Warrjon, thanks for the info re Holden pistons. As/when I get my engine apart and can see what the pistons are like, I may ask for more detail, if that is OK. Massey Ferguson first, though!

By the by, according to Allan Scott, the main bearing caps on the racing TWR XJS were iffy on the long races. New ones from a stronger material were desirable, but I seem to recall not actually made. Quite often the ended races with some of them cracked/failed.

Greg

 

They also broke conrods.

My guess is, that your pistons will fine and not need to be replaced, just new rings.

When I pulled down my spare 6.0L it was obvious it had a hard life. There was scoring on the main bearings (crank journals are fine don't even need polishing), oil was BLACK. Pistons and sleeves are fine even rings are ok but I will replace these. I don't even need to hone it.

 

I have a 6.0L block under my bench if you are interested.

All V12 cranks up until about 1994 are forged and nitrided. Stock rods are also forged. Pistons are cast, except for the TWR units. Cast HPC pistons are very good these days and would be ok in a V12 upto 500-600hp

5.3L cranks are EN16T and 6.0L are EN40, 6.0L cranks from engine number 12471 are cast.

Boost is by far the easiest and possibly cheapest way to get power from the V12. There are 3 twin turbo XJS V12's in Australia built by Gary Walker. I was lucky enough to have a good look over one of them. WRX TD04 turbos are cheap and plentiful, would give great low to midrange in the V12.

 

Since ronbros mentioned twin turbo as an option, I'll go ahead and link the quad turbo build thread:

https://www.jaguarforums.com/forum/x...-build-114735/

 

Update...
just starting on car now. sent off to a local jag shop to get running and have commissioned work to start on the v12 bottom end. 7.5L
when xjc comes back will order & install manual gearbox (tremec magnum)
6 years later and only just starting... how time flies...

 

the first batch were forging off EN 13 steel the second batch ( after Ford bought Jaguar ) were Sintered Iron.
Both are extremely stout and will handle a great deal of power. The early forged ones were what racers prefer.

 

I built a twin turbo Jag V12 and spent very little money. A pair of T2’s from Saab’s. ( easy to check if they are still good)* a $85 FMU to increase fuel pressure as boost built. And a switch to trigger the cold start injector as boost built per 4.5 pounds.
Stone stock 5.3 with 7.8 pistons I was within a whisker of 500 hp.
With E85 I would have pushed 600 horsepower at 6.0 of boost. A pair of camshafts could have brought me close to 700
there really isn’t room in the engine compartment on a XJS for turbo’d not even little T2’s but there is under the front fenders and it’s an easy straight shot.
Keep boost at 6 pounds or less and intercooler aren’t needed. Use E85 and you can run up to 10 pounds of boost.
you can either de-cap the stock injectors or use the injectors from the 4.0.
* use a sharpie to mark a blade and where it stops. Spin the impeller a few times as long as the rotor stops random it’s good.

 

Daddy,
Are you running with Rob Beere for the parts?

 

I was initially for liners & pistons, but was going to buy the crank direct from farndell engineering(uk) quote from a few years ago was 2500pounds.
At moment Im discussing with Norman Lutz from melbourne and waiting for some info from him.
Engine at moment is looking like 7.5L naturally aspirated and im leaning towards pre he heads.
I have original bare group 44 heads(flow 643hp) but the original owner is committed to rebuying them.
Car went off to just get runnning last week. waiting to find out what it needs and how much...
after rego I will transplant a tremec magnum and enjoy a stock V12 manual for a while...

 

I thought about twin turbos and even looked at Bruces racecar. I quite like the kirby twin supercharger setup, but i almost gave up on the V12 for a tesla p100d driveline conversion. However since i will buy the new cybertruck when it hits Australia Ive re committed to a potent V12. the supercharger may come later as i think 400hp and 560 foot pounds should be enough for a while.

 

I built one V12 using a 5.3 crank offset ground to increase the stroke by .400 with Aries forged 13-1 compression positions taken out to 3&9/16’s
the rods were NASCAR for Chevy’s. That I narrowed to fit in Jaguar journals
The heads were the early flatheads that’s I opened the intake ports To 1.90 and used modified Chevy titanium valve blanks.

The problem was trying to use Weber carbs. On the dyno the engine made 631 horsepower but in the car power went down to 390.
The bonnet forced air to squeeze through a 1/2 inch gap and change directions 3 times. That in spite of lowering the engine by more than an inch to where the oil pan was dangerously close to the track.

The simplest one is the cheap endurance race car I built using cast off Jaguar Junk with a pair of used Saab turbo’s

 

Saab turbo NLA!

 

Saab Turbo’s were used because they were cheap, $35 each. Yes used but they are very easy to test if they are still good or need rebuilding.
Take a marker put a dab on one blade and where it is pointing on the housing. Now give it a good spin. Mark that spot, do it several more times and as long as it stops at random points it’s good.
If you want to buy them new, E Bay sells cheap Chinese knock offs that are fairly decent. Or just buy a new T2. A T3 would actually be a better sized one but since I haven’t had one in my hands I don’t know if it can be made to fit.

 

No they are not. You can buy plenty of new turbos for Saabs.

 

do you have any diagrams or pictures of the twin turbo build?

 

No, but you can grab a couple and see how to fit them. It’s like they only fit one way.
Don’t use my way if you want to street drive it. It’s very much a kluge set up and only worked because the rules limited the whole race car to $500. ( Chump car racing)

Dont think working with a mega squirt is easy either. It takes countless hours to get it sorted out and is anything but a plug and play. Several of the engines/ cars I got were because owners just couldn’t figure out everything and they gave up on them.
it also won’t work on later HE cars.

ifbyou want to street drive the car just get the stock system working properly.

 

across the street from me , guy is a Porsche 928 rebuilder!
pic of his 928 , with a fresh from GERMANY in it, German spec hi performance engine, someting like more compession pistons, special heads , and performance race cams,etc.
sounds beautiful , MEGA SQUIRT , i listen to him getting it tuned, YEAH time involved but results are worth it!
darn i gotta download it??

 

this 928 german spec engine sounds BADD-to the BONE!

cold air system , and air filter!
across the street from me , guy is a Porsche 928 rebuilder!
pic of his 928 , with a fresh from GERMANY in it, German spec hi performance engine, someting like more compession pistons, special heads , and performance race cams,etc.
sounds beautiful , MEGA SQUIRT , i listen to him getting it tuned, YEAH time involved but results are worth it!
darn i gotta download it??

 

.

not for $35. bucks each!
i checked around local yards , seems nobody have any old 80s SAAB cars anyway!
guy says they junk most stuff older than 2000 yr.!

 

Hi,
I am also in Sydney and putting together a twin supercharged 7.3ltr V12. It sounds easy when you say it quick but it is proving very challenging to go all-out for this race only motor.
I already have a TWR 84mm crank and standard V12 block and will use Chev 6" rods. It will be running on methanol/E85 so comp will need to be around 9:1 I imagine. Pistons will need to be custom made. I have a bored/stroked V12 with the flat heads that have had a combustion chamber milled into them so I may use those heads or start again with another set of flat heads.
I have tried Rob Beere but he admits he has very little experience with blown V12's. I have sourced 96mm liners from elsewhere in the UK as well. The head studs are a problem to remove so if I need to break them off and redrill and tap then I might as well go to 1/2" studs. ARP say they don't even make the 7/16" kit (but they do) which is only supplied through a dealer so changing to 1/2" will mean custom made or someone checking their existing range for the right size. Again I need someone on my side who is interested. Those sorts of people are few and far between.
Any specific advice on the head studs from someone who has actually done the job would be appreciated.
Thanks,
Saltracer