I'm new to Jaguar and brand new to the forum, so let me know if I have or give the wrong information.

My Lincoln's 3.9 has spun a bearing and has about 1/8" of play on cylinder 7, so the engine is coming out. What I've been trying to research is how compatible 4.0L SC parts are with the 3.9. When looking for more power from engine swaps over at the LS section of LincolnVsCadillac, the Jaguar variants of the AJ V8 are always mentioned as possible substitutes. However, with any engine swap proposal comes the a comment noting the difficulty of matching electronics and sensors. It appears there is a Chevy LS_-swapped S-type with an electrical nightmare matching the LS1-swapped LS that has exchanged owners many times.

So why swap engines? It seems to me the crank, rods, and pistons from a Jag AJ should be a direct fit for the 3.9. The reason I'm leaning towards a 1998-2002.5 4.0 assembly instead of an upgraded 4.2 is because of the firing order. When Jaguar moved to the 1-2-7-3-4-5-6-8 order, the LS 3.9 stayed with the 1-5-4-2-6-3-7-8 all the way through to it's final model year in 2006 (there may be some discrepancy with the Jaguar order since the Wikipedia AJ V8 pages says the Aston 4.4 has the 1-5-4.. order and shares it with no other Jag AJ engines, but I'm finding pre-2002.5 being that order with the older 1(1)-2(1).. numbering style). Sure, you can swap the COP and fuel injector wiring and it may work fine, but when something goes wrong, will the ECU be able to respond appropriately?

As for the upper end, it would seem I could swap on the 4.0SC's intake manifold and supercharger, make an adapter plate for my cable-driven throttle body, and fab up some intake tubing for a bolt-on, non-rewiring upgrade.

A "hybrid" 3.9/4.0 engine has been done before. A guy in Poland rebuilt hs LS' engine with a used 4.0 engine, which can be found here: Lincoln LS 2001 3.9 swap to jag 4.0 with VVT

So something is possible. Maybe the 4.0SC is even closer to the 3.9 than I think, but I can't determine that without having both engines side by side. As previously mentioned, mating up sensors would likely be the hard part. The Nikasil liner issue also has me concerned, but it seems that wasn't an issue in the US?

Now one of my main questions is is there any difference between 4.0NA and 4.0SC cranks/pistons/rods? does the SC variant have stronger internals? Also, is there any reasonable place to buy those parts from? Or is my best bet to buy a lower mileage complete engine and strip out what I need for less than $1500

I hope I can figure something out. Having an XJR setup with planned StR brakes would make for an interesting LS/R.

Thanks for any help,

Frank

 

The actual firing order is the same on the 4.0 & 4.2, the cylinder numbering in the documents changed, which can be confusing...

The AM has a totally different firing order.

Welcome to the forum!

 

Turns out I never looked at the numbering of the 2002.5+ diagram or I just glazed over with the extra numbers and assumed it was now numbered the same as Ford/Lincoln (1234 match old (1)1234, 5678 matches old (2)1234 in order.




That certainly makes things a little more interesting. Thank you

 

To clarify, the 3.9's numbering matches the red numbers on the pre-02.5. My bad cylinder (not that it matters) is #(2)3 on the old or #6 on those diagrams

 

Wow, the price doubles on 4.2s

 

I am interested to see how this goes- keep us posted!

 

What's the trans in the Lincoln? In the XJR it's a Mercedes AMG to handle to added torque.

The compression drops 11s>9s and there are a couple of sensors that are required by the ECM. A remote IC pump and plumbing, larger volume rads/fans to cool the Heaton SC these things run on the warm side of hot...I don't want to put you off as I'm as interested as dsnyder!

 

The LS uses the 5R55N and 5R55S transmission used in Mustangs and Explorers, just with a unique bell housing. I believe it's good for 500hp/500ft-lbs. There are high-power rebuild options as well.

There was a supercharged LS (known as Quik LS) that ran for several years and the only heat-related items mentioned were an intercooler and an ambiguous"cooling system rework" which I believe just meant it was rerouted.

From the list of mods:
If I don't change the cooling system parts, then I guess I should add an aux temperature gauge. Is the remote pump part of an independent cooling system for the SC or does it just make sure it gets flow?

I asked before: does anyone know if there is a difference between crankshafts/rods/pistons in the NA and SC versions of either the 4.0 or 4.2? Looking at what jaguarparts.com offers, there is only one type of crank and one type of rod, but two types of pistons specifying NA/SC

Thanks for the help so far

 

The SC pistons are lower compression, but I believe you're right about the lower end.

 

Ah, thanks. I was wondering where the difference was if both engines are 4.2L when Sean stated

It makes me wonder how strong the LS bottom end is. As far as I know, there haven't been any crank/rod/piston failures unless low octane gas was used. The ECU wants 91 to be happy, prefers 93, can manage 89 unhappily, but can't manage 87 and it will knock and put rods through pistons. I'm assume you guys have similar problems. I'm not sure if this site has primarily UK/European users or if a slightly different octane rating method is used, but standard pump gas comes in 87, 89, and 93 octane.

 

Very, very few reports of bottom end failure here.

 

I guess it doesn't matter for me considering it's cheaper to buy a used 4.0 SC than it is to buy individual parts ($1500 for an engine, $1100 for a crank??)

With the LS, there has been 1 supercharged 3.9 and a handful of turbos. One LvC member named Alax7 had some kind of internal failure with a turbo setup and took 18 months to rebuild it. We're still waiting on results and a parts list, though