I've been trying to locate these specs published and I'm having a hard time. Does anyone know the following information or where to locate for the 2008 4.2 engine as well as the 5.0? I'm working on a set of tri-y headers. In order to do some calculations, I need to take all of this into account.


Intake valve head diameter:
Exhaust valve head dia.:
Intake lift at valve:
Int. duration @ .050 lift degrees*:
Intake opens @ o BTDC:
Exhaust lift at valve:
Exh. duration @ .050 lift degrees*:
Exhaust opens @ o BBDC:
Intake port dimensions:
Exhaust port dimensions:
Intake lobe centerline
Intake closes @ o ABDC
Exhaust lobe centerline
Exhaust closes @ o ATDC


Thanks in advance.

 

These specifications do not appear to be in the Workshop Manual, so you may want to contact JLR directly for such detail.

If you are constructing a new inlet and exhaust system for this vehicle, you may need to disassemble an engine and take the measurements you need independent of JLR.

 

These are from the 4.2 and 5.0 litre workshop manuals plus a bit from the 5.0L technical guide:

4.2L
Valve head diameter intake (mm) 34.8 - 35.0
Valve head diameter exhaust (mm) 30.8 - 31.0

Camshaft lobe lift intake (mm) 8.50
Camshaft lobe lift exhaust (mm) 8.50

5.0L
Intake valve head diameter:36 ± 0.1
Exhaust valve head dia.:30 ± 0.1

Intake
Opens - 29 degrees BTDC (before top dead center) to 33 degrees ATDC (after top dead center)
Closes - 207 to 269 degrees ATDC

Exhaust
Opens - 244 to 194 degrees
Closes - BTDC 6 to 56 degrees ATDC

Camshaft lobe lift intake (mm) 10
Camshaft lobe lift exhaust (mm) 9.36

From a different source:
The Camshaft Profile Swiching system controls the lifting height of the intake valves. At engine speeds from idle up to the range of 2,800 – 4,825 rpm (load dependent), the intake valves have a lifting height of 5.5mm. At speeds and loads outside of this range, the high lift cam (10.53mm) is used.

Lifting Height Valve Opens Valve Closes
Intake – 5.5 mm lifting height
Opens - 27° BTDC to 35° ATDC
Closes - 187° ATDC to 249° ATDC

Intake – 10.53 mm lifting height
Opens - 37° BTDC to 25° ATDC
Closes - 213° ATDC to 275° ATDC

Exhaust – 9.36 mm lifting height
Opens - 244° BTDC or 194° BTDC
Closes - 6° ATDC to 56° ATDC

 

Make sure you have a look at this https://www.jaguarforums.com/forum/g...-2l-s-c-80560/

The branching needs to be as per the drawings in that thread.

 

Thanks for the replies Gentlemen.

I wonder if the duration above for the 5.0 is the same for the 4.2. (I would think the numbers would be close) ?

I could potentially base my calculations for the steps/lengths upon this, I'm just a stickler for precision.

Thanks for the info.

Good link for the cheaper design and yes, that's the exact branching I was thinking with the firing sequence. I'm quite surprised Jaguar didn't go with this approach with the Supercharged setup. Cylinders 6 and 8 are a major concern for restrictive flow and excessive heat. I'm quite optimistic that a well tuned design will make surprising numbers with the exhaust fabricated.

 

One thing worth noting, the exhaust ports are different between the 4.0/4.2 and the 5.0

So you will need different flange designs depending on which engine you make the headers for...