Questions


1) Are the 4.2 and 4.0 xkr exhaust manifolds interchangeable? Basically would the factory exhaust bolt onto the 4.2 manifolds?
2) What year Aston Martin intake manifolds (naturally aspirated) works on a 4.2 head if any?
3) As far as swapping in a 4.2 engine. I have a complete one out of an xkr to swap into my 02 xkr. Im missing only accessories. Will I need to change timing cover?...Balancer etc?? I read the post on the swap but it really didn't deal with an xkr engine for an xkr engine.


Thanks all!


Damon

 

I think the manifolds are the same for a 4.0 and 4.2. Can't comment on the Aston stuff would be suprised if they were compatible. re the 4.2 swap into a 4.0 car it can be done. Easiest is just to swap all the ancillaries and electronics from your 4.0 onto the 4.2 lump, including the Mercedes 5 speed box. There are differences in the sensors between different generations of the V8 engines, the new block will work fine with the old sensors and electronics, the new engine and sensors can have issues with the old electronics. I would be surprised if there was not a thread here if you search for it. The changes have been done many times in the UK

 

I have a complete 4.2 xkr engine. I wanted to ceramic coat the exhaust manifolds from my 4.2 then swap out onto my 4.0 but wanted to make sure they were the same. The Aston martin N/A intake is a different story for another project but also for a later model 4.2. If it works on the 4.0 heads ill just have to swap heads out I just am not sure

 

Well, I am trying the Aston Martin intake thing right now. Here is what I have discovered:

Intake manifold gaskets are same as 4.2L that is about as far as it gets. Nothing else is compatible! I have been working this project for over 3 months now. here is just a small sampling of what works and what doesn't:

1. Heads on the 4.3 have longer runners on them and are cast for the intake flanges to sit at a upright position, not at an angle like the jag/Lincoln heads (which have very short runners I might add) if a head swap can be done on these cars from 4.2 to 4.3 with little difficulty, you would be on to some monster power gains in the upper band! I am working on fabricating a "lower intake manifold" piece to bolt to the jag head and the AM intake (needs to be about 2" tall to clear thermostat housing.)
2. Throttle bore on AM intake is bigger than Jag. bolt holes from intake and throttle body do not line up at all, you could manufacture an adapter plate/ spacer about 1 inch thick (how I am doing it) to solve that.
3. Water piping goes through intake instead of throttle body, you could cap the throttle body or intake if you choose, ( I am thinking of running both through a tee)
4. Fuel rails need to be modified to fit. (or pony up the $400 for the AM rails) Injectors from the 4.2 fit the intake fine. I am fabricating a hold down bracket to keep it simple and use the 4.2 rail. The crossover hose has to be inverted to run under the intake instead of on top.
5. increase in overall engine height by 5 inches. this intake is TALL!!!! (dunno if the hood will clear! thank god its in a hot rod!!!)
6. egr tube runs different than 4.2 (this I don't like! it is visible versus jag which is hidden!)

I am tempted to buy a set of AM 4.3 heads and try them out to see if they are compatible with the rest of the electronics. (not sure about the cams though. I might just swap the 4.2 cams into the 4.3 head castings if they have the same journal sizes... if the cams do work, without hitting the pistons, I may just run the entire setup. that eliminates a ton of guessing work, however, it also increases the price tag by a bunch!!!!

from all I have seen to this point the entire top half of the AM would be needed to swap it cleanly. i'll get some pics going as soon as I get closer.

 

If I recall the firing order of the AM engine is different from the Jaguar so I don't think you will be able to just swap the top end without a (different) bunch of work.

 

The firing order is actually the same, but the cylinder numbers were changed, just to be confusing!

 

Wow, I didn't know AM also offered bespoke cylinder numbering. Now that is differentiation worth paying for.

 

'optional-extra-custom cylinder numbering'.............. Great marketing ploy.

bob

 

Here is where its weirder!!!!! Lincoln uses the AM firing order!!!!

 

if the cams get swapped into the AM heads would that not solve that too?

 

Question phatcat67, what if you didn't use the intake manifold spacers and instead mounted the intercooler to the V8 Vantage heads directly? How far off would they be?

 

 

Interesting, thank you. I kinda figured you'd need adapter/spacers to make everything line up, although the difference between the manifold widths is an eye opener. Sorry, forgot you had an XJ8 not an XJR. But, since it's a NA engine, why not the LR/RR 4.4L? Should be easier to source & cheaper

 

Well, Got some mockups for ya! Here you can see the challenges!!!! besides the obvious of the intake port for the throttle body.....


Shows Just how tall the thing is!!!!

here is the problem #1. angle of attack...

Ports are different!!!! so are bolt patterns!!!! AM uses early 4.0 bolt pattern!

Angle mount of Jaguar on left, Straight mount of AM on right.

 

Are the V8 Vantage heads now on the list?

 

yep! And timing cover. Have to do both in order to use the intake.

 

Cool! Might be worth the effort & patience to try to find some 4.7L heads. The valves are bigger & the combustion chamber was better, IIRC. Looks like you have the 4.3L intake, but from my searches on the subject there's no difference between the two besides the color, so could match-up pretty well

 

Hey phatcat67, how goes the project?

 

Looking for my 4.7 heads and timing cover. I’ve abandoned the spacer option as the first mixup I did made it impossible to bolt down without hitting the valve covers. Have to change heads. Thank goodness the vvt bolts on in the same position as the AM.

lots of 4.3 stuff out there though! Note: the AM has 4 knock sensor mounts in the heads compared to our 2. Have to figure out what to do with the other two... hmmm

 

Glad to hear you're still experimenting with this project. IIRC the main changes for the 4.7L cylinder heads were modified intake ports and an inlet valve size increase from 34.9mm to 35.9mm. The intake manifold was modified to match the new port, & the cam chains were widened from a 9 plate design to an 11 plate design. If you're staying with the stock displacement, it might be better to use the 4.3L heads with the 4.7L cams. There was a few sets of 4.7L camshafts & at least 1 crankshaft on eBay recently. Don't know about your budget for this project but might be worth shooting them an offer. The worst they can do is say no.