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Joined: Dec 29 2016
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Evening Guys,

I'm pondering my next project and was just wondering about the difficulties when swapping a 4.0 Thor for a 4.6 Thor engine.

Obviously you'd need to change the ECU as it would have the mapping for the 4.0 engine.

The gearboxes were different as well, the 4.0 has the 4HP22 whereas the 4.6 has the 4P24, but I'd guess these days that most 4.6 engines are probably only putting out the power a 4.0 did when it was new lol.

I'd guess the bell housing bolts are the same across both engines?

I've got a 4.6 gearbox and torque converter here from a 96 GEMS car, would this suit to be mated to a THOR 4.6? I guess the gearbox ECU would need to be from a THOR car as well.

Any thoughts would be appreciated!

David.

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Joined: Dec 30 2015
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You can do a straight swap and even use the original ECU. The GEMS ECU has to be told whether it is fuelling a 4.0 litre or 4.6 but the Thor uses the same one, it, presumably, just uses the lambda sensors to learn the fuelling.

The bell housings are the same as the blocks are externally identical. Torque converters are different between a GEMS 4.0 litre and a GEMS 4.6 too but not on the Thor so if you decided to use the GEMS box you'd probably need to use the Thor torque converter. I believe the gearboxes are different lengths if it's from an early GEMS, so sticking with the 4.0 litre Thor gearbox would keep it simple.

I did some work on a 4.0 GEMS that wasn't starting. Started to suspect the crank sensor and pulled that out. On a GEMS, due to the different torque converter, the spacer between the flex plate and crank is a different thickness, so the crank sensor has a spacer on the 4.6 and not the 4.0 litre. Found this one had a spacer but with the lower inspection plate off, could see that the CPS was positioned correctly. Turned out, after cleaning paint off the area of the block with the engine number on it that it was actually a 4.6 (with the 4.0 litre GEMS plenum) running through the original 4HP22 gearbox without any problems.

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Joined: Dec 29 2016
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Thanks Gilbert!

Sounds like it'll just be a case of source a 4.6 engine and jobs a gud 'un!

Just need to decide if I really want another engine swap now!

David.

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Joined: Jun 17 2018
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The Latter ZF4hp24 Is known as the 065, it is 15mm shorter than the earlier Hp24..

You can use the tailend off a diesel housing to bring it back to the same length overall..

Bolt patterns are the same, torque converters are different, the 4.6 is a tad bigger!

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The 4.6 torque converter can't be bigger, the spacer between the crankshaft and flex plate is about 10mm thicker on a 4.6 meaning it must be slimmer.

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If I do go for a 4.6 conversion then I'd probably take a gamble and leave it with the 4.0 gearbox.

From what Gilbert says above it doesn't sound like it would cause much of a problem!

David.

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Swapping bits around, particularly trying to mix GEMS and Thor components is only going to make a simple swap very complicated. The 4HP22 is good for 380Nm so should cope with the 4.6 easily unless you flat foot it to the red line all day every day. Swapping a Thor engine for a Thor engine, irrespective of engine size, is simply that, a swap. Everything will mate up and all electrical connections will mate up and be in the right place. Externally the only way of telling a 4.0 litre from a 4.6 is to look at the engine number prefix, the differences are internal (crank, rods and pistons). On a GEMS the obvious way of telling the difference is by the 4.0 or 4.6 cast into the top of the plenum but I know of at least 2 cars where the plenum says it's a 4.0 litre but the engine number says it's a 4.6 (even the throttle bodies are the same), both still running the original 4HP22 gearboxes without problems.

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the HP24 has has a bigger fluid pump and longer torque converter there are 3 different size torque converters for the P38 the 4.6 has the biggest one, the 4.0 has a smaller one and the diesel the smallest.

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Well, I'd been keeping an eye on a 2002 Westminster that was going through auction this week. The cars MOT has expired in December and at it's last MOT in December 2018 it had covered 150k and the 4.0 V8 was in the boot.

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When I found the car it was sitting at £300. I had a good think about it and given that I'm a bit OCD mechanically and like my cars to be just right decided that I'd end up spending a fortune on it like I have done on all my other P38's. Don't get me wrong, parts are cheap, but when you start changing everything that wears to get rid of all the little annoyances you end up spending a lot.

I decided that I was going to set myself a limit... £700. However, if I needed to I'd go up to £800 as the car was only 40 minutes from me and I could collect it whilst I was off work this week.

Don't get me wrong, having 3 P38's and a breaker already, I needed this like I needed a hole in the head but it looked to nice a car to break for parts.

I'd checked on the price of the car a couple of times a day, usually during my morning coffee and later in the day. Yesterday was no different, except last night it had jumped from £390 to £1010. The auction site it was on charges £50 even for the opportunity to bid, then with fees on top of that it would have ended up costing me a minimum of £1250 assuming nobody else started bidding against me.

Anyway, long story short, I now no longer need to swap a 4.0 to a 4.6.

I hope it's gone to someone who is going to sort her out rather then break her for spares as she did look a nice car. Unfortunately though, it just wasn't worth what it sold for to me.

David.

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Joined: Feb 24 2017
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Piling engine parts in the back seat of the vehicle you are looking to sell is never a good marketing ploy.
I’m imagining my misses face if I told her “just wanna stop in here and look at this ole P38 Westminster that’s for sale”.......
Nice looking vehicle but not at 1250 clams......

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I think you did the right thing!

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That's a ludicrous price for a car in that state even a nice looking one when you look at what they are fetching on eBay. OK, so most list a few fairly minor faults but nothing that any of us that understand them couldn't easily sort.

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Joined: Feb 25 2020
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It was a delight to read this story!
Maybe is a phase of my life, but I also think a car like this - except for parts or because you really really really really want it - is not worth getting.
More than being put up for sale - or auction, is the same - it looks like "dumped" or "thrown". There is always a reason .... better not to find out.
I bought a number of vehicles (both personal and in my business) in various derelict stages, and it proved to be always a labor of love more than anything else, and in case of a vehicle to sell for a profit ... uufgh not always a good affair.
Like a hole in the head ... eh eh I like that :-)