sideways]

There was G13b 8v carby engines fitted to swifts. It seems plenty of Sierras ended up with them, I know of 2 Sierras that had them.

G13a is essentially the same motor with a slightly longer stroke. Still over the years quite a few things changed on these motors (there's different timing belts and pullies, for example) so parts would have to be compared on a case by case basis.

EDIT woooooo post 5500

[bumstein]

sideways wrote:

woooooo post 5500

Congrats!!!!

[sideways]

[Gwagensteve]

The DOHC g13b has a stronger bottom end and piston reliefs for the valves to suit. Yes, you can swap head and EFI from any G series motor into your bottom end but it makes more sense to keep block and head matched to ensure the engine remains a free spinner and compression ratio etc remains where it’s supposed to be.

[damø]

someone who knows more can chime in, but i had a fresh g13ba a while ago and looked at what would be involved in putting a 16v head on it. It seems you could use a 16v head with 16v pistons in a g13ba, but then youre stuck with the weaker conrods and crankshaft. If your spare engine is running fine i wouldnt go taking the head off and pulling pistons out of it.

[Gwagensteve]

Exactly.

The road of pulling g motors apart to make them better is littered with broken g motors.

[kai.spencer]

So it would be ok to fit a 16v head onto my 13b? Or keep it how it is with an 8v? And with the spare parts question i was more thinking like carby, intake manifold, sensors or even the head. Am i able to do that?

[Gwagensteve]

You’re missing the point. You don’t have a G13b. Even though that’s what’s cast into the block. You have a g13ba. That came as an 8v motor and doesn’t share any bottom end parts with the g13b.

There is no good reason to pull apart an actual G13b, g13bb, or g16b to put the 16v head on your motor. You will have just created a low compression interference motor with a flaky bottom end.

There are no useful spares from a g13a that would work with a G13b, g13bb, or g16b, however depending on what donor motor you source the sump and oil pickup from the g13a will be required to install that motor in your Sierra. Personally the DOHC G13b is the second least desirable engine to swap into a Sierra after a g16a but each to their own.

[kai.spencer]

Thanks for the help then guys, sorted a lot out