followed this up quite deeply a while back. The patterns are privately owned an no longer with MCF , the owner was drag racing and hoping for huge HP, he never got it and basically gave up. The ports are too large t work properly even for me! Also a funny shape internally which I know was altered on 1 pair by adding Ali based resin. I lent a Gp 44 CA head with a much smaller 42mm port but the chap went his own way sticking with his altogether larger set up. Shame, the chap basically LS1'd the V12 Jag heads, I think there is great merit in what he tried to do but he went too big from the start; No one here will have anything approaching this chaps budget, just shows that a big bank balance is no guarantee of success

 

Just a quick update I spoke to Calvin today on the phone for awhile. The project is stalled but not dead. He is still passionate about it and wants to finish it. Calvin's current passion is a LS 5.3 turbo engine going in an off topic car. When I met Calvin I was intrigued by his ambitions and after speaking to him I learned nothing has changed.

 

they might be good with a 7 liter or larger engine... something really Huge!
and totally custom pistons made t work with that head

 

if memory serves this was an 8 litre forced induction V12 which as the more knowledgeable poster stated had serious amounts of ££££'s thrown at it without achieving target output of in excess of 800bhp

 

Yep.

A point well made.

These heads have quite small ports (35mm at the SMALLEST point) and made 615hp from 6.0L. Chambers were kinda copied from the Austin head.

 

.

some of these turbo'd LS 5.3L are making over 1000hp, using factory stock bottom ends! NICE.

 

Yep... those are the iron block variety. Its quite amazing... I've recently returned to the 1/4 mile track as a sport and the sheer quantity of car in the 10's and 11's that are driven to the track is astonishing.

I just pickup up a LS 6.0 with a 4l80E for a great price. With stock heads and cam 600HP is possible with 9 PSI. 700 to 800 HP if I can figure how to fit an intercooler and work the top end a bit. I gotta find something to put it in becasue My XJC coupe's chassis is overwhelmed by the engine it has now so a more powerful one is not an option. I'm thinking its going in an XJS with flared rear wheel wells. Could be the first streetable 10 second xjs.

I'm going to suggest this idea is loosely relevant to this thread simply becasue this was Calvin's idea and we discussed the technical over the phone.

 

quick pix of my Buick GN converted to an LS 6.0L, iron block , aluminum heads #317. drive by wire TB.

and 4L80E trans. nice setup , Gn's light weight, and perfect 3.42 LSD.

would be great with turbo system, those LS engines are MAGIC with forced induction!

 

Heh - I always find it amusing when I can see the ground from topside of the engine bay. No chance of that with the V12!

 

Hi XJR 5006. Thanks for the interesting history of the head. Would it be possible to CNC mill a similar combustion chamber into a HE head if a scan was available?

 

even if you weld/filled in , you could do a nicely developed chamber!

but the ports would need a lot of work,Exhaust mostly!

be simpler and cheaper to get a set of race heads(xjr5006) also there is a guy in Australia who has some new ones, search this site ,he was on back few months,with some pix!

 

Simple answer is no. As Ron said you would need to fill in the exhaust pocket. Those heads and the ones I posted have the chambers machined into pre-HE heads.

HE heads can make a good street engine. Peak HP is of little use on the street. A broad power band is what is needed. I have seen HE 6.0L engines make 450HP with 150hp available from 1500rpm.

 

Very interested to hear any details you might have on what's needed get that kind of output

 

De-shroud the valves, these heads have had a fair bit removed to increase the chamber size to get CR down on a 6.7L engine, but they give you an idea of what is needed. Also o a 6.0L a cam would be needed that allowed 7000rpm. The stock cam has 0.374" lift and NO overlap 13/55 55/13 seat to seat.

A good low restriction exhaust and manifold ditch the stock air boxes and use elbows similar to XJ40 V12 or better still cut the plenums off and add larger ones to the standard runners.

.

 

warrjon, looking good !

my take on cam choice, that factory 6.0L would be great for a forced induction engine!

my choice would be any factory V12 cam made before 1981!

or a custom race cam, cost may be prohibitive tho, plus all the work getting tappets and clearencing correct!

ron

 

I have discussed this with Norm and all the cams that Jaguar used both V12 and XK were the same timing 13/55 55/13 no overlap. The differences were in the ramp and lift, but this was minimal.

Even with the stock cam the 6.7L should spin to 6000rpm with power peak at 5500rpm.

He has advised me to stick with the stock cam as the engine will make monster torque. I will need to change the diff ration from 3.58 back to 2.88 to help with traction in the lower rpm range.

 

warrjon, if those cam timing specs are correct,that cam has a theoretical overlap of 26*, subtract lash clearence its around 18/20* overlap,roughly!

those specs say its an extremely mild performance cam. just might work with the 2.88 gear?? donno.

torque peak may be around 1500rpm, but i'm seein torque dropping off at 3500rpm there about.

time will tell, for sure an unusual engine combination.

ron

 

Yes you're right with the overlap, this is the stock cam according to the ROM.

 

TWR Gr.A replica

Ole Mobeck
Forside - mobeck.com

 

how much did that cost you?