calvin whats this rumor i hear of the xj6 heads? can we indeed run these on our 5.3? i have heard one might need too be installed differently can someone enlighten me?this would be a great route if possible thanks.

 

If you are refering to installing twincan heads, it's not a simple swap. One head needs the cam drive cut off and welded back on the other end. It would be cheaper to FI than to install twincam heads.

 

i agree warrjon; twin cam xj6 heads on a V12 would be a nightmare of machining ,welding, and engineering, just to get the engine to run and cam timing all things correctly!

then you gotta make inlet manifolds, exhaust manifolds, FI injector system!!

i seen one about 25yrs ago, and it never did run well, always something of a problem!

 

see im looking for good flowing heads my tru question is why would i have to install the head like that? water jackets do not match? or bolt pattern? see my problem is i have a love for doing hard builds or things that not many have done haha it kills my wallet.

 

the other problem is i have the jag fever haha i want a nasty growling v12 that chews up everything in its path and i have the ability too build it just not soo deep pockets this will take some time .

 

Here is an Hot rod running a Jag V12 with quad cams and Blower, the builder has done a fantastic job. there are a series of Youtube clips detailing the the build.

if the links dont work search jaguar v12 quad cam.

 

88-xjsv12,
The problem is that unless you reverse one of the heads & change which end the cam sprocket is on, the intake ports of that head would be on the outside of the motor, where the exhaust ports should be, and the exhaust ports would be in the vee of the motor, where the intake ports should be.

 

88 that 4 cam jag engine should be cheap money, maybe get it done in an afternoon!!

No only kidding, on another post, i would use the Audi diesel V12 , comes from factory with twin turbos, quad cams, direct fuel injection and even a warrenty,.

and it would be way more dependable than a Jag V12 modified.

some times in these posts ,they forget that a highly modified engine could blowup, and you start all over again.
and if money is a factor , well, just may rethink things over!

 

That engine was on eBay earlier this year.

That Audi V12 diesel is an awesome engine.

 

hey ron, I'm 19, nothing reliable is any fun for me.

 

hey im an outside of the box kind of guy. i like the thought of diesel maybe for another build? but not on this car it holds some memorys and the rumble of that v12 and the smell of the interior is all i have left of my mother so i guess its a tribute build a little .

 

pjowen thank you for the posting!! i did see the much earlier videos i never realized he posted more thats awesome!

 

I have seen these vids before. Every once in a while there's another fellow somewhere in the world who wants to do this, and one in maybe 10,000 of these guys actually acts upon his impulse.

I suppose it can be done. Clearly at a tremendous cost.

But to what end?

The flat head motor, when taken to its extreme (big valves, ports, more displacement) can generate so much HP that the twin cam four valve motor only begins to show to significant advantage well above 6-7000 RPM.

Who among us operates there? On the street?

It's great for racing boats, or track cars, I guess (although the TWR team, when given a four cam version of the V12 preferred the flat head because it weighed less and the CG was lower, and they could feel this in how the cars handled).

Otherwise, in a hot rod? It's a sure-fire crowd pleaser.

I think I'd rather conjure a set of cosmetic-only boxes that resembled the twin cam covers and fit those to a standard V12, if I wanted that kind of look.

my 2 cents.

 

the twin cam would have more low end torque (and possibly even vacum at an idle) so if it has low end torque thats purfect for what im looking for and possibly others look into that route. the heads are cheap so why not ?

 

heres the real question do they flow better? if they dont then there is no point i see in doing it

 

mike90 I agree, some(most on this site) dont have a modified Jaguar V12 engine in a car. anybody got dyno sheets??
and i aint trying to pis% off the pope.

but clearly fantasy over rules logic,
(that 4 cam engine would cost,easily,$100,000. usd,or more), and i'm betting, when run hard on a dyno, would have serious problems.

its a show piece,for lookin at an dreaming of what could be.

 

and i dont like belt drives ,AT ALL. not for long distance reliability. 24hr races etc.

not when reliable chains are available and the best drive systems are gears.

 

I agree with you ron, when someone comes out with a kit to mount those heads, then they will be economical, but other than.that ill stick to my pre he ported heads.

BACK TO MY BUILD, got a.chance to work at the shop and got one of the heads on the block and torqued down

 

lookin back thru my old papers, found this interesting Dyno sheet,

likem or hatem, hard to beat a big block chevy, 5yrs ago.

course modded to the friggin hilt!

any opinions about HP and torque?

 

The twincam head would make less torque (and HP) low in the RPM band I have seen dyno graphs of the TWR twincam and it made great top end HP but lost below 4000rpm.

Ultimate flow for HP is not necessarily the best for a street motor.

I was reading an article by the guy who built Formula Ford engines for Ayrton Senna and Johnny Herbert. His heads did not flow as much as others but his engines produced lower lap times due to more torque lower in the RPM band. In testing they found Senna was 1 gear higher in the chicane on the test track. And the rest is history......