The pre 2003 LS engines don't have VVT, and just to be sure I think it is safer to use an oil pump that was used with the VVT. Don't use any of the LS electronics, use the ones from your car as described.

 

thanks a lot, i was a little confused about that, do the 4.0 vvt cams fit with no problem tho i heard that there is a difference between the two when it comes to valves and pistons? i dont think that there is an actual difference as they are the same thing but who knows....

 

Base AJ26/AJ27 car:

SC Cars (SC= Supercharged)
-Any 4.2 SC engine can be used, Stype, XKR, XJR, XF and Range Rover
-Use only the base block, so the Lower end/Base Block, heads, timing gear, camshafts, oil pump and maybe the supercharger.

Re-use from your 4.0 block:
-Front cover
-Front lower pulley
-All electronics (Ignition coils/Fuel injectors etc)
-Fuel rail/intake manifold
-For the AJ26 the camshaft positioning indicator (that one sits on the Bank A, Intake camshaft), and flywheel
-Lower sump
-Cam covers
-Camshafts (but only if the 4.2 block had VVT).

*it's important to note that the AJ26 had unisea 2 position 30 deg range VVT while the 27 used denso 47 deg range vvt unit and thus has a different CPS- like the AJ33.

Modifications needed:
-Bolt holes from Intake manifold do not line up, when counting from the front, numbers 2 and 4 fit, and new tapered holes need to be made in the heads for 1 3 and 5 (easy). Then port the intake manifold to ensure good alignment with the intake ports of the head.

* The AJ33/34/36 inlet system doesnt align up to the AJ27 because it tried to pioneer a system called CBR or controlled burn rate from a consultancy in Austria but the system was a failure thanks to optimistic claims on the part of the consulatnacy. I feel sure that they can still be adapted to one another with some ingenuity.

-The oil pickup is different with the 4.2 oil pump; you need to modify the original sump to allow space for the new pickup. This is important as the 4.2 engine uses piston oil jets to cool down the system (This is also why the 4.2 blocks do have not the issue with short running that washes away the oil film…).
-Camshafts, you can use the 4.2 camshafts without issues if it was a non-VVT one, but you need then to exchange the camshaft indicator (AJ26 only). The AJ26 has 1 vane, whereas the AJ27/33/34 has 4. This saves in changing the valve clearance and everything will fit as it should have been.


*DO NOT retrofit an AJ33 camshaft to an AJ26 or 27, they will most likely fit. A little bit of knowledge is a dangerous thing! The AJ33 has graded tappets and no shims to adjust clearances where as the AJ27 and before used shims. The peak lift of the cam profile is dictated and designed around the width of the tappet minus a small safety factor. The AJ33 utilises the wider effective width of the graded tappet to get more lift. If the Aj33 cam was retrofitted with the Aj27/26 type shimmed tappets you could pick up the edge of the tappet.

- If using the 4.2 supercharger, you als need to use the 4.2 SC to intake elbow gasket, and modify your intake elbow a bit where the bearings form the SC stick out, 1/2mm should be milled away.

For the pioneers:
-The 4.2 injectors are better; they have 12 fine openings giving a much better fuel atomization. But the impedance (is different from the 4.0 ones and you need to retune the ECU). On top of that, the 4.0 fuel system is with return line, so that also has to be plumbed. Not sure if it is worth the effort.
-Use the AJ26/27 camshafts, the AJ33/34 (4.2 engines) use a camshaft profile that is more focused un a wide power range, whereas the AJ26/27 is more focused on high end power. Never tested this, this is my guess on what I have learned so far from camshafts. This saves the trouble to exchange the camshaft indicator.

* Actually the AJ26 used a 240 period profile. On the AJ27 it was shortened to 230 intake period. The new VVT system allowed this. The AJ33 went back UP in period to 240 to compensate for the ports that were inadequate thanks to the efforts of the aforementioned consultancy.

As it is easier to take the heads off to make the new holes, better to buy new head gaskets and head bolts. The latter are stretch type and can be used only once!

The 4.2 block has some strong advatanges (especially for those that are looking for some more power), besides the bigger stroke, it has stronger internals (forged crankshaft), piston cooling via oil jets and a beter combustion chamber with a good squish area.

*The crankshaft on the 4.2 litre is NOT forged but cast- with 6 counterweights. The only AJ series which uses a forged 8 cw crank is the AJ37 as used in the Aston Martin Vantage. The squish is actually a hinderance and it shrouds the inlet flow- I would machine much of it off.


NA Engines (NA = Naturally (or Normally) Aspirated)
I have no direct experience with these; however most of the above will apply, unless stated below.
Again any 4.2 NA base engine will do, from an Stype, XK, XJ and XF and Range Rover (but not the pre 2006 engines as they where BMW originates), The Jaguar 4.4 engine used in the RR can be swapped again, so that would be a nice 10% gain ;-).

Possibly the 3.9 ltr 2003 and up Lincoln LS and Thunderbird engines as these are also based on the AJ33/34 4.2 engine from Jaguar stroked down from 4.2 to 3.9 and now with VVT. But I am not 100% sure as I see some small differences on pictures to where the AC is mounted to the block for instance.

As there are small variations in VVT systems between the AJ28/33/34 (and Lincoln/thunderbird), I would strongly advise to keep the 4.0 Camshaft/Timing gearing, that can be swapped.

What makes it more difficult for me to judge, is that the 4.0 engines use a plastic intake manifold, and I am not sure how much material is there to shave of to ensure nice mating to the intake holes on the head. Though it should be possible imho.

Swapping a 3.9 NA engine from Lincoln (pre 2003)
Another option is the older 2000-2002 3.9 ltr engine from the Lincoln LS. You might be able to reuse some parts, however to be sure, best to reuse all the parts as suggested above. Here you do not need to make any manifold modifications as far as I am aware, so it will be an easier swap. You also do not need to replace the oil pump pickup, so no extra work there, but you need to reuse the 4.0 oil pump. This engine does not have VVT, so you need to swap the camshafts/VVT gear.

For everything above
Please note that all of the above is specialist work, but that speaks for itself I think. It is not rocket science, so it is all doable for the seasoned mechanic.

 

Thanks for adding your comments!

The first part of the text was mainly for SC engines, later down I start a section for NA cars.

“* The AJ33/34/36 inlet system doesnt align up to the AJ27 because it tried to pioneer a system called CBR or controlled burn rate from a consultancy in Austria but the system was a failure thanks to optimistic claims on the part of the consulatnacy. I feel sure that they can still be adapted to one another with some ingenuity”

It is actually easy, I use this on my car, and done it just as mentioned. Except of course for the plastic manifold of the NA engines, not sure how you can get that right as I have no experience with them.

“*DO NOT retrofit an AJ33 camshaft to an AJ26 or 27, they will most likely fit. A little bit of knowledge is a dangerous thing! The AJ33 has graded tappets and no shims to adjust clearances where as the AJ27 and before used shims. The peak lift of the cam profile is dictated and designed around the width of the tappet minus a small safety factor. The AJ33 utilises the wider effective width of the graded tappet to get more lift. If the Aj33 cam was retrofitted with the Aj27/26 type shimmed tappets you could pick up the edge of the tappet.”

Can you please explain what you mean by graded tappets? Are you referring to the buckets used like in the range rover engines (these have been the only ones I have seen with buckets so far)?

 

HI Avos, when I was involved with the graded tappets or buckets-with-no-shims-on-top it was always intended that they were fitted to the AJ33s. To my knowledge I thought they were. However as Job 1 came I moved onto the next project. Its also known that Jaguar likes to do "hybrid engines" to not implement all changes at once (did you know, for instance that there was an Aj26, an AJ26.5 and an AJ27?- the AJ26.5 incoprporated SOME of the features of each). This is to lessen the load on manufacturing. Anyway, if you've come across AJ33 engines with bucket tappets WITH shims I stand corrected. However I don't reccommend using a cam profile intended for an engine with shimless buckets retro fitted onto an engine with tappets with shims

 

I had my mechanic bring in an LS engine to try and fit it into my 2000 XJR The accessory mounting holes were drilled in different locations. I was unable to inspect the two side by side but he said there was to much external differences to make a direct swap. I wish I could have seen it myself.

 

Quote:

Originally Posted by Count Iblis

HI Avos, when I was involved with the graded tappets or buckets-with-no-shims-on-top it was always intended that they were fitted to the AJ33s. To my knowledge I thought they were. However as Job 1 came I moved onto the next project. Its also known that Jaguar likes to do "hybrid engines" to not implement all changes at once (did you know, for instance that there was an Aj26, an AJ26.5 and an AJ27?- the AJ26.5 incoprporated SOME of the features of each). This is to lessen the load on manufacturing. Anyway, if you've come across AJ33 engines with bucket tappets WITH shims I stand corrected. However I don't reccommend using a cam profile intended for an engine with shimless buckets retro fitted onto an engine with tappets with shims

So far I have not seen AJ33/34 with the shim less buckets, and the first block I saw was from end of 2001/early 2002 (am not 100% sure) and the second early one was from 2002. I can double check the parts catalogue, but do you know which models/years would have a AJ33?

So far I have only seen this on the Range Rover engines, both NA and SC ones.
I'll update the first page and add a comment not to reuse these cams due to the risk you mention.

I have come across the AJ26.5 reference, but have no idea what the differences are. You do see indeed differences come in earlier, i.e. like the chain tensioners and morse chain for instance, it was being put forward (the morse chain) as an improvement for the 4.2. Not sure irrc, but also the hollow camshaft was part of the improvements for the 4.2, whereas that was also to be found on the AJ27.

 

The NA (Naturally Aspirated) LS engines can't be used on the SC cars, so I am not surprised to hear that some fittings/bolt holes are missing, maybe you are lucky here then that he could not fit it, the compression would be too high amongst others.

Indeed a shame that you couldn't have seen it, as I would still guess that the major connections to the block would be the same (but again not for a SC). Do you know which accessory hole he was speaking about?

 

so im replacing the motor in a 4.0 stype with a 3.9 ls and here is what ive found so far as for the different components that you will have to reuse
cams, tensioners, chain guides, oil pump, front engine cover, all electronics basicly all the stuff that was listed above but here is something that no one has mentioned before
CYLINDER HEADS!!!!!
because of the vvt you MUST reuse your jag head b/c the ls ones dont have the mounting points for the solenoids
also the reason you have to use your old oil pump is because the ls one routs the oil differently, the pick up is different and the the ls one sprays oil onto the timing chains where as for the stype one it picks the oil up in a different place and routs it through a different galley, also you will need to drill and tap a hole for one of the bolts in order to mount a jag oil pump to an ls block, if anyone has any questions about this swap let me know i havent completed it yet but so far ive learned a lot

 

Thanks for sharing; I’ll update the first post with your findings.

Just a question regarding the heads, do you have a picture of that one to show the mounting points? Just to be sure, where there no threads to bolt to, or was just the oil opening missing? Reason for asking is that the Jaguar SC heads are basically the same as the VVT-ones, except the oil feed is blocked (which can be opened, or closed pending on usage).

I have seen different oil pumps from Jaguar where one does have an extra feed to the primary chains and some not. Between the 4.2 and 4.0 blocks there is also a different route pending on the pump you choose, but both pumps will work fine as it is only the pickup that is different. Can you confirm if it is only the pickup, or that the pressure side is also different?

The 4.0 ltr oil pump has 4 bolts almost in a square, whereas a 4.2 oil pump the left hand top bolt is slightly of set. I actually have used a 4.2 oil pump on my old 4.0 engine and only used 3 bolts to fix it (engine was in car, so hard to work on), probably not recommendable of course but it did the job. Can you let me know what the bolt pattern was/or better a picture of the LS oil pump?

 

It was an NA engine being put into an NA car (2000 xj8 vp). I think it was the power steering pump and the alternator that were attached different.

 

I have the motor at a dealership right now to get the timing adjusted bc I don't have the tools for it, I will take some pictures and list it in details what is different between the style 4.0 and the pre 03 ls 3.9. Unfortunatly I can not take detailed pics of the oil pump but will do my best cuz I have the timing chains over it and would have to adjust them again

 

This is sooo weird!
Some of the stuff that was done years ago in my career, some of it was done quickly- by manufacturing types and management types, their only goal to get the job done quickly and to cost, some of it was done by non enthusiasts who were just working a job, both in Dearborn and Whitley designers just trying to package it in the alotted time (some worried about Jaguars future)(but most were competent)- some of it was done by interns, one of them, an intake manifold designer- died, well, I'll bet NONE of those folks from over ten years ago would have ever guessed that their work would be the subject, pontification on a forum board many years later!!

 

You must have been a proud member of the team then.

Please keep in mind the start of this thread was intended to help out others who need to exchange their 4.0 engines by a 4.2 one. That you tried to bring me in discredit by pointing out that you can’t use a camshaft from a range rover (4.2 engines) into Jaguar 4.2 or 4.0 engines was obviously out of context there, which is why I refrained from adding that into the first post.

When all you have left now is to put down members, I am more than happy to give the stick to you to carry on this thread for you to be able to contribute.

 

Avos, I don't understand. Why do you think I'm trying to put you into discredit? I think it's great that you're doing these pioneering things and sharing the knowledge with the forums, genuinely. I think the community can really benefit from this.
I dont see how the camshaft comment was out of context- I thought it genuinely useful.

 

ok so i picked up the motor from the *********** and after they set the timing the valves hit the pistons, they were saying that it could be the key way on the crank that is off so when they locked it in position it was a bit off, any ideas about that?, i just compared my original jag crank with the ls one and it seems like the key ways are in the same spots, the stroke and bore on the 3.9 ls and 4.0 stype are exacly the same so now im really confused what could it be, im going to pull the crank out all the way and compare them on the bench but so far they apper the same

 

The stroke on the 3.9 ls is 85mm compared to the 86mm stroke of the 4.0 s type.

 

This is correct.

 

Just so I understand this correctly. In order to upgrade the SC 4.0 in my 99XJR I need to use a 4.2L SC engine correct? Using NA engine and swapping the blower is not an option right?

 

Correct. Short answer is compression will be high in the boosted app.