P38A Gems to Thor?

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oakey

oakey

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1995 V8 4.6 GEMS 210k
I think my engine may be dead.
There may be a 4,6 THOR available. Is it an easy swap or would I be better to rebuild the GEMS?
The rest of the cr is in good nick and has been well looked after and I know her history as I have owned her as a daily driver since 60k
 
I am of the belief they are essentially the same engine, With the obvious intake difference.
But as you would have GEMS stuff it could be changed.

The engine management is different, not sure if the GEMS would run ok with the THOR setup, inlet manifold and sensors it uses.
But as you have all of them they could easily be changed.

How has your engine died? would be the big question on rebuilding really, and of course how full is the wallet;). Cos if it made it to that mileage the chances are you have a good block;).
Will you be doing the spannering?

J
 
oakey said:
1995 V8 4.6 GEMS 210k
I think my engine may be dead.
There may be a 4,6 THOR available. Is it an easy swap or would I be better to rebuild the GEMS?
The rest of the cr is in good nick and has been well looked after and I know her history as I have owned her as a daily driver since 60k
Click to expand...

There are some niggly differences like the aircon gets some sort of trigger from the GEMS that the Thor doesn't provide so you have to splice in a feed like on the diesel. Cruise control is different. The ABS ECU on later models is different but not sure if the looms for how the signal is relayed for the engine ECU / gearbox etc. I guess you'd have to check all the loom pinouts in RAVE and check they match.
 
Think GEMS has scratched bore and failng emissions.
Would do most of spannering myself and would enjoy it but health not so good and funds not so good
Changing to THOR would be done by garage who are not specialists
Sounds like a footer to change
 
oakey said:
Think GEMS has scratched bore and failng emissions.
Would do most of spannering myself and would enjoy it but health not so good and funds not so good
Changing to THOR would be done by garage who are not specialists
Sounds like a footer to change
Click to expand...

I would think any garage used to shoe-horning different engines into different cars would find it easy with the RAVE pinouts. Any garage used to straight - swaps would probably leave unresolved issues. An enthusiast with time to tinker would get it working with a bit of fettling.
 
Thanks Grrrrrr
They have RAVE so I may well get them to change to the Thor cos that would mean I get to keep the car whose history I know and the rest is still in pretty good nick.
I I brought the old engine back then I can spend some time getting bores cleaned etc and keep as a spare
 
Did you get the ECU with the engine?
I dont know how well the thor would run with the Gems ecu maps. Or how well the Thor ecu would work with the Gems setup on the rest.

Personally I would just swap the GEMS manifold (probably a few other bits) for the thor along with the sensors to make it a Gems engine. I think its possible cos its only a RV8 underneath the thor motronics bits.
Unless you can confirm the elec side is compatible.

Worth a bit of more investigation me thinks;).

J
 
1 thing that immediately pops to mind is the BECM send the security code to the ECU a different way. Is that changeable in the BECM????

J
 
marjon said:
1 thing that immediately pops to mind is the BECM send the security code to the ECU a different way. Is that changeable in the BECM????

J
Click to expand...

Definitely need to swap the ECU as well, I would have thought. Also, I seem to recall there was an awful lot of imperial stuff on the GEMS that I suspect went metric on the Thor so mix and match might require a bit of fettling.
 
Datatek said:
Maybe just by changing the engine type?
Click to expand...

You are not changing engine type though are you?
you are changing management system.
The THOR runs similar to the Diesel security but GEMS is totally different, I don't know.
But was worth pointing out before spending a bunch of money to swap and then the mechs to say we cant get it started;).

J
 
marjon said:
You are not changing engine type though are you?
you are changing management system.
The THOR runs similar to the Diesel security but GEMS is totally different, I don't know.
But was worth pointing out before spending a bunch of money to swap and then the mechs to say we cant get it started;).

J
Click to expand...
Changing the management system amounts to the same thing as engine type. However as I have never looked, I do not know if there is an option for Thor or GEMS in the BECM. I do know that V8 or diesel can be selected.
 
Last edited:
I like the idea of turning a Thor to a GEMS
I think I can get the electronics gizmos with the Thor engine but if I change the entire BECM that could be a world of hurt
The new engine is also a 4.0 whilst my original is 4.6
 
oakey said:
I like the idea of turning a Thor to a GEMS
I think I can get the electronics gizmos with the Thor engine but if I change the entire BECM that could be a world of hurt
The new engine is also a 4.0 whilst my original is 4.6
Click to expand...

You really know how to make it difficult don’t you:D.
The 4.6 is a stroked 4.0 so change the crank, not sure which of the pistons or rods you would use:eek:.

I am sure the GEMS ecu has a 4.0 or 4.6 selection that could be changed so it runs correct maps. Might be in the BECM. Again needs more investigation.

Any garage can change a like for like(ish) engine but when it comes to the electrickery bits of the Range Rover they need to know a bit more about them, and have proper kit to sort it.

I am no eqqsquirt but to me you are heading for a world of hurt. Maybe revisit the rebuild, perhaps a short block and use your other bits;).

J
 
Best option IMHO is to stick with the GEMS electronics & use the Thor block, crank, pistons & heads (assuming that's all in good condition). Camshaft & pulleys need to be GEMS version, plus use the GEMS flywheel.

If you stick with GEMS ECU, Intake, etc. then all you need to change is engine capacity setting in GEMS ECU & possibly Gearbox ECU. No major electronis or wiring to change. Not sure if the crank sensor mount is same or not.
 
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