Omega Owners Forum

Omega Help Area => Omega General Help => Topic started by: GrahamK on 01 May 2021, 10:50:22

Title: Engine and gearbox change 2.6 to 3.2
Post by: GrahamK on 01 May 2021, 10:50:22
Hi all,
I've recently picked up a 3.2 engine and AR35 gearbox and I'm planning a DIY engine change.

Will the ancillaries off my 2.6 fit and work correctly with the 3.2?

I have the 3.2 plenum but I am particularly interested in issues for the throttle body, MAF?

Are there any other issues regarding the swap that I need to be aware of?

I understand that the final drive is different on the 2.6, but have seen threads here discussing the 3.2 with its standard (Auto) Diff is considered a little high geared, so this may be a positive. If there are any other views on this, I would be interested to hear.

Regards,

Graham.



Title: Re: Engine and gearbox change 2.6 to 3.2
Post by: Doctor Gollum on 01 May 2021, 11:56:57
Just fit it as is and keep your ecu.

No point overcomplicating it.
Title: Re: Engine and gearbox change 2.6 to 3.2
Post by: biggriffin on 01 May 2021, 16:57:53
Remove 2.6 and ar25, fit 3.2 and ar35, job done.
Title: Re: Engine and gearbox change 2.6 to 3.2
Post by: Migv6 le Frog Fan on 01 May 2021, 18:44:06
I thought the 2.6 / 3.2 ECU were different from one another ?  :-\
Title: Re: Engine and gearbox change 2.6 to 3.2
Post by: biggriffin on 01 May 2021, 19:13:52
I thought the 2.6 / 3.2 ECU were different from one another ?  :-\

 Changing ecu creates even more problems, needing tech2, unless you have the key,transponder, door controller etc.
Title: Re: Engine and gearbox change 2.6 to 3.2
Post by: Doctor Gollum on 02 May 2021, 11:54:31
I thought the 2.6 / 3.2 ECU were different from one another ?  :-\
Nope, both v6 dbw. Fuelling is self adjusting via the MAF, so capacity difference is largely irrelevant.  :y

As BG has pointed out, swapping the ecu is a much more that it seems. Not difficult, just a ball ache if you don't have ALL the items required.
Title: Re: Engine and gearbox change 2.6 to 3.2
Post by: GrahamK on 02 May 2021, 15:50:25
Hi all,

Thanks for the replies.

I'm not looking to overcomplicate matters, just fore arm so to speak.

I understand that the fuelling self regulates, but I am a little surprised that the throttle bodies and/or the MAF's are not a different size. The jump from 2.6 to 3.2 is more than a 20% increase in capacity and I would have thought that might have been reflected in the size of something. Thinking about carb venturi sizes and how they used to go up with higher capacity engines, sometimes quite markedly. Perhaps it is more a matter of making a single throttle body that can flow sufficient for all the engines in the range?

More than anything, If I do this change I want to yield all the extra power that appears on paper and not limit the output by overlooking some small detail.

Of course, I'm not a racer and the Omega is far from a sports car but the 3.2's I have driven were a fair bit spritelier than the 2.6. Had I been able to find a 3.2 worth the money I would have gone for it, but I bought on condition mainly. It's also a fun project and I like the idea! Anyway, I've bought an engine hoist now so I suppose I'd better do it.

Regards,

Graham.
Title: Re: Engine and gearbox change 2.6 to 3.2
Post by: Kevin Wood on 03 May 2021, 08:44:03
On a fuel injected car there doesn't need to be a venturi and the throttle body is really just an air valve so these items could be made identical across the range of engine size.

I seem to recall there was a change in either the injctor flow rate or fuel pressure so might be work keeping the injectors and fuel rail from the 3.2.

As said, there won't be enough difference in the fuel and ignition maps to warrant the pain of swapping the ECU over so just leave the 2.6 one.
Title: Re: Engine and gearbox change 2.6 to 3.2
Post by: Doctor Gollum on 03 May 2021, 13:37:29
To Kevin's point, the fuel rail and FPR are identical, as are the fuel pumps ;)
Title: Re: Engine and gearbox change 2.6 to 3.2
Post by: biggriffin on 03 May 2021, 14:37:49
And yes you can put engine and gearbox in as 1 piece. :y
Title: Re: Engine and gearbox change 2.6 to 3.2
Post by: GrahamK on 03 May 2021, 17:48:12
yes, as one piece, absolutely.
I have done a cambelt on an Omega before and although it was straightforward really, it had my full attention. It also took about 2 months for the scars to clear from my forearms as they were shredded in the process.
I'm looking forward to doing the essentials on both engine and gearbox whilst on the bench.
Please see my new thread on which essentials.

Cheers all.

Graham.
Title: Re: Engine and gearbox change 2.6 to 3.2
Post by: Nick W on 03 May 2021, 18:46:22
yes, as one piece, absolutely.
I have done a cambelt on an Omega before and although it was straightforward really, it had my full attention. It also took about 2 months for the scars to clear from my forearms as they were shredded in the process.
I'm looking forward to doing the essentials on both engine and gearbox whilst on the bench.
Please see my new thread on which essentials.

Cheers all.

Graham.


if the engine isn't in the car, you should seriously consider changing the rear crankshaft seal. The front is probably easier in the car as it takes a lot of effort to undo the crank pulley bolt
Title: Re: Engine and gearbox change 2.6 to 3.2
Post by: GrahamK on 04 May 2021, 14:13:44
Yes, cheers.

Graham.