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[GrahamT]

Has anyone converted their 2.5 manual to 3.0?

If so was it worth it and did the 2.5 gearbox survive?

Thanks

[henryd]

Easy swap as plug and play but AR25 gearbox will not cope with 3.0 torque

[tigers_gonads]

How many miles has the manual box done ?

I ran a 3ltr with a R25 box with no problems but it was a relatively low millage box with only 90K on it.


With the R28's liable to have plenty of miles on by now / in short supply and the R30 like rocking horse shite, i'd just do it and enjoy 

[Kevin Wood]

Yep, the manual 2.5 gearboxes are no problem with a bit more power. It's the automatic gearboxes that are an issue.

You might want to consider a diff with a taller ratio, though, but you can see how it goes with your current diff first.

[GrahamT]

Thanks guys.

A few more questions. Finding a x30xe from an auto doesn't seem to be a problem. But will my 2.5 flywheel fit and will an auto ecu be happy running a manual?

[tigers_gonads]

Thanks guys.

A few more questions. Finding a x30xe from an auto doesn't seem to be a problem. But will my 2.5 flywheel fit and will an auto ecu be happy running a manual?

IIRC if its a auto ecu with a manual box, you need to ground a wire to earth  or the engine wont run 
If you do a search on here, you should find it 

As for the R25 gearbox with the auto's (3.91) diff, you will find that the revs will be about 200 rpm higher at 70 mph ish so depends on how deaf you are or how much motorway driving you do tbh.

I run a 3.2 / R28 box with the auto's diff and it gets off the line very well  .

Pros are you can stick it in 5th at 30mph and it will pull away with ease.
Cons are 1st is too low BUT i've a lpg tank in the back and occasionally pull a pikey van so that 1st really helps getting out of junctions quickly 

[henryd]

Easy swap as plug and play but AR25 gearbox will not cope with 3.0 torque

If I had read the post properly I would have read the manual bit

[GrahamT]

My car is already a manual and as far as I can tell has the same diff ratio as the 3L.

I have actually contemplated putting in the auto diff to get a bit more acceleration.

As right now it sits at about 2800rpm at 70mph.

Thanks

[Migv6 le Frog Fan]

From memory - the flywheels are interchangeable, but the spigot bearing on the end of the crank will need swapping for your manual one.

[tigers_gonads]

From memory - the flywheels are interchangeable, but the spigot bearing on the end of the crank will need swapping for your manual one.

Yup 
Also the 3ltr engine will also run okay on a 2.5 manual engine ecu abit very slightly down on power due to the slightly reduced fueling right at he top end 

[GrahamT]

From memory - the flywheels are interchangeable, but the spigot bearing on the end of the crank will need swapping for your manual one.

Yup 
Also the 3ltr engine will also run okay on a 2.5 manual engine ecu abit very slightly down on power due to the slightly reduced fueling right at he top end 

That's good. So I can swap the engine over while I look for the correct ecu, transponder and chip.

One other question just to make life a little easier. I take it the wiring harness etc for the engine management is the same for the X25XE and the X30xe?

Thanks

[Migv6 le Frog Fan]

Im sure it will be the same. 3.0 ECU etc. shouldn't be difficult to find. Not many people will be looking for one either so I wouldn't pay too much money for one. 

Edit. One here for £20. 
https://www.ebay.co.uk/itm/VAUXHALL-OMEGA-1994-9-3-0-V6-COMPLETE-ECU-UNIT-IGNITION-MODUAL-1-KEY-CHIPS-AF-/332552551874

[tigers_gonads]

From memory - the flywheels are interchangeable, but the spigot bearing on the end of the crank will need swapping for your manual one.

Yup 
Also the 3ltr engine will also run okay on a 2.5 manual engine ecu abit very slightly down on power due to the slightly reduced fueling right at he top end 

That's good. So I can swap the engine over while I look for the correct ecu, transponder and chip.

One other question just to make life a little easier. I take it the wiring harness etc for the engine management is the same for the X25XE and the X30xe?

Thanks

When I dropped a 3ltr lump into my 2.5, All I needed was the bearing because the 3ltr lump came off a auto 
Forget about the shorting wire bit 
That was for a auto engine ecu 

Also iirc, the 2.5 manual diff is a 3.7 so again just bolt together then go and play 

[GrahamT]

To find a decent engine now.

Thanks for all the advice. I have a week off work in nine weeks. Enough time to find engine clutch spigot bearing etc.

Thanks again.

[Migv6 le Frog Fan]

To find a decent engine now.

Thanks for all the advice. I have a week off work in nine weeks. Enough time to find engine clutch spigot bearing etc.

Thanks again.

Here ya go.  http://www.omegaowners.com/forum/index.php?topic=142594.0

[zirk]

My car is already a manual and as far as I can tell has the same diff ratio as the 3L.

I have actually contemplated putting in the auto diff to get a bit more acceleration.

As right now it sits at about 2800rpm at 70mph.

Thanks

In a 3.0 set up with the correct Diff, both the Manual (3.7) and the Auto (3.9) will run around the 2625 to 2650 RPM mark at 70MPH allowing for some Speedo error, your probably find your 70MPH is actually around 67/68 in true speed as the speedo's tend to read high, even on the Ex Police with Calibrated Speedo's they run around the same RPM at a tue speed of 70.

What I can tell you is if you run a Manual set up with a Auto diff (3.9) on the 3.0 setups you be doing around 3000RPm at 70, which is a tad anoying on a Motorway Cruise IMHO.

I cant remember now if the 2.5 (never owned one) had the same 5th gear ratio as the 3.0's, seem to remember hearing the very early ones were and the later prior to going to 2.6 were slightly different. 

[GrahamT]

My car is already a manual and as far as I can tell has the same diff ratio as the 3L.

I have actually contemplated putting in the auto diff to get a bit more acceleration.

As right now it sits at about 2800rpm at 70mph.

Thanks

In a 3.0 set up with the correct Diff, both the Manual (3.7) and the Auto (3.9) will run around the 2625 to 2650 RPM mark at 70MPH allowing for some Speedo error, your probably find your 70MPH is actually around 67/68 in true speed as the speedo's tend to read high, even on the Ex Police with Calibrated Speedo's they run around the same RPM at a tue speed of 70.

What I can tell you is if you run a Manual set up with a Auto diff (3.9) on the 3.0 setups you be doing around 3000RPm at 70, which is a tad anoying on a Motorway Cruise IMHO.

I cant remember now if the 2.5 (never owned one) had the same 5th gear ratio as the 3.0's, seem to remember hearing the very early ones were and the later prior to going to 2.6 were slightly different. 

My sat navigation and my GPS on my phone both agree that at 70mph I am only doing 2800rpm.

Thanks

[GrahamT]

To find a decent engine now.

Thanks for all the advice. I have a week off work in nine weeks. Enough time to find engine clutch spigot bearing etc.

Thanks again.

Here ya go.  http://www.omegaowners.com/forum/index.php?topic=142594.0

I'm in North Wales so I will try and find one that can be delivered or is a little closer to collect.

Thanks

[zirk]

My car is already a manual and as far as I can tell has the same diff ratio as the 3L.

I have actually contemplated putting in the auto diff to get a bit more acceleration.

As right now it sits at about 2800rpm at 70mph.

Thanks

In a 3.0 set up with the correct Diff, both the Manual (3.7) and the Auto (3.9) will run around the 2625 to 2650 RPM mark at 70MPH allowing for some Speedo error, your probably find your 70MPH is actually around 67/68 in true speed as the speedo's tend to read high, even on the Ex Police with Calibrated Speedo's they run around the same RPM at a tue speed of 70.

What I can tell you is if you run a Manual set up with a Auto diff (3.9) on the 3.0 setups you be doing around 3000RPm at 70, which is a tad anoying on a Motorway Cruise IMHO.

I cant remember now if the 2.5 (never owned one) had the same 5th gear ratio as the 3.0's, seem to remember hearing the very early ones were and the later prior to going to 2.6 were slightly different. 

My sat navigation and my GPS on my phone both agree that at 70mph I am only doing 2800rpm.

Thanks

Ok, so what the speedo telling you?, 72/73? if so and without doing the Maths RPM sounds about right then, be it a tad high.

[Doctor Gollum]

Easy swap as plug and play but AR25 gearbox will not cope with 3.0 torque

Manual

It will be fine

[Kevin Wood]

One other question just to make life a little easier. I take it the wiring harness etc for the engine management is the same for the X25XE and the X30xe?

I have a feeling there is a gotcha with the throttle position sensor on some configs when swapping. Not sure if it was between 2.5 and 3.0 or long and short plenums but there is a combination where it won't work. If running with the 2.5 ECU, probably best to keep the 2.5 throttle body and wiring harness. (might need to keep the 2.5 plenum if it's a short one).

[GrahamT]

One other question just to make life a little easier. I take it the wiring harness etc for the engine management is the same for the X25XE and the X30xe?

I have a feeling there is a gotcha with the throttle position sensor on some configs when swapping. Not sure if it was between 2.5 and 3.0 or long and short plenums but there is a combination where it won't work. If running with the 2.5 ECU, probably best to keep the 2.5 throttle body and wiring harness. (might need to keep the 2.5 plenum if it's a short one).

That's good to know thank you

[omegod]

Just a point of order there are only 2 manual gearbox types fitted to petrol Migs, R25-28 and the super rare unicorn that is the R30, I've never seen one but believe it simply is an R25-28 with shot peened gearsets

[GrahamT]

Just a point of order there are only 2 manual gearbox types fitted to petrol Migs, R25-28 and the super rare unicorn that is the R30, I've never seen one but believe it simply is an R25-28 with shot peened gearsets

I have a few spare gearboxes so one day I might take one apart and look to see if I can spot any differences.

I was told that the V6 manual gearboxes had the shot peened gears and the four cylinder cars didn't.

Does anyone know for sure?

[tigers_gonads]

Just a point of order there are only 2 manual gearbox types fitted to petrol Migs, R25-28 and the super rare unicorn that is the R30, I've never seen one but believe it simply is an R25-28 with shot peened gearsets

I have a few spare gearboxes so one day I might take one apart and look to see if I can spot any differences.

I was told that the V6 manual gearboxes had the shot peened gears and the four cylinder cars didn't.

Does anyone know for sure?

R25 box cogs are forged, R28 / 30's are ground out from billet 

R25's are used on the 2ltr, 2.2, 2.5, 2.6 and 2.5 td.
R28's are used on 3ltr's and are good for a 3.2 conversion.

R30's was used exclusively for the 3.2 traffic cars 

[zirk]

R25 box cogs are forged, R28 / 30's are ground out from billet 

R25's are used on the 2ltr, 2.2, 2.5, 2.6 and 2.5 td.
R28's are used on 3ltr's and are good for a 3.2 conversion.

R30's was used exclusively for the 3.2 traffic cars 

They also used the R30 on the 2.5DTi 24V Euro Diesel, the one we never got in the UK, but Im guessing with different Gear Ratios though being a Oil Burner. 

[omegod]

Every box I've pulled from manual:

2.0 pet
2.2 Pet/Diesel
2.5 Pet
2.6 Pet
3.0 Pet

has been marked R25-28 ? Regardless they are tough buggers and have took some serious power

[Kevin Wood]

This might be handy when considering gear ratios:

[Kevin Wood]

.. and this: http://www.omegaowners.com/forum/index.php?topic=90497.0

[GrahamT]

Thanks

I do agree all the spare gearboxes I have are marked r25-r25.

[zirk]

In a 3.0 set up with the correct Diff, both the Manual (3.7) and the Auto (3.9) will run around the 2625 to 2650 RPM mark at 70MPH allowing for some Speedo error, your probably find your 70MPH is actually around 67/68 in true speed as the speedo's tend to read high, even on the Ex Police with Calibrated Speedo's they run around the same RPM at a tue speed of 70.

What I can tell you is if you run a Manual set up with a Auto diff (3.9) on the 3.0 setups you be doing around 3000RPm at 70, which is a tad anoying on a Motorway Cruise IMHO.

I cant remember now if the 2.5 (never owned one) had the same 5th gear ratio as the 3.0's, seem to remember hearing the very early ones were and the later prior to going to 2.6 were slightly different.

Here you go, just checked my hand written Notes from a few years back -

PFL 1994 to 1997/8
 2.5 Manual 5th Gear Ratio 0.85 Diff 3.7
 3.0 Manual 5th Gear Ratio 0.81 Diff 3.7

MFL 1997 to 2000
 2.5 Manual 5th Gear Ratio 0.85 Diff 3.7
 3.0 Manual 5th Gear Ratio 0.81 Diff 3.7

FL 1999 to 2000/1
 2.5 Manual 5th Gear Ratio 0.85 Diff 3.9
 3.0 Manual 5th Gear Ratio 0.81 Diff 3.7

FL 2000 to 2003
 2.6 Manual 5th Gear Ratio 0.85 Diff 3.9
 3.2 Manual 5th Gear Ratio 0.81 Diff 3.7

[Kevin Wood]

Thanks

I do agree all the spare gearboxes I have are marked r25-r25.

Is that a cast-in marking, though? The casing will be common to both, so it probably has (had?) a metal tag or sticker on it indicating the actual spec. Either way, plenty of 3.0/3.2 manual conversions have used the R25 without issue so it's not worth worrying about.

[GrahamT]

Thanks

I do agree all the spare gearboxes I have are marked r25-r25.

Is that a cast-in marking, though? The casing will be common to both, so it probably has (had?) a metal tag or sticker on it indicating the actual spec. Either way, plenty of 3.0/3.2 manual conversions have used the R25 without issue so it's not worth worrying about.

It is in the casting. I should have said R25-R28.

Thanks               

[olm]

From memory - the flywheels are interchangeable, but the spigot bearing on the end of the crank will need swapping for your manual one.

Do you know the reference of this? I´m in the same situation as GrahamT

[Migv6 le Frog Fan]

I don't, but hopefully someone who does we come along. 

[olm]

I don't, but hopefully someone who does we come along. 

Thanks, I believe find it, is this?

https://www.ebay.co.uk/itm/Vauxhall-FRONTERA-OMEGA-CARLTON-SENATOR-CRANKSHAFT-NEEDLE-SPIGOT-BEARING-NEW/171235003370

[LC0112G]

The crank needle bearing on manual Carltons/Sentors is VX-90105743 / OP-6-14-706. The same part number is listed against X25XE, Y26SE, X30XE and Y32SE.

On Carltons its a bu99er to get out. I usually end up using an M12 tap, tapping it into the bearing and then pulling it out. Others say pack it with grease and then drift it out. Every time I've tried that I just end up covered in grease.